Perhaps you should try some spelling variations:
thuoc sach » nuoc sach, thuat sach, thuoc sinh
toc sach » doc sach, nuoc sach, toc san
hoc sach » hoc sinh, hoc cac, hoc anh
nam thuc » nam thuoc, am thuc, nam thu
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
dan hai » doan hai, dang hai, dan khai
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
va nam » van nam, ha nam, va nay
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: ((toc sach) or (((thuoc sach) OR (hoc sach)))) ky nang xa hoi. hieu va nam thuc va dan hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (((thuoc sach) OR (hoc sach)))) ky nang xa hoi. hieu va nam thuc va dan hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (((thuoc sach) OR (hoc sach)))) ky nang xa hoi. hieu va nam thuc va dan hai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (((thuoc sach) OR (hoc sach)))) ky nang xa hoi. hieu va nam thuc va dan hai cua tre*.