Perhaps you should try some spelling variations:
thong trong » thuong trong, thong thong, thong thuong
manh trung » manh tung, thanh trung, manh hung
trong vinh » trong kinh, trong sinh, trong linh
hieu luch » hieu luat, hieu cach, hieu tuc
trung cua » truong cua, trung tuan, trung cap
cua thong » cua thuong, cua khong, cua tong
vinh toan » tinh toan, hinh toan, minh toan
hieu luc » hieu luat, hieu qua
toan cao » toan ban, toan tap

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)) - manh trung cua thong trong vinh toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu luch) OR (hieu luc)) - manh trung cua thong trong vinh toan cao.
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu luch) or (hieu luc)) - manh trung cua thong trong vinh toan cao*.