全文获取类型
收费全文 | 4604篇 |
免费 | 205篇 |
国内免费 | 1篇 |
出版年
2023年 | 29篇 |
2022年 | 25篇 |
2021年 | 53篇 |
2020年 | 78篇 |
2019年 | 94篇 |
2018年 | 134篇 |
2017年 | 150篇 |
2016年 | 179篇 |
2015年 | 109篇 |
2014年 | 139篇 |
2013年 | 566篇 |
2012年 | 254篇 |
2011年 | 242篇 |
2010年 | 173篇 |
2009年 | 136篇 |
2008年 | 212篇 |
2007年 | 213篇 |
2006年 | 182篇 |
2005年 | 151篇 |
2004年 | 161篇 |
2003年 | 142篇 |
2002年 | 112篇 |
2001年 | 92篇 |
2000年 | 81篇 |
1999年 | 54篇 |
1998年 | 54篇 |
1997年 | 59篇 |
1996年 | 55篇 |
1995年 | 58篇 |
1994年 | 41篇 |
1993年 | 51篇 |
1992年 | 56篇 |
1991年 | 38篇 |
1990年 | 51篇 |
1989年 | 36篇 |
1988年 | 46篇 |
1987年 | 34篇 |
1986年 | 17篇 |
1985年 | 30篇 |
1984年 | 31篇 |
1983年 | 24篇 |
1982年 | 43篇 |
1981年 | 23篇 |
1980年 | 19篇 |
1979年 | 27篇 |
1978年 | 27篇 |
1977年 | 21篇 |
1974年 | 22篇 |
1971年 | 16篇 |
1970年 | 16篇 |
排序方式: 共有4810条查询结果,搜索用时 15 毫秒
221.
Lawler CP Croen LA Grether JK Van de Water J 《Mental retardation and developmental disabilities research reviews》2004,10(4):292-302
The potential role of environmental factors in autism spectrum disorders (ASD) is an area of emerging interest within the public and scientific communities. The high degree of heritability of ASD suggests that environmental influences are likely to operate through their interaction with genetic susceptibility during vulnerable periods of development. Evaluation of the plausibility of specific neurotoxicants as etiological agents in ASD should be guided by toxicological principles, including dose-effect dependency and pharmacokinetic parameters. Clinical and epidemiological investigations require the use of sufficiently powered study designs with appropriate control groups and unbiased case ascertainment and exposure assessment. Although much of the existing data that have been used to implicate environmental agents in ASD are limited by methodological shortcomings, a number of efforts are underway that will allow more rigorous evaluation of the role of environmental exposures in the etiology and/or phenotypic expression of the disorder. Surveillance systems are now in place that will provide reliable prevalence estimates going forward in time. Anticipated discoveries in genetics, brain pathology, and the molecular/cellular basis of functional impairment in ASD are likely to provide new opportunities to explore environmental aspects of this disorder. 相似文献
222.
223.
Joerden JC 《Science and engineering ethics》2004,10(1):65-72
This article considers issues concerning cases where the use of placebo is lawful or is not lawful under aspects of German
criminal law. It will differentiate between cases of individual therapy and cases of supervised experiments within the scope
of medical tests. Thereby, it reveals that a medication of placebo with regard to an individual patient seems to be lawful
if there is no alternative possibility of a better treatment using a chemically effective medicine and if the limits of presumed
consent are complied with. On the other hand, in the context of the supervised experiment, the assignment of a patient to
a group treated with placebo is only lawful if the patient has been fully informed about the possibilities of a treatment
and if the patient has given consent to it.
An earlier version of this paper was presented at an international conference, “Placebo: Its Action and Place in Health Research
Today,” held in Warsaw, Poland on 12–13 April, 2003.
The author’s interests include International Criminal Law, Comparative Criminal Law and Philosophy of Law. 相似文献
224.
Sleep is crucial to the 'off-line' consolidation of procedural memory. A recent study by Robertson et al. shows that this might hold true only if the task is trained explicitly, that is, with the subject being aware of the task structure. These new data add to emerging evidence that sleep-related memory consolidation involves an interaction between different memory systems. 相似文献
225.
