Perhaps you should try some spelling variations:
va trinh » van trinh, va tinh, lap trinh
trinh vu » trinh va, trinh ve, trinh vi
nang xa » nang x, lang xa, nang ma
qua nam » quan nam, cua nam, quang nam
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky
nam tu » nam thu, nam thuc
vu cua » hu cua, tu cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sac ky) or (sai ky)) nang xa hoi. hieu qua nam tu va trinh vu cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (sai ky)) nang xa hoi. hieu qua nam tu va trinh vu cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) or (sai ky)) nang xa hoi. hieu qua nam tu va trinh vu cua tre*.