全文获取类型
收费全文 | 1079篇 |
免费 | 83篇 |
国内免费 | 83篇 |
专业分类
林业 | 81篇 |
农学 | 88篇 |
基础科学 | 40篇 |
146篇 | |
综合类 | 465篇 |
农作物 | 69篇 |
水产渔业 | 55篇 |
畜牧兽医 | 128篇 |
园艺 | 76篇 |
植物保护 | 97篇 |
出版年
2024年 | 5篇 |
2023年 | 14篇 |
2022年 | 49篇 |
2021年 | 55篇 |
2020年 | 55篇 |
2019年 | 50篇 |
2018年 | 29篇 |
2017年 | 57篇 |
2016年 | 40篇 |
2015年 | 43篇 |
2014年 | 67篇 |
2013年 | 63篇 |
2012年 | 78篇 |
2011年 | 88篇 |
2010年 | 81篇 |
2009年 | 53篇 |
2008年 | 75篇 |
2007年 | 60篇 |
2006年 | 59篇 |
2005年 | 45篇 |
2004年 | 19篇 |
2003年 | 19篇 |
2002年 | 20篇 |
2001年 | 20篇 |
2000年 | 30篇 |
1999年 | 17篇 |
1998年 | 14篇 |
1997年 | 10篇 |
1996年 | 7篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1981年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有1245条查询结果,搜索用时 13 毫秒
1.
集雨农业是指收集、存储雨水径流并将其作为农村家庭人畜饮用水、环境卫生用水和农业补充灌溉用水的农业生产活动,包括收集、存储、输送、利用等多个过程,但目前各地的集雨农业技术研究多注重单项技术研究,而没有把它们当作一个整体来进行研究,导致许多地方出现收集与存储、收集与利用、存储与输送、存储与利用等脱节的现象,使各个环节的雨水利用转化效率普遍偏低。本文首先比较系统完整地提出了集雨农业雨水利用转化效率的概念,将集雨农业的雨水收集、雨水存储、雨水输送和雨水利用等各个过程看作一个整体进行研究分析,然后结合有关试验资料提出了提高集雨农业雨水利用转化效率的途径。 相似文献
2.
3.
福建省牛病毒性腹泻病的血清学调查 总被引:2,自引:0,他引:2
为了了解福建省牛感染牛病毒性腹泻(BVDV)的情况,本中心对福建省9个地区2006-2008年的15个非免疫牛场和56个散养户共计511份样品进行了该病的检测。结果规模场BVDV血清学阳性一直保持在较高的水平,年平均阳性率维持在80%以上,散养户BVDV血清学阳性,2006、2007、2008年的血清学阳性分别为12.3%,21.4%和18.5%。调查表明,我省规模牛场感染BVDV较为严重,散养户感染BVDV的数量在逐年增加。 相似文献
4.
5.
猪瘟是由猪瘟病毒引起的一种急性、发热性、接触性传染病,可引起各种年龄猪发病。随着对猪瘟病毒研究的深入,猪瘟在一定程度上得到了有效控制。但是近年来,世界各国流行的猪瘟在流行病学、临床症状和病理变化等方面出现了一些新的变化,猪瘟的防控出现了许多新的情况。我国猪瘟的发病率亦呈上升趋势,严重威胁着我国养猪业的发展,给养猪业造成了极大的经济损失。因此,建立准确的实验室诊断方法,对于预防和控制猪瘟有重要意义。本文综述了猪瘟诊断技术方面的研究进展,为猪瘟的及时诊断提供参考。 相似文献
6.
