全文获取类型
收费全文 | 23644篇 |
免费 | 131篇 |
出版年
2022年 | 18篇 |
2021年 | 19篇 |
2020年 | 40篇 |
2019年 | 57篇 |
2018年 | 3536篇 |
2017年 | 2866篇 |
2016年 | 2314篇 |
2015年 | 265篇 |
2014年 | 152篇 |
2013年 | 415篇 |
2012年 | 712篇 |
2011年 | 2512篇 |
2010年 | 2607篇 |
2009年 | 1563篇 |
2008年 | 1834篇 |
2007年 | 2326篇 |
2006年 | 164篇 |
2005年 | 324篇 |
2004年 | 274篇 |
2003年 | 239篇 |
2002年 | 197篇 |
2001年 | 94篇 |
2000年 | 100篇 |
1999年 | 82篇 |
1998年 | 81篇 |
1997年 | 70篇 |
1996年 | 67篇 |
1995年 | 40篇 |
1994年 | 44篇 |
1993年 | 43篇 |
1992年 | 54篇 |
1991年 | 43篇 |
1990年 | 56篇 |
1989年 | 35篇 |
1988年 | 30篇 |
1987年 | 32篇 |
1986年 | 36篇 |
1985年 | 38篇 |
1984年 | 50篇 |
1983年 | 36篇 |
1982年 | 50篇 |
1981年 | 39篇 |
1980年 | 32篇 |
1979年 | 31篇 |
1978年 | 20篇 |
1977年 | 29篇 |
1976年 | 27篇 |
1975年 | 14篇 |
1974年 | 17篇 |
1973年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
801.
This paper examines the issue of acid mine drainage in South Africa and environmental decision making processes that could be taken to mitigate the problem in the context of both conventional risk assessment and the precautionary principle. It is argued that conventional risk assessment protects the status quo and hence cannot be entirely relied upon as an effective tool to resolve environmental problems in the context of South Africa, a developing country with complex environmental health concerns. The complexity of the environmental issues is discussed from historical and political perspectives. An argument is subsequently made that the precautionary principle is an alternative tool, and its adoption can be used to empower local communities. This work, therefore, adds to new knowledge by problematising conventional risk assessment and proposing the framing of the acid mine drainage issues in a complex and contextual scenario of a developing country—South Africa. 相似文献
802.
Deep brain stimulation (DBS), a surgical procedure involving the implantation of electrodes in the brain, has rekindled the medical community’s interest in psychosurgery. Whereas many researchers argue DBS is substantially different from psychosurgery, we argue psychiatric DBS—though a much more precise and refined treatment than its predecessors—is nevertheless a form of psychosurgery, which raises both old and new ethical and legal concerns that have not been given proper attention. Learning from the ethical and regulatory failures of older forms of psychosurgery can help shed light on how to address the regulatory gaps that exist currently in DBS research. To show why it is important to address the current regulatory gaps within psychiatric DBS, we draw on the motivations underlying the regulation of earlier forms of psychosurgery in the US. We begin by providing a brief history of psychosurgery and electrical brain stimulation in the US. Against this backdrop, we introduce psychiatric DBS, exploring current research and ongoing clinical trials. We then draw out the ethical and regulatory similarities between earlier forms of psychosurgery and psychiatric DBS. As we will show, the factors that motivated strict regulation of earlier psychosurgical procedures mirror concerns with psychiatric DBS today. We offer three recommendations for psychiatric DBS regulation, which echo earlier motivations for regulating psychosurgery, along with new considerations that reflect the novel technologies used in DBS. 相似文献
803.
Pablo A. Pellegrini 《Science and engineering ethics》2018,24(4):1297-1313
Practices related to research misconduct seem to have been multiplied in recent years. Many cases of scientific fraud have been exposed publicly, and journals and academic institutions have deployed different measures worldwide in this regard. However, the influence of specific social and cultural environments on scientific fraud may vary from society to society. This article analyzes how scientists in Japan deal with accusations of scientific fraud. For such a purpose, a series of scientific fraud cases that took place in Japan has been reconstructed through diverse sources. Thus, by analyzing those cases, the social basis of scientific fraud and the most relevant aspects of Japanese cultural values and traditions, as well as the concept of honour which is deeply involved in the way Japanese scientists react when they are accused of and publicly exposed in scientific fraud situations is examined. 相似文献
804.
Supported by easier and cheaper access to tools and expanding communities, maker cultures are pointing towards the ideas of (almost) everyone designing, creating, producing and distributing renewed, new and improved products, machines, things or artefacts. A careful analysis of the assumptions and challenges of maker cultures emphasizes the relevance of what may be called technological action, that is, active and critical interventions regarding the purposes and applications of technologies within ordinary lives, thus countering the deterministic trends of current directions of technology. In such transformative potential, we will explore a set of elements what is and could be technological action through snapshots of maker cultures based on the empirical research conducted in three particular contexts: the Fab Lab Network, Maker Media core outputs and initiatives such as Maker Faires, and the Open Source Hardware Association (OSHWA). Elements such as control and empowerment through material engagement, openness and sharing, and social, cultural, political and ethical values of the common good in topics such as diversity, sustainability and transparency, are critically analysed. 相似文献
805.
