全文获取类型
收费全文 | 1765篇 |
免费 | 97篇 |
国内免费 | 3篇 |
专业分类
林业 | 130篇 |
农学 | 63篇 |
基础科学 | 4篇 |
462篇 | |
综合类 | 124篇 |
农作物 | 117篇 |
水产渔业 | 94篇 |
畜牧兽医 | 706篇 |
园艺 | 49篇 |
植物保护 | 116篇 |
出版年
2024年 | 3篇 |
2023年 | 27篇 |
2022年 | 41篇 |
2021年 | 80篇 |
2020年 | 83篇 |
2019年 | 95篇 |
2018年 | 75篇 |
2017年 | 63篇 |
2016年 | 72篇 |
2015年 | 58篇 |
2014年 | 64篇 |
2013年 | 116篇 |
2012年 | 139篇 |
2011年 | 149篇 |
2010年 | 84篇 |
2009年 | 53篇 |
2008年 | 114篇 |
2007年 | 104篇 |
2006年 | 93篇 |
2005年 | 77篇 |
2004年 | 61篇 |
2003年 | 48篇 |
2002年 | 41篇 |
2001年 | 14篇 |
2000年 | 8篇 |
1999年 | 11篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1977年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1958年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有1865条查询结果,搜索用时 15 毫秒
91.
92.
Tüdös AJ Lucas-van den Bos ER Stigter EC 《Journal of agricultural and food chemistry》2003,51(20):5843-5848
Deoxynivalenol belongs to a group of highly toxic fungal metabolites produced by Fusarium species that may contaminate food and animal feed, mostly grains. Three different monoclonal mouse anti-deoxynivalenol antibodies were compared for the development of a surface plasmon resonance (SPR)-based immunoassay for the selective and quantitative determination of deoxynivalenol in naturally contaminated matrices. A conjugate of deoxynivalenol with the protein casein was prepared and immobilized on the sensor chip surface. An excess of antibody was added to each test solution before the measurement. The assay was based on the competition for antibody binding between the immobilized deoxynivalenol conjugate on the sensor and the free deoxynivalenol molecules in the test solution. The deoxynivalenol-casein sensor could be reused more than 500 times without significant loss of activity using 6 M guanidine chloride solution for regeneration. The cross-reactivity of the three antibodies in the SPR assay was tested with other trichothecene mycotoxins (3-acetyl-deoxynivalenol, 15-acetyl-deoxynivalenol, nivalenol, HT2-toxin, and T2-toxin). The only sample preparation was extraction with max 80 vol % acetonitrile and 10-fold dilution with the running buffer. The assay had an optimal range between 2.5 and 30 ng/mL deoxynivalenol in the test solution. Most results of the SPR-based assay were in agreement with liquid chromatography/tandem mass spectrometry measurements of naturally contaminated wheat samples. 相似文献
93.
94.
Characterization of commercial kava-kava herbal drug and herbal drug preparations by means of nuclear magnetic resonance spectroscopy 总被引:1,自引:0,他引:1
Bilia AR Bergonzi MC Lazari D Vincieri FF 《Journal of agricultural and food chemistry》2002,50(18):5016-5025
The efficiency of one- and two-dimensional NMR experiments in characterizing the content of the constituents of both herbal drugs and herbal drug preparations is demonstrated for kava-kava. These experiments directly detect active constituents represented by kavalactones in both a finely powdered herbal drug and a commercial extract. In addition, NMR spectroscopy can detect all other compounds present in the extract. As previously evidenced, NMR experiments can represent a generally applicable technique for rapid screening and are a complement to the classical analytical techniques such as high-performance thin-layer chromatography, high-performance liquid chromatography, capillary gas chromatography, and electrophoresis. These experiments can be considered a very simple and fast analytical method to obtain a fingerprint of the herbal drugs and their preparations, and to quantify the content of the active principles of the extract. 相似文献
95.
96.
