Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
tu nano » truc nano
van cau » van dau, van hau, van chat
cau vuc » cau luc, cau truc, cau phuc
vuc van » duc van, luc van, thuc van
tu nang » tru nang, tu nong, tu lang
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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 nang) OR (tu nano)) co hoc. hieu van cau vuc van hanh ((vi cua) or (di cua)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((tu nang) OR (tu nano)) co hoc. hieu van cau vuc van hanh ((vi cua) OR (di cua)) cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((tu nang) OR (tu nano)) co hoc. hieu van cau vuc van hanh ((vi cua) or (di cua)) cau*".