全文获取类型
收费全文 | 389篇 |
免费 | 28篇 |
专业分类
林业 | 12篇 |
农学 | 6篇 |
基础科学 | 6篇 |
51篇 | |
综合类 | 43篇 |
农作物 | 9篇 |
水产渔业 | 34篇 |
畜牧兽医 | 208篇 |
园艺 | 26篇 |
植物保护 | 22篇 |
出版年
2023年 | 7篇 |
2022年 | 2篇 |
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 13篇 |
2017年 | 9篇 |
2016年 | 15篇 |
2015年 | 5篇 |
2014年 | 9篇 |
2013年 | 19篇 |
2012年 | 27篇 |
2011年 | 28篇 |
2010年 | 17篇 |
2009年 | 19篇 |
2008年 | 23篇 |
2007年 | 30篇 |
2006年 | 20篇 |
2005年 | 17篇 |
2004年 | 13篇 |
2003年 | 19篇 |
2002年 | 15篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1994年 | 3篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1987年 | 3篇 |
1984年 | 3篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1970年 | 3篇 |
1957年 | 1篇 |
1954年 | 1篇 |
1953年 | 1篇 |
1949年 | 1篇 |
1944年 | 1篇 |
1940年 | 1篇 |
1931年 | 1篇 |
1893年 | 1篇 |
排序方式: 共有417条查询结果,搜索用时 0 毫秒
1.
2.
How to perform transvenous electrical cardioversion in horses with atrial fibrillation 总被引:1,自引:1,他引:1
M. Kimberly J. McGurrin DVM Dipl ACVIM Peter W. Physick-Sheard BVSc MSc FRCVS Daniel G. Kenney DVM Dipl ACVIM 《Journal of Veterinary Cardiology》2005,7(2):109
Electrical cardioversion of atrial fibrillation is a well-established technique for restoration of sinus rhythm in humans. While transthoracic cardioversion is more commonly used, transvenous electrical cardioversion (TVEC) has been reported as having higher efficacy at substantially lower energy levels. In horses, treatment of atrial fibrillation has essentially been limited to the administration of quinidine salts either orally or intravenously. TVEC provides an alternative to quinidine salts, especially for those animals in which quinidine is neither effective nor tolerated. The present report details this technique in horses, discusses possible complications of the procedure, and provides guidance for successful outcome. Still and video images are used to illustrate details with regard to TVEC techniques in horses. Please view supplemental material for the videos. 相似文献
3.
Reece SY Hamel JA Sung K Jarvi TD Esswein AJ Pijpers JJ Nocera DG 《Science (New York, N.Y.)》2011,334(6056):645-648
We describe the development of solar water-splitting cells comprising earth-abundant elements that operate in near-neutral pH conditions, both with and without connecting wires. The cells consist of a triple junction, amorphous silicon photovoltaic interfaced to hydrogen- and oxygen-evolving catalysts made from an alloy of earth-abundant metals and a cobalt|borate catalyst, respectively. The devices described here carry out the solar-driven water-splitting reaction at efficiencies of 4.7% for a wired configuration and 2.5% for a wireless configuration when illuminated with 1 sun (100 milliwatts per square centimeter) of air mass 1.5 simulated sunlight. Fuel-forming catalysts interfaced with light-harvesting semiconductors afford a pathway to direct solar-to-fuels conversion that captures many of the basic functional elements of a leaf. 相似文献
4.
Mold JE Venkatasubrahmanyam S Burt TD Michaëlsson J Rivera JM Galkina SA Weinberg K Stoddart CA McCune JM 《Science (New York, N.Y.)》2010,330(6011):1695-1699
Although the mammalian immune system is generally thought to develop in a linear fashion, findings in avian and murine species argue instead for the developmentally ordered appearance (or "layering") of distinct hematopoietic stem cells (HSCs) that give rise to distinct lymphocyte lineages at different stages of development. Here we provide evidence of an analogous layered immune system in humans. Our results suggest that fetal and adult T cells are distinct populations that arise from different populations of HSCs that are present at different stages of development. We also provide evidence that the fetal T cell lineage is biased toward immune tolerance. These observations offer a mechanistic explanation for the tolerogenic properties of the developing fetus and for variable degrees of immune responsiveness at birth. 相似文献
5.
