全文获取类型
收费全文 | 22804篇 |
免费 | 1191篇 |
国内免费 | 1935篇 |
专业分类
林业 | 3149篇 |
农学 | 1487篇 |
基础科学 | 2984篇 |
2440篇 | |
综合类 | 8488篇 |
农作物 | 995篇 |
水产渔业 | 423篇 |
畜牧兽医 | 1740篇 |
园艺 | 587篇 |
植物保护 | 3637篇 |
出版年
2024年 | 186篇 |
2023年 | 422篇 |
2022年 | 689篇 |
2021年 | 829篇 |
2020年 | 837篇 |
2019年 | 925篇 |
2018年 | 512篇 |
2017年 | 722篇 |
2016年 | 1004篇 |
2015年 | 804篇 |
2014年 | 1301篇 |
2013年 | 1234篇 |
2012年 | 1645篇 |
2011年 | 1650篇 |
2010年 | 1200篇 |
2009年 | 1316篇 |
2008年 | 1088篇 |
2007年 | 1302篇 |
2006年 | 1168篇 |
2005年 | 909篇 |
2004年 | 862篇 |
2003年 | 774篇 |
2002年 | 619篇 |
2001年 | 614篇 |
2000年 | 494篇 |
1999年 | 422篇 |
1998年 | 347篇 |
1997年 | 343篇 |
1996年 | 269篇 |
1995年 | 269篇 |
1994年 | 220篇 |
1993年 | 188篇 |
1992年 | 188篇 |
1991年 | 151篇 |
1990年 | 140篇 |
1989年 | 105篇 |
1988年 | 82篇 |
1987年 | 47篇 |
1986年 | 22篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1955年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
非洲猪瘟在我国流行已有两年多的时间,尽管很多科研团队都在致力于非洲猪瘟疫苗的研发,但尚未有治疗措施和有效的疫苗来控制该病。因此现阶段“生物安全”是控制非洲猪瘟最为有效,也是唯一的方法。文章总结出目前规模化猪场常见的感染风险有“人员流动、物品流动、车辆流动、水源流动、猪群流动”(即“五流”),并提出严格控制“五流”的生物安全防控措施(即“五流”生物安全防控),以减少外界病原与猪只的接触,稀释病原浓度,降低病原载量,最大程度地降低规模化养猪场感染疾病的风险。为当前规模化猪场建立有效的生物安全措施提供参考。 相似文献
92.
93.
天祝县莫客片一带牛梨形虫病发病率达24.6%,病死率28.6%;羊发病率34.2%,病死率27.5%,与往年相比变化不大,笔者从蜱控制、梨形虫病预防加治疗相结合综合防控入手,作控制、预防药物试验对比,筛选药效长、低毒、安全、广谱药物,结果显示用敌杀死环境灭蜱,同时注施可诺注射液控制蜱感染,用蒿甲醚注射液或盐酸咪唑苯脲,预防和治疗梨形虫病,能有效降低当地牛羊梨形虫病的发病率和病死率。 相似文献
94.
欧美牛病毒性腹泻防控措施及对我国的启示 总被引:1,自引:0,他引:1
牛病毒性腹泻是牛的重要疫病,导致产奶量下降、肉产量降低、繁殖障碍、生长迟缓、继发其他病原几率增加甚至死亡等,给养牛业造成较大的经济损失。欧美国家在牛病毒性腹泻防控方面形成了一套行之有效的方法,有效地控制并逐步根除了BVD。借鉴欧美牛病毒性腹泻防控策略可对我国该病的防制提供一定的指导。 相似文献
95.
L. H. Taylor L. Knopf the Partners for Rabies Prevention 《Zoonoses and public health》2015,62(7):543-552
Effective prevention of deaths due to human rabies is currently hampered by a lack of understanding of the scale of the problem, and the distribution of both animal and human cases across countries, regions and continents. Unfortunately, despite the severity of the disease, accurate data on which to assess these questions and to prioritize and direct public health interventions are not available for many parts of the world. This survey sought to understand the current global situation regarding the surveillance of human rabies. Data were collected from 91 countries across all continents and all categories of human rabies risk, generating the most complete and representative global data set currently available. Respondents were asked key questions about whether human rabies was a notifiable disease, how the surveillance system for human rabies operated and whether the respondent considered that the surveillance system was working effectively. Across the 91 countries from which data were collated, human rabies was a notifiable disease in all but eight. Despite international guidance, surveillance systems were very varied. Even where rabies is a notifiable disease, many countries had surveillance system judged to be ineffective, almost all of these being high and moderate rabies risk countries in Africa and Asia. Overall, 41% of the population covered by this survey (around 2.5 billion people) live in countries where there is no or ineffective rabies surveillance. The lack of robust surveillance is hindering rabies control efforts. However, whilst worldwide rabies surveillance would be improved if rabies were notifiable in all countries, many other challenges to the implementation of effective global human rabies surveillance systems remain. 相似文献
96.
