http://www.nlm.nih.gov/hmd.dir/oli.dir/help.html (Einblicke ins Internet, 10/1995)

OnLine Images from the History of Medicine

OnLine Images from the History of Medicine (OLI/HMD):
Help Page

IMPORTANT NOTE: If you are having difficulties with OLI/HMD, it may be due to your using a Web client that does not support forms properly. Please return to the entry document for OLI/HMD and read it fully.

Basic Capabilities

The OnLine Images from the History of Medicine system provides these capabilities:

Retrieval of images by one of three mechanisms.
Browsing of subsets of thumbnail representations of the retrieved images, with minimal descriptive information.
Examination of large-size versions of the images.
Examination of full catalog data for the images.
Marking of particularly interesting images for later retrieval as a set.
Local printing of thumbnail/catalog browsing sets and large-size images.
Examination of extensive online documentation.

Supported Operations: Methods of Retrieving Images

Items from the OnLine Images collection may be retrieved using one of three mechanisms:

Search for Images Using Text Expressions
Search for Images by Frame Number
Browse (Retrieve 10 Random Frames)

Buttons corresponding to these choices appear near the bottom of the OnLine Images home page.

Search for Images Using Text Expressions

Searches are formulated interacting with a form which provides text windows and selection boxes.

If you are employing an appropriate World-Wide Web browser, the form will look something like this:

Click here to see full-size example

Use of this form requires three sequential steps:

Specify a search expression
Specify the action to be performed from among the list:
Click on the Execute Action button.

Search for Images by Frame Number

Each image in the collection is associated with a unique identifier, the side (A or B) together with the frame number (0-35000) associated with its position on the laser videodisc from which images were extracted. Consecutive images can be extracted by specifying a starting frame number and the number of images to display.

Browse (Retrieve 10 Random Frames)

This method is intended for casual examinations and demonstrations. The laser videodisc from which the images were extracted has images on each of its two sides, labeled A and B. Five images from each of the two sides are selected at random and returned for viewing.

Specify a Search Expression

A search is specified by manipulating one or more of the following (text window and selection list) fields of the search form:

Enter a text expression in one or more of the text windows entitled:
Text expressions may contain combinations of simple Boolean expressions, phrases, or truncated strings.
Enter a one to four digit year in either or both of the text windows:
- Start Year
- End Year
using the attached radio buttons to specify whether the date is A.D. or B.C.
Select geographical locations from either or both of the selection lists labeled Locations(s):
- World
- US

Search Form Fields

The following fields appear in the search form:

Any Text Field: Text in this field is matched against all indexed text fields of the catalog record, including title, abstract, name-related, and topical heading (RLIN 650a) fields of catalog records.
Title/Abstract: Text in this field is restricted to matching title, subtitle, and abstract fields of catalog records.
Name Field(s): Text in this field is matched to the several name-related fields of catalog records (RLIN 600a, 610a, 700a, and 100a).
Start Year: Specify the first year in a range of years. If this value is set and End Year is not specified, all dates including and following this date will be searched for. Any dates overlapping a specified range will match. Note that catalog dates are stored as a decade number for A.D. and as a century number for B.C. time periods. The attached radio buttons indicate whether the date is A.D. or B.C.
End Year: Specify the last year in a range of years. If this value is set and Start Year is not specified, all dates prior to and including this date will be searched for. Any dates overlapping a specified range will match. Note that catalog dates are stored as a decade number for A.D. and as a century number for B.C. time periods. The attached radio buttons indicate whether the date is A.D. or B.C.
Location(s): The World selection box contains regions of the world (alphabetized lists, of all cataloged countries and of cataloged countries falling within each region, are available). The US selection box contains the names of the 50 U.S. States and the District of Columbia. Multiple selections may be specified in each of these lists (in NCSA Mosaic, this is accomplished by holding down the control key while clicking the mouse button over a selection).

Text Expressions

Strings entered into any of the text windows can take advantage of several features:

Words within double quotes are treated as intact phrases (for example, "nursing school" will match the word nursing followed immediately by the word school.
An asterisk appearing at the end of a word indicates suffix truncation (for example, disease* matches any word with the prefix disease, including disease, diseased, and diseases.
Stop words are effectively ignored in search expressions. Common words such as around, but, and with are stripped from the catalog indices and therefore will never result in matches. Note that the word "and," normally regarded as a stop word, is here interpreted as a Boolean operator. For example, a search expression such as disease with complications, where with is a stopword, is evaluated as (disease OR complications). Similarly, the expression diseases and their complications, where their is a stopword, is evaluated (perhaps incorrectly) as (diseases OR complications). Presence of stopwords within phrases will currently yield incorrect results, since the stopwords will not be found in the index. An alphabetically ordered list of the stop words is available. Note that in this list, lines with leading '#' characters are treated as comments and as such these words are not stopwords.
Case is insignificant.
The words and and or have significance as Boolean logical operations.

Boolean Logical Operations

By default, words, phrases and suffix-truncated strings entered into a single text window are implicitly treated as if connected by a Boolean OR. If the word and appears between words, the Boolean operator AND is assumed. The Boolean operator NOT is unavailable. Boolean expressions can not be grouped by parentheses. Both the AND and OR operators are assumed to be left associative with equal precedence. For example, the query disease* and adult* or child* is evaluated as though it were the expression ((disease* and adult*) or child*), probably not what was intended. To search for adult or childhood diseases, use the search term: child* or adult* and disease*.

