烯空气跟空气十分近似.Olefin gas closely approximates air.所有的主要难点都涌现在烯酮 ( 1 ) 的合成中.All the chief difficulties crop up in the synthesis of the enone ( 1 ).某碳氢化合物已知可能是烯烃或是烷烃.A hydrocarbon was known to be either an alkene or alkane....
Taxonomic species are defined on phenetic discontinuities, not on interfertility.分类学上的种是根据表型不连续性而不是根据互交可孕性来确定的.A TAXONOMIC STUDY ON WHITEFLIES IN BEIJING ( HOMOPTERA: ALEYRODIDAE )北京地区粉虱分类研究 ( 同翅目: 粉虱科 )The temptation to...