Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
hanh trinh » canh tranh, hanh chinh
nhung cong » dung cong, thong cong, hang cong
hien sach » dien sach, kien sach, chieu sach
tran gian » tran giang, tran gia, trang giai
trinh va » trinh van, trinh vat, trinh ve
tan gian » dan gian, van gian, tan giao

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 (thien hach)) - hanh trinh va nhung cong ((tan gian) OR (tran gian)) cac~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien sach) OR (thien hach)) - hanh trinh va nhung cong ((tan gian) OR (tran gian)) cac.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hien sach) or (thien hach)) - hanh trinh va nhung cong ((tan gian) OR (tran gian)) cac".
• Adding a wildcard symbol may retrieve word variants: hoc ((hien sach) or (thien hach)) - hanh trinh va nhung cong ((tan gian) OR (tran gian)) cac*.