全文获取类型
收费全文 | 78721篇 |
免费 | 3743篇 |
国内免费 | 8165篇 |
专业分类
林业 | 9006篇 |
农学 | 10660篇 |
基础科学 | 5842篇 |
12154篇 | |
综合类 | 25833篇 |
农作物 | 4971篇 |
水产渔业 | 3321篇 |
畜牧兽医 | 10381篇 |
园艺 | 3403篇 |
植物保护 | 5058篇 |
出版年
2024年 | 301篇 |
2023年 | 971篇 |
2022年 | 2398篇 |
2021年 | 3187篇 |
2020年 | 2856篇 |
2019年 | 2855篇 |
2018年 | 2020篇 |
2017年 | 2806篇 |
2016年 | 2478篇 |
2015年 | 3380篇 |
2014年 | 3400篇 |
2013年 | 4268篇 |
2012年 | 5007篇 |
2011年 | 5381篇 |
2010年 | 5156篇 |
2009年 | 4850篇 |
2008年 | 4534篇 |
2007年 | 4486篇 |
2006年 | 4130篇 |
2005年 | 3847篇 |
2004年 | 1862篇 |
2003年 | 1608篇 |
2002年 | 1482篇 |
2001年 | 1465篇 |
2000年 | 1639篇 |
1999年 | 1965篇 |
1998年 | 1704篇 |
1997年 | 1449篇 |
1996年 | 1351篇 |
1995年 | 1213篇 |
1994年 | 1146篇 |
1993年 | 1089篇 |
1992年 | 891篇 |
1991年 | 780篇 |
1990年 | 656篇 |
1989年 | 538篇 |
1988年 | 439篇 |
1987年 | 264篇 |
1986年 | 189篇 |
1985年 | 105篇 |
1984年 | 70篇 |
1983年 | 66篇 |
1982年 | 64篇 |
1981年 | 82篇 |
1980年 | 47篇 |
1979年 | 27篇 |
1978年 | 11篇 |
1965年 | 11篇 |
1964年 | 15篇 |
1963年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
111.
112.
113.
Yueh SC Wang YH Lin KY Tseng CF Chu HP Chen KJ Wang SS Lai IH Mao SJ 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2008,70(4):379-387
Porcine haptoglobin (Hp) is an acute phase protein. Its plasma level increases significantly during inflammation and infection. One of the main functions of Hp is to bind free hemoglobin (Hb) and inhibit its oxidative activity. In the present report, we studied the Hp phenotype of Taiwanese Lanyu miniature pigs (TLY minipigs; n=43) and found their Hp structure to be a homodimer (beta-alpha-alpha-beta) similar to human Hp 1-1. Interestingly, Western blot and high performance liquid chromatographic (HPLC) analysis showed that 25% of the TLY minipigs possessed low or no plasma Hp level (<0.05 mg/ml). The Hp cDNA of these TLY minipigs was then cloned, and the translated amino acid sequence was analyzed. No sequences were found to be deficient; they showed a 99.7% identity with domestic pigs (NP_999165). The mean overall Hp level of the TLY minipigs (0.21 +/- 0.25 mg/ml; n=43) determined by enzyme-linked immunosorbent assay (ELISA) was markedly lower than that of domestic pigs (0.78 +/- 0.45 mg/ml; p<0.001), while 25% of the TLY minipigs had an Hp level that was extremely low (<0.05 mg/ml). In addition, the initial recovery rate (first 40 min) in the circulation of infused fluorescein isothiocyanate (FITC)-Hb was significantly higher in the TLY minipigs with extremely low Hp levels than those with high levels. This data suggests that the low concentration of Hp-Hb complex is responsible for the higher recovery rate of Hb in the circulation. TLY minipigs have been used as an experimental model for cardiovascular diseases; whether they can be used as a model for inflammatory diseases, with Hp as a marker, remains a topic of interest. However, since the Hp level varies significantly among individual TLY minipigs, it is necessary to prescreen the Hp levels of the animals to minimize variation in the experimental baseline. The present study may provide a reference value for future use of the TLY minipig as an animal model for inflammation-associated diseases. 相似文献
114.
115.
2008年9月14日上午9时许,广东省高州市宝光街道朝培桐村发生一起凶杀案,茂名市茂南区村民沈某在中秋节时前往朝培桐村岳母莫某家,劝说因争吵而赌气回娘家的妻子程某回家,但遭到妻子和岳母的反对。一气之下,沈某持菜刀将77岁的岳母莫某杀死,将妻子程某及出租车司机砍致重伤, 相似文献
116.
我国生猪生产的波动性研究 总被引:2,自引:0,他引:2
本文针对生猪产量数据存在的问题,对肉类市场放开至第一次农业普查期间的生产数据进行了调整,在此基础上运用趋势分解法描述了改革开放后我国生猪生产的波动情况,进而对历史数据所描述的波动特征表示置疑,认为我国生猪生产存在明显的周期性,最后提出当前我国生猪生产急需采取的一些必要措施,以建立生猪供给安全长效机制。 相似文献
117.
AbstractThe objectives of the present study were to evaluate the effects of different concentrations of the mycotoxin T-2 toxin in feed on muscle performance in the Pacific white shrimp Litopenaeus vannamei, evaluate indexes of physiological variables that indicate T-2 toxin contamination in the shrimp using the grey relational method, and determine the dose–response relationships between T-2 toxin and the indexes. Of the 6 physical, 7 biochemical, and 17 nutritional indexes examined, the values of the grey relational coefficients were highest for the hepatopancreas: body weight ratio (HBR), alanine aminotransferase (ALT) activity, and serine (SER) content (0.83, 0.68, and 0.82, respectively). Therefore, the HBR, ALT activity, and SER content were selected as appropriate indexes for contamination of Pacific white shrimp muscle with T-2 toxin. Based on their dose–response relationship curves, mean effective doses of 1.45, 1.69, and 1.33 mg of T-2 toxin/kg of feed were obtained for the HBR, ALT activity, and SER content, respectively. These results offer technical reference points for the evaluation and control of T-2 toxin in shrimp feed.Received April 28, 2016 accepted April 9, 2017 Published online July 26, 2017 相似文献
118.
Yan Li Ying Jia Kai Wen Hua Liu Mingchun Gao Bo Ma Wenlong Zhang Junwei Wang 《Veterinary immunology and immunopathology》2013,151(3-4):331-336
Bovine viral diarrhea virus (BVDV) is a member of the genus Pestivirus within the family Flaviviridae. NS3 is one of the immunodominance regions of the BVDV viral proteins. To identify the potential B-cell linear antigenic epitopes within BVDV NS3 region, serial overlapping truncations covering the whole region were expressed and purified, and screened by multistep of Western-blot. We found (1VCKKITEHERCHVNI15), (20AFFGVMPRGTTPRAPVR36), (46RRGLETGWAYTHQGGI61), (281EGDMATGITYASYGYFC297), (426YSGEDPANLRVVTSQSPYVVVATNAIESGV455) and (481FIVTGLKRMAVTVGEQA497) can be recognized by the BVDV infected bovine serum. These proteins have been confirmed by indirect enzyme-linked immunosorbent assay (I-ELISA). The results of this study might open new perspectives on the structure and antibody–antigen reaction of the non-structural proteins and may aid in the clinical application as well. 相似文献
119.
120.