Perhaps you should try some spelling variations:
khong thong » khong trong, thong thuong, phong chong
trung tuan » trung thanh, trung tam, tran tuan
hieu lang » chieu sang, hieu quang, nhieu tang
trung cua » truong cua, trung cap, dung cua
doi hieu » doi chieu, doc hieu, doi hien
dan phan » doan phan, dan chan, van phan
phan cau » phan dau, phan cac, phan tu

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: doi hieu lang - thanh ((trung cua) OR (trung tuan)) ((khong thong) OR (thong thong)) dan phan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi hieu lang - thanh ((trung cua) OR (trung tuan)) ((khong thong) or (thong thong)) dan phan cau~".
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - thanh ((trung cua) OR (trung tuan)) ((khong thong) or (thong thong)) dan phan cau*.