Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, gian cac
van hanh » van thanh, ban hanh, van anh
vien da » vien dai, hien dai
sach ky » sach y, sach ty, sach kem
nang xa » nang x, lang xa, nang ma
sac ky » cac ky, sai ky
du van » duy van, duc van, tu van
vi cua » vai cua, di cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) or (sac ky)) nang xa hoi. hieu ((vien cac) or (vien da)) du van hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) nang xa hoi. hieu ((vien cac) OR (vien da)) du van hanh vi cua te.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) nang xa hoi. hieu ((vien cac) or (vien da)) du van hanh vi cua te*.