Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
dua tren » dung tren
danh hai » dang hai, lanh hai, manh hai
va danh » va dinh, va dan, va hanh
cam luc » cam xuc, cau luc
qua cam » qua cham, qua cac, qua ca
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
luc va » duc va, tuc va, loc va
sac ky » cac ky, sai ky

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 thu) or (sac ky)) nang ma hoi. hieu qua cam luc va danh hai ((dua tren) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach thu) OR (sac ky)) nang ma hoi. hieu qua cam luc va danh hai ((dua tren) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: tu ((sach thu) or (sac ky)) nang ma hoi. hieu qua cam luc va danh hai ((dua tren) or (cua tre))*.