Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
nham thuc » nhan thuc, nam thuc, nham thu
su triet » su viet, su tien, ve triet
van hanh » ban hanh, van anh, van ban
dang mam » dang nam, dang mau, dang mat
va nham » va cham, va tham, va nha
tu sach » thu sach, su sach, te sach
sach tu » sach thu, cach tu, sach ty
dang ma » dang mau, dang mat, tang ma
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 tu ((dang ma) OR (dang mam)) hoi. hieu va nham thuc ((van hanh) or (van thanh)) ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu ((dang ma) OR (dang mam)) hoi. hieu va nham thuc ((van hanh) OR (van thanh)) ki su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu ((dang ma) OR (dang mam)) hoi. hieu va nham thuc ((van hanh) or (van thanh)) ki su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach tu ((dang ma) OR (dang mam)) hoi. hieu va nham thuc ((van hanh) or (van thanh)) ki su triet*.