全文获取类型
收费全文 | 338篇 |
免费 | 26篇 |
国内免费 | 1篇 |
专业分类
林业 | 12篇 |
农学 | 2篇 |
44篇 | |
综合类 | 77篇 |
农作物 | 10篇 |
水产渔业 | 12篇 |
畜牧兽医 | 199篇 |
植物保护 | 9篇 |
出版年
2021年 | 16篇 |
2020年 | 4篇 |
2019年 | 11篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 11篇 |
2012年 | 22篇 |
2011年 | 13篇 |
2010年 | 16篇 |
2009年 | 8篇 |
2008年 | 10篇 |
2007年 | 12篇 |
2006年 | 15篇 |
2005年 | 16篇 |
2004年 | 20篇 |
2003年 | 8篇 |
2002年 | 11篇 |
2001年 | 12篇 |
2000年 | 14篇 |
1999年 | 10篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 7篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1974年 | 4篇 |
1970年 | 3篇 |
1969年 | 16篇 |
1968年 | 3篇 |
1937年 | 2篇 |
1935年 | 1篇 |
1932年 | 1篇 |
1928年 | 1篇 |
1914年 | 2篇 |
排序方式: 共有365条查询结果,搜索用时 531 毫秒
361.
The removal of atmospheric effects from Nimbus-7 Coastal Zone Color Scanner (CZCS) images reveals eddy-like ocean turbidity patterns not apparent in the original calibrated images. Comparisons of the phytoplankton pigment concentrations derived from the corrected CZCS radiances with surface measurements agree to within less than 0.5 log C, where C is the sum of the concentrations of chlorophyll a plus phaeopigments a (in milligrams per cubic meter). 相似文献
362.
Coleman JR Papamichail D Skiena S Futcher B Wimmer E Mueller S 《Science (New York, N.Y.)》2008,320(5884):1784-1787
As a result of the redundancy of the genetic code, adjacent pairs of amino acids can be encoded by as many as 36 different pairs of synonymous codons. A species-specific "codon pair bias" provides that some synonymous codon pairs are used more or less frequently than statistically predicted. We synthesized de novo large DNA molecules using hundreds of over-or underrepresented synonymous codon pairs to encode the poliovirus capsid protein. Underrepresented codon pairs caused decreased rates of protein translation, and polioviruses containing such amino acid-independent changes were attenuated in mice. Polioviruses thus customized were used to immunize mice and provided protective immunity after challenge. This "death by a thousand cuts" strategy could be generally applicable to attenuating many kinds of viruses. 相似文献
363.
Activation of endothelial cell protease activated receptor 1 by the protein C pathway 总被引:1,自引:0,他引:1
The coagulant and inflammatory exacerbation in sepsis is counterbalanced by the protective protein C (PC) pathway. Activated PC (APC) was shown to use the endothelial cell PC receptor (EPCR) as a coreceptor for cleavage of protease activated receptor 1 (PAR1) on endothelial cells. Gene profiling demonstrated that PAR1 signaling could account for all APC-induced protective genes, including the immunomodulatory monocyte chemoattractant protein-1 (MCP-1), which was selectively induced by activation of PAR1, but not PAR2. Thus, the prototypical thrombin receptor is the target for EPCR-dependent APC signaling, suggesting a role for this receptor cascade in protection from sepsis. 相似文献
364.
Stefan H. Witte Abayomi K. Olaifa Andrew J. Lewis Randy B. Eggleston Jaroslava Halper Manfred Kietzmann Wolfgang Baeumer P.O. Eric Mueller 《Journal of Equine Veterinary Science》2009
The objective of this study was to evaluate the efficacy of topical application of a hyaluronan (HA) derivative in wound healing with respect to the rate of epithelialization, fibroplasia, angiogenesis and contraction, magnitude of the local inflammatory response, local expression of transforming growth factor-β 1 and 3 (TGF-β 1 and 3), tumor necrosis factor-α (TNF-α), and collagen type III deposition. In six healthy adult horses, six full-thickness skin wounds were created on the dorsal aspect of both metacarpi using a sterile template. Sites were sampled at 0, 1, 2, 5, 14, 21, and 35 days following wounding. Wounds on one limb were dressed with commercially available esterified HA fleece under a nonadherent dressing. The opposite limb was covered with the nonadherent dressing alone (control). Images of the most proximal wounds were used to determine the area of total healing and the relative contributions of epithelialization and contraction to healing. At each sample time, a control and treatment biopsy were taken for histological evaluation and special stains. All samples were evaluated for degree of inflammation, fibroplasia and angiogenesis; in situ hybridization for type III collagen, TGFβ1 and 3, and immunohistochemistry for TNF-α. Mean percentages of total wound healing, epithelialization, and wound contraction were not significantly different between control and treatment groups. In treated horses, initial wound expansion was significantly decreased during the first 2 weeks. Mononuclear cell numbers, counted in the granulation tissue, increased in both control and treated limbs over the entire course of the study. However at day 35 the macrophage numbers counted in the treated horses were significantly increased compared with the control limbs (P < .05). Although not statistically significant, relative staining for type III collagen in the treated wounds was less than that of control wounds. Results of the present study do not support a benefit of an exogenous HA-derivative in the healing of distal limb wounds in horses. The shortcomings of the study design are discussed. 相似文献
365.
Lenise Freitas Mueller Júlio Csar Carvalho Balieiro Adrielle Matias Ferrinho Taiane da Silva Martins Rosana Ruegger Pereira da Silva Corte Tamyres Rodrigues de Amorim Joyce de Jesus Mangini Furlan Fernando Baldi Anglica Simone Cravo Pereira 《Animal Science Journal》2019,90(8):1078-1089
The study evaluated the effect of gender status on carcass and meat quality of feedlot Angus × Nellore cattle. A total of 176 cattle, 20 months old, were confined for 190‐days and assigned to four treatments: bulls, immunocastrated, steers, and heifers. Bulls had greater rib eye area and HCW (p = 0.0001). Heifers had increased fat thickness (p = 0.0001). Steers and heifers had higher marbling scores (p = 0.0001). There was interaction between gender and aging time for Warner‐Bratzler Shear Force (p = 0.0002), L* (p = 0.0118), and b* (p = 0.0113) values of beef. The sensory panel results showed that beef from bulls had the lowest consumer overall acceptance (p = 0.0278). Especially, regardless tenderness, steers and immunocastrated beef were considered tender, independent of aging time. Beef produced by heifers, steers, and immunocastrated is considered to be of higher quality than bulls. Thus, it is may be an interesting alternative to produce high‐quality beef than bulls, to attend the consumer demand for high‐quality products. Additionally, the low fatty acids n6 levels and low n6:n3 ratio, high levels of CLA, MUFAs, and oleic acid suggests that the heifer meat is favorable for human health. 相似文献