全文获取类型
收费全文 | 711篇 |
免费 | 56篇 |
国内免费 | 102篇 |
专业分类
林业 | 42篇 |
农学 | 16篇 |
基础科学 | 4篇 |
95篇 | |
综合类 | 190篇 |
农作物 | 5篇 |
水产渔业 | 61篇 |
畜牧兽医 | 452篇 |
植物保护 | 4篇 |
出版年
2024年 | 3篇 |
2023年 | 23篇 |
2022年 | 22篇 |
2021年 | 31篇 |
2020年 | 37篇 |
2019年 | 50篇 |
2018年 | 25篇 |
2017年 | 22篇 |
2016年 | 37篇 |
2015年 | 30篇 |
2014年 | 45篇 |
2013年 | 28篇 |
2012年 | 51篇 |
2011年 | 57篇 |
2010年 | 48篇 |
2009年 | 49篇 |
2008年 | 28篇 |
2007年 | 39篇 |
2006年 | 40篇 |
2005年 | 18篇 |
2004年 | 24篇 |
2003年 | 25篇 |
2002年 | 13篇 |
2001年 | 15篇 |
2000年 | 12篇 |
1999年 | 9篇 |
1998年 | 9篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 12篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有869条查询结果,搜索用时 78 毫秒
31.
Christina von ZallingerDVM Karlheinz TempelDVM 《Veterinary radiology & ultrasound》1998,39(6):495-503
With respect to clinical signs of the radiation syndromes, some remarkable species variations exist. For example the marked delayed reaction of the acute hematologic response in cows. An unusually high sensitivity of the central nervous system is found in burros, which is probably caused by acute vascular and/or metabolic changes in the brain. The species-specific number of intestinal crypt and hemopoietic stem cells may explain the early survival differences among species after high doses of irradiation. Mortality due to acute radiation syndromes is lowest in chickens. Regarding late effects, various neoplasms are typical in dogs, and cattle more commonly develop cataracts. 相似文献
32.
33.
腾冲北海湿地动植物资源及其环境状况评价 总被引:2,自引:0,他引:2
云南腾冲北海湿地为中国西南唯一的高原火山堰塞湖,是云南省典型的高原自然永久性浅水湖和沼泽,景观独特,属"漂浮状苔草沼泽湿地"。在北海湿地16 29km2的狭小区域内,湿地植被类型丰富,物种多样性程度高,有重要的国家级水生保护植物5种、国家级保护树种达9种;28种鸟类被分别列入国家和全球的重要鸟类保护名录。由于过去不合理的"围湖造田"和过度的森林砍伐,加之外来有害物种的不断侵入,导致北海湿地生态系统功能降低,生物多样性流失严重,本文通过对北海湿地的资源与环境状况进行分析评价,提出了相应的保护措施与发展策略。 相似文献
34.
35.
为了解四川省食品动物源大肠杆菌mcr-1耐药基因流行情况,及其与超广谱β-内酰胺酶基因(ESBLs)共存和共转移的特征,采用微量肉汤稀释法检测菌株对不同抗菌药物的敏感性;采用PCR检测菌株mcr-1,以及mcr-1阳性菌株中ESBLs基因类型;采用质粒接合转移试验分析了mcr-1与ESBLs基因共转移的耐药机制。结果显示:190株大肠杆菌的mcr-1检出率为36.84%,75.71% mcr-1阳性菌株中同时检出ESBLs基因,主要以blaTEM-1、blaCTX-M-55和blaCTX-M-14为优势基因;mcr-1阳性菌对氨曲南(ATM)、头孢噻肟(CTX)和多黏菌素E(COL)耐药率极显著高于mcr-1阴性菌(P<0.01);质粒转移率为47.14%,其中获得mcr-1和ESBLs基因共转移的接合子表现出与供体菌相同的耐药表型及耐药基因。综上,在四川省食品动物源大肠杆菌中,mcr-1与ESBLs基因共存现象广泛存在,且耐药基因易发生水平传播,对菌株多重耐药性的产生具有重要意义。 相似文献
36.
37.
Chelsea M. Kunst Anthony P. Pease Nathan C. Nelson Greg Habing Elizabeth A. Ballegeer 《Veterinary radiology & ultrasound》2014,55(5):511-520
Elbow dysplasia is a heritable disease that is a common cause of lameness and progressive elbow osteoarthritis in young large breed dogs. The Orthopedic Foundation for Animals (OFA) screens elbow radiographs, and assigns grades 0–3 based on presence and severity of bony proliferation on the anconeal process. Grade 1 is assigned when less than 3 mm is present and considered positive for dysplasia. We investigated the incidence of elbow dysplasia and progression of osteoarthritis in elbows with grades 0 and 1 in 46 elbows screened at least 1 year previously, using CT as a gold standard and with the addition of CT absorptiometry. The incidence of dysplasia based on CT was 62% in grade 0, and 75% in grade 1 elbows, all of which had medial coronoid disease. Progressive osteoarthritis at recheck was consistent with elbow dysplasia. The sensitivity and specificity of the OFA grade for elbow dysplasia compared to CT findings was 75% and 38%, respectively. Increased bone mineral density of the medial coronoid process as characterized by osteoabsorptiometry warrants further investigation with respect to elbow dysplasia. Proliferation on the anconeal process without CT evidence of dysplasia or osteoarthritis was present in 20% of the elbows, and is theorized to be an anatomic variant or enthesopathy of the olecranon ligament/synovium. Results of our study suggest that the “anconeal bump” used for elbow screening by the OFA is a relatively insensitive characteristic, and support the use of CT for identifying additional characteristics of elbow dysplasia. 相似文献
38.
39.
《Journal of Exotic Pet Medicine》2014,23(3):244-249
Live food items are often fed to exotic pet species whether they are birds, amphibians, reptiles, or mammals. This raises issues of welfare, both of the animals fed live prey items and the prey itself. Concerns over live food welfare are particularly marked in the feeding of vertebrate prey items and evidence presented here shows the prolonged time taken for rodents to die. However, the welfare of all exotic pets relies both on providing optimal nutrition to the predator and ensuring, as much as possible, that their natural behaviours can be expressed. Does that mean that predatory species must be fed live prey? This article discusses this problem and seeks potential solutions. 相似文献
40.