Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach ty, sach kem
van cau » van dau, van hau, van chat
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
su viet » so viet
cau tu » dau tu, cau truc
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu ((sach ky) or (sach y)) nang x hoi. hieu van cau tu ((va hanh) or (va danh)) va su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu ((sach ky) OR (sach y)) nang x hoi. hieu van cau tu ((va hanh) OR (va danh)) va su viet.
• Adding a wildcard symbol may retrieve word variants: vu ((sach ky) or (sach y)) nang x hoi. hieu van cau tu ((va hanh) or (va danh)) va su viet*.