Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
cao truc » cau truc, vao truc, cao thuoc
cau treo » cau theo, cau tren, cau triet
doc sach » hoc sach, nuoc sach, dac sac
vu nang » vuc nang, va nang, vu dang
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
truc va » thuc va, thuc vat, trung va
cua tre » cua te, cuu tre, cua triet
va dan » ca dan, va dao, va dau
dan di » danh di, dan da, dan de
va cao » va cac, va co, va dao

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 (doc sach)) vu nang xa hoi. hieu va cao truc va dan di ((cua tre) or (cau treo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) vu nang xa hoi. hieu va cao truc va dan di ((cua tre) OR (cau treo)).
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) vu nang xa hoi. hieu va cao truc va dan di ((cua tre) or (cau treo))*.