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
nang cho » nang chon, ngang cho, nang cao
vuc van » duc van, luc van, thuc van
cac vuc » cac nuoc, cac vung, cac cuoc
vai cua » dai cua, hai cua, lai cua
sach ty » sach y, sach tu, sach thu
hieu ve » hieu va
cho hoc » co hoc, khoa hoc
ty nang » ky nang, ty xang, ty hang
vi cua » di 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 ty nang cho hoc. ((hieu ve) or (hieu van)) cac vuc van hanh ((vi cua) OR (vai cua)) cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang cho hoc. ((hieu ve) OR (hieu van)) cac vuc van hanh ((vi cua) OR (vai cua)) cac*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty nang cho hoc. ((hieu ve) or (hieu van)) cac vuc van hanh ((vi cua) OR (vai cua)) cac*".