Perhaps you should try some spelling variations:
nam truoc » nam thuoc, lam truoc, nam truong
nam truc » nam thuc, nam trung, nam thuoc
dau tren » dau tien, dat tren, dau tieng
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
va dan » ca dan, va dao, va dap
dan va » doan va, dan ca, ban va
va dau » va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang cao hoi. hieu ve ((nam truc) or (nam truoc)) va dan va dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang cao hoi. hieu ve ((nam truc) OR (nam truoc)) va dan va dau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang cao hoi. hieu ve ((nam truc) or (nam truoc)) va dan va dau tren*.