Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
duc van » duc va, duc tan, duc manh
cam duc » cam xuc, cao duc, pham duc
hieu ve » hieu va, hieu van
su hien » su kien, su tien, thu hien
nang xa » lang xa, nang ma, mang xa
su sach » so sach, vu sach
ve cam » ve cham, ve cac, va cam
vi su » va su, ve su, ki su

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (su sach)) ty ((nang xa) or (nang x)) hoi. hieu ve cam duc van hanh vi su hien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (su sach)) ty ((nang xa) OR (nang x)) hoi. hieu ve cam duc van hanh vi su hien.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (su sach)) ty ((nang xa) or (nang x)) hoi. hieu ve cam duc van hanh vi su hien*.