Perhaps you should try some spelling variations:
cau theo » cau thi, cau tao
hieu van » hieu va, thien van, lieu va
danh hai » dang hai, lanh hai, manh hai
hai cau » hai chau, hai chu, hai hau
thuc va » thuc vat, thuc dan, thuc day
su sach » so sach, vu sach
nang ma » tang ma, sang ma, mang may
van lam » van nam
sach v » sach va, sach y, sach 2
tuc va » truc va, tuc xa, duc va

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