Perhaps you should try some spelling variations:
dau tien » van tien
toc sach » hoc sach, doc sach, thuoc sach
nam mua » nam cua, nam qua, nam luat
nam xua » nam cua, nam qua, nam luat
hieu va » lieu va, hieu qua
nang ro » nang co, nang ho, nang ra
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) OR (toc sach)) ky nang ro hoi. hieu va ((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) OR (toc sach)) ky nang ro hoi. hieu va ((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) OR (toc sach)) ky nang ro hoi. hieu va ((nam xua) or (nam mua)) va dan du dau tien*".