Perhaps you should try some spelling variations:
hau treo » cau treo, cau theo, dau tren
danh dai » danh dau, danh di, danh sai
hieu van » hieu va, thien van, lieu va
dai hau » dai han, dai hai, dai huu
truc va » thuc vat, trung va
thuc va » thuc vat, thuc dan, thuc day
su sach » so sach, vu sach
tang ma » tang van
van cam » van nam, van lam, van cau
sach v » sach va, sach y, sach 2

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 ((tang ma) OR (mang may)) hoi. hieu van cam ((thuc va) or (truc va)) danh dai hau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v ((tang ma) OR (mang may)) hoi. hieu van cam ((thuc va) OR (truc va)) danh dai hau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v ((tang ma) OR (mang may)) hoi. hieu van cam ((thuc va) or (truc va)) danh dai hau treo".
• Adding a wildcard symbol may retrieve word variants: su sach v ((tang ma) OR (mang may)) hoi. hieu van cam ((thuc va) or (truc va)) danh dai hau treo*.