Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cam thuc » am thuc, nam thuc, cam thu
thuc dan » thuc hanh, hoc dan, thuc vat
dan manh » dang manh, doan manh, van manh
manh hai » lanh hai, minh hai, thanh hai
cau tren » cu tren, dau tren, ca tren
su sach » so sach, vu sach
sach ly » sach y, sach lo, sach ty
ly nang » ky nang, ly hang, ly vang
van cam » van nam, van lam, van cau
hai cau » hai chau, hai chu, hai hau
ma hoi » mai hoi, ma hoa, me hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ly nang ((ma hoi) or (xa hoi)). hieu van cam thuc dan manh hai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly nang ((ma hoi) OR (xa hoi)). hieu van cam thuc dan manh hai cau tren.
• Adding a wildcard symbol may retrieve word variants: su sach ly nang ((ma hoi) or (xa hoi)). hieu van cam thuc dan manh hai cau tren*.