Koster EH Crombez G Van Damme S Verschuere B De Houwer J 《Emotion (Washington, D.C.)》2004,4(3):312-317
According to models of attention and emotion, threat captures and holds attention. In behavioral tasks, robust evidence has been found for attentional holding but not for attentional capture by threat. An important explanation for the absence of attentional capture effects is that the visual stimuli used posed no genuine threat. The present study investigated whether visual cues that signal an aversive white noise can elicit attentional capture and holding effects. Cues presented in an attentional task were simultaneously provided with a threat value through an aversive conditioning procedure. Response latencies showed that threatening cues captured and held attention. These results support recent views on attention to threat, proposing that imminent threat captures attention in everyone. 相似文献
226.
Serniclaes W Van Heghe S Mousty P Carré R Sprenger-Charolles L 《Journal of experimental child psychology》2004,87(4):336-361
Perceptual discrimination between speech sounds belonging to different phoneme categories is better than that between sounds falling within the same category. This property, known as "categorical perception," is weaker in children affected by dyslexia. Categorical perception develops from the predispositions of newborns for discriminating all potential phoneme categories in the world's languages. Predispositions that are not relevant for phoneme perception in the ambient language are usually deactivated during early childhood. However, the current study shows that dyslexic children maintain a higher sensitivity to phonemic distinctions irrelevant in their linguistic environment. This suggests that dyslexic children use an allophonic mode of speech perception that, although without straightforward consequences for oral communication, has obvious implications for the acquisition of alphabetic writing. Allophonic perception specifically affects the mapping between graphemes and phonemes, contrary to other manifestations of dyslexia, and may be a core deficit. 相似文献
227.
Suicide rates may be affected by world news. Our objective was to investigate the possible impact of the terrorist attacks of September 11, 2001, on suicidal behavior in the Netherlands. There was evidence of an increase in rates of suicide and deliberate self-harm in the weeks immediately following the attacks. These findings contrast with Durkheim's (1897) original suggestion that suicide rates decline in times of war and outside threat but are in line with findings of increases in suicidal behavior after media coverage of lethal violence. 相似文献
228.
Husaini BA Cummings S Kilbourne B Roback H Sherkat D Levine R Cain VA 《International journal of group psychotherapy》2004,54(3):295-319
We describe and evaluate a group therapy program targeting depression among elderly residents (N=303) of subsidized high-rise apartments in Nashville, TN. This eclectic program was comprised of 12 sessions (a total of 24 hours) that included modules on exercise and preventive health behaviors, cognitive and re-motivation therapy, reminiscence and grief therapy, and social skills development. Our multivariate regression analyses of pre-post measures using the Geriatric Depression Scale (GDS) showed that the effects of the group therapy varied by race, age, and level of initial depression among the participants. The program was effective in reducing depression, but only among Caucasian women who reported at least moderate depression prior to the program, and it yielded greater benefits for women between 55 and 75 years of age. 相似文献
229.
This study investigated whether parent-adolescent disagreement regarding adolescents' behavioral and emotional problems predicted adverse outcome. A Dutch sample of 15- to 18-year-olds was prospectively followed across a 4-year interval. The Child Behavior Checklist (CBCL: T. M. Achenbach, 1997) and Youth Self-Report (YSR; T. M. Achenbach, 1991b) were administered at initial assessment, and the following signs of poor outcome were assessed 4 years later: police/judicial contacts, expulsion from school/job, suicidal ideation, unwanted pregnancy, suicide attempts, deliberate self-harm, referral to mental health services, report of having a behavioral or emotional problem, and feeling the need for professional help without actually receiving help. Twenty CBCL syndrome scores, 23 YSR syndrome scores, and 16 discrepancy scores were significant predictors of poor outcome. It was concluded that to determine the prognosis of psychopathology in adolescents, discrepancies between informants may be important. 相似文献
230.
The effects of a symbolic "yield here to pedestrians" sign and advance yield pavement markings on pedestrian/motor vehicle conflicts, motorists' yielding behavior, and the distance motorists' yield in advance of crosswalks were evaluated at multilane crosswalks at uncontrolled T intersections. In Experiment 1, the sign, when used alone, reduced pedestrian/motor vehicle conflicts and increased motorist yielding distance. The use of fluorescent yellow-green sheeting as the background of the sign did not increase the effectiveness of the sign. Further reductions in pedestrian/motor vehicle conflicts and further increases in yielding distance were associated with the addition of advance yield pavement markings. In Experiment 2, advance yield pavement markings, when used alone, were as effective in reducing pedestrian/motor vehicle conflicts and increasing yielding distance as the sign combined with pavement markings. These data suggest that the pavement markings were the essential component for reducing conflicts and increasing yielding distance. 相似文献