Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
nang cho » nang chon, ngang cho, nang cao
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
cho hoc » co hoc, khoa hoc
hieu ve » hieu va, hieu van
cua cau » cua cac, cua chu, cua cay
xu van » vu van, su van
tu van » tu va
vi cua » vai 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: doc sach ty nang cho hoc. ((hieu ve) or (hieu qua)) chao ((xu van) OR (tu van)) hanh vi cua cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty nang cho hoc. ((hieu ve) OR (hieu qua)) chao ((xu van) OR (tu van)) hanh vi cua cau*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ty nang cho hoc. ((hieu ve) or (hieu qua)) chao ((xu van) OR (tu van)) hanh vi cua cau*".