Perhaps you should try some spelling variations:
van quang » van quan, tran quang, van tuan
vien cac » vien bach, vien dai, vien da
van nang » van ban, van dong, van dung
dao hanh » dao thanh, dang hanh, ban hanh
thuc dao » thuc dan, thuc day, chuc dao
su sach » so sach, vu sach
va cao » va cac, va co, va dao
vi cua » vai cua, di cua
cua te » cua tu

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 ((van nang) OR (van quang)) xa hoi. hieu ((vien cac) or (va cao)) thuc dao hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((van nang) OR (van quang)) xa hoi. hieu ((vien cac) OR (va cao)) thuc dao hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((van nang) OR (van quang)) xa hoi. hieu ((vien cac) or (va cao)) thuc dao hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ((van nang) OR (van quang)) xa hoi. hieu ((vien cac) or (va cao)) thuc dao hanh vi cua te*.