The most commonly used operators are AND and OR. AND is used to narrow a search. For example, if I am researching the topic of the effect of gloal warning on the polar ice caps, then I want articles that contain both of those terms. terms. As a result, my search would loo! li!e this" gloal warming AND ice caps. If I searched gloal warming OR ice caps, cap s, then I would find articles that contained either one of those terms # ut not necessarily oth. To explain further, the results results might contain $ust the term gloal warming or $ust the term ice caps %and thus not e what I&m loo!ing for, ecause I want oth of the terms'. This is why A AND ND narrows a search # I&m telling the dataase or search engine that A(( of the terms must e present in the results. OR is used to roaden a search. Typically, Typically, you want any terms lin!ed with OR to e li!e terms or synonyms # for example, gloal gloal warming OR climate change. OR then roadens the search y pro)iding alternati)e, related terms to search. *hen you you lin! terms with OR, put them in parenthesis %gloal warming OR climate change' # this helps the dataase put the search in the right order %without nesting, your results may not e what you expect, ecause the search engine needs them to interpret your search. Nesting should not e used with single terms or phrases # that&s where you can employ +uotation mar!s %explained a it later'. NOT can also e effecti)e if you want to eliminate a certain term...ut it is not used as often as AND OR. One way that I use NOT is when I want literary criticis criticism m aout a oo! or author, ut not a oo! re)iew of that author&s wor!. -o I might say Nathaniel /awthorne A AND ND -carlet (etter NOT oo! re)iew to weed out the oo! re)iews from my results. -ome other techni+ues to use are +uotation mar!s # so, if I searched gloal warming, I&m as!ing to find those two words right next to each other. If i search without the +uotation mar!s, then the word gloal might might appear in one paragraph, and the term warm warming ing in another. -o, putting short, common phrases %instant messaging, messaging, gloal warming' in +uotation mar!s simply increases your chances of retrie)ing highly rele)ant results. Truncation can also e effecti)e, ut you ha)e to e careful that you&re not truncating so far ac! that you end up retrie)ing many unrelated terms. 0ou 0ou also don&t need to use the truncation symol %1' if you all you would retrie)e is the plural of the word # dataases will usually automatically retrie)e the plural %for example, there&s no need to do this" daughter1 # the dataase will retrie)e oth daughter and daughters without the symol' -o, a more detailed search statement might loo! li!e this" %gloal warming OR climate change' AND AND ice caps. *hat you want to a)oid is searching in long phrases, or using phrases that contain words li!e of, from, etc. 0ou 0ou want to pic! out the !ey terms2concepts in your research +uestion, and then lin! those terms with 3oolean 3oo lean operators.