Perhaps you should try some spelling variations:
manh tuong » manh tung, manh cuong, minh tuong
cong ngang » cong nhan, cong lang, cong nong
cong quang » luong quang, thong quang, duong quang
hoc hieu » hoc thieu, hoc hien, doc hieu
tuong va » truong va, thuong va, luong va
toan tai » toan tap, doanh tai, toan ban
toan cao » toan ban, toan tap
hieu va » lieu va, hieu qua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu va - manh tuong va nhung ((cong ngang) OR (cong quang)) ((toan tai) OR (toan cao))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu va - manh tuong va nhung ((cong ngang) OR (cong quang)) ((toan tai) or (toan cao))~".
• Adding a wildcard symbol may retrieve word variants: hoc hieu va - manh tuong va nhung ((cong ngang) OR (cong quang)) ((toan tai) or (toan cao))*.