全文获取类型
收费全文 | 54843篇 |
免费 | 1099篇 |
国内免费 | 1332篇 |
专业分类
教育 | 30230篇 |
科学研究 | 10944篇 |
各国文化 | 250篇 |
体育 | 3739篇 |
综合类 | 3258篇 |
文化理论 | 185篇 |
信息传播 | 8668篇 |
出版年
2024年 | 6篇 |
2023年 | 58篇 |
2022年 | 639篇 |
2021年 | 1467篇 |
2020年 | 1039篇 |
2019年 | 570篇 |
2018年 | 643篇 |
2017年 | 685篇 |
2016年 | 667篇 |
2015年 | 1838篇 |
2014年 | 2831篇 |
2013年 | 3649篇 |
2012年 | 4074篇 |
2011年 | 4581篇 |
2010年 | 4227篇 |
2009年 | 3737篇 |
2008年 | 3737篇 |
2007年 | 4226篇 |
2006年 | 4192篇 |
2005年 | 3285篇 |
2004年 | 1841篇 |
2003年 | 1693篇 |
2002年 | 1602篇 |
2001年 | 1519篇 |
2000年 | 1004篇 |
1999年 | 883篇 |
1998年 | 589篇 |
1997年 | 427篇 |
1996年 | 349篇 |
1995年 | 228篇 |
1994年 | 218篇 |
1993年 | 173篇 |
1992年 | 153篇 |
1991年 | 98篇 |
1990年 | 40篇 |
1989年 | 72篇 |
1988年 | 36篇 |
1987年 | 15篇 |
1986年 | 38篇 |
1985年 | 22篇 |
1984年 | 27篇 |
1983年 | 27篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1976年 | 2篇 |
1974年 | 3篇 |
1957年 | 21篇 |
1951年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
851.
852.
本文根据K.Pearson X~2的检验法,对中国工商银行浙江省分行1981年1月~1987年12月所有的由摇奖机摇出的有奖储蓄的中奖号码,利用电子计算机进行了统计分析.运算结果肯定了中国工商银行浙江省分行目前的摇奖方法是可靠的.也就是说,每个月在全省的某一地、市、县轮流用不同的摇奖机、不同的号珠,由不同的操作人员摇出中奖号码的方法,是行得通的.同时也指出,广大储户完全没有必要去择号购奖券,甚至买好以后再去调换所谓“中意的奖券,因为相对于信度10%而言,我们肯定了假设H:0~9这十个号珠中的每一个被摇奖机摇出的概率是相等的.” 相似文献
853.
This quasi-experimental study examined the effects of a self-reflection intervention on college (college in this article refers to university-level education) students’ positive thinking, learning motivation and self-regulation in Taiwan. One hundred and two college students were selected to participate in an 18-week intervention forming the experimental group (EG) which emphasized providing main lecture, role-play, self-reflection activity, group discussion and group work. Another 179 college students from two other courses were selected as a comparison group. This study showed that supportive, resourced discussion with peers and instructor, self-reflection activities and assignment as a facilitative agent improved the EG students’ positive thinking, learning motivation and self-regulation. In addition, three structural equation models revealed that positive thinking had a strong and direct relation to Taiwanese college students’ pretest learning motivation (β?=?.85) and self-regulation (β?=?.77); learning motivation had a strong and direct relation to students’ pretest positive thinking (β?=?.86) and self-regulation (β?=?.81); and self-regulation had a strong and direct relation to students’ pretest positive thinking (β?=?.83) and learning motivation (β?=?.86). Instructional implications and research recommendations are discussed. 相似文献
854.
知识型企业能力集优化及其组织智商 总被引:1,自引:0,他引:1
知识型企业是具有动态优化能力集合的有机生命体 .为具备快速应变能力 ,知识型企业在组织结构上应是由智能单元、中央决策智能单元通过适时、适当连接形成的动态网络 .本文基于知识型企业的生存与发展的定义 ,给出知识型企业生命体动态优化的能力集的子集———能力基的概念 ,研究了能力基的动态优化过程 ;本文证明了知识型企业生命体智能单元间联权重的变化率———生命体智商 ,随知识型企业生命体应变能力的提高而提高 ;应变能力的提高 ,通过智能单元间权重的变化而实现 相似文献
855.
