Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
thi van » thi lan, thi hanh, thi nang
nang xa » nang x, lang xa, nang ma
thuc va » thuc vat, thuc dan, thuc day
dinh cu » dinh cuu, dinh chuc, dinh chau
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
tuc va » truc va, tuc xa, duc va
cu cua » cau cua, ca cua, co cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach y nang xa hoi. ((thien van) or (thi van)) cham ((tuc va) OR (thuc va)) dinh cu cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach y nang xa hoi. ((thien van) OR (thi van)) cham ((tuc va) OR (thuc va)) dinh cu cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach y nang xa hoi. ((thien van) or (thi van)) cham ((tuc va) OR (thuc va)) dinh cu cua tre".
• Adding a wildcard symbol may retrieve word variants: doc sach y nang xa hoi. ((thien van) or (thi van)) cham ((tuc va) OR (thuc va)) dinh cu cua tre*.