这种书需要量很大.There is a great demand for such books.输血的需要量应根据血球压积来确定.The blood requirements should be determined by the hematocrit.电视机和立体声音响设备现在的需要量很大.Television sets and stereo sound sets are now in great demand....

“需要量”的英语可以翻译为：[医] requisite amount ...