全文获取类型
收费全文 | 612篇 |
免费 | 51篇 |
国内免费 | 1篇 |
专业分类
林业 | 35篇 |
农学 | 18篇 |
基础科学 | 12篇 |
168篇 | |
综合类 | 35篇 |
农作物 | 42篇 |
水产渔业 | 49篇 |
畜牧兽医 | 242篇 |
园艺 | 15篇 |
植物保护 | 48篇 |
出版年
2023年 | 8篇 |
2022年 | 14篇 |
2021年 | 47篇 |
2020年 | 32篇 |
2019年 | 26篇 |
2018年 | 27篇 |
2017年 | 29篇 |
2016年 | 35篇 |
2015年 | 22篇 |
2014年 | 27篇 |
2013年 | 30篇 |
2012年 | 42篇 |
2011年 | 57篇 |
2010年 | 39篇 |
2009年 | 25篇 |
2008年 | 34篇 |
2007年 | 27篇 |
2006年 | 22篇 |
2005年 | 24篇 |
2004年 | 24篇 |
2003年 | 16篇 |
2002年 | 25篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1977年 | 1篇 |
1970年 | 1篇 |
1950年 | 1篇 |
排序方式: 共有664条查询结果,搜索用时 15 毫秒
561.
孵化场对一日龄雏鸡进行免疫接种可给产业链带来利益,但是要应用良好的卫生标准。在孵化场内进行早期的疫苗接种带给雏鸡健康和雏鸡质量的好处是众所周知的,近几十年来临床上已经得到广泛的应用。然而,理想的种蛋孵化环境也是致病性细菌、病毒、霉菌的最佳繁殖场所, 相似文献
562.
Mateus de Souza Ribeiro Mioni Bruna Letícia Devid Ribeiro Marina Gea Peres Wanderson Sirley Reis Teixeira Vanessa Cristina Pelícia Rodrigo Garcia Motta Marcelo Bahia Labruna Mrcio Garcia Ribeiro Karim Sidi‐Boumedine Jane Megid 《Zoonoses and public health》2019,66(6):695-700
Coxiella burnetii is a zoonotic pathogen with a worldwide distribution that is responsible for Q fever in humans. It is a highly infectious bacterium that can be transmitted from cattle to humans through the consumption of unpasteurized milk. We report the molecular identification of C. burnetii in raw cow's milk being sold directly for human consumption in Brazil without official inspection or pasteurization. One hundred and twelve samples of raw milk were analysed by real‐time quantitative PCR (qPCR), and C. burnetii was detected in 3.57% (4/112) of the samples at a concentration ranging from 125 to 404 bacteria per millilitre. The identification of this zoonotic pathogen in raw milk sold directly for human consumption is a public health concern since C. burnetii can be transmitted through the oral route. This result indicates that health education and other preventive measures should be officially implemented in Brazil to prevent the spread of infection. To our knowledge, this is the first qPCR‐based detection of C. burnetii in raw milk samples from cows sold in Brazil that do not undergo official inspection or pasteurization. 相似文献
563.
564.
565.
Raúl Hernando Posada Gabriela Heredia-Abarca Ewald Sieverding Marina Sánchez de Prager 《Archives of Agronomy and Soil Science》2013,59(2):185-196
Almost 900 fungal isolates were obtained from eight coffee plantations in Colombia and Mexico. Of these, 76 isolates showed activity to solubilize Ca3(PO4)2 (PCa) and FePO4·H2O (PFe), which had been added to agar in a plate test. Generally, PCa was better solubilized than PFe. Colombian isolates were generally somewhat less effective than Mexican isolates. The two most effective isolates from each country with apparent highest PFe, solubilization potential were selected and cultivated in liquid medium containing PFe, which is more prevalent in tropical soils. The pH value, solubilized P in the medium and P uptake in fungal biomass were determined. After 24 days, Cylindrocarpon didymum and C. obtusisporum (both from Colombia) had solubilized 9.9 and 6.4 mg PO4 3--P L?1 and took up 8.6 and 11.6 mg P in biomass. Penicillium janthinellum and Paecilomyces marquandii (both from Mexico) solubilized 7.0 and 1.9 mg PO4 3--P L?1 and took up 11.3 and 17.3 mg P in biomass. The potential practical use of the four fungal isolates for different strategies in making more P available for coffee growth is discussed. 相似文献
566.
567.
Changes in root morphology and acid phosphatase activity (APA) were followed during the developent of P‐deficiency in tomato plants grown for 7, 14, and 21 days in 0.16 P well aereated nutrient solutions, followed by a period of sufficiency (recovery) in 1 mM P. Plants were harvested weekly for APA, dry weight, and P concentration in roots, stems and leaves, and every 2 weeks for root morphology determinations. APA was highly correlated to development and recovery from P stress. Mixmium values were attained during growth under deficiency and decreased to that of the control plants after a period of recovery in 1 mM P nutrient solutions. Total root weight and average root diameter decreased under P‐stress and root surface area per unit dry weight increased. Efficiency of P utilization (g dry weight/mg absorbed P) was much higher at the end of the stress period but approached that of the controls as P‐supply was restored to sufficiency levels. The implications of these results in developing rapid and reliable screening technigues to detect successful plant performance under P‐stress is discussed. 相似文献
568.
Phytoparasitica - During a study on soft scales (Hemiptera: Coccomorpha: Coccidae) and their natural enemies in Serbia, the parasitoid Coccophagus shillongensis Hayat and Singh 1989 (Hymenoptera:... 相似文献
569.
Paula Gonzlez-Andrs Laura Fernndez-Pea Carlos Díez-Poza Carlos Villalobos Lucía Nuez Asuncin Barbero 《Marine drugs》2021,19(2)
Intracellular Ca2+ plays a pivotal role in the control of a large series of cell functions in all types of cells, from neurotransmitter release and muscle contraction to gene expression, cell proliferation and cell death. Ca2+ is transported through specific channels and transporters in the plasma membrane and subcellular organelles such as the endoplasmic reticulum and mitochondria. Therefore, dysregulation of intracellular Ca2+ homeostasis may lead to cell dysfunction and disease. Accordingly, chemical compounds from natural origin and/or synthesis targeting directly or indirectly these channels and proteins may be of interest for the treatment of cell dysfunction and disease. In this review, we show an overview of a group of marine drugs that, from the structural point of view, contain one or various heterocyclic units in their core structure, and from the biological side, they have a direct influence on the transport of calcium in the cell. The marine compounds covered in this review are divided into three groups, which correspond with their direct biological activity, such as compounds with a direct influence in the calcium channel, compounds with a direct effect on the cytoskeleton and drugs with an effect on cancer cell proliferation. For each target, we describe its bioactive properties and synthetic approaches. The wide variety of chemical structures compiled in this review and their significant medical properties may attract the attention of many different researchers. 相似文献
570.