Perhaps you should try some spelling variations:
van quang » van quan, tran quang, van tuan
van nang » van ban, van dong, van dung
dau ngoc » dau nuoc, dang ngoc, doan ngoc
dao xuan » do xuan, ngo xuan, dao van
van hanh » van thanh, ban hanh, van anh
vu sach » vu bach, su sach, vu khach
hieu va » lieu va, hieu qua
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: vu sach ((van nang) OR (van quang)) xa hoi. hieu va ((dau ngoc) or (dao xuan)) van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ((van nang) OR (van quang)) xa hoi. hieu va ((dau ngoc) OR (dao xuan)) van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ((van nang) OR (van quang)) xa hoi. hieu va ((dau ngoc) or (dao xuan)) van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach ((van nang) OR (van quang)) xa hoi. hieu va ((dau ngoc) or (dao xuan)) van hanh vi cua tre*.