全文获取类型
收费全文 | 18780篇 |
免费 | 87篇 |
国内免费 | 3篇 |
专业分类
教育 | 13876篇 |
科学研究 | 2147篇 |
各国文化 | 83篇 |
体育 | 816篇 |
综合类 | 2篇 |
文化理论 | 430篇 |
信息传播 | 1516篇 |
出版年
2021年 | 71篇 |
2020年 | 84篇 |
2019年 | 147篇 |
2018年 | 2334篇 |
2017年 | 2212篇 |
2016年 | 1702篇 |
2015年 | 207篇 |
2014年 | 246篇 |
2013年 | 1424篇 |
2012年 | 354篇 |
2011年 | 811篇 |
2010年 | 946篇 |
2009年 | 536篇 |
2008年 | 763篇 |
2007年 | 1241篇 |
2006年 | 182篇 |
2005年 | 490篇 |
2004年 | 560篇 |
2003年 | 441篇 |
2002年 | 219篇 |
2001年 | 127篇 |
2000年 | 137篇 |
1999年 | 105篇 |
1998年 | 70篇 |
1997年 | 85篇 |
1996年 | 81篇 |
1995年 | 73篇 |
1994年 | 55篇 |
1993年 | 87篇 |
1992年 | 108篇 |
1991年 | 117篇 |
1990年 | 110篇 |
1989年 | 94篇 |
1988年 | 87篇 |
1987年 | 103篇 |
1986年 | 93篇 |
1985年 | 103篇 |
1984年 | 89篇 |
1983年 | 96篇 |
1982年 | 96篇 |
1981年 | 76篇 |
1980年 | 75篇 |
1979年 | 100篇 |
1978年 | 90篇 |
1977年 | 84篇 |
1976年 | 77篇 |
1974年 | 69篇 |
1973年 | 64篇 |
1972年 | 55篇 |
1971年 | 58篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
This paper presents an approach aimed at creating business ontologies for knowledge codification in company. It is based on the principles of ontological engineering and cognitive psychology. Ontologies that describe the main concepts of knowledge are used both for knowledge creation and codification. The proposed framework is targeted at the development of methodologies that can scaffold the process of knowledge structuring and orchestrating for better understanding and knowledge sharing. The orchestrating procedure is the kernel of ontology development. The main stress is put on using visual techniques of mind mapping. Cognitive bias and some results of Gestalt psychology are highlighted as a general guideline. The ideas of balance, clarity, and beauty are applied to the ontology orchestrating procedures. The examples are taken mainly from the project management practice. The paper contributes to managerial practice by describing the practical recommendations for effective knowledge management based on ontology engineering and knowledge structuring techniques. 相似文献
992.
It has been argued that the Internet and social media increase the number of available viewpoints, perspectives, ideas and opinions available, leading to a very diverse pool of information. However, critics have argued that algorithms used by search engines, social networking platforms and other large online intermediaries actually decrease information diversity by forming so-called “filter bubbles”. This may form a serious threat to our democracies. In response to this threat others have developed algorithms and digital tools to combat filter bubbles. This paper first provides examples of different software designs that try to break filter bubbles. Secondly, we show how norms required by two democracy models dominate the tools that are developed to fight the filter bubbles, while norms of other models are completely missing in the tools. The paper in conclusion argues that democracy itself is a contested concept and points to a variety of norms. Designers of diversity enhancing tools must thus be exposed to diverse conceptions of democracy. 相似文献
993.
Rami Ali 《Ethics and Information Technology》2015,17(4):267-274
Luck (2009) argues that gamers face a dilemma when it comes to performing certain virtual acts. Most gamers regularly commit acts of virtual murder, and take these acts to be morally permissible. They are permissible because unlike real murder, no one is harmed in performing them; their only victims are computer-controlled characters, and such characters are not moral patients. What Luck points out is that this justification equally applies to virtual pedophelia, but gamers intuitively think that such acts are not morally permissible. The result is a dilemma: either gamers must reject the intuition that virtual pedophelic acts are impermissible and so accept partaking in such acts, or they must reject the intuition that virtual murder acts are permissible, and so abstain from many (if not most) extant games. While the prevailing solution to this dilemma has been to try and find a morally relevant feature to distinguish the two cases, I argue that a different route should be pursued. It is neither the case that all acts of virtual murder are morally permissible, nor are all acts of virtual pedophelia impermissible. Our intuitions falter and produce this dilemma because they are not sensitive to the different contexts in which games present virtual acts. 相似文献
994.
