Perhaps you should try some spelling variations:
cau treo » cau theo, cau tren, cau triet
sach hay » sach han, sach ha, sach nay
danh hai » dang hai, lanh hai, manh hai
thuc dan » thuc hanh, hoc dan, thuc vat
hieu van » hieu va, thien van, lieu va
hai cau » hai chau, hai chu, hai hau
thuc va » thuc vat, thuc day
nang ma » tang ma, sang ma, nang cao
sach ty » sach y, sach tu, sach thu
van cam » van nam, van lam, van cau
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: su ((sach hay) or (sach ty)) nang ma hoi. hieu van cam ((thuc va) OR (thuc dan)) danh hai cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach hay) OR (sach ty)) nang ma hoi. hieu van cam ((thuc va) OR (thuc dan)) danh hai cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach hay) or (sach ty)) nang ma hoi. hieu van cam ((thuc va) OR (thuc dan)) danh hai cau treo".
• Adding a wildcard symbol may retrieve word variants: su ((sach hay) or (sach ty)) nang ma hoi. hieu van cam ((thuc va) OR (thuc dan)) danh hai cau treo*.