Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hanh trung » thanh trung, hanh trang, manh trung
hieu lang » chieu sang, hieu quang, nhieu tang
trung cua » truong cua, trung tuan, trung cap
cua nhung » va nhung
hoc hieu » hoc thieu, hoc hien, doc hieu
tap toan » bai toan
tap quan » tac quan, hai quan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu lang - hanh trung cua nhung cong ((tap toan) or (((tap doan) OR (tap quan)))) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - hanh trung cua nhung cong ((tap toan) OR (((tap doan) OR (tap quan)))) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu lang - hanh trung cua nhung cong ((tap toan) or (((tap doan) OR (tap quan)))) cao".
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - hanh trung cua nhung cong ((tap toan) or (((tap doan) OR (tap quan)))) cao*.