Frederic Gilbert Cathal D. O’Connell Tajanka Mladenovska Susan Dodds 《Science and engineering ethics》2018,24(1):73-91
Recent developments of three-dimensional printing of biomaterials (3D bioprinting) in medicine have been portrayed as demonstrating the potential to transform some medical treatments, including providing new responses to organ damage or organ failure. However, beyond the hype and before 3D bioprinted organs are ready to be transplanted into humans, several important ethical concerns and regulatory questions need to be addressed. This article starts by raising general ethical concerns associated with the use of bioprinting in medicine, then it focuses on more particular ethical issues related to experimental testing on humans, and the lack of current international regulatory directives to guide these experiments. Accordingly, this article (1) considers whether there is a limit as to what should be bioprinted in medicine; (2) examines key risks of significant harm associated with testing 3D bioprinting for humans; (3) investigates the clinical trial paradigm used to test 3D bioprinting; (4) analyses ethical questions of irreversibility, loss of treatment opportunity and replicability; (5) explores the current lack of a specific framework for the regulation and testing of 3D bioprinting treatments. 相似文献
806.
Aging has been assumed to go along with deficient inhibitory processes in cognitive performance. According to this inhibition deficit hypothesis, older adults are less able to suppress or ignore irrelevant thoughts and actions than young adults are. This hypothesis has been investigated in a large number of studies. We conducted a meta-analysis to determine whether there is an inhibition deficit in older age and whether this deficit is general or task-specific. We selected 176 studies in which young and older adults were tested on tasks commonly assumed to measure inhibition (i.e., the color Stroop, flanker, Simon, stop-signal, go/no-go, global–local, positive and negative compatibility tasks, as well as the paradigm assessing n-2 repetition costs in task switching). For most tasks (i.e., the color Stroop, flanker, and local tasks, as well as the n-2 repetition costs), the results speak against an inhibition deficit in older age. Only in a few tasks (i.e., the go/no-go and stop-signal tasks), older adults showed impaired inhibition. Moreover, for four tasks (i.e., the Simon, global, positive and negative compatibility tasks), the results suggest that more studies are necessary to draw a firm conclusion. Together, the present findings call into question the hypothesis of a general inhibition deficit in older age. 相似文献
807.
The degree to which humans have top-down control over which information they process remains a central debate within the attention literature. Most of the evidence supporting the top-down control of visuospatial attention has come from cueing paradigms in which target stimuli are preceded by cues that are similar or dissimilar from the target. These studies find that the cues similar to targets capture attention, but dissimilar cues do not, suggesting the top-down control of attention. Here, we used a modified cueing paradigm to investigate an alternative possibility that the cue type differences are due to sequential dependency effects occurring between cue and target processing rather than the top-down control of attention. When individuals searched for color targets, we replicated contingent capture effects in RTs, which are susceptible to sequential dependencies, but memory performance was always best at the cued locations, regardless of the cue’s identity. When individuals searched for onset targets, we observed contingent capture in both tasks. These results demonstrate the utility of the memory probe paradigm and suggest an asymmetry between how strongly onsets and color defined cues capture attention. 相似文献
808.
Cynthia Y. H. Chan Antoni B. Chan Tatia M. C. Lee Janet H. Hsiao 《Psychonomic bulletin & review》2018,25(6):2200-2207
The Hidden Markov Modeling approach for eye-movement data analysis is able to quantitatively assess differences and similarities among individual patterns. Here we applied this approach to examine the relationships between eye-movement patterns in face recognition and age-related cognitive decline. We found that significantly more older than young adults adopted “holistic” patterns, in which most eye fixations landed around the face center, as opposed to “analytic” patterns, in which eye movements switched among the two eyes and the face center. Participants showing analytic patterns had better performance than those with holistic patterns regardless of age. Interestingly, older adults with lower cognitive status (as assessed by the Montreal Cognitive Assessment), particularly in executive and visual attention functioning (as assessed by Tower of London and Trail Making Tests) were associated with a higher likelihood of holistic patterns. This result suggests the possibility of using eye movements as an easily deployable screening assessment for cognitive decline in older adults. 相似文献
809.
Pupillometry research has experienced an enormous revival in the last two decades. Here we briefly review the surge of recent studies on task-evoked pupil dilation in the context of cognitive control tasks with the primary aim being to evaluate the feasibility of using pupil dilation as an index of effort exertion, rather than task demand or difficulty. Our review shows that across the three cognitive control domains of updating, switching, and inhibition, increases in task demands typically leads to increases in pupil dilation. Studies show a diverging pattern with respect to the relationship between pupil dilation and performance and we show how an effort account of pupil dilation can provide an explanation of these findings. We also discuss future directions to further corroborate this account in the context of recent theories on cognitive control and effort and their potential neurobiological substrates. 相似文献
810.
The dominant paradigm for inference in psychology is a null-hypothesis significance testing one. Recently, the foundations of this paradigm have been shaken by several notable replication failures. One recommendation to remedy the replication crisis is to collect larger samples of participants. We argue that this recommendation misses a critical point, which is that increasing sample size will not remedy psychology’s lack of strong measurement, lack of strong theories and models, and lack of effective experimental control over error variance. In contrast, there is a long history of research in psychology employing small-N designs that treats the individual participant as the replication unit, which addresses each of these failings, and which produces results that are robust and readily replicated. We illustrate the properties of small-N and large-N designs using a simulated paradigm investigating the stage structure of response times. Our simulations highlight the high power and inferential validity of the small-N design, in contrast to the lower power and inferential indeterminacy of the large-N design. We argue that, if psychology is to be a mature quantitative science, then its primary theoretical aim should be to investigate systematic, functional relationships as they are manifested at the individual participant level and that, wherever possible, it should use methods that are optimized to identify relationships of this kind. 相似文献