Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
sach cay » sach cap, sach hay, sach nay
cay mang » cach mang, cay mac, cay cong
van hanh » ban hanh, van anh, van ban
dau tren » dau tien, dat tren, dau tieng
tu sach » thu sach, su sach, te sach
mang xa » lang xa, mang may, dang xay
hieu va » lieu va, hieu qua
vi dau » vi dai, va dau, bi dau

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach cay mang xa hoi. hieu va ((chao xu) OR (cau truc)) ((van hanh) OR (van thanh)) vi dau tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach cay mang xa hoi. hieu va ((chao xu) or (cau truc)) ((van hanh) OR (van thanh)) vi dau tren~".
• Adding a wildcard symbol may retrieve word variants: tu sach cay mang xa hoi. hieu va ((chao xu) or (cau truc)) ((van hanh) OR (van thanh)) vi dau tren*.