Perhaps you should try some spelling variations:
thuat thuc » thuat thuy, thuyet thuc, thuat tu
thuc thuc » hoc thuc
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
anh dai » vanh dai, anh bai, anh dat
van anh » van thanh, tuan anh, van minh
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet

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 y ((nang xa) or (dang xay)) hoi. hieu va ((thuat thuc) OR (thuc thuc)) van anh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((nang xa) OR (dang xay)) hoi. hieu va ((thuat thuc) OR (thuc thuc)) van anh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y ((nang xa) or (dang xay)) hoi. hieu va ((thuat thuc) OR (thuc thuc)) van anh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach y ((nang xa) or (dang xay)) hoi. hieu va ((thuat thuc) OR (thuc thuc)) van anh dai cua tre*.