Perhaps you should try some spelling variations:
nang cau » nang cao, hang cau, nang dau
cau tren » dau tren, ca tren, cau treo
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
cam tuc » cam tu, nam thuc, dam thuc
cu tren » tu tren, dua tren
va dan » ca dan, va dao, va dau

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 cau hoi. hieu ve ((cam tuc) or (cam xuc)) va dan ca ((cau tren) OR (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang cau hoi. hieu ve ((cam tuc) OR (cam xuc)) va dan ca ((cau tren) OR (cu tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang cau hoi. hieu ve ((cam tuc) or (cam xuc)) va dan ca ((cau tren) OR (cu tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang cau hoi. hieu ve ((cam tuc) or (cam xuc)) va dan ca ((cau tren) OR (cu tren))*.