I have a domain, thieulam.com . Although I put the keywords : thieu lam, thieulam ... in the keywords meta tag, when I search on google (for thieulam, or thieu lam), it still displays other websites that are sub domains.

so how can I make it on top of search engine of google and yahoo?

Have you submitted this to google and the like?
The more links you receive and have the better chances your website has of being listed towards the top. It's a pagerank thing, more than anything else.

You have to optimise your website for be on the top. Better contact a Search Engine Optimiser for that.