首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1664篇
  免费   194篇
  国内免费   18篇
林业   212篇
农学   92篇
基础科学   75篇
  122篇
综合类   962篇
农作物   24篇
水产渔业   158篇
畜牧兽医   149篇
园艺   19篇
植物保护   63篇
  2024年   1篇
  2023年   49篇
  2022年   44篇
  2021年   87篇
  2020年   56篇
  2019年   64篇
  2018年   54篇
  2017年   73篇
  2016年   68篇
  2015年   68篇
  2014年   95篇
  2013年   127篇
  2012年   134篇
  2011年   142篇
  2010年   105篇
  2009年   104篇
  2008年   94篇
  2007年   102篇
  2006年   94篇
  2005年   68篇
  2004年   40篇
  2003年   45篇
  2002年   36篇
  2001年   37篇
  2000年   22篇
  1999年   12篇
  1998年   7篇
  1997年   9篇
  1996年   3篇
  1995年   8篇
  1994年   1篇
  1993年   8篇
  1992年   4篇
  1991年   1篇
  1990年   8篇
  1988年   2篇
  1987年   2篇
  1985年   2篇
排序方式: 共有1876条查询结果,搜索用时 21 毫秒
1.
[目的/意义]各级政府鼓励和支持社会力量参与公共数字文化服务建设,为政社合作共建公共文化服务平台提供了良好契机。[方法/过程]文章梳理了基层公共文化服务平台政社共建的相关文献,结合政府与社会力量的角色作用、平台资源与服务的建设导向,分析了基层公共文化服务平台的政社共建模式,并结合政社共建平台的实践案例,分析其政社共建现状和取得的服务成效,指出政社共建平台存在的不足。[结果/结论]提出针对性的优化策略,旨在发挥政府与社会力量共建的强大合力,为提升中国基层公共数字文化服务效能提供参考。  相似文献   
2.
3.
本研究旨在通过分析包容性生态规划中各利益相关者的作用,指出其能够推动社会治理范式的转换。生态规划是中国正在推行的区域国土空间规划的一项重要内容,它是沟通自然与社会生态系统的桥梁,通过生态规划过程推进基层社会治理能力是区域国土空间规划能够取得成效的关键。本研究基于2000年以来的研究和实践,分析生态规划中基层政府及其部门、公众、规划师、其他社会力量等各方在生态规划的编制、实施、监测与评估等交互合作过程中的作用,将生态规划面临的两种社会治理范式进行了比较,指出生态规划包容合作的治理范式有能力助力社会治理范式转换。通过对包容性生态规划过程的描述,指出可以通过其具体过程中协调主体间性的方式助力社会治理转变为各利益相关者共同参与的、多方合作的治理体系和多元协商平台。  相似文献   
4.
流浪犬猫是生存于人类社会、介于宠物犬猫和野生动物之间的一类特殊动物,其生存、活动、繁衍与社区人群的利益有时会产生直接冲突。本文介绍了流浪犬猫福利的特征和内涵,指出了其存在传播狂犬病、易攻击人类、粪便污染、噪声污染等与人群利益的有关冲突,由此提出减少遗弃宠物遗弃,减少食物浪费,加强社区公共管理等人为因素控制措施,以及对流浪犬猫实施安乐死,重新收养以及人工绝育等方式化解两者利益冲突,同时优化管理政策措施,平衡流浪犬猫福利和人群利益的关系。  相似文献   
5.
基于IPA分析的上海典型滨江公共空间游憩满意度   总被引:1,自引:0,他引:1  
上海黄浦滨江是国内滨水区建设的代表,如今已完成核心段两岸公共空间贯通,但各段发展并不均衡。文章以两岸4段典型公共空间为例,对社交媒体数据进行IPA分析,得到影响滨江各段公共空间游憩满意度的主要因素,并进一步通过方差分析了解4段滨江之间的差异情况。结果表明:1)滨江公共空间整体游憩满意度较高,但多段商业服务、外部交通、管理维护因素的满意度偏低;2)满意度由高到低为:徐汇滨江>世博滨江>杨浦滨江>虹口滨江,体现3种不同的发展程度;3)不同段影响游憩满意度的主要因素不同。最后,根据研究结果对浦江两岸公共空间提出优化建议,以期为城市滨水区规划设计提供有效的技术支持和决策依据。  相似文献   
6.
乡村社会对我国时代改革进程有举足轻重的作用。随着现代化建设的不断深入,现有的乡村治理机制显然跟不上乡村社会结构性变革的步伐,各种治理困境和挑战层出不穷。其在治理层面的主要表现是开放流动的乡村社会现状与封闭排他、僵化保守和过分依靠行政权力的传统乡村治理模式存在明显背离。因此,要想突破乡村发展的制度性障碍,化解现有的治理困境,有序推动乡村社会的现代化改革,需要将乡村社会协同参与机制、农村经济合作治理模式、统筹城乡整体发展作为治理导向,构建乡村社会治理机制的发展新路径。  相似文献   
7.