Yuichi Kuroiwa Ryo Ando Kenichiro Kasahara Mariko Nagatani Seiki Yamakawa Shuzo Okazaki 《Journal of toxicologic pathology》2013,26(2):227-230
Historical control data of tumor incidence were collected from the control groups (215
animals of each sex) in four recent carcinogenicity studies that were started between 2005
to 2009 (terminally sacrificed between 2007 and 2011) at BoZo Research Center Inc.
(Gotemba, Shizuoka, Japan) using Fischer 344 rats (F344/DuCrlCrlj). These data were
compared to the previous historical control data (from 1990 to 2004, previously reported)
in the same facility. In the results, the incidence of C-cell adenoma in the thyroid
tended to increase in both sexes in recent years (30.8% for males and 24.4% for females in
2005-2009) as compared with the previous data (17.4% and 20.1% for males and 11.5% and
11.8% for females in 1990–1999 and 2000–2004, respectively). In addition, the incidences
of pancreatic islet cell adenoma in males and uterine adenocarcinoma tended to increase
from around 2000 and remained high in recent years (incidences of islet cell adenoma in
males of 10.5%, 17.1% and 20.5% in 1990–1999, 2000–2004 and 2005–2009; incidences of
uterine adenocarcinoma of 3.3%, 12.0% and 13.5% in 1990–1999, 2000–2004 and 2005–2009,
respectively). There was no apparent difference in the incidence of other tumors. 相似文献
97.
Background
Microbiological standards within pork slaughter processing plants in the European Union are currently governed by Commission Regulation (EC) 2073/2005, which describes detailed performance criteria at specific stages of the procedure (following carcass dressing and before chilling) for total viable counts (TVC), Enterobacteriaceae (EB) and Salmonella spp. In this study, 95 carcasses from an Irish pork slaughter plant were sampled by swabbing 100 cm2 of surface at three sites (belly, ham, jowl) to examine the effects of eight processing stages (stunning, bleeding, scalding, singeing, polishing, evisceration, final inspection and chilling) on contamination levels.Results
TVC ranged from approximately 1.7–6.3 log cfu cm2 during sampling. There were significant reductions in TVC for all sites after scalding and singeing (p < 0.05), whilst there was a significant increase in counts after polishing and evisceration (p < 0.05) compared with preceding stages. EB counts indicated hygienic weak points in the examined slaughter plant leading to faecal (cross)-contamination, with elevated counts after stunning, bleeding and evisceration (p < 0.05), compared with final counts after chilling.Conclusions
Although the bacterial numbers reported in this study may reflect specific plant practices and temporal influences, results show that contamination can be introduced at various steps in the process and highlight the importance of monitoring locations other than those required by legislation within the process. Monitoring can be used to establish baseline levels for high-risk stages specific to each plant and to assess the effectiveness of additional interventions. 相似文献98.
E. J. Pluimers 《The Veterinary quarterly》2013,33(2):82-89
Summary In a trial involving 542 dairy cattle on 28 farms, 276 were treated once with thiabendazole within two days of calving. The treated group showed an average increase in milk yielded over the non‐return group of 229.8 kg during the subsequent lactation. In the treated group, total milk fat production was increased over that of the controls by 7.4 kg per cow; milk protein was increased by 6.9 kg per cow. All treatment parameter differences were highly significant at the 1% level of probability. 相似文献
99.
巫溪红池坝改良草地鼠类调查报告 总被引:1,自引:0,他引:1
对重庆巫溪红池坝改良草地中鼠形动物的种类进行抽样调查、室内饲养、解剖鼠胃和洞道研究,结果显示,该改良草地中有鼠形动物2目3科4种,其对草地危害方式和为害程度均不一样。提出了改良草地中鼠害的防治措施。 相似文献
100.