全文获取类型
收费全文 | 15739篇 |
免费 | 82篇 |
国内免费 | 10篇 |
专业分类
教育 | 11906篇 |
科学研究 | 1522篇 |
各国文化 | 78篇 |
体育 | 662篇 |
综合类 | 3篇 |
文化理论 | 416篇 |
信息传播 | 1244篇 |
出版年
2023年 | 26篇 |
2022年 | 56篇 |
2021年 | 93篇 |
2020年 | 162篇 |
2019年 | 228篇 |
2018年 | 2388篇 |
2017年 | 2297篇 |
2016年 | 1767篇 |
2015年 | 270篇 |
2014年 | 310篇 |
2013年 | 1133篇 |
2012年 | 365篇 |
2011年 | 822篇 |
2010年 | 969篇 |
2009年 | 544篇 |
2008年 | 763篇 |
2007年 | 1239篇 |
2006年 | 169篇 |
2005年 | 456篇 |
2004年 | 503篇 |
2003年 | 417篇 |
2002年 | 178篇 |
2001年 | 50篇 |
2000年 | 69篇 |
1999年 | 29篇 |
1998年 | 32篇 |
1997年 | 45篇 |
1996年 | 25篇 |
1995年 | 24篇 |
1994年 | 23篇 |
1993年 | 25篇 |
1992年 | 19篇 |
1991年 | 35篇 |
1990年 | 13篇 |
1989年 | 20篇 |
1988年 | 13篇 |
1987年 | 24篇 |
1986年 | 20篇 |
1985年 | 25篇 |
1984年 | 21篇 |
1983年 | 17篇 |
1982年 | 20篇 |
1981年 | 12篇 |
1980年 | 12篇 |
1979年 | 16篇 |
1978年 | 13篇 |
1975年 | 7篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1971年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Bibliometric mapping of computer and information ethics 总被引:1,自引:0,他引:1
Richard Heersmink Jeroen van den Hoven Nees Jan van Eck Jan van den Berg 《Ethics and Information Technology》2011,13(3):241-249
This paper presents the first bibliometric mapping analysis of the field of computer and information ethics (C&IE). It provides
a map of the relations between 400 key terms in the field. This term map can be used to get an overview of concepts and topics
in the field and to identify relations between information and communication technology concepts on the one hand and ethical
concepts on the other hand. To produce the term map, a data set of over thousand articles published in leading journals and
conference proceedings in the C&IE field was constructed. With the help of various computer algorithms, key terms were identified
in the titles and abstracts of the articles and co-occurrence frequencies of these key terms were calculated. Based on the
co-occurrence frequencies, the term map was constructed. This was done using a computer program called VOSviewer. The term
map provides a visual representation of the C&IE field and, more specifically, of the organization of the field around three
main concepts, namely privacy, ethics, and the Internet. 相似文献
993.
Gordon Hull Heather Richter Lipford Celine Latulipe 《Ethics and Information Technology》2011,13(4):289-302
Social networking sites like Facebook are rapidly gaining in popularity. At the same time, they seem to present significant
privacy issues for their users. We analyze two of Facebooks’s more recent features, Applications and News Feed, from the perspective
enabled by Helen Nissenbaum’s treatment of privacy as “contextual integrity.” Offline, privacy is mediated by highly granular
social contexts. Online contexts, including social networking sites, lack much of this granularity. These contextual gaps
are at the root of many of the sites’ privacy issues. Applications, which nearly invisibly shares not just a users’, but a
user’s friends’ information with third parties, clearly violates standard norms of information flow. News Feed is a more complex
case, because it involves not just questions of privacy, but also of program interface and of the meaning of “friendship”
online. In both cases, many of the privacy issues on Facebook are primarily design issues, which could be ameliorated by an
interface that made the flows of information more transparent to users. 相似文献
994.
Thomas W. Simpson 《Ethics and Information Technology》2011,13(1):29-38
Trust online can be a hazardous affair; many are trustworthy, but some people use the anonymity of the web to behave very badly indeed. So how can we improve the quality of evidence for trustworthiness provided online? I focus on one of the devices we use to secure others’ trustworthiness: tracking past conduct through online reputation systems. Yet existing reputation systems face problems. I analyse these, and in the light of this develop some principles for system design, towards overcoming these challenges. In providing better evidence for trustworthiness online, so we can also encourage people actually to be trustworthy more often, which is an ethically welcome outcome. 相似文献
995.
