Perhaps you should try some spelling variations:
dau tien » van tien
nam mua » nam cua, nam qua, nam luat
sach ky » sac ky, sach y, sach ty
te sach » toc sach
nang ro » nang co, nang ho, nang ra
hieu va » lieu va
nam xua » nam cua, nam qua, nam luat
ro hoi » co hoi, o hoi, mo hoi
va dan » ca dan, va dao, va dau
dan du » dan dau, danh du, dan su
du dau » tu dau, dung dau

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang ro hoi. ((hieu va) OR (hieu qua)) ((nam xua) or (nam mua)) va dan du dau tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ro hoi. ((hieu va) OR (hieu qua)) ((nam xua) OR (nam mua)) va dan du dau tien*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang ro hoi. ((hieu va) OR (hieu qua)) ((nam xua) or (nam mua)) va dan du dau tien*".