Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
dau tren » dau tien, dat tren, dau tieng
van hanh » ban hanh, van anh, van ban
su sach » so sach, vu sach
tang xa » trang xa, tang ma, lang xa
sach 7 » sach y, sach 2
ve cam » ve cham, va cam, ve cai
7 tang » 6 tang
vi dau » vi dai, va dau, bi dau
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: su sach 7 tang xa hoi. hieu ((ve cam) or (ve cac)) tuc ((van hanh) OR (van thanh)) vi dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach 7 tang xa hoi. hieu ((ve cam) OR (ve cac)) tuc ((van hanh) OR (van thanh)) vi dau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach 7 tang xa hoi. hieu ((ve cam) or (ve cac)) tuc ((van hanh) OR (van thanh)) vi dau tren".
• Adding a wildcard symbol may retrieve word variants: su sach 7 tang xa hoi. hieu ((ve cam) or (ve cac)) tuc ((van hanh) OR (van thanh)) vi dau tren*.