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   25355篇
  免费   278篇
  2023年   56篇
  2022年   76篇
  2021年   107篇
  2020年   159篇
  2019年   143篇
  2018年   3656篇
  2017年   2998篇
  2016年   2403篇
  2015年   334篇
  2014年   231篇
  2013年   727篇
  2012年   893篇
  2011年   2679篇
  2010年   2685篇
  2009年   1590篇
  2008年   1958篇
  2007年   2390篇
  2006年   248篇
  2005年   360篇
  2004年   301篇
  2003年   260篇
  2002年   180篇
  2001年   89篇
  2000年   127篇
  1999年   70篇
  1998年   73篇
  1997年   64篇
  1996年   46篇
  1995年   36篇
  1994年   42篇
  1993年   46篇
  1992年   32篇
  1991年   34篇
  1990年   46篇
  1989年   43篇
  1988年   38篇
  1987年   27篇
  1986年   24篇
  1985年   32篇
  1984年   34篇
  1983年   23篇
  1982年   30篇
  1981年   30篇
  1980年   23篇
  1979年   14篇
  1978年   24篇
  1976年   20篇
  1975年   18篇
  1973年   13篇
  1968年   14篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
In this review, we consider three possible criteria by which knowledge might be regarded as implicit or inaccessible: It might be implicit only in the sense that it is difficult to articulate freely, or it might be implicit according to either an objective threshold or a subjective threshold. We evaluate evidence for these criteria in relation to artificial grammar learning, the control of complex systems, and sequence learning, respectively. We argue that the convincing evidence is not yet in, but construing the implicit nature of implicit learning in terms of a subjective threshold is most likely to prove fruitful for future research. Furthermore, the subjective threshold criterion may demarcate qualitatively different types of knowledge. We argue that (1) implicit, rather than explicit, knowledge is often relatively inflexible in transfer to different domains, (2) implicit, rather than explicit, learning occurs when attention is focused on specific items and not underlying rules, and (3) implicit learning and the resulting knowledge are often relatively robust.  相似文献   
92.
A literature search was conducted on studies of new drugs used with patients with schizophrenia reported by U.S. and non-U.S. researchers from 1966–1993, yielding 41 U.S., and a total of 24 other non-U.S. studies, among them 11 British studies. Results of the U.S. and non-U.S. studies were pooled separately and compared. Among several comparable conditions discussed, the lack of any data on suicides in the U.S. studies was observed. For a second statistical analysis of suicide rates ‘person-years’ were calculated to adjust for differing washout durations. The results obtained include findings that the percentage of patients relapsing in U.S. studies was slightly lower (37.9%) than in non-U.S. studies (46%); the percentage of patients dropping out in U.S. studies (10.5%) was higher than in non-U.S. studies (7.6%); known location of dropout patients in U.S. studies was 1.7%, compared to 2.6% in non-U.S. studies. The most interesting finding was that no suicides were reported in U.S. studies, compared to 0.6% of patients reported in British studies. Some U.S. studies used ‘challenge doses’, such as amphetamines or L-dopa; no non-U.S. studies reported their use. Compared to U.S. studies, those by non-U.S., and particularly British, researchers appeared to report adverse events in their studies. ‘Challenge’ drugs were not used; suicides were reported. It is estimated that the probability that no patients suicided who participated in the U.S. is small—one in 500.  相似文献   
93.
94.
The musical instrument digital interface (MIDI) offers a way for perception and behavior researchers to implement high-quality experiments using inexpensive, commercially available hardware and software. We describe the MIDI and illustrate its applicability to research using a replication of the oscillator signature finding reported recently by Collyer, Broadbent, and Church (1992, 1994).  相似文献   
95.
A dialogue between virtue and care ethics is formed as a step towards meeting Pellegrino's challenge to create a more comprehensive moral philosophy. It is also a dialogue between nursing and medicine since each practice draws on the Greek Virtue Tradition and the Judeo-Christian Tradition of care differently. In the Greek Virtue Tradition, the point of scrutiny lies in the inner character of the actor, whereas in the Judeo-Christian Tradition the focus is relational, i.e. how virtues are lived out in specific relationships, particularly unequal relationships where vulnerability of one of the members is an issue. In a care ethic relational qualities such as attunement rather than inner qualities are the point of scrutiny. A dialogue between these two traditions makes it possible to consider the relational virtues and skills of openness and responsiveness that are required for a respectful meeting of the other.  相似文献   
96.
Subjects were presented with briefly exposed visual displays of words that were common first names with a length of four to six letters. In the main experiment, each display consisted of four words: two names shown in red and two shown in white. The subject’s task was to report the red names (targets), but ignore the white ones (distractors). On some trials the subject’s own name appeared as a display item (target or distractor). Presentation of the subject’s name as a distractor caused no more interference with report of targets than did presentation of other names as distractors. Apparently, visual attention was not automatically attracted by the subject’s own name.  相似文献   
97.
98.
There is evidence supporting the hypothesis that the historically favorable views of Protestants regarding the practice of family planning are changing among selected sub-groups. Such an attitudinal shift among Protestants has been rarely investigated by social scientists. This literature review represents an initial step in examining the phenomenon. A profile of Protestants' historical views of family planning will be presented first, followed by a discussion of the recent questioning of this group's favorable attitudes towards the practice. Additionally, research literature on contraceptive behavior and fertility patterns will provide empirical evidence supporting the hypothesis.  相似文献   
99.
Hájek  Petr 《Studia Logica》1997,58(1):129-141
A very simple many-valued predicate calculus is presented; a completeness theorem is proved and the arithmetical complexity of some notions concerning provability is determined.  相似文献   
100.
This study of semantic verbal fluency addressed two research questions: (1) What are the between-language similarities and differences in the performance of balanced bilinguals? (2) What is the relationship between productivity and the use of a semantic grouping strategy to organize responses? Forty neurologically normal, bilingual adults were tested twice in each language (French/English), in a 2 (Language) by 2 (Test) by 2 (Group) design. On Test 2, half the 40 subjects were instructed to group items by subcategory, while half simply repeated the test. Results showed (1) many more between-language similarities than differences and (2) no between-group differences in productivity.  相似文献   
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