Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
toan cau » toan cao, toan ban, toan tap
van chat » cao chat
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
duc van » duc va, duc tan, duc manh
vi va » vi van, vai va, vu va
su va » su van, tu va

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky nang xa hoi. hieu ((toan cau) or (van chat)) duc van hanh ((vi va) or (su va)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xa hoi. hieu ((toan cau) OR (van chat)) duc van hanh ((vi va) OR (su va)) triet.
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. hieu ((toan cau) or (van chat)) duc van hanh ((vi va) or (su va)) triet*.