全文获取类型
收费全文 | 34534篇 |
免费 | 722篇 |
国内免费 | 5篇 |
出版年
2022年 | 125篇 |
2021年 | 184篇 |
2020年 | 264篇 |
2019年 | 292篇 |
2018年 | 3796篇 |
2017年 | 3125篇 |
2016年 | 2559篇 |
2015年 | 479篇 |
2014年 | 404篇 |
2013年 | 1340篇 |
2012年 | 1155篇 |
2011年 | 2972篇 |
2010年 | 2870篇 |
2009年 | 1721篇 |
2008年 | 2193篇 |
2007年 | 2575篇 |
2006年 | 480篇 |
2005年 | 536篇 |
2004年 | 456篇 |
2003年 | 368篇 |
2002年 | 317篇 |
2001年 | 476篇 |
2000年 | 490篇 |
1999年 | 319篇 |
1998年 | 139篇 |
1997年 | 111篇 |
1996年 | 108篇 |
1995年 | 106篇 |
1992年 | 225篇 |
1991年 | 227篇 |
1990年 | 225篇 |
1989年 | 218篇 |
1988年 | 215篇 |
1987年 | 194篇 |
1986年 | 181篇 |
1985年 | 181篇 |
1984年 | 165篇 |
1983年 | 118篇 |
1982年 | 122篇 |
1979年 | 154篇 |
1975年 | 144篇 |
1974年 | 164篇 |
1973年 | 190篇 |
1972年 | 163篇 |
1971年 | 151篇 |
1970年 | 127篇 |
1969年 | 140篇 |
1968年 | 187篇 |
1967年 | 132篇 |
1966年 | 146篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
961.
Objectives: To understand the impact of physicians and patients religious/spiritual orientation on discussions of spiritual issues. Methods: We performed semi-structured interviews of 10 Missouri family physicians and 10 patients of these physicians, selecting subjects nonrandomly to represent a range of demographic factors, practice types, and chronic or terminal illness. We coded and evaluated transcribed interviews for themes. Results: Respondents expressed that similar belief systems facilitate patient–physician spiritual interactions and bring confidence to their relationships. Those holding dissimilar faiths noted limited ability to address spiritual questions directly. They cited significant barriers to spiritual interaction but considered that ecumenism, use of patient-centered care, and negotiation skills lessen these barriers. Conclusions: Our respondents view spirituality similarly to other aspects of the physician–patient relationship involving differing viewpoints. Where discordance exists, cross-cultural, patient-centered, diplomatic approaches facilitate spiritual discussions. 相似文献
962.
963.
Kalenscher T Güntürkün O Calabrese P Gehlen W Kalt T Diekamp B 《Journal of the experimental analysis of behavior》2005,84(3):521-535
Working memory, the ability to temporarily retain task-relevant information across a delay, is frequently investigated using delayed matching-to-sample (DMTS) or delayed Go/No-Go tasks (DGNG). In DMTS tasks, sample cues instruct the animal which type of response has to be executed at the end of a delay. Typically, performance decreases with increasing delay duration, indicating that working memory fades across a delay. However, no such performance decrease has been found when the sample cues exist of present vs. absent stimuli, suggesting that pigeons do not rely on working memory, but seem to respond by default in those trials. We trained 3 pigeons in a DGNG task and found a similar default response pattern: The diverging slopes of the retention functions on correct Go and No-Go trials suggested that pigeons by default omitted their response following No-Go stimuli, but actively retained task-relevant information across the delay for successful responses on Go trials. We conducted single-cell recordings in the avian nidopallium caudolaterale, a structure comparable to the mammalian prefrontal cortex. On Go trials, many neurons displayed sustained elevated activity during the delay preceding the response, replicating previous findings and suggesting that task-relevant information was neurally represented and maintained across the delay. However, the same units did not show enhanced delay activity preceding correct response suppressions in No-Go trials. This activation-inactivation pattern presumably constitutes a neural correlate of the default response strategy observed in the DGNG task. 相似文献
964.
Several researchers have suggested that conditioning history may have long-term effects on fixed-interval performances of rats. To test this idea and to identify possible factors involved in temporal control development, groups of rats initially were exposed to different reinforcement schedules: continuous, fixed-time, and random-interval. Afterwards, half of the rats in each group were studied on a fixed-interval 30-s schedule of reinforcement and the other half on a fixed-interval 90-s schedule of reinforcement. No evidence of long-term effects attributable to conditioning history on either response output or response patterning was found; history effects were transitory. Different tendencies in trajectory across sessions were observed for measures of early and late responding within the interreinforcer interval, suggesting that temporal control is the result of two separate processes: one involved in response output and the other in time allocation of responding and not responding. 相似文献
965.
