Perhaps you should try some spelling variations:
thieu sach » thien hach, hieu cach, theo sach
chieu sach » chinh sach, chiet tach, chieu sang
nhung cong » thong cong, hang cong, nhung don
hanh tram » hanh tam, hanh trang, thanh tran
dung cong » dung trong
manh toan » thanh toan, anh tuan, tinh toan
tram van » tran van, tam van, trang van
toan cao » toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu sach) OR (chieu sach)) - hanh tram van ((nhung cong) or (dung cong)) manh toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sach) OR (chieu sach)) - hanh tram van ((nhung cong) OR (dung cong)) manh toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sach) OR (chieu sach)) - hanh tram van ((nhung cong) or (dung cong)) manh toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sach) OR (chieu sach)) - hanh tram van ((nhung cong) or (dung cong)) manh toan cao*.