Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
danh sai » dung sai, danh bat, danh dau
thu lang » thu hang, thu bang, phu lang
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, hoc dan, thuc vat
sai cua » dai cua, hai cua, lai cua
van lam » van nam
thuc va » thuc vat, thuc day
lang xa » lang ha, dang xay, lang van
tu sach » su sach, te sach, tu cach
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) OR (tu sach)) thu lang xa hoi. hieu van lam ((thuc va) or (thuc dan)) danh sai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) thu lang xa hoi. hieu van lam ((thuc va) OR (thuc dan)) danh sai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (tu sach)) thu lang xa hoi. hieu van lam ((thuc va) or (thuc dan)) danh sai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (tu sach)) thu lang xa hoi. hieu van lam ((thuc va) or (thuc dan)) danh sai cua tre*.