全文获取类型
收费全文 | 20328篇 |
免费 | 1027篇 |
国内免费 | 8篇 |
出版年
2020年 | 302篇 |
2019年 | 239篇 |
2018年 | 349篇 |
2017年 | 413篇 |
2016年 | 459篇 |
2015年 | 341篇 |
2014年 | 413篇 |
2013年 | 1781篇 |
2012年 | 660篇 |
2011年 | 611篇 |
2010年 | 441篇 |
2009年 | 437篇 |
2008年 | 581篇 |
2007年 | 611篇 |
2006年 | 561篇 |
2005年 | 504篇 |
2004年 | 437篇 |
2003年 | 419篇 |
2002年 | 447篇 |
2001年 | 741篇 |
2000年 | 726篇 |
1999年 | 505篇 |
1998年 | 229篇 |
1997年 | 214篇 |
1996年 | 247篇 |
1995年 | 203篇 |
1994年 | 188篇 |
1992年 | 436篇 |
1991年 | 419篇 |
1990年 | 409篇 |
1989年 | 352篇 |
1988年 | 344篇 |
1987年 | 330篇 |
1986年 | 308篇 |
1985年 | 303篇 |
1984年 | 294篇 |
1983年 | 243篇 |
1982年 | 212篇 |
1979年 | 274篇 |
1978年 | 228篇 |
1977年 | 204篇 |
1976年 | 178篇 |
1975年 | 220篇 |
1974年 | 275篇 |
1973年 | 265篇 |
1972年 | 196篇 |
1971年 | 201篇 |
1969年 | 183篇 |
1968年 | 222篇 |
1967年 | 203篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
We investigated longitudinally the effects of a stroke on the social support systems and well-being of the patient's primary support person, both acutely and as the condition stabilized. Individuals who had suffered a first stroke and a primary support person participated in two waves of data collection, carried out in 6-month intervals beginning 7 weeks after the stroke. Our data show that the prevalence of depressive symptoms is from 2 1/2 to 3 1/2 times higher than rates found among representative samples of middle-aged and elderly populations. Mean level of depression did not change over time, although level of optimism declined significantly. Multiple regression analyses showed that levels of depression and perceived burden in support persons are highly related to aspects of the stroke such as its severity, and that demographic variables such as age and income play a relatively minor role in attenuating these relations in the acute adjustment phase. However, from 7 to 9 months after the stroke, well-established demographic variables such as health, income, and age were significant predictors of depression. Individuals who were older and who had good health and higher incomes were least depressed. 相似文献
102.
The belief is widely held that humor is related to recovery from, and perhaps an increased resistance to, coronary and other
stress-related diseases. Such generalizations do not typically distinguish between benign and hostile humor. In the present
research, the relationship between a measure of proneness to coronary heart disease (CHD) and appreciation of hostile and
nonhostile humor is examined. In two studies, one with college students and one with patients suffering from CHD, the relationship
between humor preferences and the coronary-prone (Type A) behavior pattern was examined. Each subject was given the Jenkins
Activity Survey as a measure of the coronary-prone personality type, and aggressive and nonaggressive jokes to rate for funniness.
Hostile humor was preferred to nonhostile humor by all groups, but among those suffering from CHD, those who could be classified
as “Type B’s” preferred nonhostile humor. The results indicate that those less prone to CHD appreciate both hostile and nonhostile
humor, while Type A’s seem to enjoy hostile humor only. 相似文献
103.
104.
A software package called PAST (Programmer Assessment Software Tools) is described. PAST was designed as a research and diagnostic tool to analyze how programmers develop and test program code. PAST uses line changes between successive compiles to estimate a programmer’s cognitive processing. Line changes are highlighted and graphically presented between any two versions or compiles. Summary graphs and statistics across all versions also are provided. Applications of PAST for expanding our understanding of programming and applying it to research, teaching, and learning are discussed. 相似文献
105.
High-resolution CRT displays are subject togeometric distortion: lines that are straight in the internal coordinates of the graphics software and hardware are curved when projected onto a plane in the observer’s line of sight. As the available resolution of CRT screens increases, it becomes more difficult to measure and correct for this distortion. We present a simple, highly accurate method for determining the mapping between internal coordinates and the viewing plane. It requires that an observer, using a calibration program, adjust triples of displayed points until they are collinear. A metal straightedge placed between the observer and the screen aids in this judgment. We describe the calibration of an IBM Enhanced Graphics Display in high-resolution mode (350 × 640 pixels), and illustrate how to use the estimated mapping to choose internal coordinates to draw undistorted figures that are accurate to within 0.5 pixel. The method can be used to assess or to correct the accuracy of visual displays. The method is relevant to experiments in spatial vision, spatial perception, perception of dot patterns, and any application in which geometrically accurate stimuli are required. 相似文献
106.
107.
D. E. McMillan PhD. 《Integrative psychological & behavioral science》1988,23(2):57-66
Pigeons were trained to acquire a new four-response position sequence each day by pecking three response keys in a predetermined order. The key color varied after each correct response prior to food delivery. Acute administration of Γ9-tetrahydrocannabinol (Δ9-THC) up to a dose that completely eliminated responding, had no effect on total acquisition errors, or on within session patterns of error elimination. Chronic administration of Δ9-THC (3–10 mg/kg/day), either before or after the session for 4–7 weeks, also did not affect these error measures, although rates of responding were markedly suppressed and at times no responding occurred Discontinuation of Δ9-THC administration for periods of 4–6 weeks also was without effect on errors. These experiments suggest that neither acute nor chronic Δ9-THC produce specific effects on the repeated acquisition of serial position responses in pigeons. 相似文献
108.
Maternal handling and motor development: an intracultural study 总被引:1,自引:0,他引:1
Citing a distinction between informal and formal routines used by mothers in handling their infants, we examined formal handling routines, in which the caregiver acts in a pedagogical manner; these routines are widespread in many non-Western countries. We hypothesised that formal handling serves to facilitate gross motor development during early infancy. To examine this hypothesis, the effects of a Jamaican formal handling routine on a broad range of developmental outcomes was examined. Results showed that the effects were specific to early gross motor development and in particular to postural control along the vertical axis of the body. Information is also provided on other aspects of Jamaican child care. It seems that the handling routine forms part of a folk (developmental) medicine system and may serve not only to promote child health but also as a sort of developmental neurological examination. 相似文献
109.
110.
Neutrality is a central concept within the theory of psychoanalytic technique. We spell out the major controversies in which the concept has become embroiled, and provide a definition that we believe coincides with actual psychoanalytic practice. We discuss its merits and weaknesses, noting also the negative consequences of relying on older definitions. We relate neutrality to the interpretive process, indicating ways interpretation protects neutrality and is made more effective by it. We discuss the complex and controversial relation between neutrality and the analyst's therapeutic intent. 相似文献