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   14820篇
  免费   200篇
  国内免费   10篇
教育   10879篇
科学研究   1238篇
各国文化   92篇
体育   1159篇
综合类   8篇
文化理论   90篇
信息传播   1564篇
  2021年   117篇
  2020年   167篇
  2019年   284篇
  2018年   373篇
  2017年   394篇
  2016年   368篇
  2015年   230篇
  2014年   313篇
  2013年   2748篇
  2012年   330篇
  2011年   388篇
  2010年   257篇
  2009年   239篇
  2008年   352篇
  2007年   247篇
  2006年   316篇
  2005年   208篇
  2004年   201篇
  2003年   187篇
  2002年   228篇
  2001年   339篇
  2000年   304篇
  1999年   285篇
  1998年   138篇
  1997年   161篇
  1996年   186篇
  1995年   179篇
  1994年   145篇
  1993年   172篇
  1992年   242篇
  1991年   215篇
  1990年   215篇
  1989年   250篇
  1988年   249篇
  1987年   211篇
  1986年   212篇
  1985年   223篇
  1984年   192篇
  1983年   237篇
  1982年   174篇
  1981年   160篇
  1980年   160篇
  1979年   232篇
  1978年   187篇
  1977年   168篇
  1976年   151篇
  1975年   130篇
  1974年   119篇
  1973年   128篇
  1971年   109篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
This paper is an attempt to present disclosive ethics as a framework for computer and information ethics – in line with the suggestions by Brey, but also in quite a different manner. The potential of such an approach is demonstrated through a disclosive analysis of facial recognition systems. The paper argues that the politics of information technology is a particularly powerful politics since information technology is an opaque technology – i.e. relatively closed to scrutiny. It presents the design of technology as a process of closure in which design and use decisions become black-boxed and progressively enclosed in increasingly complex socio-technical networks. It further argues for a disclosive ethics that aims to disclose the nondisclosure of politics by claiming a place for ethics in every actual operation of power – as manifested in actual design and use decisions and practices. It also proposes that disclosive ethics would aim to trace and disclose the intentional and emerging enclosure of politics from the very minute technical detail through to social practices and complex social-technical networks. The paper then proceeds to do a disclosive analysis of facial recognition systems. This analysis discloses that seemingly trivial biases in recognition rates of FRSs can emerge as very significant political acts when these systems become used in practice. Paper prepared for the Technology and Ethics Workshop at Twente  相似文献   
992.
Sixteen weeks of chronic vitamin C deficiency, induced in guinea pigs by restricted vitamin C intake, resulted in a marked increase in the serum total LDL- and VLDL- cholesterol, triglycerides and total lipids. HDL-cholesterol decreased resulting in a highly significant increase in LDL/HDL ratio. The results reconfirm that vitamin C deficiency causes changes in blood lipid profile which could promote atherogenesis.  相似文献   
993.
Infertility is well-established harmful effect in chronic alcoholism and so far, there is no effective treatment for this condition. The study was conducted to determine the effects of alpha tocopherol on ethanol induced testicular injuries in male albino rats of Wistar strain. Five groups (n=6) of animals were used. Group I served as control. Group II received daily 1.6g ethanol/kg body weight/day for 4 weeks orally. Group III received 1.6g ethanol+80mg alpha tocopherol/kg body weight/day for four weeks orally. Group IV received 1.6g ethanol/kg body weight for/day 4 weeks and followed by 80mg alpha tocopherol/kg body weight/day for four weeks orally. Group V received 1.6g ethanol/kg body weight/day orally for 4 weeks, followed by 4 weeks abstinence. Twently-four hours after the last treatment the rats were sacrificed using anesthetic ether. Testes were removed and used for the estimation of extent of lipid peroxidation and tissue levels of antioxidants and steroidogenic enzymes. Alpha tocopherol treatment increased the activities of testicularΔ 5, 3β-HSD. Moreover, the treatment was also associated with significant decrease in testicular oxidative stress. Ethanol-induced oxidative stress and decreased steroidogenesis can be reversed by treatment with alpha tocopherol.  相似文献   
994.
任何一个复杂的问题都是近乎无数的事实和关系的组合。商业行为尤其受到方方面面的影响,包括过去的、非逻辑的和不可知的事物的影响。这种复杂性又因目标不同与服务于各种各样的顾客的需要而更加盘根错节,而顾客的许多目标不得不经过权衡后放弃。在这样复杂的条件下解决问题需要井井有条的、系统的方法以试图优化最后的决定。  相似文献   
995.
996.
It is shown that a p+q node graph Gc representation can be drawn for a chessboard C(p,q) i.e. an array of p rows and q columns. It is shown further that the coefficients of the rook polynomial for C(p,q) correspond 1:1 inversely with the coefficients of the chromatic polynomial for Gc written in factorial form.  相似文献   
997.
Aim of present study was to compare the adenosine deaminase (ADA) activity in various types of arthritis conditions with synovial effusion. No. significant difference was observed in ADA activity in serum of control and study groups but results have shown a definite pattern of ADA activity in synovial fluid in various arthritic conditions. The highest value of ADA activity was observed in synovial fluid of patients with tubercular arthritis followed by rheumatoid, septic, osteo and post traumatic arthritis. Thus measurement of ADA activity in synovial fluid can be used as a parameter of differential diagnosis of arthritis specially tubercular in initial stages.  相似文献   
998.
For some 300 years the modelling of uncertainty in the sciences has been totally dominated by probabilistic methods. Now, following major criticism of the theoretical foundations of probability theory, other approaches to dealing with uncertainty are being explored.  相似文献   
999.
1000.
In response to both problematic and extant gaps in Bachelor??s degree completion rates, this mixed methods study investigated whether a theoretically based undergraduate course intervention measurably contributed to participants?? competence as self-regulated learners. Respective quantitative and qualitative analyses of data collected from two samples showed that intervention participants experienced growth in the targeted self-regulatory constructs. Moreover, differential effects by race/ethnicity and gender were not observed. We conclude with a discussion of this study??s implications for institutions of higher education, pertinent considerations in designing and implementing this self-regulated learning intervention, and a review of the literature on effective practices for doing so.  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