Search techniques are:

i. Keywords or String search 

ii. Phrase search 

iii. Subject search 

iv. Boolean operator (AND, OR, NOT) 

v. Truncation 

vi. Proximity search 

vii. Limiting search 

viii. Range search

i. Boolean Search: The three operators of Boolean logic are logical sum (+) -OR, logical Product(x)-AND, and logical difference (-) – NOT.

AND operators: ‘AND” logic allows the searcher to specify the coincidence of two or more product.

OR Operators: When two terms are connected with “ÓR” and searched then the search engines retrieve those records which have either of terms or both.

NOT Operators: When two terms are connected using the NOT operators and searched then, the search engines retrieve those records which do not have the second term.

ii. Proximity Search: This search facility allow the users to specify 

(i) whether two search terms should occur adjacent to each other 

(ii) whether one or more words occur in between the search terms 

(iii) whether the search term should occur in the same paragraph irrespective of the intervening words and so on.

Ex: FISH SAME CHIPS

FISH WITH CHIPS 

FISH ADJ CHIPS 

FISH NEAR CHIPS

iii. Range Search: It is useful with numerical information. It is important in selecting records with certain data ranges. 

The following options are used for range searching:

• Greater than(>)
• Less than (<)
• Equal to(=)
• Greater than and equal to (> =)
• Less than and equal to(< =)