Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
danh hai » dang hai, lanh hai, manh hai
thuc dan » thuc hanh, hoc dan
hieu van » hieu va, thien van, lieu va
mai hoi » mai khoi, dai hoi, lai hoi
sach ly » sach y, sach lo, sach ty
van cam » van nam, van lam, van cau
ly nang » ky nang, ly hang, ly vang
hai cau » hai chau, hai chu, hai hau
vu sach » vu bach, su sach, vu khach
ma hoi » xa 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: vu sach ly nang ((ma hoi) or (mai hoi)). hieu van cam ((thuc vat) or (thuc dan)) danh hai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ly nang ((ma hoi) OR (mai hoi)). hieu van cam ((thuc vat) OR (thuc dan)) danh hai cau tren.
• Adding a wildcard symbol may retrieve word variants: vu sach ly nang ((ma hoi) or (mai hoi)). hieu van cam ((thuc vat) or (thuc dan)) danh hai cau tren*.