Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
qua cac » cua cac
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
truc va » thuc va, thuc vat, trung va
su sach » so sach, vu sach
qua cau » quan cau, qua ca, qua cai
ky dang » ky nang, ky danh
ky lang » ky nang, ky tang, tay lang
va cau » van cau, va cac, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((ky lang) OR (ky dang)) xa hoi. hieu ((qua cau) or (qua cac)) truc va hanh va cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky lang) OR (ky dang)) xa hoi. hieu ((qua cau) OR (qua cac)) truc va hanh va cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky lang) OR (ky dang)) xa hoi. hieu ((qua cau) or (qua cac)) truc va hanh va cau tren".
• Adding a wildcard symbol may retrieve word variants: su sach ((ky lang) OR (ky dang)) xa hoi. hieu ((qua cau) or (qua cac)) truc va hanh va cau tren*.