Perhaps you should try some spelling variations:
dang hanh » dang thanh, ban hanh, dang van
thuc dang » thuoc dang, thuc dan, thuc dung
vu khach » vu khanh, vu khac, vay khach
thu sach » tu sach, thuat sach, thuoc sach
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
va nam » ha nam, va nay
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu khach) or (thu sach)) ky nang xa hoi. lieu ((va nam) OR (van nam)) thuc dang hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu khach) OR (thu sach)) ky nang xa hoi. lieu ((va nam) OR (van nam)) thuc dang hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu khach) or (thu sach)) ky nang xa hoi. lieu ((va nam) OR (van nam)) thuc dang hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu khach) or (thu sach)) ky nang xa hoi. lieu ((va nam) OR (van nam)) thuc dang hanh vi cua tre*.