Multiple selections may be entered into the geographical location lists; all of the selections are treated as if joined by the Boolean OR (that is, images will be found for which the textual catalog contains any of the one or more specified locations -- but at least one).

Expressions entered into different text windows are treated as if joined by a Boolean AND (that is, images must match the expressions appearing in all of the text windows). Similarly, the geographical locations are joined to the text windows with an AND. As a reminder, these relationships are indicated on the form by the appearance of the words AND and OR in appropriate locations.

Simple Search Examples

diabetes and cur*: Looks for all records that have both the word diabetes and any words with the prefix cur, including cure, cures, curable, curing, etc.
"heart disease": Looks for all records that have the phrase heart disease; that is, the word heart is followed immediately by the word disease.
"abraham lincoln" gettysburg: Looks for all records that have either the phrase abraham lincoln or the word gettysburg, or both.

Further examples are available.

Tips for Text-based Searching

Always select the "Clear Search Pattern" button on the search form prior to formulating a new search. This will clear any geographical location selections which have been made in previous searches which are not currently visible due to the limited size of the location selection windows.
Due to the incomplete state of the catalog, only about 10% of catalog records are associated explicitly with dates.
Geographical codes are present in a minority of records, so specifying a location in the Any Text Field or Title/Abstract windows is likely to be more useful than employing the geographical selection lists.
Keep searches simple. Due to the incomplete nature of the current catalog, highly detailed search expressions are likely to match few or no images.

Search Results Summary
A search for images terminates with a display that looks something like this:
Click here to see full-size example
which summarizes the search expression, and reports the duration of the search in clock time and the number of matches found. Note that a timeout period now begins for purposes of image browsing.

Browsing the Retrieval Set
A retrieval page will appear something like this (this example contains only 1 image):
Click here to see full-size example
The browsing subset is a collection of thumbnail representations of images along with minimal descriptive information from the associated catalog record. Note that special alternate thumbnail images may be substituted for the actual thumbnail in situations where the image may not be shown outside of the NLM, or if the image is missing. Clicking on these thumbnail images provides an explanatory message.
You may scroll through the browsing subset, and do any of the following:
- Click on a thumbnail image to view a larger version of the image.
- Click on a brief descriptive title to view the full catalog record. Note that all text presented by the system will correctly display special characters such as foreign accent marks. However, special codes employed in the catalog record, such as those used to indicate geographical location, are not translated into human-readable form.
- Mark an image for later retrieval.
Once a search is triggered and a retrieval set returned, a timeout period, proportional to the size of the retrieval set, is computed. The timeout period is equal to (10 + 2 * rs) minutes, where rs is the size of the result set.
If browsing continues past the timeout period, the OnLine Images server terminates the search session and information about the current retrieval set is lost. Requesting another browsing subset will produce an error message.
Requesting the next subset of images prior to the expiration of the timeout period resets the timeout clock. The following actions do not reset the clock: retrieving a larger-size image, retrieving a full catalog entry, saving and/or printing files, or using the controls of your World-Wide Web browser to navigate forward or backward.

Marking Images
You may only be interested in a subset of images returned by a search. Images can be marked and then extracted into a subset. To mark an image, click on the small button near the upper-left-hand corner of the in-line image. When all of the desired images have been marked, select the action Extract Marked Subset. A new retrieval set is created, populated only by the marked images; the original retrieval set is lost.

Printing Images and Catalog Information
Ability to print depends upon which World-Wide Web browser is being used, and which printers you have access to. NCSA Mosaic for X will allow you to send anything contained in the current display to a printer. If you use an appropriate printer, such as a PostScript device, sending a displayed set will result in output containing both the text and in-line images.
When you click over an in-line image to display the larger version of the image, the imaging is generally done by an application external to the World-Wide Web browser. For example, when using NCSA Mosaic for X, it is often the case the the shareware program xv is employed for viewing larger images. This application does not allow displayed images to be sent directly to a printer but you can save an image in the form of a PostScript file and print that.

Selecting An Action
When presented with a menu titled Select Action, one or more of the following choices may be available. Selecting one of these actions indicates what will occur when the Execute Action button is selected:

Begin New Search
Retrieve a fresh search page, removing information associated with the current search.
Close Session
Quit a search session, removing information associated with it.
Explain Search
Present an English language explanation of the search expression. This can be helpful to novice users and those uncomfortable with Boolean logic, but may not produce clear explanations of complex expressions.
Extract Images m through n (of s)
Display images m through n of the retrieval set (out of s images total).
Extract Marked Subset
Replace the retrieval set with the set of marked images.
OnLine Images Home Page
Return to the home page of OnLine Images from the History of Medicine.
Perform Search
Perform a text-expression based search and display a Search Results summary. You may encounter an error message if the search expression is malformed.
Retrieve First Batch
Display the first batch of images from the retrieval set.

NLM HyperDOC / OnLine Images from the HMD / April 1994

OnLine Images from the History of Medicine (OLI/HMD): Help Page