Get exactly what you're searching for easily with one of these google commands.
-Searching for a precise Sentence,in google's search textbox type your sentence between quotes:
"your sentence"

-seaching for a specific file type(extensions:pdf,rar,zip,mp3,flv.....),in google's search textbox type the name of the file you are search for then filetype:extension
query file_type:pdf

-searching for a sentence that exist in a specific domaine name(domaine_name:com,info,org,biz,us,co,uk,fr,nl....),in google's search textbox type your query then
site:domain_name
query site:uk


-searching for a sentence that exist in titlebar of the browser:
allintext: query

-searching for a sentence that exist in a website content:
allintext: query

-searching for a sentence that existe in website Link/URL:
allinurl: query