For most purposes, the case-sensitive option should be set to no, and search type should be string. With these options selected, if you search for `tibet', this will match both `Tibet' and `Tibetan', since `tibet' is part of the second word. Set search type to word when you want to match whole words exactly, e.g. you want `tibet' to match `Tibet' but not `Tibetan'.
For most purposes, the Treatment of multiple `words' in search
expression option should be set to all words must be
found, order not important. If you choose the all words must
be found exactly as specified option, and (for example) you search
for two words, a match will only occur if the two words are exactly
adjacent in the WWW files (i.e. HTML files), with the same number
of spaces between them as you have typed in the Search for:
field. Because one or more spaces or a line break in an HTML file
generally result in a single space in the WWW page as you see it,
multiple word searches may not succeed, even if you think they should
based on the way a particular WWW page looks.