Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
dang cac » dung cac, bang cac, dong cac
cac cau » cac mau, bac cau, ca cau
ca dang » cao dang, cua dang, cac dang
cam tuc » cam tu, nam thuc, dam thuc
su sach » so sach, vu sach
cao hoi » cau hoi, co hoi, cao hoc
te sach » toc sach

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 (te sach)) ky nang cao hoi. hieu van ((cam tuc) OR (cam xuc)) ca dang cac cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (te sach)) ky nang cao hoi. hieu van ((cam tuc) OR (cam xuc)) ca dang cac cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (te sach)) ky nang cao hoi. hieu van ((cam tuc) OR (cam xuc)) ca dang cac cau tren".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (te sach)) ky nang cao hoi. hieu van ((cam tuc) OR (cam xuc)) ca dang cac cau tren*.