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   676篇
  免费   31篇
  2023年   9篇
  2022年   6篇
  2021年   19篇
  2020年   25篇
  2019年   30篇
  2018年   23篇
  2017年   28篇
  2016年   25篇
  2015年   11篇
  2014年   26篇
  2013年   85篇
  2012年   34篇
  2011年   43篇
  2010年   24篇
  2009年   14篇
  2008年   21篇
  2007年   31篇
  2006年   22篇
  2005年   18篇
  2004年   17篇
  2003年   14篇
  2002年   10篇
  2001年   11篇
  2000年   14篇
  1999年   9篇
  1998年   5篇
  1997年   6篇
  1996年   7篇
  1995年   8篇
  1994年   9篇
  1993年   7篇
  1992年   9篇
  1991年   6篇
  1990年   6篇
  1989年   5篇
  1988年   6篇
  1987年   5篇
  1985年   3篇
  1983年   5篇
  1982年   4篇
  1981年   4篇
  1979年   3篇
  1975年   2篇
  1973年   5篇
  1972年   2篇
  1971年   2篇
  1970年   3篇
  1969年   2篇
  1967年   6篇
  1966年   2篇
排序方式: 共有707条查询结果,搜索用时 31 毫秒
181.
Although Directive 2001/20/EC of the European Parliament and of Council of 4 April 2001 on the approximation of the laws regulations and administrative provisions of the Member States relating to the implementation of good clinical practice in the conduct of clinical trials on medicinal products for human use does not contain an exception for emergency situations, and requires the informed consent of a legal representative in all cases where research is conducted on legally competent individuals who are unable to give informed consent, in Poland, emergency research can be conducted without consent. Polish regulations on emergency research can hardly be treated as a result of intentional legislative policy. Our provisions arise from multiple and sophisticated interpretations of different regulations that govern medical experiments on human subjects and clinical trials. These interpretations can be summarized as follows: (1) There are two categories of medical experiments: therapeutic and non-therapeutic experiments. Emergency research without consent may be conducted in the category of therapeutic experiment only (therapeutic experiment consists of the introduction by the physician of new or only partially proven diagnostic, therapeutic or preventive methods in order to achieve direct benefit to the health of the patients, and it can be carried out when hitherto applied methods were ineffective or their effectiveness was insufficient). (2). Emergency research may be conducted without consent if there is a situation of great urgency in which the research subject's life is in danger and there is no possibility of obtaining immediate consent from the research subject him or herself, or from his or her legal representative or guardianship court, and the research subject has not refused to give consent for the participation in an emergency therapeutic experiment. The legal representative or guardianship court shall be provided with all the relevant information concerning subject's participation in an experiment as soon as possible. All projects of emergency research with intent to be done without the research subject's consent must be approved by an independent bioethics committee. Because these five requirements seem to provide insufficient protection for a subject's autonomy and rights it is necessary to add to them two other conditions: (1) the emergency research could not be conducted using other research participants capable of giving informed consent; and (2) informed consent for continued participation in the emergency research shall be obtained from either the participant him or herself or the legally authorized representative as soon as possible (requirement of obtaining deferred consent). A consolidated single Act that will govern all aspects of medical experiments on human subjects, including emergency research, should be prepared and enacted as soon as possible.  相似文献   
182.
Transitive performance (TP) is a learning-based behaviour exhibited by a wide range of species, where if a subject has been taught to prefer A when presented with the pair AB but to prefer B when presented with the pair BC, then the subject will also prefer A when presented with the novel pair AC. Most explanations of TP assume that subjects recognize and learn an underlying sequence from observing the training pairs. However, data from squirrel monkeys (Saimiri sciureus) and young children contradict this, showing that when three different items (a triad) are drawn from the sequence, subjects' performance degrades systematically (McGonigle and Chalmers, Nature 267:694-696, 1977; Chalmers and McGonigle, Journal of Experimental Child Psychology 37:355-377, 1984; Harris and McGonigle, The Quarterly Journal of Experimental Psychology 47B:319-348, 1994). We present here the two-tier model, the first learning model of TP which accounts for this systematic performance degradation. Our model assumes primate TP is based on a general-purpose task learning system rather than a special-purpose sequence-learning system. It supports the hypothesis of Heckers et al. (Hippocampus 14:153-162, 2004) that TP is an expression of two separate general learning elements: one for associating actions and contexts, another for prioritising associations when more than one context is present. The two-tier model also provides explanations for why phased training is important for helping subjects learn the initial training pairs and why some subjects fail to do so. It also supports the Harris and McGonigle (The Quarterly Journal of Experimental Psychology 47B:319-348, 1994) explanation of why, once the training pairs have been acquired, subjects perform transitive choice automatically on two-item diads, but not when exposed to triads from the same sequence.  相似文献   
183.
