If you trawl through a large number of similar things, you search through them looking for something that you want or something that is suitable for a particular purpose.
例句
A team of officers is trawling through the records of thousands of petty thieves...一组警员正在翻查数以千计的小偷小摸者的犯罪记录。Her private secretary has carefully trawled the West End for a suitable show.她的私人秘书已经在伦敦西区进行了拉网式搜索，以寻找一部合适的剧目。
VERB
用拖网捕(鱼)
When fishermen trawl for fish, they pull a wide net behind their ship in order to catch fish.
例句
They had seen him trawling and therefore knew that there were fish...他们曾见过他用拖网捕鱼，因此知道那里有鱼。We came upon a fishing boat trawling for Dover sole.我们碰上一艘正用拖网捕鳎的渔船。
英汉词典释义
n.
拖网
We did a wide trawl to find the right person to play the part.我们到处寻找一个合适的人来演这个角色。
vt. & vi.
(在…)以拖网捕鱼
The boat were out trawling the bay.渔船已出海, 在海湾用拖网捕鱼。
vt.
查阅（档案等）
The police are trawling (through) their files for similar cases.警方正在查阅类似案件的档案。
英英词典释义
Noun
1. a long fishing line with many shorter lines and hooks attached to it (usually suspended between buoys)
2. a conical fishnet dragged through the water at great depths