Perhaps you should try some spelling variations:
thieu sach » chieu sach, thien hach, theo sach
hieu cach » hieu cac, chieu sach, hieu ca
dung cong » dung trong
trang va » hang va
tran van » luan van
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cau » 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 (hieu cach)) - hanh ((trang va) OR (tran van)) dung cong dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sach) OR (hieu cach)) - hanh ((trang va) OR (tran van)) dung cong dan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sach) or (hieu cach)) - hanh ((trang va) OR (tran van)) dung cong dan toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sach) or (hieu cach)) - hanh ((trang va) OR (tran van)) dung cong dan toan cau*.