Tips for Searching
You can search for any word or phrase except for certain common words (this includes “and”, “how”, “where”, and other words), which are ignored during a search. Queries are case-insensitive, so you can type your query in uppercase or lowercase letters.
Wildcard Character (*)
You can employ the wildcard character (*) to match words with a given prefix. For example, type:
to find words that have the prefix bench such as “benchmark”, “benchmarking”, and so on.
Quotation Marks
Put quotation marks around keywords, if you want them to be taken literally. For instance, if you type:
“World Wide Web”
(including the quotation marks) any document containing the exact expression World Wide Web is retrieved. Documents with, for example, the phrase:
web browser are used world-wide
are not listed because the words do not appear in the exact order.
Exclusion of Common Words
Common words such as “and”, “how”, “where”, and other words are ignored, as well as single digits and single letters, because they tend to slow down your search without improving the results. Don't be surprised if you type in:
What about?
and get nothing returned since these words are all ignored.
Search Option
Simple search is based on the option "All Words". If this returns no results, it is followed by a "Natural Language" query.

The following search options are available with advanced search:
All Words
All documents are returned that include all of your search terms. The order in which the terms are typed will not affect the search results. For example, both of these queries:
price performance
performance price
will match the same documents.
Any Word
This query finds all documents that mention any of the search terms. For instance, type in:
computer economics
to find all documents containing either “computer” or “economics”, or both.
Natural Language
All documents are returned that match the meaning, not the exact wording, of the query. For instance, type in:
How to negotiate a good price?
to find documents that mention “negotiation” and “good price”. Wildcard and quotation marks are ignored within a natural language query.
Word variations
Search for all forms of a word based on the same stem word. For example, in the form type in:
to find all documents with words based on the same stem as fly, such as “flying”, “flown”, “flew”, and so on.
Boolean Expression

You can enter the Boolean operators (AND, OR, and NOT) and the proximity operator (NEAR) to specify additional search information. Boolean and proximity operators can create a more precise query.

The AND operator has a higher precedence than OR. For example, the first three queries are equal, but the fourth is not:

price AND drop OR decline
decline OR drop AND price
decline OR (drop AND price)
(decline OR drop) AND price

Search with the keyword NEAR, rather than AND, for words close to each other. For example, both of these queries:

computer AND economics
computer NEAR economics

look for the words “computer” and “economics” on the same document. But with NEAR, the returned documents are ranked in order of proximity: The closer together the words are, the higher the rank of that document. If the searched words are more than 50 words apart, they are not considered near enough, and the document is assigned a rank of zero.

Refine your queries with the NOT keyword to exclude certain text from your search. For example, if you want to find all instances of “surfing” but not the “Internet”, write the following query:

surfing NOT Internet
The NOT operator can be used only to exclude documents that match a previous content restriction. Hence it should be the last statement in your query.
Sort Order
You can display the query results ordered by search rank, publication date or alphabetical. The search rank of each document indicates how well the document matched the query.