Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
lang van » dang van, tang van, hoang van
thuc day » thuc dan
dan vai » dan tai, dan vat, den vai
sach ky » sac ky, sach y, sach ty
cuu tre » cua tre, cau tren, cau treo
hieu va » lieu va, hieu qua
van hoe » van hoa, van hoc, van hieu
ky lang » ky nang, ky dang, ky tang
va nam » van nam, ha nam, va nay
dan va » doan va, dan ca, ban va

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 ky lang van hoe. hieu va nam ((thuc vat) or (thuc day)) ((dan vai) OR (dan va)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky lang van hoe. hieu va nam ((thuc vat) OR (thuc day)) ((dan vai) OR (dan va)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky lang van hoe. hieu va nam ((thuc vat) or (thuc day)) ((dan vai) OR (dan va)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang van hoe. hieu va nam ((thuc vat) or (thuc day)) ((dan vai) OR (dan va)) cuu tre*.