Perhaps you should try some spelling variations:
trinh nghien » trinh nghe, kinh nghiem, trinh thiet
hanh trinh » canh tranh, hanh chinh
thi nghiem » thuc nghiem
nghien tin » nghiem tin, nghiem tinh, nghiem tien
nghiem ad » nghiem d, nghiem ban, nghiem lam
su sach » vu sach
so sach » so sanh, bo sach, co sach
vu hanh » vu khanh, vu thanh, du hanh
tin hoc » sinh hoc

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: (( ((su sach) OR (so sach)) thi nghiem ad hoc ) OR ( vu hanh trinh nghien tin hoc ))~.
• Adding a wildcard symbol may retrieve word variants: (( ((su sach) or (so sach)) thi nghiem ad hoc ) or ( vu hanh trinh nghien tin hoc ))*.