Searching for a document is as simple as typing some descriptive words in
the input box above and either pressing the Enter key or clicking the
Search button. A results page appears with a list of documents or web
pages that match your search terms, with the most relevant search results
appearing at the top. If more than 25 documents match your search, you will
be presented with links to navigate to your other search results. By default
only web pages or documents that include all of your search terms are
returned. If you wish to broaden or restrict the search, include fewer or
more terms, respectively. You do not need to include "AND" between
the terms; that is implied.
Most every search result includes an excerpt from the page or document,
displaying the search terms in context. In the excerpt your search terms are
displayed in bold so that you can quickly determine if that result is from a
page or document you want to visit.
Our site search is powered by a Google Search Appliance, owned and
operated by NASA / Goddard Space Flight Center.
You may choose a specific collection of web pages to search by selecting
one from the Index: menu immediately below the above search box. You
can also specify whether to sort the search results by relevance or date. By
default search results are sorted by relevance, with the most relevant result
appearing at the top of the page. If you want to sort the documents by date
instead, click the Sort by date link on the search results or select
Date from the Sort: menu above. The most recent document
appears at the top of the page and the date of each file is returned in the
results. Search results that do not have dates are displayed at the end and
are sorted by relevance.
The search method uses advanced matching techniques to find pages that are
both relevant and important to your search. The search method prefers pages
in which your query terms are near each other and is smart enough to include
variants (plurals, different tenses of verbs) of some search terms, while
ignoring common words and characters, such as "where" and
"how," as well as certain single digits and single letters, because
they tend to slow down your search without improving the results. If a common
word is essential to getting the results you want, you can include it by
putting a plus ("+") sign in front of it. Include a space before
the "+" sign, but not after it.
You can also search for a specific phrase by enclosing a series of words
within quotation marks or by using hyphens (or slashes or periods or equal
signs or apostrophes) between the words (x-ray, for example).
Searches are not case sensitive. All letters are handled as lower case.
For example, searches for "gamma ray burst", "Gamma Ray
Burst", and "Gamma ray burst" will each return the same
results.
You can expand your search by using the OR operator. To retrieve
pages that include either any of a number of search terms, use an uppercase
OR between the terms. For example, to search for either red or blue
giant stars, type the following: giant star red OR blue.
You can exclude some results by adding a minus sign ("-") in
front of words related to the topics you want to avoid. Make sure you include
a space before the minus sign, but not after it. You can exclude multiple
terms in that fashion. For example, to search for the word "black"
and exclude search results related to black holes, type the the following:
black -hole -holes.
To search for documents or items that contain numbers within a range, type
your search term and the range of numbers separated by two periods
(".."). Each number in the range should not include more than six
significant digits. For example, if you were to type the search query,
"1..1234567," only the first six significant digits in the
"1234567" term would be included in the range search; that is, it
is as though you have just typed, "1..1234560".
You can search for documents that contain dates that fall within a time
frame. To use date range search, type all of the following:
- The search term
- The daterange: operator
- The start date
- The range separator (which is two periods if you are using a YYYY-MM-DD
format or a hyphen if you are using the Julian format)
- The end date
Do not add a space between the search operator and the date range. The
dates could be in either of the following formats:
- The YYYY-MM-DD (ISO 8601) format. Date ranges using this format should
be separated by two periods ("..").
- The Julian format. The Julian date is calculated by the number of days
since January 1, 4713 BC. For example, the Julian date for August 1,
2001 is 2452122. Date ranges in this format should be separated by a
hyphen ("-").
For example, to search for a document about calibration that was modified
within a specific period, type the following: calibration
daterange:2005-01-13..2006-04-05.
The earliest date that you can use in your date range search is January 1,
1990; and the latest date is November 9, 2034.
The search method supports several advanced operators, which are query
words that restricts your search to a smaller set of documents. When you
enter your search query, do not add a space between the search operator and
the search terms.
| Search Operator |
Description |
Example |
| daterange: |
See the discussion of date ranges above. |
|
| filetype: |
Restricts the search to specific file types such as Excel
spreadsheets, PDF files, or PowerPoint documents. Type the
filetype: operator followed by the file extension. |
Typing glast filetype:pdf in the search box returns only PDF
files about GLAST. |
| intext: |
Restricts the search to documents that contain the search word in the
body text of documents. |
Typing intext:heasarc returns documents that mention the
word "HEASARC" in their body text. If a document has
"HEASARC" in the HTML title, but not in the body text, the
document will not be included in the search results. |
| intitle: |
Restricts the search to documents that contain the search word in the
HTML title. |
Typing intitle:pulsar timing returns documents that mention
the word "pulsar" in their HTML title, and mention the word
"timing" in the title, body text, anchor, or anywhere else
in the document. |
| inurl: |
Restricts the search to documents that contain the search word in the
URL.This operator works on words, not URL components such as
punctuation. Slashes ("/"), for example, are ignored. |
Typing inurl:pulsar timing in the search box returns
documents that mention the word "pulsar" in their URL and
mention the word "timing" in the URL, body text, title, or
anywhere else in the document. |
|
