Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
thiet bang » thien bang, khien bang, thep bang
nhiet nang » nhiet dong, viet nang, nhieu tang
hien sach » kien sach, thien hach, chieu sach
dien sach » dien anh
cong van » cong vang, cong san, song van
van bang » van ban, van nang, von bang
bang cac » nang cao, hang ca, dung cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hien sach) OR (dien sach)) - hanh trinh ((thiet bang) or (nhiet nang)) cong van bang cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien sach) OR (dien sach)) - hanh trinh ((thiet bang) OR (nhiet nang)) cong van bang cac.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hien sach) OR (dien sach)) - hanh trinh ((thiet bang) or (nhiet nang)) cong van bang cac".
• Adding a wildcard symbol may retrieve word variants: hoc ((hien sach) OR (dien sach)) - hanh trinh ((thiet bang) or (nhiet nang)) cong van bang cac*.