全文获取类型
收费全文 | 17737篇 |
免费 | 932篇 |
国内免费 | 5篇 |
专业分类
18674篇 |
出版年
2021年 | 155篇 |
2020年 | 272篇 |
2019年 | 296篇 |
2018年 | 449篇 |
2017年 | 479篇 |
2016年 | 475篇 |
2015年 | 339篇 |
2014年 | 404篇 |
2013年 | 1588篇 |
2012年 | 656篇 |
2011年 | 705篇 |
2010年 | 438篇 |
2009年 | 411篇 |
2008年 | 569篇 |
2007年 | 569篇 |
2006年 | 501篇 |
2005年 | 457篇 |
2004年 | 437篇 |
2003年 | 395篇 |
2002年 | 417篇 |
2001年 | 524篇 |
2000年 | 501篇 |
1999年 | 378篇 |
1998年 | 196篇 |
1997年 | 166篇 |
1996年 | 189篇 |
1995年 | 185篇 |
1994年 | 160篇 |
1993年 | 153篇 |
1992年 | 292篇 |
1991年 | 281篇 |
1990年 | 258篇 |
1989年 | 252篇 |
1988年 | 255篇 |
1987年 | 230篇 |
1986年 | 221篇 |
1985年 | 244篇 |
1984年 | 216篇 |
1983年 | 165篇 |
1982年 | 185篇 |
1981年 | 160篇 |
1979年 | 201篇 |
1977年 | 162篇 |
1975年 | 181篇 |
1974年 | 195篇 |
1973年 | 227篇 |
1972年 | 192篇 |
1971年 | 164篇 |
1968年 | 196篇 |
1966年 | 152篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
91.
The Companeros model of HIV infection prevention in Ciudad Juarez, Mexico, is presented as conceived by the National Institute of Drug Abuse (NIDA). 518 women who were IV drug users, sexual partners of drug addicts, or prostitutes were requested to participate, and 232 consented. Initial and follow-up AIDS assessments were utilized along with an assessment of sociodemographic variables, including knowledge, sexual behavior, use and abuse of drugs, and previous health history. Educative sessions about AIDs and sexually transmitted diseases (STDs) included group discussions and interaction, video watching, personal experiences, and sociodramas. 61% of prostitutes were 29, 12.6% were 13-19 years old, 31.1% were aged 30-39, and 8.9% were 40. 11% had no formal education, 58% had 6 years of primary and part of 3 years of secondary education, only 18.6% completed secondary education; and 13% had higher education. 19% lived in a hotel or shelter. Family disintegration reached 44%; these women did not live with their children. Only 5.2% thought they had excellent health, 51% said they had good health, 31% stated they had average health, and 12% admitted having had health problems. 14.6% had genital ulcers, 1.3% had herpes, 15% had gonorrhea, and 10% had syphilis. Since IV drug use among these women was almost nonexistent sexual relations constituted the principal risk factor. Responses to a questionnaire showed that the most frequent sexual behavior was vaginal penetration followed by fellatio; anal penetration was less common. 34.9% of the women practiced fellatio without protection, 16.3% had anal intercourse without protection. The proportion of AIDS cases in Mexico in women of reproductive age was growing at an exponential rate, possible because of misinformation about AIDS, a history of STDs, and a low rate of condom use. 相似文献
92.
Although visuoconstructive impairment has been reported in both Alzheimer's (DAT) and Huntington's (HD) disease, there is little knowledge concerning how this cognitive deficit differs quantitatively and qualitatively in these two progressive dementias. To address this issue, the present study compared performances on the Clock Drawing Test (CDT: command and copy) of 25 DAT patients, 25 equally demented HD patients, and 25 elderly normal controls (NC). In the command condition, both patients groups were significantly impaired compared to the NC group. Although there was no significant difference between DAT and HD patients' total quantitative scores, a qualitative error analysis revealed a number of dissociations between the two patient groups. Graphic difficulties, very common in HD patients, were virtually absent in DAT patients; in contrast, conceptual errors were almost exclusively seen in DAT patients and were related to the severity of their dementia. Perseveration and "stimulus-bound" responses were also more frequent in DAT patients, and both groups made visuospatial errors. In the copy condition, the DAT, but not the HD, patients evidenced a marked improvement in performance. These results indicate that while both DAT and HD patients have significant visuoconstructive difficulties even in the early stages of their disorders, the specific cognitive processes underlying their quantitative impairments are quite different. It is possible that the DAT patients' conceptual errors are yet another indicator of the deterioration of their semantic knowledge. 相似文献
93.
