Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » thien van, lieu va, hieu ve
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
hieu va » lieu va, hieu qua
duy van » duy vat, dung van
minh ve » dinh ve, minh va, kinh ve
cua tre » cua te, cuu tre, cua triet
du van » duc van, tu van, vu van
ve cua » le cua, de cua, te cua
x hoi » xa hoi, o hoi, x ho

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ty nang x hoi. ((hieu van) OR (hieu va)) hoc ((du van) or (duy van)) minh ve cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang x hoi. ((hieu van) OR (hieu va)) hoc ((du van) OR (duy van)) minh ve cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty nang x hoi. ((hieu van) OR (hieu va)) hoc ((du van) or (duy van)) minh ve cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang x hoi. ((hieu van) OR (hieu va)) hoc ((du van) or (duy van)) minh ve cua tre*.