Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
chieu tinh » trieu tinh, lieu tinh, chau tinh
dang cong » dung cong
hoa chat » hop chat, hoa phan
chat lua » chat cua, chat va, chat huu
lua dang » cua dang, lua sang, luan nang
cong tac » cong ty
phi phi » phi thi, thi phi

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi ((chieu sach) or (chieu tinh)) - hoa chat lua dang cong tac ((phi phi) OR (chi phi))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((chieu sach) OR (chieu tinh)) - hoa chat lua dang cong tac ((phi phi) OR (chi phi)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi ((chieu sach) or (chieu tinh)) - hoa chat lua dang cong tac ((phi phi) OR (chi phi))".
• Adding a wildcard symbol may retrieve word variants: doi ((chieu sach) or (chieu tinh)) - hoa chat lua dang cong tac ((phi phi) OR (chi phi))*.