Perhaps you should try some spelling variations:
thanh lap » thanh san, phan lap, thanh hai
dau tren » dau tien, dat tren, dau tieng
cau tren » cu tren, ca tren, cau treo
hieu ve » hieu va, hieu van
ve chat » va chat, van chat
sach ky » sac ky, sach y, sach ty
dang ma » dang mau, dang mam, dang mat
ky dang » ky nang, ky danh
tu sach » thu sach, su sach, te sach
doc va » duoc va, hoc va, loc va
ma hoi » mai hoi, xa hoi, ma hoa

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 ky dang ma hoi. hieu ve chat ((doc va) OR (duc va)) thanh lap ((cau tren) OR (dau tren))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang ma hoi. hieu ve chat ((doc va) or (duc va)) thanh lap ((cau tren) OR (dau tren))~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ma hoi. hieu ve chat ((doc va) or (duc va)) thanh lap ((cau tren) OR (dau tren))*.