Perhaps you should try some spelling variations:
thieu sach » chieu sach, thien hach, hieu cach
dung cong » dung trong
cong thpt » cong thuc, cong thai, cong nhat
phan ung » phan xuong, phan cong
van dung » van dong, xay dung, tin dung
thpt dan » thuc dan, tho dan
dan chat » van chat, dan chan, ban chat

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc thieu sach - ((phan ung) or (phan tu)) van dung cong thpt dan chat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc thieu sach - ((phan ung) OR (phan tu)) van dung cong thpt dan chat*.