On the Relation Between Time Perception and the Timing of Motor Action: Evidence for a Temporal Oscillator Controlling the Timing of Movement 总被引:7,自引:0,他引:7
Michel Treisman Andrew Faulkner Peter L. N. Naish 《The Quarterly Journal of Experimental Psychology Section A: Human Experimental Psychology》1992,45(2):235-263
Studies of time estimation have provided evidence that human time perception is determined by an internal clock containing a temporal oscillator and have also provided estimates of the frequency of this oscillator (Treisman, Faulkner, Naish, & Brogan, 1992; Treisman & Brogan, 1992). These estimates were based on the observation that when the intervals to be estimated are accompanied by auditory clicks that recur at certain critical rates, perturbations in time estimation occur. To test the hypothesis that the mechanisms that underlie the perception of time and those that control the timing of motor performance are similar, analogous experiments were performed on motor timing, with the object of seeing whether evidence for a clock would be obtained and if so whether its properties resemble those of the time perception clock. The prediction was made that perturbations in motor timing would be seen at the same or similar critical auditory click rates. The experiments examined choice reaction time and typing. The results support the hypothesis that a temporal oscillator paces motor performance and that this oscillator is similar to the oscillator underlying time perception. They also provide an estimate of the characteristic frequency of the oscillator. 相似文献
94.
Traditionally, communication skills training has focused principally on overt behaviours that are clearly identifiable. In recent years there has been an increasing awareness that cognitive processes can have considerable influence on behaviour. An attempt was made to establish whether changes in cognitions occurred as a result of a behaviourally-based communication skills training programme in which there had been no explicit attempt to bring about such cognitive changes. More specifically, the study examined whether such a programme resulted in changes in aspects of the personal construct space of students on a Diploma in Careers Guidance course. The results offered some support for the hypothesis that the programme produced changes in the students' personal construct space. 相似文献
95.
N J Osgood 《Suicide & life-threatening behavior》1992,22(1):98-106
One major purpose of this study was to identify environmental factors related to suicide in long-term care facilities. Questionnaires were mailed to a random sample of administrators at 1,080 facilities. Information was collected on facility characteristics, overt suicide, and intentional life-threatening behavior. Chi-square analyses revealed 4 environmental characteristics related to suicidal behavior and deaths from suicide: staff turnover, size, auspices, and per diem cost. More suicides occurred in larger facilities and facilities with higher staff turnover. Religious or "other" facilities experienced more suicidal deaths than public or private facilities; facilities charging less experienced more deaths. 相似文献
96.
N G Bliwise 《Psychology and aging》1992,7(1):83-88
Elderly women in subjectively good health--free of acute illness and major sleep pathologies--who were self-identified as good (n = 22) and poor (n = 16) sleepers were compared on measures of physical health, psychological symptoms, psychosocial status, and life-style. Poor sleepers reported longer sleep latencies, less total sleep time, more nonrestorative sleep, and more daytime fatigue than did good sleepers. Sleep recordings confirmed subjective reports, with shorter total sleep times and trends for lower sleep efficiency, longer sleep latencies, and more wake-after-sleep onset among women with subjective poor sleep. Poor sleepers also were more frequent users of sedative-hypnotic medications in the past. Current medication use, alcohol and caffeine use, daytime napping, and exercise were equivalent in both groups. Psychosocial status failed to discriminate groups. Poor sleepers reported significantly more psychological symptoms than did good sleepers. The levels of both psychological symptoms and sleep disturbance were mild. 相似文献
97.
98.
A MOTIVATIONAL ANALYSIS OF EMOTION: Reflex-Cortex Connections 总被引:1,自引:0,他引:1
99.
100.
A number of investigators have suggested that affective states influence the focus of attention. One recent proposal is that negative moods increase self-focus. This review considers the evidence that bears on this hypothesis. Conceptual issues pertaining to the construct of self-focus are discussed first. Next, the various parameters that influence attentional focus are presented in order to provide a way of organizing the mood/selffocus literature. Studies that have used state measures of mood and self-focus are considered in this context. Methodological limitations of existing studies are discussed and directions for future work provided. 相似文献