Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
lanh manh » lanh tranh, lan anh, van manh
hieu luch » hieu luat, hieu cach, hieu tuc
cua nhung » va nhung
cong tinh » cong trinh, cong vinh, long tinh
hieu luc » hieu luat, hieu qua
manh cua » doanh cua, ban cua
toan cao » toan tap
toan ban » van ban

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