856.
胡明花 《北京城市学院学报》2001,(4):125-127
通过科技成果转让及中介服务专业2000级生的暑期实习,文章总结了学生实习中的所学所感,提出当代大学生应进一步加强综合素质的培养,以适应社会各行业的需求. 相似文献
857.
A new site-specific nutrient management approach was developed to break the apparent attainable yield barrier of 6 t·ha−1 in the double rice cropping system of Zhejiang. On-farm experiments involving 21 rice-growing farmer families and NPK long-term
experiments commenced in 1997 in the central part of Zhejiang Province to assess the status of soil fertility and productivity
under intensive rice-rice cropping. A new site-specific nutrient management (SSNM) approach has been developed for this studied
area. Field-specific fertilizer recommendations are calculated considering indigenous nutrient supply, reasonable grain yield
targets and corresponding nutrient demand, nutrient balance and nutrient use efficiency, as well as socio-economic factors.
The agronomic performance of SSNM was tested against the farmer's fertilizer practice (FFP) in four 1998–1999 cropping seasons.
Across seasons and years, SSNM consistently increased plant nutrient uptake, grain yield and profit by about 10%–15% compared
to the FFP. Yield levels of 7.5 t·ha−1 or more seem achievable and sustainable through introduction of SSNM and improved extension services in Zhejiang Province.
Project supported by the International Fertilizer Industry Association(IFA), the Potash and Phosphate Institute, Canada (PPIC),
and International Potash Institute(IPI). 相似文献
858.
A novel floating foundation to support the NREL offshore 5 MW wind turbine was designed conceptually by combining the characteristics of barge and Spar. The main focus was structural design and hydrodynamic modelling. Based on this novel floating foundation, the hydrodynamic performance was investigated in the frequency domain and time domain by using the wave analysis software HydroD and DeepC from Det Norske Veritas. The frequency domain analysis was conducted to investigate the effects of the incident wave angle and water depth. The time-domain analysis was carried out to evaluate the response of the floating foundation under a selected operational condition. The hydrodynamic performances of this floating foundation with respect to time series and response spectra were also investigated in this study. 相似文献
859.
Chang Xin Zhang Chengyu Gao Lan Liu Xiao You Shengping Qi Wei Wang Kang Guo Xin Su Rongxin Lu Han He Zhimin 《天津大学学报(英文版)》2019,25(5):488-496
2,5-Furandicarboxylic acid(FDCA) is a potential biorenewable chemical for applications including plastics, polyamides, drugs, etc. The selective biosynthesis of FDCA from 5-hydroxymethylfurfural(HMF) by a specific enzyme poses a great challenge. In this study, we reported an efficient strategy to produce FDCA from HMF by the tandem biocatalysis of laccase(Cot A-TJ102@UIO-66-NH_2) and Novozym 435. For the first step, a nanoparticle metal–organic framework was synthesized as a carrier to immobilize Cot A-TJ102@UIO-66-NH_2, which was assigned for the production of 5-formyl-2-furancarboxylic acid(FFCA) and featured an enzyme loading of 255.54 mg/g, specific activity of 135.90 U/mg, and solid loading ratio of 99.65%. Under optimal conditions, an ideal FFCA yield of 98.5% was achieved, and the Cot A-TJ102@UIO-66-NH_2 presented a high recycling capacity after 10 cycles. For the second step, Novozym 435 was applied for the further conversion of FFCA into FDCA, presenting a high FDCA yield of 95.5% under the optimized conditions. Novozym 435 also exhibited a high recyclability after eight cycles. As a result, the tandem biocatalysis strategy provided a 94.2% FDCA yield from HMF, indicating its excellence as a method for FDCA production. 相似文献
860.
中国共产党作为我国的执政党,其执政方式的确立及演变有一个历史过程,取决于各方面的因素。在新的历史条件下,也要适应国情和社会环境的变化而不断的改进,从而使党的领导效能趋向优化,更快的把我们国家带入现代化社会。本文就试图从法律角度来研究我党执政方式的演变与改进,更好的推进依法治国方略的贯彻实施。 相似文献