Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
kham soc » kham cuoc, ham so, khac son
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
hieu vu » hieu va, hieu ve, hieu su
nang xa » nang x, lang xa, nang ma
lang ha » long ha
cua tre » cua te, cuu tre, cua triet
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: so sach ty ((nang xa) or (lang ha)) hoi. hieu vu ((kham soc) OR (cham soc)) van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty ((nang xa) OR (lang ha)) hoi. hieu vu ((kham soc) OR (cham soc)) van hanh vi cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty ((nang xa) or (lang ha)) hoi. hieu vu ((kham soc) OR (cham soc)) van hanh vi cua tre*".