Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hieu cach » hieu cac, hieu ca, biet cach
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
duong van » duong va, luong va, dang van
van toan » van tuan, van tan, van thanh
toan cao » toan ban, toan tap
cua van » cua ban, cua dan, cua can

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chieu sach) or (hieu cach)) - hanh tinh ((cua van) or (cua vat)) duong van toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sach) OR (hieu cach)) - hanh tinh ((cua van) OR (cua vat)) duong van toan cao.
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sach) or (hieu cach)) - hanh tinh ((cua van) or (cua vat)) duong van toan cao*.