全文获取类型
收费全文 | 8633篇 |
免费 | 506篇 |
国内免费 | 598篇 |
专业分类
林业 | 843篇 |
农学 | 997篇 |
基础科学 | 503篇 |
1820篇 | |
综合类 | 1743篇 |
农作物 | 418篇 |
水产渔业 | 548篇 |
畜牧兽医 | 2035篇 |
园艺 | 177篇 |
植物保护 | 653篇 |
出版年
2024年 | 23篇 |
2023年 | 115篇 |
2022年 | 188篇 |
2021年 | 311篇 |
2020年 | 281篇 |
2019年 | 272篇 |
2018年 | 251篇 |
2017年 | 281篇 |
2016年 | 353篇 |
2015年 | 354篇 |
2014年 | 376篇 |
2013年 | 516篇 |
2012年 | 678篇 |
2011年 | 584篇 |
2010年 | 441篇 |
2009年 | 359篇 |
2008年 | 501篇 |
2007年 | 483篇 |
2006年 | 484篇 |
2005年 | 461篇 |
2004年 | 283篇 |
2003年 | 273篇 |
2002年 | 270篇 |
2001年 | 239篇 |
2000年 | 195篇 |
1999年 | 158篇 |
1998年 | 137篇 |
1997年 | 85篇 |
1996年 | 91篇 |
1995年 | 94篇 |
1994年 | 98篇 |
1993年 | 91篇 |
1992年 | 72篇 |
1991年 | 48篇 |
1990年 | 70篇 |
1989年 | 54篇 |
1988年 | 36篇 |
1987年 | 16篇 |
1986年 | 12篇 |
1985年 | 7篇 |
1984年 | 9篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 11篇 |
1980年 | 5篇 |
1976年 | 4篇 |
1974年 | 5篇 |
1969年 | 4篇 |
1968年 | 5篇 |
1953年 | 3篇 |
排序方式: 共有9737条查询结果,搜索用时 0 毫秒
1.
2.
Transitional Cell Carcinoma of the Urinary Bladder in a Beluga Whale (Delphinapterus leucas) 总被引:1,自引:0,他引:1 下载免费PDF全文
Martineau D Lagacé A Massé R Morin M Béland P 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(10):297-302
A transitional cell carcinoma of the urinary bladder was found in a beluga whale stranded in the St. Lawrence middle estuary. Various organs of this animal were submitted to high resolution gas chromatography coupled with mass spectrometry analysis. High frequency of urinary bladder cancer in the human population of the same area and the presence of carcinogenic compounds in the marine environment of this animal are discussed.
Concurrent isolation of Edwardsiella tarda from various organs of this whale is also reported.
相似文献3.
Summary On two occasions an anaplasm was isolated from sheep on the Dutch island of Ameland. The organism proved to be highly pathogenic for splenectomised sheep; a non-splenectomised animal recovered spontaneously after the packed cell volume had decreased by 40%. Treatment with oxytetracycline was effective. Its pathogenicity for goats appeared to be low, and the organism was apparently not infective to splenectomised cattle. This anaplasm differs from Anaplasma ovis in that less than 30% of the organisms are marginally situated in the red cell, as against over 70% in A. ovis; cross-immunity with A. ovis was incomplete and the latter appeared to be far more pathogenic to goats than the Dutch anaplasm, for which the name Anaplasma mesaeterum sp.n. is proposed. Its ultrastructure is similar to that of A. marginale and A. ovis. The vector is either Ixodes ricinus or Haemaphysalis punctata. Its practical importance remains to be ascertained. 相似文献
4.
5.
6.
7.
Cheng-Zhe Ren Hui-Min Gao Jun Dai Wen-Zhuo Zhu Fei-Fei Xu Yun Ye Xiao-Ling Zhang Qiao Yang 《Marine drugs》2022,20(5)
Microalgae host varied microbial consortium harboring cross-kingdom interactions with fundamental ecological significance in aquatic ecosystems. Revealing the complex biofunctions of the cultivable bacteria of phycosphere microbiota is one vital basis for deeply understanding the mechanisms governing these dynamic associations. In this study, a new light-yellow pigmented bacterial strain LZ-28 was isolated from the highly-toxic and harmful algal bloom-forming dinoflagellate Alexandrium catenella LZT09. Collective phenotypic and genotypic profiles were obtained to confidently identify this strain as a new Mameliella alba member. Comparative genomic analysis showed that strain LZ-28 shared highly similar functional features with other four marine algae-derived M. alba strains in spite of their distinctive isolation sources. Based on the bioactivity assaying, the mutual growth-promoting effects between bacterial strain LZ-28 and algal strain LZT09 were observed. After the culture conditions were optimized, strain LZ-28 demonstrated an extraordinary production ability for its bioflocculanting exopolysaccharides (EPS). Moreover, the portions of two monosaccharides glucose and fucose of the EPS were found to positively contribute to the bioflocculanting capacity. Therefore, the present study sheds light on the similar genomic features among the selected M. alba strains, and it also reveals the potential pharmaceutical, environmental and biotechnological implications of active EPS produced by this new Mameliella alba strain LZ-28 recovered from toxic bloom-forming marine dinoflagellate. 相似文献
8.
Ana M. Casas Carlota R. Gazulla Arantxa Monteagudo Carlos P. Cantalapiedra Marian Moralejo M. Pilar Gracia Francisco J. Ciudad William T.B. Thomas José L. Molina-Cano Scott Boden Bruno Contreras-Moreira Ernesto Igartua 《作物学报(英文版)》2021,(4):862-872
Response to vernalization and photoperiod are the main determinants controlling the time to flowering in temperate cereals. While the individual genes that dete... 相似文献
9.
粗纤维是母猪营养的未来,也是今后母猪营养的发展方向。文章着重介绍母猪能利用粗纤维的原因及粗纤维对母猪的影响,为今后粗纤维在母猪饲粮中的利用提供科学指导。 相似文献
10.
随着国民经济的飞跃发展和人们日益增长的生活需求,机械系统越来越复杂,功能越来越完善。同时,鉴于各行业对机械使用的密切性和广泛性,机械故障的发生和检测诊断技术也引起了各国的关注和研究。在机械中,旋转机械是使用最广泛的,几乎每个机械系统中都有旋转部件的存在,因此,对旋转机械故障的检测和诊断技术的研究也备受关注。基于此,从振动信号处理技术和图像处理技术对国内外故障检测和诊断的研究进行分析,以及对故障检测诊断领域的发展方向进行展望。 相似文献