Perhaps you should try some spelling variations:
cau treo » cau theo, cau tren, cau triet
toc sach » hoc sach, doc sach, thuoc sach
thuc dan » thuc hanh, hoc dan, thuc vat
vat cau » dat cau, va cau, van cau
dan vat » dang vat, van vat, dan va
thuc va » thuc vat, thuc day
toc sac » toc san, hoc sach, doc sach
hieu va » lieu va, hieu qua
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
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 sac) OR (toc sach)) ky tang xa hoi. hieu va nam ((thuc va) or (thuc dan)) dan vat cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sac) OR (toc sach)) ky tang xa hoi. hieu va nam ((thuc va) OR (thuc dan)) dan vat cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sac) OR (toc sach)) ky tang xa hoi. hieu va nam ((thuc va) or (thuc dan)) dan vat cau treo".
• Adding a wildcard symbol may retrieve word variants: ((toc sac) OR (toc sach)) ky tang xa hoi. hieu va nam ((thuc va) or (thuc dan)) dan vat cau treo*.