Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
thu sach » thuat sach, thuoc sach, thu hoach
dang mam » dang nam, dang mau, dang mat
thuc van » thuc vat, thuc dan, thuc hanh
hanh ki » hanh vi, hanh ky, hanh kien
thuc va » thuc vat, thuc dan, thuc day
tu sach » su sach, te sach, tu cach
va cham » va chat, va tham
mam hoi » mam hoai, nam hoi, mai hoi
tu dang » thu dang, tu dong, su dang
hieu va » lieu va, hieu qua
ki su » ky su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (thu sach)) tu dang mam hoi. hieu va cham ((thuc van) OR (thuc va)) hanh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) tu dang mam hoi. hieu va cham ((thuc van) OR (thuc va)) hanh ki su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) tu dang mam hoi. hieu va cham ((thuc van) OR (thuc va)) hanh ki su triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) tu dang mam hoi. hieu va cham ((thuc van) OR (thuc va)) hanh ki su triet*.