Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
thu sach » tu sach, thuat sach, thuoc sach
hoc bang » hoc bong, hoc tang, hoc dan
dang xay » dang van, van xay
su sach » so sach, vu sach
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
lo ban » co ban, lo van, ly ban
vi cau » va cau, ve cau, di cau

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) or (thu sach)) ky dang xay hoi. hieu ve cam ((hoc bang) or (lo ban)) hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (thu sach)) ky dang xay hoi. hieu ve cam ((hoc bang) OR (lo ban)) hanh vi cau tren.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (thu sach)) ky dang xay hoi. hieu ve cam ((hoc bang) or (lo ban)) hanh vi cau tren*.