Lancioni GE Singh NN O'Reilly MF Oliva D Severini L 《Perceptual and motor skills》2005,101(1):212-216
We applied a new microswitch-based stimulation procedure for eye-blinking responses with a young woman with profound multiple disabilities, and compared effects of this procedure on the eye-blinking responses and smiling with the effects of a caregiver-based stimulation condition. Analysis showed that the microswitch-based stimulation procedure, with stimulation occurring contingent on eye-blinking responses, increased the frequencies of these responses significantly above the levels recorded in baseline and caregiver-based stimulation conditions. No changes in smiling frequencies occurred. Implications of the findings in terms of alertness, learning, and quality of life are discussed. 相似文献
966.
Four experiments were designed to investigate whether the frequency of words used to create pseudowords plays an important role in lexical decision. Computational models of the lexical decision task (e.g., the dual route cascaded model and the multiple read-out model) predict that latencies to low-frequency pseudowords should be faster than latencies to high-frequency pseudowords. Consistent with this prediction, results showed that when the pseudowords were created by replacing one internal letter of the base word (Experiments 1 and 3), high-frequency pseudowords yielded slower latencies than low-frequency pseudowords. However, this effect occurred only in the leading edge of the response time (RT) distributions. When the pseudowords were created by transposing two adjacent internal letters (Experiment 2), high-frequency pseudowords produced slower latencies in the leading edge and in the bulk of the RT distributions. These results suggest that transposed-letter pseudowords may be more similar to their base words than replacement-letter pseudowords. Finally, when participants performed a go/no-go lexical decision task with one-letter different pseudowords (Experiment 4), high-frequency pseudowords yielded substantially faster latencies than low-frequency pseudowords, which suggests that the lexical entries of high-frequency words can be verified earlier than the lexical entries of low-frequency words. The implications of these results for models of word recognition and lexical decision are discussed. 相似文献
967.
Statistical learning is one of the key mechanisms available to human infants and adults when they face the problems of segmenting a speech stream (Saffran, Aslin, & Newport, 1996) and extracting long-distance regularities (G6mez, 2002; Pe?a, Bonatti, Nespor, & Mehler, 2002). In the present study, we explore statistical learning abilities in rats in the context of speech segmentation experiments. In a series of five experiments, we address whether rats can compute the necessary statistics to be able to segment synthesized speech streams and detect regularities associated with grammatical structures. Our results demonstrate that rats can segment the streams using the frequency of co-occurrence (not transitional probabilities, as human infants do) among items, showing that some basic statistical learning mechanism generalizes over nonprimate species. Nevertheless, rats did not differentiate among test items when the stream was organized over more complex regularities that involved nonadjacent elements and abstract grammar-like rules. 相似文献
968.
The purpose of this study was to examine the Body Mass Index of 180 female Spanish Olympic athletes (M age = 27.1 yr., SD = 5.9 yr.) who participate in presentation sports and nonpresentation sports, in comparison with 114 female nonathletes (M age = 20.7, SD = 1.5 yr.). Presentation sports athletes have a profile similar to that of a university student but by age with a lower Body Mass Index. In particular, rhythmic gymnasts have a lower weight and Body Mass Index than other athletes and nonathletes. 相似文献
969.
970.
On March 11, 2004, Al-Qaeda set off 10 bombs on several train routes in Madrid. 192 people were killed and 2,000 wounded. In this study, 1,179 questionnaires were administered Week 2 after the attacks to residents 18 years and over from the affected geographical areas. The questionnaire included items about sociodemographic variables and exposure to the attacks. Psychological effects were assessed as presence of acute stress and depressive symptomatology and functional impairment. 46.7% of the sample presented symptomatology of acute stress and 49.6% depressive symptoms. Among the symptoms of acute stress, the most frequent were re-experiencing (72.5%) and dissociative symptoms (71.8%). The chief predicting variables in symptomatology were being female, over 65 yr. old, and a habitual train user. The large number of affected people was refined with an item analysis and the consideration of severity of interference in psychosocial functioning. 相似文献