Populations at the periphery of a species’ range often show reduced genetic variability within populations and increased genetic
divergence among populations compared to those at the core, but the mechanisms that give rise to this core-periphery pattern
in genetic structure can be multifaceted. Peripheral population characteristics may be a product of historical processes,
such as founder effects or population expansion, or due to the contemporary influence of landscape context on gene flow. We
sampled collared lizards (Crotaphytus collaris) at four locations within the northern Flint Hills of Kansas, which is at the northern periphery of their range, to determine
the genetic variability and extent of genetic divergence among populations for ten microsatellite loci (n = 229). We found low genetic variability (average allelic richness = 3.37 ± 0.23 SE; average heterozygosity = 0.54 ± 0.05
SE) and moderate population divergence (average FST = 0.08 ± 0.01 SE) among our sample sites relative to estimates reported in the literature at the core of the species’ range
in Texas. We also identified differences in dispersal rates among sampling locations. Gene flow within the Flint Hills was
thus greater than for other peripheral populations of collared lizards, such as the Missouri glade system where most of the
mesic grasslands have been converted to forest since the last glacial retreat, which appears to have greatly impeded gene
flow among populations. Our findings signify the importance of considering landscape context when evaluating core-peripheral
trends in genetic diversity and population structure. 相似文献
6.
Mariano Carossino Rudy Bauer Mark A. Mitchell Charles O. Cummings Anke C. Sthr Nobuko Wakamatsu Kimberly Harper Ingeborg M. Langohr Kendra Schultz Maria S. Mitchell Daniel K. Howe Udeni B. R. Balasuriya 《Journal of veterinary diagnostic investigation》2021,33(3):554
Toxoplasma gondii is a zoonotic protozoan pathogen that infects many endothermic vertebrates, including humans; the domestic cat and other felids serve as the definitive host. Macropodids are considered highly susceptible to toxoplasmosis. Here, we describe the clinical, pathologic, and immunohistochemical findings of an outbreak of systemic toxoplasmosis in a mob of 11 red kangaroos (Macropus rufus), with high morbidity (73%) and mortality (100%) rates. Affected animals had either severe and rapidly deteriorating clinical conditions or sudden death, which was correlated with widespread necrotizing lesions in multiple organs and intralesional T. gondii organisms identified via MIC3-specific immunohistochemistry and confirmed by REP529-specific rtPCR. Quantification of parasites demonstrated the highest parasite density in pulmonary parenchyma compared with other tissues. Our study highlights the continued importance of this severe condition in Australian marsupials. 相似文献
7.
Kimberly Bridges Nicole Beckel Claire Sharp Laura Stern 《The Canadian veterinary journal. La revue veterinaire canadienne》2016,57(5):511-513
A 5-month-old pit bull terrier was presented for evaluation of progressive lethargy, vomiting, diarrhea, and anorexia 45 hours after ingestion of 625 mg/kg body weight (BW) (9000 mg) of the antiviral medication, ribavirin. Abnormalities that were detected included dehydration, tachycardia, elevated liver enzymes, and prolonged prothrombin time. The dog was discharged after 5 days of aggressive supportive care consisting of intravenous fluids, antiemetics, gastroprotectants, hepatoprotectants, dextrose supplementation, and vitamin B/K1 supplementation. 相似文献
8.
Initial analytic quality assessment and method comparison of an immunoassay for adrenocorticotropic hormone measurement in equine samples 下载免费PDF全文
9.
Landscape Ecology - Habitat fragmentation can exacerbate the negative effects of habitat loss for some species. Mitigating fragmentation is difficult, however, because population responses depend... 相似文献
10.