Perhaps you should try some spelling variations:
luc tieng » hoc tieng
duoc tren » nuoc tren, thuoc tren, dung tren
phan duc » pham duc, phan dau, tran duc
hang tai » hang va, dung tai
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
va hang » van hang, va nang, va lang
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: vu sach ky nang ma hoi. hieu ve ((phan duc) or (phan tu)) va hang tai ((luc tieng) or (duoc tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang ma hoi. hieu ve ((phan duc) OR (phan tu)) va hang tai ((luc tieng) OR (duoc tren)).
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang ma hoi. hieu ve ((phan duc) or (phan tu)) va hang tai ((luc tieng) or (duoc tren))*.