本文使用中國製造業廠商資料，並採取分量迴歸法探究研發活動、研發外溢與內銷外溢對內銷比例之影響。本文發現，傳統文獻之主張「研發創新活動有助於廠商出口 ( Posner, 1961; Vernon, 1966; Barrios et al., 2003)」的論點，並不適用於在中國的製造商；相反的，廠商提高研發密度有助於提升其內銷比例，且此研發效果隨著內銷傾向之提高而遞減。此外，本文亦發現，研發外溢效果與內銷外溢效果皆為正，但中資企業在低內銷傾向時所擷取之外溢效果較外資企業為大；反之，外資企業則在中、高內銷傾向時擷取較大之外溢效果。

This paper studies how firms’ R&D intensity and two types of spillovers, i.e. R&D spillovers and domestic sales spillovers, affect their domestic sales ratios (the proportion of goods sold domestically). By using survey data of manufacturing firms in China for the period 2001- 2006 and applying the quantile regression, we show that R&D intensity has a positive effect on the domestic sales ratio, and the effect declines as the quantile of the domestic sales ratio increases. This is in contrast to traditional wisdom, in which R&D intensity tends to increase export intensity (e.g. Posner, 1961; Vernon, 1966; Barrios et al., 2003). In addition, we show that R&D spillovers and domestic sales spillovers are positive for both local and foreign firms, but their effects vary with quantiles.