全文获取类型
收费全文 | 274篇 |
免费 | 22篇 |
专业分类
林业 | 12篇 |
农学 | 5篇 |
基础科学 | 2篇 |
30篇 | |
综合类 | 71篇 |
农作物 | 6篇 |
水产渔业 | 6篇 |
畜牧兽医 | 140篇 |
园艺 | 13篇 |
植物保护 | 11篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 12篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 10篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 9篇 |
2013年 | 15篇 |
2012年 | 18篇 |
2011年 | 15篇 |
2010年 | 8篇 |
2009年 | 8篇 |
2008年 | 16篇 |
2007年 | 26篇 |
2006年 | 5篇 |
2005年 | 8篇 |
2004年 | 10篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1994年 | 2篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1985年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1969年 | 2篇 |
1966年 | 3篇 |
1948年 | 2篇 |
1943年 | 4篇 |
1934年 | 2篇 |
1930年 | 3篇 |
1928年 | 2篇 |
1925年 | 2篇 |
1923年 | 2篇 |
1919年 | 2篇 |
1916年 | 1篇 |
1913年 | 1篇 |
1912年 | 1篇 |
1905年 | 1篇 |
1900年 | 1篇 |
1899年 | 2篇 |
1893年 | 1篇 |
1885年 | 1篇 |
排序方式: 共有296条查询结果,搜索用时 15 毫秒
21.
22.
23.
24.
Observations of Comet West (1975n) at wavelengths from 0.5 to 18 microns and at a variety of scattering angles are used to infer the scattering phase function for the cometary dust. This function is strongly peaked in the forward direction. The form of the function indicates that the particles are dielectric grains with radii of approximately 1 micron. Abrupt increases in the intrinsic brightness of the coma (both in scattered sunlight and in thermal emission) are consistent with the projected times of comet fragmentation. 相似文献
25.
26.
van Schaik CP Ancrenaz M Borgen G Galdikas B Knott CD Singleton I Suzuki A Utami SS Merrill M 《Science (New York, N.Y.)》2003,299(5603):102-105
Geographic variation in some aspects of chimpanzee behavior has been interpreted as evidence for culture. Here we document similar geographic variation in orangutan behaviors. Moreover, as expected under a cultural interpretation, we find a correlation between geographic distance and cultural difference, a correlation between the abundance of opportunities for social learning and the size of the local cultural repertoire, and no effect of habitat on the content of culture. Hence, great-ape cultures exist, and may have done so for at least 14 million years. 相似文献
27.
Messenger KM Davis JL LaFevers DH Barlow BM Posner LP 《Veterinary anaesthesia and analgesia》2011,38(4):374-384
ObjectiveTo describe the pharmacokinetics and adverse effects of intravenous (IV) and sublingual (SL) buprenorphine in horses, and to determine the effect of sampling site on plasma concentrations after SL administration.Study designRandomized crossover experiment; prospective study.AnimalsEleven healthy adult horses between 6 and 20 years of age and weighing 487–592 kg.MethodsIn the first phase; buprenorphine was administered as a single IV or SL dose (0.006 mg kg?1) and pharmacokinetic parameters were determined for each route of administration using a noncompartmental model. In the second phase; the jugular and lateral thoracic veins were catheterized for simultaneous venous blood sampling, following a dose of 0.006 mg kg?1 SL buprenorphine. For both phases, plasma buprenorphine concentrations were measured using ultra-performance liquid chromatography with mass spectrometry. At each sampling period, horses were assessed for behavioral excitement and gastrointestinal motility.ResultsFollowing IV administration, buprenorphine mean ± SD half-life was 5.79 ± 1.09 hours. Systemic clearance (Cl) following IV administration was 6.13 ± 0.86 mL kg?1 minute?1 and volume of distribution at steady-state was 3.16 ± 0.65 L kg?1. Following IV administration, horses showed signs of excitement. Gastrointestinal sounds were decreased following both routes of administration; however, none of the horses exhibited signs of colic. There was a significant discrepancy between plasma buprenorphine concentrations measured in the jugular vein versus the lateral thoracic vein following phase 2, thus pharmacokinetic parameters following SL buprenorphine are not reported.Conclusions and clinical relevanceBuprenorphine has a long plasma half-life and results in plasma concentrations that are consistent with analgesia in other species for up to 4 hours following IV administration of this dose in horses. While buprenorphine is absorbed into the circulation following SL administration, jugular venous sampling gave a false measurement of the quantity absorbed and should not be used to study the uptake from SL administration. 相似文献
28.
A 19-yr-old intact male Coquerel's sifaka (Propithecus coquereli) was evaluated for a crusting facial dermatopathy. Fungal culture and histopathology of skin biopsies were consistent with dermatophytosis caused by Trichophyton mentagrophytes, and treatment with the antifungal medication terbinafine was initiated. After 1 mo of treatment, all clinical signs had resolved and a fungal culture of the skin was negative. The sifaka was treated with terbinafine for a total of 81 days. Two additional fungal cultures were taken and found to be negative for the presence of dermatophytes, the last culture being taken 1 mo after discontinuation of terbinafine. To the authors' knowledge, this is the first reported case of dermatophytosis in a prosimian species and the first reported treatment of a prosimian with the antifungal drug terbinafine. 相似文献
29.
Walker KA Horning M Mellish JA Weary DM 《Veterinary journal (London, England : 1997)》2011,190(1):160-164
This study examined the effects of two non-steroidal anti-inflammatory drug (NSAID) treatment protocols on the behavioral responses of juvenile Steller sea lions after abdominal surgery. Sea lions were randomly assigned to one of two treatments designed to control post-operative pain. The flunixin group (n=6) received flunixin meglumine (1mg/kg) administered as a single intramuscular (IM) injection before extubation from surgery. The carprofen group (n=5) received carprofen (4.4 mg/kg) as an IM injection before extubation, then orally at 24, 48 and 72 h after surgery. Seven behaviors related to post-operative pain were monitored by observers, blinded to treatment, for a total of 10 days (3 days pre-, day of surgery, and 6 days post-surgery). All seven behaviors changed after surgery regardless of NSAID treatment, two of which returned to baseline within 6 days of surgery. Only one behavior was mildly affected by analgesic treatment: sea lions in the carprofen group tended to spend less time lying down in Days 1-3 following surgery (i.e., the days which they received oral carprofen). These results suggested that neither treatment, at the dose administered, was effective in controlling pain in the days following this surgery. 相似文献
30.
Trace element deposition chronologies are presented for radionuclide dated sediment cores collected from four Utah lakes. A core collected from Mirror Lake, a remote lake located in northern Utah, records a century long period of atmospheric deposition of anthropogenic Pb, Zn, Cu, Cd and Sn. Trace element concentration profiles in a core collected from Panguitch Lake, a remote lake located in southern Utah, give no indication of enhanced atmospheric deposition of trace elements in that part of the state. Sediment cores collected from Echo Reservoir and Deer Creek Reservoir, located near Salt Lake City, record releases of Pb, Zn, Cu, Cd, As, Sb, and Tl rich mine wastes into watershed streams from the now defunct Park City mining complex. 相似文献