Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
nam thuc » nam thuoc, nam thu, nam tu
ky lang » ky dang, ky tang, tay lang
van hoi » van hoa, van hoc, van hoe
hieu va » lieu va, hieu qua
dan vai » dan va, dan tai, dan vat
vai cuu » vai cua
cuu tre » cua tre, cau tren, cau treo
va dan » ca dan, va dao, va dau

You may be able to get more results by adjusting your search query.

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