Perhaps you should try some spelling variations:
sach tranh » canh tranh
quang dung » quang trung, ung dung, cuong dung
giai thuat » giai thoai, giai khat
theo hieu » theo chieu, theo tieu, thien hieu
hieu lang » chieu sang, hieu quang, nhieu tang
cach manh » cach mang, cach nhanh, sach danh
dung cong » dung trong
gian thua » gian cua, gian ha, gian phu
cong tan » cong tac, cong san, cong thanh

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo hieu lang - ((cach manh) or (sach tranh)) quang dung cong tan ((gian thua) OR (giai thuat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo hieu lang - ((cach manh) OR (sach tranh)) quang dung cong tan ((gian thua) OR (giai thuat)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo hieu lang - ((cach manh) or (sach tranh)) quang dung cong tan ((gian thua) OR (giai thuat))".
• Adding a wildcard symbol may retrieve word variants: theo hieu lang - ((cach manh) or (sach tranh)) quang dung cong tan ((gian thua) OR (giai thuat))*.