Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
hanh vai » hanh vi, hanh va, hanh tai
thuc dan » thuc hanh, thuc vat
sach thu » sach thue, sach thieu, sach tham
cua viet » ca viet, hoa viet, cua vat
thu lang » thu hang, thu bang, phu lang
thuc va » thuc vat, thuc day
hieu vi » hieu voi, hieu va, hieu ve
lang xa » lang ha, dang xay, lang van
vai cua » dai cua, hai cua, lai cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach thu lang xa hoi. hieu vi pham ((((thuc va) or (thuc dan))) or (hoc dan)) hanh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach thu lang xa hoi. hieu vi pham ((((thuc va) OR (thuc dan))) OR (hoc dan)) hanh vai cua viet.
• Adding a wildcard symbol may retrieve word variants: doc sach thu lang xa hoi. hieu vi pham ((((thuc va) or (thuc dan))) or (hoc dan)) hanh vai cua viet*.