Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
sach tai » sach bai, sach tham, sach dao
su triet » su viet, su tien, ve triet
hanh lai » hanh lam, hanh tai, thanh lap
thuc dan » thuc hanh, hoc dan, thuc vat
thuc day » thuc vat
tai lang » tai cong, thi lan, tai san
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
su sach » so sach, vu sach
ve cam » ve cham, ve cac, va cam

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 tai lang xa hoi. hieu ve cam ((thuc day) OR (thuc dan)) hanh lai ((su triet) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tai lang xa hoi. hieu ve cam ((thuc day) OR (thuc dan)) hanh lai ((su triet) OR (cua viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach tai lang xa hoi. hieu ve cam ((thuc day) OR (thuc dan)) hanh lai ((su triet) or (cua viet))".
• Adding a wildcard symbol may retrieve word variants: su sach tai lang xa hoi. hieu ve cam ((thuc day) OR (thuc dan)) hanh lai ((su triet) or (cua viet))*.