Perhaps you should try some spelling variations:
hien sach » kien sach, thien hach, chieu sach
dien sach » dien anh
dung cong » dung trong
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap
mang va » mang vua, bang va, dang va

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 ((mang va) or (hang va)) dung cong dan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien sach) OR (dien sach)) - hanh ((mang va) OR (hang va)) dung cong dan toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hien sach) OR (dien sach)) - hanh ((mang va) or (hang va)) dung cong dan toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((hien sach) OR (dien sach)) - hanh ((mang va) or (hang va)) dung cong dan toan cao*.