未知题型 In a push-pull strategy, some stages of the supply chain, typically the initial stages are operated in a push-based manner, while the remaining stages employ a pull-based strategy. The interface between the push-based stages and the pull-based stages is known as the .

未知题型 猪适于驯化的特点：杂食、体格适中、产肉和产仔能力强（）

未知题型 光学显微镜成像质量好坏的最重要指标是其放大倍数。