Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
nam thuc » nam thuoc, am thuc, nam thu
cau theo » cau thi, cau tao
hoc sach » hoc sinh, hoc cac, hoc anh
ky lang » ky nang, ky tang, tay lang
ky dang » ky nang, ky danh
hieu ha » hieu hoa, hieu va, hieu ca
thuc va » thuc vat, thuc dan, thuc day
dan tai » van tai, dan thi, han tai
tai cau » tai cac, tai cao
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 (hoc sach)) ((ky lang) or (ky dang)) xa hoi. hieu ha nam thuc va dan tai cau theo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) ((ky lang) OR (ky dang)) xa hoi. hieu ha nam thuc va dan tai cau theo.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) ((ky lang) or (ky dang)) xa hoi. hieu ha nam thuc va dan tai cau theo*.