全文获取类型
收费全文 | 574篇 |
免费 | 15篇 |
专业分类
林业 | 60篇 |
农学 | 8篇 |
114篇 | |
综合类 | 38篇 |
农作物 | 5篇 |
水产渔业 | 16篇 |
畜牧兽医 | 295篇 |
园艺 | 20篇 |
植物保护 | 33篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 12篇 |
2019年 | 17篇 |
2018年 | 17篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2015年 | 18篇 |
2014年 | 23篇 |
2013年 | 35篇 |
2012年 | 39篇 |
2011年 | 46篇 |
2010年 | 23篇 |
2009年 | 30篇 |
2008年 | 38篇 |
2007年 | 50篇 |
2006年 | 36篇 |
2005年 | 33篇 |
2004年 | 32篇 |
2003年 | 27篇 |
2002年 | 18篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 5篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有589条查询结果,搜索用时 31 毫秒
141.
Andrea Schwarz Karin Kalchofner Julia Palm Stephanie Picek Sonja Hartnack Regula Bettschart‐Wolfensberger 《Veterinary anaesthesia and analgesia》2014,41(5):480-490
ObjectiveTo determine the induction doses, then minimum infusion rates of alfaxalone for total intravenous anaesthesia (TIVA), and subsequent, cardiopulmonary effects, recovery characteristics and alfaxalone plasma concentrations in cats undergoing ovariohysterectomy after premedication with butorphanol-acepromazine or butorphanol-medetomidine.Study designProspective randomized blinded clinical study.AnimalsTwenty-eight healthy cats.MethodsCats undergoing ovariohysterectomy were assigned into two groups: together with butorphanol [0.2 mg kg?1 intramuscularly (IM)], group AA (n = 14) received acepromazine (0.1 mg kg?1 IM) and group MA (n = 14) medetomidine (20 μg kg?1 IM). Anaesthesia was induced with alfaxalone to effect [0.2 mg kg?1 intravenously (IV) every 20 seconds], initially maintained with 8 mg kg?1 hour?1 alfaxalone IV and infusion adjusted (±0.5 mg kg?1 hour?1) every five minutes according to alterations in heart rate (HR), respiratory rate (fR), Doppler blood pressure (DBP) and presence of palpebral reflex. Additional alfaxalone boli were administered IV if cats moved/swallowed (0.5 mg kg?1) or if fR >40 breaths minute?1 (0.25 mg kg?1). Venous blood samples were obtained to determine plasma alfaxalone concentrations. Meloxicam (0.2 mg kg?1 IV) was administered postoperatively. Data were analysed using linear mixed models, Chi-squared, Fishers exact and t-tests.ResultsAlfaxalone anaesthesia induction dose (mean ± SD), was lower in group MA (1.87 ± 0.5; group AA: 2.57 ± 0.41 mg kg?1). No cats became apnoeic. Intraoperative bolus requirements and TIVA rates (group AA: 11.62 ± 1.37, group MA: 10.76 ± 0.96 mg kg?1 hour?1) did not differ significantly between groups. Plasma concentrations ranged between 0.69 and 10.76 μg mL?1. In group MA, fR, end-tidal carbon dioxide, temperature and DBP were significantly higher and HR lower.Conclusion and clinical relevanceAlfaxalone TIVA in cats after medetomidine or acepromazine sedation provided suitable anaesthesia with no need for ventilatory support. After these premedications, the authors recommend initial alfaxalone TIVA rates of 10 mg kg?1 hour?1. 相似文献
142.
143.
Fagiolini M Fritschy JM Löw K Möhler H Rudolph U Hensch TK 《Science (New York, N.Y.)》2004,303(5664):1681-1683
Weak inhibition within visual cortex early in life prevents experience-dependent plasticity. Loss of responsiveness to an eye deprived of vision can be initiated prematurely by enhancing gamma-aminobutyric acid (GABA)-mediated transmission with benzodiazepines. Here, we use a mouse "knockin" mutation to alpha subunits that renders individual GABA type A (GABA(A)) receptors insensitive to diazepam to show that a particular inhibitory network controls expression of the critical period. Only alpha1-containing circuits were found to drive cortical plasticity, whereas alpha2-enriched connections separately regulated neuronal firing. This dissociation carries implications for models of brain development and the safe design of benzodiazepines for use in infants. 相似文献
144.
K Muegge T M Williams J Kant M Karin R Chiu A Schmidt U Siebenlist H A Young S K Durum 《Science (New York, N.Y.)》1989,246(4927):249-251
145.
Naugler WE Sakurai T Kim S Maeda S Kim K Elsharkawy AM Karin M 《Science (New York, N.Y.)》2007,317(5834):121-124
Hepatocellular carcinoma (HCC), the most common liver cancer, occurs mainly in men. Similar gender disparity is seen in mice given a chemical carcinogen, diethylnitrosamine (DEN). DEN administration caused greater increases in serum interleukin-6 (IL-6) concentration in males than it did in females. Furthermore, ablation of IL-6 abolished the gender differences in hepatocarcinogenesis in mice. DEN exposure promoted production of IL-6 in Kupffer cells (KCs) in a manner dependent on the Toll-like receptor adaptor protein MyD88, ablation of which also protected male mice from DEN-induced hepatocarcinogenesis. Estrogen inhibited secretion of IL-6 from KCs exposed to necrotic hepatocytes and reduced circulating concentrations of IL-6 in DEN-treated male mice. We propose that estrogen-mediated inhibition of IL-6 production by KCs reduces liver cancer risk in females, and these findings may be used to prevent HCC in males. 相似文献
146.
Rhesus Macaque Genome Sequencing Analysis Consortium Gibbs RA Rogers J Katze MG Bumgarner R Weinstock GM Mardis ER Remington KA Strausberg RL Venter JC Wilson RK Batzer MA Bustamante CD Eichler EE Hahn MW Hardison RC Makova KD Miller W Milosavljevic A Palermo RE Siepel A Sikela JM Attaway T Bell S Bernard KE Buhay CJ Chandrabose MN Dao M Davis C Delehaunty KD Ding Y Dinh HH Dugan-Rocha S Fulton LA Gabisi RA Garner TT Godfrey J Hawes AC Hernandez J Hines S Holder M Hume J Jhangiani SN 《Science (New York, N.Y.)》2007,316(5822):222-234
147.
148.
149.
Control of experimental autoimmune encephalomyelitis by T cells responding to activated T cells 总被引:21,自引:0,他引:21
T cell vaccination against experimental autoimmune disease is herein shown to be mediated in part by anti-ergotypic T cells, T cells that recognize and respond to the state of activation of other T cells. The anti-ergotypic response thus combines with the previously shown anti-idiotypic T cell response to regulate autoimmunity. 相似文献
150.
Pfennig KS 《Science (New York, N.Y.)》2007,318(5852):965-967
Mating with another species (hybridization) is often maladaptive. Consequently, females typically avoid heterospecifics as mates. Contrary to these expectations, female spadefoot toads were more likely to choose heterospecific males when exposed to environmental conditions that favor hybridization. Indeed, those females with phenotypic characteristics for which hybridization is most favorable were most likely to switch from choosing conspecifics to heterospecifics. Moreover, environmentally dependent mate choice has evolved only in populations and species that risk engaging in, and can potentially benefit from, hybridization. Thus, when the benefits of mate choice vary, females may radically alter their mate selection in response to their own phenotype and their environment, even to the point of choosing males of other species. 相似文献