全文获取类型
收费全文 | 13999篇 |
免费 | 671篇 |
国内免费 | 5篇 |
出版年
2021年 | 138篇 |
2020年 | 204篇 |
2019年 | 254篇 |
2018年 | 377篇 |
2017年 | 356篇 |
2016年 | 376篇 |
2015年 | 281篇 |
2014年 | 294篇 |
2013年 | 1151篇 |
2012年 | 518篇 |
2011年 | 547篇 |
2010年 | 329篇 |
2009年 | 276篇 |
2008年 | 429篇 |
2007年 | 403篇 |
2006年 | 356篇 |
2005年 | 339篇 |
2004年 | 319篇 |
2003年 | 292篇 |
2002年 | 272篇 |
2001年 | 465篇 |
2000年 | 439篇 |
1999年 | 303篇 |
1998年 | 133篇 |
1996年 | 116篇 |
1995年 | 110篇 |
1993年 | 112篇 |
1992年 | 230篇 |
1991年 | 244篇 |
1990年 | 233篇 |
1989年 | 219篇 |
1988年 | 231篇 |
1987年 | 203篇 |
1986年 | 192篇 |
1985年 | 191篇 |
1984年 | 180篇 |
1983年 | 134篇 |
1982年 | 123篇 |
1979年 | 159篇 |
1977年 | 108篇 |
1975年 | 143篇 |
1974年 | 165篇 |
1973年 | 188篇 |
1972年 | 158篇 |
1971年 | 148篇 |
1970年 | 124篇 |
1969年 | 137篇 |
1968年 | 183篇 |
1967年 | 138篇 |
1966年 | 147篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Nanotechnology — A new field of ethical inquiry? 总被引:2,自引:0,他引:2
Grunwald A 《Science and engineering ethics》2005,11(2):187-201
Parallel to the public discussion on the benefits and risks of nanotechnology, a debate on the ethics of nanotechnology has
begun. It has been postulated that a new “nano-ethics” is necessary. In this debate, the — positive as well as negative —
visionary and speculative innovations which are brought into connection with nanotechnology stand in the foreground. In this
contribution, an attempt is made to discover new ethical aspects of nanotechnology in a more systematic manner than has been
the case. It turns out that there are hardly any completely new ethical aspects raised by nanotechnology. It is much rather
primarily a case of gradual shifts of emphasis and of relevance in questions which, in principle, are already known and which
give reason for ethical discussions on nanotechnology. In a certain manner, structurally novel ethical aspects arise through
the important role played by visions in the public discourse. New questions are also posed by the fact that previously separate
lines of ethical reflection converge in the field of nanotechnology. The proposal of an independent “nano-ethics”, however,
seems exaggerated. 相似文献
952.
Are abstract representations of number – representations that are independent of the particular type of entities that are enumerated – a product of human language or culture, or do they trace back to human infancy? To address this question, four experiments investigated whether human infants discriminate between sequences of actions (jumps of a puppet) on the basis of numerosity. At 6 months, infants successfully discriminated four‐ versus eight‐jump sequences, when the continuous variables of sequence duration, jump duration, jump rate, jump interval and duration, and extent of motion were controlled, and rhythm was eliminated. In contrast, infants failed to discriminate two‐ versus four‐jump sequences, suggesting that infants fail to form cardinal number representations of small numbers of actions. Infants also failed to discriminate between sequences of four versus six jumps at 6 months, and succeeded at 9 months, suggesting that infants’ number representations are imprecise and increase in precision with age. All of these findings agree with those of studies using visual–spatial arrays and auditory sequences, providing evidence that a single, abstract system of number representation is present and functional in infancy. 相似文献
953.
954.
Miles JN 《Behavior research methods》2005,37(4):672-676
This article presents a method for using Microsoft (MS) Excel for confirmatory factor analysis (CFA). CFA is often seen as
an impenetrable technique, and thus, when it is taught, there is frequently little explanation of the mechanisms or underlying
calculations. The aim of this article is to demonstrate that this is not the case; it is relatively straightforward to produce
a spreadsheet in MS Excel that can carry out simple CFA. It is possible, with few or no programming skills, to effectively
program a CFA analysis and, thus, to gain insight into the workings of the procedure. 相似文献
955.
956.
Background: To introduce a person with multiple disabilities to a microswitch-aided program, one has to select a plausible response(s),
that is, a response(s) that can be performed reliably and without excessive effort by the person and can successfully activate
the microswitch(es) available (producing preferred stimuli). This paper provides an overview of the responses adopted for
microswitch activation in research studies during the last 20 years. Method: Computerized and manual searches were carried out to identify the studies published between 1986 and 2005. Forty-eight research
studies were identified. They concerned the use of (1) a single (typical) response, (2) a single (non-typical) response, (3)
multiple (typical and non-typical) responses, and (4) multiple (vocal) responses. Results and discussion: The results showed that 151 of the 190 participants involved in the studies had a positive outcome (i.e., clear increases
in their responding, which suggested that they had learned the association between responding and consequent preferred stimuli).
Failures were largely concentrated in the first group of studies. The discussion focused on (a) the importance of selecting
plausible responses for increasing the chances of success, (b) the need of non-typical responses for persons with minimal
motor behavior, (c) implications of programs with multiple responses on engagement and choice, and (d) relevance of using
vocal utterances. Some suggestions for future research concerning these points were also examined. 相似文献
957.
Weak phantasmata have a decisive and specifically transcendental function in our everyday perception. This paper provides several different arguments for this claim based on evidence from both empirical psychology and phenomenology.I would like to express my gratitude to Bill McKenna for his help with the English text and his critical remarks. This paper was presented in the Cork Roundtable for Philosophy in March 2003, at University College, Cork, and I would like to thank Julia Jansen, Tony O’Connor and the other participants for their constructive critique. 相似文献
958.
959.
960.