Perhaps you should try some spelling variations:
duong sach » duong manh
dua tren » dung tren
van hanh » van thanh, ban hanh, van anh
tuc van » thuc van, truc van, tuc va
cuu tre » cua tre, cau tren, cau treo
nang xa » nang x, lang xa, nang ma
y nang » ky nang, ly nang, v nang
ve cam » ve cham, va cam, ve cai
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: duong sach y nang xa hoi. hieu ((ve cam) OR (ve cac)) tuc van hanh vi ((dua tren) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: duong sach y nang xa hoi. hieu ((ve cam) OR (ve cac)) tuc van hanh vi ((dua tren) OR (cuu tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "duong sach y nang xa hoi. hieu ((ve cam) OR (ve cac)) tuc van hanh vi ((dua tren) or (cuu tre))*".