Perhaps you should try some spelling variations:
thien van » thi van
van hanh » van thanh, ban hanh, van anh
van pham » san pham, van phan, van phat
su triet » su tien, ve triet
nang ma » tang ma, sang ma, nang cao
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
duc van » duc va, duc tan, duc manh
su viet » so viet
tu sach » thu sach, su sach, te sach

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 ky ((lang xa) or (nang ma)) hoi. thien van pham duc van hanh vi ((su viet) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((lang xa) OR (nang ma)) hoi. thien van pham duc van hanh vi ((su viet) OR (su triet)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((lang xa) or (nang ma)) hoi. thien van pham duc van hanh vi ((su viet) or (su triet))*.