The words "No" and "Yes" are involved in conditioning to prohibit or encourage behavior, respectively. The authors, therefore, hypothesized that these words would be attributed to endogenous valence, activating neuronal circuits involved with valence and emotional control. Functional MRI (fMRI) at 4 Tesla was used to record regional brain activity while participants were exposed to emphatic vocalizations of the words. Results showed that No and Yes were associated with opposite brain-behavior responses; while No was negatively valenced, produced slower response times, and evoked a negative signal in the right lateral orbitofrontal cortex (OFC), Yes was positively valenced, produced faster response times, and evoked a positive signal in a contiguous region of the OFC. Attribution of negative valence to No and trait anger control were associated with increased responsivity of the OFC to No. Inasmuch as sensitivity to the prohibitive command No develops during childhood through interaction with primary caregivers as the first social objects, our findings may implicate the lateral OFC in the neurobiology of emotion regulation and subsequent social development.  相似文献   
184.
185.
Adult children of people with alcoholism (ACAs; n = 21) and adults with no family history of alcoholism (non-ACAs; n = 24) completed a task designed to test inhibitory ability using a reaction-time based negative priming task. Although participants in the ACA group responded more slowly overall, they did not differ on this task as compared with participants in the non-ACA group. This pattern of results suggests that inhibitory ability is preserved in ACAs, at least within the context of the current negative priming task. The authors discuss study limitations and inconsistencies in the ACA literature.  相似文献   
186.
Palmer SE  Brooks JL  Lai KS 《Perception》2007,36(5):650-669
In the occlusion illusion, the visible portion of a partly occluded object (eg a semicircle partly hidden behind a rectangle) appears to be significantly larger than a physically identical region that is fully visible. This illusion may occur either because the visual system 'fills in' a thin strip along the occluded border (the partial-modal-completion hypothesis) or because the partly occluded object is perceived as farther away (the apparent-distance hypothesis). We measured the magnitude of the occlusion illusion psychophysically in several experiments to investigate its causes. The results of experiments 1-3 are consistent with the general proposal that the magnitude of the illusion varies with the strength of the evidence for occlusion, supporting the inference that it is due to occlusion. Experiment 4 provides a critical test between apparent-distance and partial-modal-completion explanations by determining whether the increase in apparent size of the occluded region results from a change in its perceived shape (due to the modal extension of the occluded shape along the occluding edge, as predicted by the partial-modal-completion hypothesis) or from a change in its perceived overall size (as predicted by the apparent-distance hypothesis). The results more strongly support the partial-modal-completion hypothesis.  相似文献   
187.
Brooks KR  Kemp RI 《Perception》2007,36(11):1646-1659
Previous studies of face recognition and of face matching have shown a general improvement for the processing of internal features as a face becomes more familiar to the participant. In this study, we used a psychophysical two-alternative forced-choice paradigm to investigate thresholds for the detection of a displacement of the eyes, nose, mouth, or ears for familiar and unfamiliar faces. No clear division between internal and external features was observed. Rather, for familiar (compared to unfamiliar) faces participants were more sensitive to displacements of internal features such as the eyes or the nose; yet, for our third internal feature-the mouth no such difference was observed. Despite large displacements, many subjects were unable to perform above chance when stimuli involved shifts in the position of the ears. These results are consistent with the proposal that familiarity effects may be mediated by the construction of a robust representation of a face, although the involvement of attention in the encoding of face stimuli cannot be ruled out. Furthermore, these effects are mediated by information from a spatial configuration of features, rather than by purely feature-based information.  相似文献   
188.
Comprehending 3D diagrams is critical for success in scientific practice and research demonstrates that understanding of 3D geology diagrams can be improved by making predictive sketches. In mathematics, explaining erroneous examples can support learning. This study combined these approaches to better understand how to effectively support 3D geologic diagram understanding. Participants generated sketches, explained erroneous example sketches, or copied and explained correct sketches. It was hypothesized that generating sketches or explaining erroneous cases would improve understanding, but an open question was whether these conditions would differ from each other. Explaining erroneous examples and sketching improved understanding whereas explaining correct sketches did not. Further, explaining erroneous examples was a more efficient strategy than sketching. These results indicate that erroneous examples can be effective for supporting 3D diagram comprehension and may be a practical substitute for some traditional sketching activities in the context of real classrooms where class time is limited.  相似文献   
189.
This study investigates the hypothesis that congruence in value perspectives distinguishes science-able students who persist in science from those who do not (nonpersisters). A science values measure was administered to 173 undergraduates with high levels of commitment and ability in the sciences. On each of six hypothetical dilemmas from everyday science, respondents rated the importance of three justice and three care considerations for self and for science, using a Likert-type 7-point scale. A significant three way interaction involving sex, persistence, and point of view (self/sience) emerged, with persisters generally demonstrating congruence between self and science on the value perspectives; female persisters, however, were more likely to combine justice and care perspectives than were males. Nonpersisters' self/science ratings of justice and care were sharply dissimilar, with females demonstrating the most incongruence. In all groups, justice was the prominent perspective attributed to science.  相似文献   
190.
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