Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
duc toan » duc tan, duc ton, duc thang
duc hoan » duc hoang, duc hoa, duc thuan
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, va cam
anh vi » hanh vi, anh va, anh ve
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: ((thuat sach) or (thu hoach)) ky nang xa hoi. hieu ve cam ((duc toan) OR (duc hoan)) anh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuat sach) OR (thu hoach)) ky nang xa hoi. hieu ve cam ((duc toan) OR (duc hoan)) anh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuat sach) or (thu hoach)) ky nang xa hoi. hieu ve cam ((duc toan) OR (duc hoan)) anh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thuat sach) or (thu hoach)) ky nang xa hoi. hieu ve cam ((duc toan) OR (duc hoan)) anh vi cua tre*.