Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
ban hanh » ban hang
hieu van » hieu va, thien van, lieu va
tru nang » tra nang, tri nang, truc nano
cho hoc » co hoc, khoa hoc
van cau » van dau, van hau, van chat
cau vuc » cau luc, cau truc, cau phuc
vuc ban » vu ban, duc ban, cuc ban
tu nang » tu nong, tu nano, 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 (tru nang)) cho hoc. hieu van cau vuc ban 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 (tru nang)) cho hoc. hieu van cau vuc ban 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 (tru nang)) cho hoc. hieu van cau vuc ban hanh ((vi cua) or (di cua)) cau*".