Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
su triet » su viet, su tien, ve triet
sach ty » sach y, sach tu, sach thu
sac ky » cac ky, sai ky
nam tu » nam thu, nam thuc
va dan » ca dan, va dao, va dau
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: vu ((sac ky) or (sach ty)) nang x ho. hieu van nam tu ((va thanh) or (va dan)) ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu ((sac ky) OR (sach ty)) nang x ho. hieu van nam tu ((va thanh) OR (va dan)) ki su triet.
• Adding a wildcard symbol may retrieve word variants: vu ((sac ky) or (sach ty)) nang x ho. hieu van nam tu ((va thanh) or (va dan)) ki su triet*.