本研究旨在阐明猬迭宫绦虫湖南分离株线粒体烟酰胺腺嘌呤二核苷酸(NADH)脱氢酶亚单位5基因(nad5)部分序列(pnad5)和核糖体小亚基基因(rrnS)部分序列(prrnS)的遗传变异情况,并用pnad5和prrnS序列重构猬迭宫绦虫与其他绦虫的种群遗传关系。利用聚合酶链反应(PCR)扩增猬迭宫绦虫的pnad5和prrnS,应用ClustalX 1.81程序对序列进行比对,再用Phylip3.67程序MP法和Mega4.0程序NJ法绘制种系发育树,并用Puzzle5.2程序构建最大似然树。结果显示,所获得的pnad5和prrnS序列与预期(片段的)长度一致,分别为531bp和328bp。种系发育树表明,湖南分离株与已知猬迭宫绦虫位于同一分枝。结果表明,由于猬迭宫绦虫pnad5和prrnS序列种内相对保守,种间差异较大,均可作为种间遗传变异研究的标记。 相似文献
7.
Effect of chopping time and heating on 1H nuclear magnetic resonance and rheological behavior of meat batter matrix 下载免费PDF全文
Fen Zhou Hui Dong Jun‐Hua Shao Jun‐Long Zhang Deng‐Yong Liu 《Animal Science Journal》2018,89(4):695-702
The effect of chopping time and heating on physicochemical properties of meat batters was investigated by low‐field nuclear magnetic resonance and rheology technology. Cooking loss and L* increased while texture profile analysis index decreased between chopping 5 and 6 min. The relaxation time T21 (bound water) and its peak area ratio decreased, while the ratio of T22 peak area (immobilized water) in raw meat batters gradually increased with the extension of chopping time. However, T22 was opposite after being heated and a new component T23 (free water) appeared (T2i is the spin – spin relaxation time for the ith component.). The initial damping factor (Tan δ) gradually decreased and there were significant difference between 4 and 5 min of chopping time. There were significantly positive correlations between the ratio of peak area of T22 and chopping time, the storage modulus (G′), cooking loss, and L*, respectively. Continued chopping time could improve the peak area proportion of T22 in raw meat batters. Further, the higher the peak area proportion of T22 in raw meat batters, the cooking loss of heated meat gel was higher. Also, the stronger the mobility of immobilized water in meat batter, the higher the L* of the fresh meat batters. Thus, it is revealed that the physicochemical properties of meat batter are significantly influenced by chopping time which further affects the water holding capacity and the texture of emulsification gel. 相似文献
8.
9.
The purpose of the experiment was to study the effect of Momordica grosvenori saponins on improving the effect of high-sucrose/high-fat diet combined with streptozotocin induced type 2 diabetes in rats.The type 2 diabetes rat model was established with a high-sucrose and high-fat diet combined with streptozotocin.Successfully modeled rats were given the total saponins of Momordica grosvenori (100,200,400 mg/kg) or metformin (268 mg/kg) by gavage,once a day for 4 weeks.Recording the "three more and one less"index (24 h internal urine output,water intake and feed intake,body weight);Detecting of biochemical indicators,analysis of fasting blood glucose (FBG),serum total cholesterol (TC),triglycerides (TG),low-density lipoprotein cholesterol (LDL-C),high-density lipoprotein cholesterol (HDL-C),insulin (INS),catalase (CAT),superoxide dismutase (SOD),malondialdehyde (MDA),alanine aminotransferase (AST),aspartate aminotransferase (ALT),blood urea nitrogen (BUN) and creatinine (Cr) levels.Hematoxylin-eosin staining (HE) was used to observe the pathological changes of the pancreas.Compared with the model group,the feed intake,water intake,urine output,blood indicators FBG,INS,MDA,TC,TG,BUN and Cr levels,AST and ALT activities were significantly or extremely significantly decreased in the total saponins of Momordica grosvenori each dose group and metformin group (P<0.05;P<0.01),while CAT,SOD activities and HDL-C level were significantly or extremely significantly increased (P<0.05;P<0.01).In pancreatic tissue,the number of pancreatic cells was increased significantly,and the pathological damage of the pancreas was significantly reduced. Momordica grosvenori saponins and metformin had obvious effects on improving glucose metabolism disorders,and at the same time could significantly reduce insulin resistance,enhance the body’s ability to resist oxidative stress and improve liver and kidney functions. 相似文献
10.