捜索【そうさく】
search (esp. for someone or something missing), manhunt, legally authorized search of a person, building, etc.
検索【けんさく】
looking up (e.g. a word in a dictionary), search (e.g. on the Internet), retrieval (of information), reference
探索【たんさく】
search, lookup, hunt, (item of) research, exploration, investigation
索引【さくいん】
index (in a book)
思索【しさく】
speculation, thinking, meditation
模索【もさく】
groping (for), fumbling around (for), searching (for an answer, solution, etc.), trying to find
捜索隊【そうさくたい】
search party