Although pork producers typically aim to optimize growth rates, occasionally it is necessary to slow growth, such as when harvest facility capacity is limited. In finishing pigs, numerous dietary strategies can be used to slow growth so pigs are at optimal slaughter body weights when harvest facility capacity and/or access is restored. However, the impact of these diets on pork carcass quality is largely unknown. Thus, this study aimed to evaluate the efficacy of dietary strategies to slow growth in late finishing pigs and evaluate their effects on carcass composition and pork quality. Mixed-sex pigs (n = 897; 125 ± 2 kg BW) were randomly allotted across 48 pens and assigned to 1 of 6 dietary treatments (n = 8 pens/treatment): (1) Control diet representative of a typical finisher diet (CON); (2) diet containing 3% calcium chloride (CaCl2); (3) diet containing 97% corn and no soybean meal (Corn); (4) diet deficient in isoleucine (LowIle); (5) diet containing 15% neutral detergent fiber (NDF) from soybean hulls (15% NDF); and (6) diet containing 20% NDF from soybean hulls (20% NDF). Over 42 d, pen body weights and feed disappearance were collected. Pigs were harvested in 3 groups (14, 28, and 42 d on feed) and carcass data collected. From the harvest group, 1 loin was collected from 120 randomly selected carcasses (20 loins/treatment) to evaluate pork quality traits. Overall, ADG was reduced in CaCl2, Corn, and 20% NDF pigs compared with CON pigs (P < 0.001). However, ADFI was only reduced in CaCl2 and 20% NDF pigs compared with CON (P < 0.001). Feed efficiency was reduced in CaCl2 and Corn pigs compared with CON (P < 0.001). Hot carcass weights were reduced in CaCl2 pigs at all harvest dates (P < 0.001) and were reduced in Corn and 20% NDF pigs at days 28 and 42 compared with CON pigs (P < 0.001). In general, CaCl2 and 20% NDF diets resulted in leaner carcasses, whereas the Corn diet increased backfat by 42 d on test (P < 0.05). Loin pH was reduced and star probe increased in CaCl2 pigs compared with CON pigs (P < 0.05); no treatments differed from CON pigs regarding drip loss, cook loss, color, firmness, or marbling (P ≥ 0.117). Overall, these data indicate that several dietary strategies can slow finishing pig growth without evidence of behavioral vices. However, changes to carcass composition and quality were also observed, indicating quality should be taken into consideration when choosing diets to slow growth.  相似文献   
8.
Social security has, as one of its primary aims, the provision of financial support to those deemed to be poor or facing the threat of poverty. Based on China's national statistical data covering social insurance, social assistance, and social welfare between the period 1978–2018, this paper evaluates the effect of social security expenditure in reducing income inequality and rural poverty with cointegration analysis. It was found that there is a positive correlation between social security expenditure and the income gap of urban and rural residents in the long run, but the effect is very limited; nearly 99% of the changes of the urban–rural income gap come from its own contributions. Further research also shows that the elasticity of rural poverty incidence to social security expenditure is –0.2255, which indicates social security expenditure helps reduce rural absolute poverty. Based on these findings, the policy implications can be that much social security expenditure and a more equitable social security system should be encouraged. It will become one of the major anti-poverty strategies after 2020 in China when we win the battle against absolute poverty.  相似文献   
9.
车红莉 《中国农学通报》2018,34(34):159-164
家庭农场作为一种新的农业组织形式近年来在国内得到大力推广,但北京家庭农场的发展还处于试点阶段,没有形成适合的模式,对北京在试点过程中出现的规模标准缺失、劳动力缺乏、土地使用和劳动力成本高、市场运作能力弱、融资难等问题进行分析研究,借鉴国内外家庭农场发展的成功经验,提出北京家庭农场的发展要因地制宜,以特色农产品为抓手进行专业化生产,发展生态型家庭农场,进行市场化经营,同时要加强政策引导、制度保障和农场主培训等,从而形成适宜北京的家庭农场发展模式。  相似文献   
10.
This paper presents the development of a simple and generally applicable hydrodynamic method for the estimation of production carrying capacity (PCC) of coastal finfish cage aquaculture. Dimensional analysis was used to find significant and general interdependencies between the hydrodynamics at fish farm locations and particulate wastes deposited on the seafloor by fish farms. Modeled ratios of deposition to emission of particulate wastes underneath fish farms were found to be primarily a function of the flow Reynolds numbers at the farming locations and the non-dimensional settling velocity of emitted wastes. In the non-dimensional model, farming conditions include daily feed rate, proportion of unconsumed feed, and carbon content in feed and fish feces. The relationship can be used to estimate the PCC of floating net cages imposing a threshold value for deposition. Results of in-situ assessments of the benthic impacts of several fish farms in an aquaculture site in the northwest of Bali, Indonesia were used to validate and demonstrate the effectiveness of the method. Predicted results were able to clearly identify fish farms operating beyond ecologically sustainable carrying capacity. The proposed method has broad applicability and could help make decisions regarding the estimation of production potential of individual farms in pristine areas, for providing first estimates in sites that have scarce data, and for assessment, expansion, and optimization of the currently operating aquaculture sites in Southeast Asia, China and potentially other data-poor island nations. As the method relies on dynamic models, it enables straightforward assessments over the entire aquaculture region.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号