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

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 van anh dai ((cua tre) OR (cuu 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 van anh dai ((cua tre) OR (cuu 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 van anh dai ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: toc sach y ((nang xa) or (dang xay)) hoi. hieu va thuat thuc van anh dai ((cua tre) OR (cuu tre))*.