Perhaps you should try some spelling variations:
trinh thiet » trinh viet, trinh thi
hanh trinh » canh tranh, hanh chinh
khach trai » khac trai, khanh tra, kham trai
nghiem ban » nghiem van, nghiem xuan, nghiep bang
sach trai » sach tai, sach tranh, sach tham
hoc hanh » hoc nhanh, hoc thanh, hoc anh
thiet d » thiet de, thiet ke, thiet bi
ban hoc » bang hoc, van hoc, bai hoc
d hoc » du hoc, ad hoc, de hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( hoc hanh trinh thiet d hoc ) or ( te ((sach trai) or (khach trai)) nghiem ban hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( hoc hanh trinh thiet d hoc ) OR ( te ((sach trai) OR (khach trai)) nghiem ban hoc )).
• Adding a wildcard symbol may retrieve word variants: (( hoc hanh trinh thiet d hoc ) or ( te ((sach trai) or (khach trai)) nghiem ban hoc ))*.