Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
nam thuc » nam thuoc, am thuc, nam thu
hoc sach » hoc sinh, hoc cac, hoc anh
dinh tai » dinh toai, dinh tri, dinh thi
tai cua » thai cua, tai cuc, tri cua
ky dang » ky nang, ky danh
va dinh » van dinh, va kinh, va tinh
thuc va » thuc vat, thuc dan, thuc day
qua nam » quan nam, cua nam, quang nam
ky anh » ky danh, ly anh, ty anh
cua te » cua tu

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 dang) or (ky anh)) xa hoi. hieu qua nam thuc va dinh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) ((ky dang) OR (ky anh)) xa hoi. hieu qua nam thuc va dinh tai cua te.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) ((ky dang) or (ky anh)) xa hoi. hieu qua nam thuc va dinh tai cua te*.