Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
dinh hai » dinh thai, tinh hai, dinh ha
cam thuc » am thuc, nam thuc, cam thu
vu khach » vu khanh, vu khac, vay khach
ly nang » ky nang, ly hang, ly vang
nang ma » tang ma, sang ma, nang cao
van cam » van nam, van lam, van cau
thuc va » thuc vat, thuc dan, thuc day
va dinh » van dinh, va kinh, va tinh
hai cau » hai chau, hai chu, hai hau
so sach » so sanh, bo sach, co sach
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) or (vu khach)) ly nang ma hoi. hieu van cam thuc va dinh hai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (vu khach)) ly nang ma hoi. hieu van cam thuc va dinh hai cau tren.
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (vu khach)) ly nang ma hoi. hieu van cam thuc va dinh hai cau tren*.