Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
cau theo » cau thi, cau tao
tu lang » cu lang, tu lanh, xu lang
van cam » van nam, van lam, van cau
xuc van » duc van, luc van, vuc van
vi cau » va cau, ve cau, di cau

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 ((tu lang) or (truc nano)) xa hoi. hieu van cam xuc van hanh vi cau theo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((tu lang) OR (truc nano)) xa hoi. hieu van cam xuc van hanh vi cau theo.
• Adding a wildcard symbol may retrieve word variants: toc sach ((tu lang) or (truc nano)) xa hoi. hieu van cam xuc van hanh vi cau theo*.