loai vdi r a t n h i e u he qua ma hien nay,
chiing ta chxla the n h a n thiic va t h a u hieu
het. Co le cuoc khiing h o a n g toan cau ma c h u n g ta d a n g chilng kien hien nay chi la mot t r o n g n h i e u bieu hien ciia sii xung dot giiia kinh te tri thiic d a n g hinh t h a[r]