Perhaps you should try some spelling variations:
hanh dong » anh dong, ha dong
toc sach » hoc sach, thuoc sach, nuoc sach
dong cua » dung cua, cong cua, huong cua
doc sach » hoc sach, nuoc sach, dac sac
day hanh » day nhanh, day thanh, dao hanh
thuc day » thuc dan, thuc vat
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
ky tang » ky nang, ky dang, kho tang
ky lang » ky nang, ky dang, tay lang
cua tre » cua te, cuu tre, cua triet

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)) ((ky lang) OR (ky tang)) xa hoi. hieu van nam thuc day hanh dong cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ((ky lang) OR (ky tang)) xa hoi. hieu van nam thuc day hanh dong cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) ((ky lang) OR (ky tang)) xa hoi. hieu van nam thuc day hanh dong cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) ((ky lang) OR (ky tang)) xa hoi. hieu van nam thuc day hanh dong cua tre*.