要素密集度 meaning in English

factor intensity

But after world war ii . especially in the recent 30 years , intra - industry trade which means the mutual trade of same kind products between developed countries flourished . furthermore , the trend that intra - industry trade would replace inter - industry trade and become the mainstream of world trade can be seen , which could not be explained by traditional trade theory
但二战以后特别是20世纪70年代以来，发达国家间这种要素密集度相似的货物的双向贸易? ?产业内贸易的发展非常迅速，有取代产业间贸易而成为世界贸易主流的趋势，这显然是传统的国际贸易理论不能解释的了。