全文获取类型
收费全文 | 1923733篇 |
免费 | 194322篇 |
国内免费 | 1847篇 |
出版年
2018年 | 20225篇 |
2017年 | 19034篇 |
2016年 | 30217篇 |
2015年 | 44266篇 |
2014年 | 52517篇 |
2013年 | 78807篇 |
2012年 | 57867篇 |
2011年 | 50955篇 |
2010年 | 50647篇 |
2009年 | 49739篇 |
2008年 | 46479篇 |
2007年 | 46085篇 |
2006年 | 47391篇 |
2005年 | 47912篇 |
2004年 | 47107篇 |
2003年 | 44214篇 |
2002年 | 41898篇 |
2001年 | 66715篇 |
2000年 | 65087篇 |
1999年 | 55453篇 |
1998年 | 28348篇 |
1997年 | 28262篇 |
1996年 | 27041篇 |
1995年 | 26590篇 |
1994年 | 26143篇 |
1993年 | 25688篇 |
1992年 | 47659篇 |
1991年 | 45843篇 |
1990年 | 44484篇 |
1989年 | 44456篇 |
1988年 | 41075篇 |
1987年 | 39268篇 |
1986年 | 36856篇 |
1985年 | 38181篇 |
1984年 | 34342篇 |
1983年 | 29865篇 |
1982年 | 26704篇 |
1981年 | 25000篇 |
1980年 | 23370篇 |
1979年 | 31087篇 |
1978年 | 26542篇 |
1977年 | 24763篇 |
1976年 | 23381篇 |
1975年 | 24258篇 |
1974年 | 25740篇 |
1973年 | 25832篇 |
1972年 | 22628篇 |
1971年 | 20845篇 |
1970年 | 18184篇 |
1969年 | 17686篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
992.
993.
994.
995.
996.
The Invisibility of Disability: Using Dance to Shake from Bioethics the Idea of ‘Broken Bodies’ 下载免费PDF全文
Shawn H.E. Harmon 《Bioethics》2015,29(7):488-498
Complex social and ethical problems are often most effectively solved by engaging them at the messy and uncomfortable intersections of disciplines and practices, a notion that grounds the InVisible Difference project, which seeks to extend thinking and alter practice around the making, status, ownership, and value of work by contemporary dance choreographers by examining choreographic work through the lenses of law, bioethics, dance scholarship, and the practice of dance by differently‐abled dancers. This article offers a critical thesis on how bioethics has come to occupy a marginal and marginalizing role in questions about the differently‐abled body. In doing so, it has rendered the disabled community largely invisible to and in bioethics. It then defends the claim that bioethics – as a social undertaking pursued collaboratively by individuals from different disciplines – must take much better notice of the body and the embodied individual if it is to better achieve its ends, which include constructing a moral and just society. Finally, this article considers how the arts, and specifically dance (and here dance by differently‐abled dancers), provides us with rich evidence about the body and our ability to respond positively to normally ‘othered’ bodies. It concludes that greater attention to empirical evidence like that being generated in InVisible Difference will help to expand the reach and significance of bioethics, and thereby its relevance to (and consciousness of) important questions about the status of bodies and bodily differences, which must be considered as central to its ambitions. 相似文献
997.
C. A. Kreikemeier T. B. Engle K. L. Lucot S. D. Kachman T. E. Burkey D. C. Ciobanu 《Animal genetics》2015,46(2):205-208
Tumor necrosis factor alpha (TNF‐α) is a pro‐inflammatory cytokine with a role in activating adaptive immunity to viral infections. By inhibiting the capacity of plasmacytoid dendritic cells to produce interferon‐α and TNF‐α, porcine circovirus 2 (PCV2) limits the maturation of myeloid dendritic cells and impairs their ability to recognize viral and bacterial antigens. Previously, we reported QTL for viremia and immune response in PCV2‐infected pigs. In this study, we analyzed phenotypic and genetic relationships between TNF‐α protein levels, a potential indicator of predisposition to PCV2 co‐infection, and PCV2 susceptibility. Following experimental challenge with PCV2b, TNF‐α reached the peak at 21 days post‐infection (dpi), at which time a difference was observed between pigs that expressed extreme variation in viremia and growth (P < 0.10). A genome‐wide association study (n = 297) revealed that genotypes of 56 433 SNPs explained 73.9% of the variation in TNF‐α at 21 dpi. Major SNPs were identified on SSC8, SSC10 and SSC14. Haplotypes based on SNPs from a SSC8 (9 Mb) 1‐Mb window were associated with variation in TNF‐α (P < 0.02), IgG (P = 0.05) and IgM (P < 0.13) levels at 21 dpi. Potential overlap of regulatory mechanisms was supported by the correlations between genomic prediction values of TNF‐α and PCV2 antibodies (21 dpi, r > 0.22), viremia (14–21 dpi, P > 0.29) and viral load (r = 0.31, P < 0.0001). Characterization of the QTL regions uncovered genes that could influence variation in TNF‐α levels as well as T‐ and B‐cell development, which can affect disease susceptibility. 相似文献
998.
999.
1000.
Nutrients are assimilated efficiently by Lymantria dispar caterpillars from the mature leaves of trees in the Salicaceae 下载免费PDF全文
Raymond V. Barbehenn Jennifer Knister Frank Marsik Chelsea Jahant‐Miller William Nham 《Physiological Entomology》2015,40(1):72-81
The efficient aquisition of nutrients from leaves by insect herbivores increases their nutrient assimilation rates and overall fitness. Caterpillars of the gypsy moth (Lymantria dispar L.) have high protein assimilation efficiencies (PAE) from the immature leaves of trees such as red oak (Quercus rubra) and sugar maple (Acer saccharum) (71–81%) but significantly lower PAE from their mature leaves (45–52%). By contrast to this pattern, both PAE and carbohydrate assimilation efficiencies (CAE) remain high for L. dispar larvae on the mature leaves of poplar (Populus alba × Populus tremula) grown in greenhouse conditions. The present study tests two alternative hypotheses: (i) outdoor environmental stresses cause decreased nutrient assimilation efficiencies from mature poplar leaves and (ii) nutrients in the mature leaves of trees in the poplar family (Salicaceae) remain readily available for L. dispar larvae. When poplar trees are grown in ambient outdoor conditions, PAE and CAE remain high (approximately 75% and 78%, respectively) in L. dispar larvae, in contrast to the first hypothesis. When larvae feed on the mature leaves of species in the Salicaceae [aspen (Populus tremuloides), cottonwood (Populus deltoides), willow (Salix nigra) and poplar], PAE and CAE also remain high (68–76% and 72–92%, respectively), consistent with the second hypothesis. Larval growth rates are strongly associated with protein assimilation rates, and more strongly associated with protein assimilation rates than with carbohydrate assimilation rates. It is concluded that tree species in the Salicaceae are relatively high‐quality host plants for L. dispar larvae, in part, because nutrients in their mature leaves remain readily available. 相似文献