Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
dang xay » dang van, van xay
nam thuc » nam thuoc, am thuc, nam thu
cau treo » cau theo, cau tren, cau triet
doc sach » hoc sach, nuoc sach, dac sac
ky dang » ky nang, ky danh
xay hoi » xa hoi, tay hoi, cay phoi
dan vai » dan va, dan tai, den vai
dan vat » dang vat, van vat, dan va
hieu va » lieu va, hieu qua
va nam » van nam, ha nam, va nay

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) or (doc sach)) ky dang xay hoi. hieu va nam thuc vat ((dan vai) or (dan vat)) cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky dang xay hoi. hieu va nam thuc vat ((dan vai) OR (dan vat)) cau treo.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) ky dang xay hoi. hieu va nam thuc vat ((dan vai) or (dan vat)) cau treo*.