Tom Harrison 《Ethics and Information Technology》2015,17(4):275-283
This article draws on a study investigating how 11–14 year olds growing up in England understand cyber-bullying as a moral concern. Three prominent moral theories: deontology, utilitarianism and virtue ethics, informed the development of a semi-structured interview schedule which enabled young people, in their own words, to describe their experiences of online and offline bullying. Sixty 11–14 year olds from six schools across England were involved with the research. Themes emerging from the interviews included anonymity; the absence of rules, monitoring and guidance and, the challenges associated with determining the consequences of online actions. The findings demonstrate the advantages of adopting a character-based moral theory to compliment rules and/or consequence based moral theories as the basis for future research into cyber-bullying. The findings evoke some wider implications for future research into cyber-bullying that might equally be applied to investigations into other Internet related moral concerns. 相似文献
995.
A. Hokkanen I. Stuns P. Schmid A. Kokkonen F. Gao A. Steinecker J. Budczies P. Heimala L. Hakalahti 《Biomicrofluidics》2015,9(5)
We have developed a microfluidics based sampling system for tissue analytics. The proof-of-concept of the sampling system was demonstrated by extracting lipid samples from tissue biopsies. The sample collection system consists of a disposable silicon based multiport microneedle integrated with polymer microfluidics. The polymethyl methacrylate polymer microfluidic chip has a 10 μl sample reservoir and actuation membranes for liquid pumping. A special automated robotic system was developed to control the positioning of the needle and the sampling procedure on preselected spots on the tissue. Real breast cancer tissue samples were used to test the feasibility of the sampling system. We successfully measured indicative cancer biomarkers from the tissue surface. Phosphatidylcholine and phosphoethanolamine were extracted from the tissue membrane with methyl tert-butyl ether solvent and detected by mass spectrometry. In the future, this tool could be used in characterization of preoperative biopsies and tumour tissues removed during surgery. 相似文献
996.
A. Zaher S. Li K. T. Wolf F. N. Pirmoradi O. Yassine L. Lin N. M. Khashab J. Kosel 《Biomicrofluidics》2015,9(5)
Implantable drug delivery systems can provide long-term reliability, controllability, and biocompatibility, and have been used in many applications, including cancer pain and non-malignant pain treatment. However, many of the available systems are limited to zero-order, inconsistent, or single burst event drug release. To address these limitations, we demonstrate prototypes of a remotely operated drug delivery device that offers controllability of drug release profiles, using osmotic pumping as a pressure source and magnetically triggered membranes as switchable on-demand valves. The membranes are made of either ethyl cellulose, or the proposed stronger cellulose acetate polymer, mixed with thermosensitive poly(N-isopropylacrylamide) hydrogel and superparamagnetic iron oxide particles. The prototype devices'' drug diffusion rates are on the order of 0.5–2 μg/h for higher release rate designs, and 12–40 ng/h for lower release rates, with maximum release ratios of 4.2 and 3.2, respectively. The devices exhibit increased drug delivery rates with higher osmotic pumping rates or with magnetically increased membrane porosity. Furthermore, by vapor deposition of a cyanoacrylate layer, a drastic reduction of the drug delivery rate from micrograms down to tens of nanograms per hour is achieved. By utilizing magnetic membranes as the valve-control mechanism, triggered remotely by means of induction heating, the demonstrated drug delivery devices benefit from having the power source external to the system, eliminating the need for a battery. These designs multiply the potential approaches towards increasing the on-demand controllability and customizability of drug delivery profiles in the expanding field of implantable drug delivery systems, with the future possibility of remotely controlling the pressure source. 相似文献
997.
998.
Songliang Wang Claude Caldwell Liqing Wei Haiyan Su 《Frontiers of Education in China》2015,10(3):427-438
The Fujian Agriculture and Forestry University-Nova Scotia Agricultural College (FAFU-NSAC) 2 + 2 undergraduate program initiated in 2003 is a model for creative collaboration between China and Canada in undergraduate education. This paper addresses the achievements of the program development and highlights the process for successful curriculum development in the joint program. The authors also discuss some issues and challenges related to the Chinese-Canadian experience in undergraduate education, and propose some recommendations for further collaborations including: enlarging the scale of qualified programs; proposing a systematic baseline to control the program at a macro-level; simplifying coordination procedures with foreign partners; and adjusting the emphasis of courses introduced by the cooperative partner from quantity to quality. 相似文献
999.
1000.