Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
van cham » van chat, van tham, van pham
dat cua » dai cua, day cua, mat cua
va kinh » va tinh
va cham » va chat, va tham
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang

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