The successful encapsulation of human hepatocellular carcinoma (HepG2) cells would greatly assist a broad range of applications in tissue engineering. Due to the harsh conditions during standard chitosan fiber fabrication processes, encapsulation of HepG2 cells in chitosan fibers has been challenging. Here, we describe the successful wet-spinning of chitosan-alginate fibers using a coaxial flow microfluidic chip. We determined the optimal mixing conditions for generating chitosan-alginate fibers, including a 1:5 ratio of 2% (w∕w) water-soluble chitosan (WSC) solution to 2% (w∕w) alginate solution. Ratio including higher than 2% (w∕w) WSC solution increased aggregation throughout the mixture. By suspending cells in the WSC-alginate solution, we successfully fabricated HepG2 cell-laden fibers. The encapsulated HepG2 cells in the chitosan-alginate fibers were more viable than cells encapsulated in pure alginate fibers, suggesting that cross-linked chitosan provides a better environment for HepG2 cells than alginate alone. In addition, we found that the adhesion of HepG2 cells on the chitosan-alginate fiber is much better than that on the alginate fibers. 相似文献
996.
Microfluidic techniques have been recently developed for cell-based assays. In microfluidic systems, the objective is for these microenvironments to mimic in vivo surroundings. With advantageous characteristics such as optical transparency and the capability for automating protocols, different types of cells can be cultured, screened, and monitored in real time to systematically investigate their morphology and functions under well-controlled microenvironments in response to various stimuli. Recently, the study of stem cells using microfluidic platforms has attracted considerable interest. Even though stem cells have been studied extensively using bench-top systems, an understanding of their behavior in in vivo-like microenvironments which stimulate cell proliferation and differentiation is still lacking. In this paper, recent cell studies using microfluidic systems are first introduced. The various miniature systems for cell culture, sorting and isolation, and stimulation are then systematically reviewed. The main focus of this review is on papers published in recent years studying stem cells by using microfluidic technology. This review aims to provide experts in microfluidics an overview of various microfluidic systems for stem cell research. 相似文献
997.
Raúl Rigo-Bonnin Noelia Díaz-Troyano Laura García-Tejada Albert Marc-Galindo Míriam Valbuena-Asensio Francesca Canalias 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2021,31(1)
Clinicians request a large part of measurements of biological quantities that clinical laboratories perform for diagnostic, prognostic or diseases monitoring purposes. Thus, laboratories need to provide patient’s results as reliable as possible. Metrological concepts like measurement uncertainty and metrological traceability allow to know the accuracy of these results and guarantee their comparability over time and space. Such is the importance of these two parameters that the estimation of measurement uncertainty and the knowledge of metrological traceability is required for clinical laboratories accredited by ISO 15189:2012. Despite there are many publications or guidelines to estimate the measurement uncertainty in clinical laboratories, it is not entirely clear what information and which formulae they should use to calculate it. On the other hand, unfortunately, there are a small number of clinical laboratories that know and describe the metrological traceability of their results, even though they are aware of the lack of comparability that currently exists for patient’s results. Thus, to try to facilitate the task of clinical laboratories, this review aims to provide a proposal to estimate the measurement uncertainty. Also, different suggestions are shown to describe the metrological traceability. Measurement uncertainty estimation is partially based on the ISO/TS 20914:2019 guideline, and the metrological traceability described using the ISO 17511:2020. Different biological quantities routinely measured in clinical laboratories are used to exemplify the proposal and suggestions. 相似文献
998.
999.
1000.
The combined use of dry cooling (DC) system and dedicated ventilation (DV) system to decouple cool-ing and dehumidification process for energy efficiency was proposed for subtropical climates like Hong Kong. In this study, the energy performance and condensation risk of the use of DCDV system were examined by analyzing its ap-plication in a typical office building in Hong Kong. Through hour-by-hour simulation using actual equipment per-formance data and realistic building and system characteristics, it was found that with the use of DCDV system, the annual energy consumption could be reduced by 54%in comparison with the conventional system (constant air vol-ume with reheat system). In respect of condensation risk, it was found that the annual frequency of occurrence of con-densation on DC coil was 35 h. Additional simulations were conducted to examine the influence of different parame-ters on the condensation risk of DCDV system. Measures to ensure condensate-free on DC coil were also discussed. 相似文献