Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
chu treo » cau treo, cu tren, chu tri
dan hai » doan hai, dang hai, dan khai
sach ky » sac ky, sach y, sach ty
so sach » so sanh, bo sach, co sach
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va
cam tuc » cam xuc, cam tu, nam thuc
tuc va » thuc va, truc va, tuc xa
va dan » ca dan, va dao, va dau
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang ma hoi. ((hieu va) or (hieu qua)) cam tuc va dan hai ((chu treo) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang ma hoi. ((hieu va) OR (hieu qua)) cam tuc va dan hai ((chu treo) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang ma hoi. ((hieu va) or (hieu qua)) cam tuc va dan hai ((chu treo) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang ma hoi. ((hieu va) or (hieu qua)) cam tuc va dan hai ((chu treo) OR (cau tren))*.