全文获取类型
收费全文 | 691篇 |
免费 | 58篇 |
专业分类
林业 | 15篇 |
农学 | 10篇 |
基础科学 | 3篇 |
71篇 | |
综合类 | 65篇 |
农作物 | 19篇 |
水产渔业 | 44篇 |
畜牧兽医 | 482篇 |
园艺 | 14篇 |
植物保护 | 26篇 |
出版年
2024年 | 3篇 |
2023年 | 19篇 |
2022年 | 14篇 |
2021年 | 24篇 |
2020年 | 14篇 |
2019年 | 26篇 |
2018年 | 25篇 |
2017年 | 25篇 |
2016年 | 13篇 |
2015年 | 19篇 |
2014年 | 29篇 |
2013年 | 21篇 |
2012年 | 42篇 |
2011年 | 48篇 |
2010年 | 23篇 |
2009年 | 19篇 |
2008年 | 37篇 |
2007年 | 30篇 |
2006年 | 29篇 |
2005年 | 51篇 |
2004年 | 42篇 |
2003年 | 43篇 |
2002年 | 50篇 |
2001年 | 15篇 |
2000年 | 10篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 8篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 3篇 |
1969年 | 4篇 |
1956年 | 1篇 |
1950年 | 1篇 |
1940年 | 1篇 |
1939年 | 1篇 |
1923年 | 1篇 |
1918年 | 1篇 |
1888年 | 1篇 |
排序方式: 共有749条查询结果,搜索用时 78 毫秒
71.
I C Fuentealba S E Wikse W K Read J F Edwards G S Visvesvara 《Journal of the American Veterinary Medical Association》1992,200(3):363-365
A 1.5-year-old Suffolk ewe with acute onset of incoordination and blindness unresponsive to antibiotic treatment was examined at necropsy. The meninges were congested, opaque, and thick. Microscopically, focal areas of hypercellularity in the left cortical gray matter and the meninges were observed. The inflammatory response consisted of gliosis and perivascular cuffing (lymphocytes, plasma cells, and variable numbers of eosinophils). An amebic organism in 2 life stages was found in the cerebral parenchyma. Numerous large (15 to 35 microns in diameter) organisms, interpreted as trophozoites, were characterized by vacuolated cytoplasm and small nuclei with a prominent eosinophilic nucleolus (karyosome). The smaller (10 to 17 microns in diameter) encysted stage was surrounded by a capsule-like membrane, and contained a large central body sometimes surrounded by a clear halo. Immunofluorescence studies for amebic antigens were strongly positive for an ameba recently isolated in human beings and baboons (Leptomyxid sp). 相似文献
72.
73.
Read MR 《Journal of the American Veterinary Medical Association》2004,224(4):547-552
OBJECTIVE: To determine anesthetic techniques and the drugs used to provide anesthesia and analgesia to reptiles. DESIGN: Mail-out questionnaire. SAMPLE POPULATION: 367 members of the Association of Reptile and Amphibian Veterinarians. PROCEDURE: 1,091 members listed in the 2002 directory of the Association of Reptile and Amphibian Veterinarians were asked to complete a questionnaire regarding anesthesia and analgesia. RESULTS: 367 of 1,091 (33.6%) individuals completed the questionnaire; 88.8% used inhalants (particularly isoflurane) for anesthesia, and ketamine, propofol, and butorphanol were the most commonly used injectable agents. Intubation, fluids, and having a dedicated anesthetist were most commonly used for patient support, and pulse oximetry and Doppler ultrasonography were most commonly used for monitoring. Respiratory depression, difficulty monitoring anesthetic depth, prolonged recovery, and hypothermia were the most frequent complications. Nearly all respondents believed that reptiles feel pain, but analgesics were used infrequently for many reasons. CONCLUSIONS AND CLINICAL RELEVANCE: Providing anesthesia in reptiles is difficult, especially regarding anesthetic depth and vital parameters, and methods of support are used less frequently than in domestic species. Provision of analgesia is uncommon. Research regarding pain and its assessment, response to analgesics, and drug pharmacokinetics is needed. Dissemination of this information to practitioners needs to be improved for enhancement of the standard of care for reptiles. 相似文献
74.
75.
Use of a jugular vein autograft for reconstruction of the cranial vena cava in a dog with invasive thymoma and cranial vena cava syndrome 总被引:1,自引:0,他引:1
Holsworth IG Kyles AE Bailiff NL Hopper K Long C Ilkiw JE 《Journal of the American Veterinary Medical Association》2004,225(8):1205-10, 1196
A spayed female dog was evaluated because of edema of the ventral cervical region, lethargy, cough, and reduced exercise tolerance. Invasive thymoma and cranial vena cava syndrome were diagnosed by use of ultrasound-guided fine-needle biopsy and contrast-enhanced helical computed tomography. Resection of the cranial vena cava and an autogenous jugular vein graft were used for restoration of normal venous return to the right atrium and alleviation of the cranial vena cava syndrome. 相似文献
76.
77.
78.
Foley J Hurley K Pesavento PA Poland A Pedersen NC 《Journal of Feline Medicine and Surgery》2006,8(1):55-61
Virulent systemic feline calicivirus (VS-FCV) is a novel, emerging pathogen with mortality up to 67% even in previously healthy adult cats; VS-FCV has resulted in at least six epidemics since 1998. Affected cats have systemic vascular compromise and hemorrhagic-fever like signs in part due to viral invasion of epithelium and endothelium, coupled with host cytokine responses. Affected skin tissues had, on average, 3.8 elevated cytokines compared with control tissue, with prominent upregulation in IL-10, TNF-alpha, and MIP-1alpha. Sequencing of most of the genomes of two VS-FCV strains documented patterns of virus relatedness and implicated changes in the capsid gene in the emerging phenotype, possibly through initiation of immune mechanisms manifest in the cytokine changes. Understanding the features contributing to the emergence of this disease is critical for management and prevention of this and similar outbreaks attributable to RNA viruses in animals and humans. 相似文献
79.
Richards JR Elston TH Ford RB Gaskell RM Hartmann K Hurley KF Lappin MR Levy JK Rodan I Scherk M Schultz RD Sparkes AH 《Journal of the American Veterinary Medical Association》2006,229(9):1405-1441
Vaccination is a medical procedure, and the decision to vaccinate should be based on a risk-based assessment for each cat and each vaccine. 相似文献
80.
Artificial spin ice, made up of planar nanostructured arrays of simple ferromagnetic bars, is a playground for rich physics associated with the spin alignment of the bars and spin texture associated with the magnetic frustration at the bar vertices. The phase diagram is exotic, showing magnetic monopole-like defects and liquid and solid phases of spins arranged in loop states with predicted chiral order. We show that magnetotransport measurements in connected honeycomb structures yield the onset of an anomalous Hall signal at 50 kelvin. The temperature scale can be attributed to the long-range dipolar ice phase. The topological Hall signal arises because chiral loops form at the sample edges, indicating a generic route to exotic states via nanoarray edge structure. 相似文献