Perhaps you should try some spelling variations:
tinh voi » trinh voi, tinh doi, binh voi
hieu van » thien van, lieu va, hieu ve
cau treo » cau theo, cau triet, cau trieu
cau tren » cu tren, dau tren, ca tren
te sach » toc sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
va tinh » may tinh

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: te sach ky nang x ho. ((hieu van) OR (hieu va)) cac duc va tinh voi ((cau treo) OR (cau tren))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang x ho. ((hieu van) OR (hieu va)) cac duc va tinh voi ((cau treo) or (cau tren))~".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang x ho. ((hieu van) OR (hieu va)) cac duc va tinh voi ((cau treo) or (cau tren))*.