Perhaps you should try some spelling variations:
nam thuoc » nam thu, nha thuoc, cay thuoc
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » am thuc, nam thu, nam tu
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
hieu va » lieu va, hieu qua
vat dan » va dan, van dan, vat ran
dan vai » dan va, dan tai, dan vat
vai cau » va cau, van cau, vai cac

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 (hoc sinh)) ky tang xa hoi. hieu va ((nam thuc) OR (nam thuoc)) vat dan vai cau tao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sinh)) ky tang xa hoi. hieu va ((nam thuc) OR (nam thuoc)) vat dan vai cau tao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (hoc sinh)) ky tang xa hoi. hieu va ((nam thuc) OR (nam thuoc)) vat dan vai cau tao".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sinh)) ky tang xa hoi. hieu va ((nam thuc) OR (nam thuoc)) vat dan vai cau tao*.