Perhaps you should try some spelling variations:
cau treo » cau theo, cau tren, cau triet
danh hai » dang hai, lanh hai, manh hai
thuc day » thuc dan, thuc vat
hieu van » hieu va, thien van, lieu va
sach ly » sach y, sach lo, sach ty
thuc va » thuc vat, thuc dan
nang ma » tang ma, sang ma, mang may
hai cau » hai chau, hai chu, hai hau
su sach » so sach, vu sach

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) or (nang cao)) hoi. hieu van nam ((thuc va) OR (thuc day)) danh hai cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly ((nang ma) OR (nang cao)) hoi. hieu van nam ((thuc va) OR (thuc day)) danh hai cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ly ((nang ma) or (nang cao)) hoi. hieu van nam ((thuc va) OR (thuc day)) danh hai cau treo".
• Adding a wildcard symbol may retrieve word variants: su sach ly ((nang ma) or (nang cao)) hoi. hieu van nam ((thuc va) OR (thuc day)) danh hai cau treo*.