Fluorescence polarization immunoassay based on a monoclonal antibody for the detection of the organophosphorus pesticide parathion-methyl 总被引:11,自引:0,他引:11
Kolosova AY Park JH Eremin SA Kang SJ Chung DH 《Journal of agricultural and food chemistry》2003,51(5):1107-1114
A fluorescence polarization immunoassay (FPIA) based on a monoclonal antibody for the detection of parathion-methyl (PM) was developed and optimized. Fluorescein-labeled PM derivatives (tracers) with different structures were synthesized and purified by thin-layer chromatography. The influence of immunogen and tracer structures on the assay characteristics was investigated. PM concentration determinable by the FPIA ranged from 25 to 10000 ppb. The detection limit was 15 ppb. Methanol extracts of vegetable, fruit, and soil samples were diluted 1/10 for the analysis. Recovery in spiked samples averaged between 85 and 110%. The method developed is characterized by high specificity and reproducibility (CV ranged from 1.5 to 9.1% for interassay and from 1.8 to 14.1% for intra-assay). The FPIA method can be applied to the screening of food and environmental samples for PM residues without complicated cleanup. 相似文献
97.
Budanov AV Sablina AA Feinstein E Koonin EV Chumakov PM 《Science (New York, N.Y.)》2004,304(5670):596-600
Acting as a signal, hydrogen peroxide circumvents antioxidant defense by overoxidizing peroxiredoxins (Prxs), the enzymes that metabolize peroxides. We show that sestrins, a family of proteins whose expression is modulated by p53, are required for regeneration of Prxs containing Cys-SO(2)H, thus reestablishing the antioxidant firewall. Sestrins contain a predicted redox-active domain homologous to AhpD, the enzyme catalyzing the reduction of a bacterial Prx, AhpC. Purified Hi95 (sestrin 2) protein supports adenosine triphosphate-dependent reduction of overoxidized PrxI in vitro, indicating that unlike AhpD, which is a disulfide reductase, sestrins are cysteine sulfinyl reductases. As modulators of peroxide signaling and antioxidant defense, sestrins constitute potential therapeutic targets. 相似文献
98.
Pyle AM 《Science (New York, N.Y.)》2005,309(5740):1530-1531
The number of naturally occurring RNA enzymes has just been expanded by the discovery of a new branching ribozyme. But this ribozyme has unexpected relatives: group I introns. 相似文献
99.
Endocannabinoid hydrolysis generates brain prostaglandins that promote neuroinflammation 总被引:2,自引:0,他引:2
Nomura DK Morrison BE Blankman JL Long JZ Kinsey SG Marcondes MC Ward AM Hahn YK Lichtman AH Conti B Cravatt BF 《Science (New York, N.Y.)》2011,334(6057):809-813
Phospholipase A(2)(PLA(2)) enzymes are considered the primary source of arachidonic acid for cyclooxygenase (COX)-mediated biosynthesis of prostaglandins. Here, we show that a distinct pathway exists in brain, where monoacylglycerol lipase (MAGL) hydrolyzes the endocannabinoid 2-arachidonoylglycerol to generate a major arachidonate precursor pool for neuroinflammatory prostaglandins. MAGL-disrupted animals show neuroprotection in a parkinsonian mouse model. These animals are spared the hemorrhaging caused by COX inhibitors in the gut, where prostaglandins are instead regulated by cytosolic PLA(2). These findings identify MAGL as a distinct metabolic node that couples endocannabinoid to prostaglandin signaling networks in the nervous system and suggest that inhibition of this enzyme may be a new and potentially safer way to suppress the proinflammatory cascades that underlie neurodegenerative disorders. 相似文献
100.
Kicheva A Pantazis P Bollenbach T Kalaidzidis Y Bittig T Jülicher F González-Gaitán M 《Science (New York, N.Y.)》2007,315(5811):521-525
In the developing fly wing, secreted morphogens such as Decapentaplegic (Dpp) and Wingless (Wg) form gradients of concentration providing positional information. Dpp forms a longer-range gradient than Wg. To understand how the range is controlled, we measured the four key kinetic parameters governing morphogen spreading: the production rate, the effective diffusion coefficient, the degradation rate, and the immobile fraction. The four parameters had different values for Dpp versus Wg. In addition, Dynamin-dependent endocytosis was required for spreading of Dpp, but not Wg. Thus, the cellular mechanisms of Dpp and Wingless spreading are different: Dpp spreading requires endocytic, intracellular trafficking. 相似文献