全文获取类型
收费全文 | 22961篇 |
免费 | 941篇 |
国内免费 | 11篇 |
专业分类
23913篇 |
出版年
2020年 | 235篇 |
2019年 | 317篇 |
2018年 | 435篇 |
2017年 | 449篇 |
2016年 | 480篇 |
2015年 | 358篇 |
2014年 | 400篇 |
2013年 | 1899篇 |
2012年 | 703篇 |
2011年 | 722篇 |
2010年 | 431篇 |
2009年 | 400篇 |
2008年 | 533篇 |
2007年 | 593篇 |
2006年 | 510篇 |
2005年 | 467篇 |
2004年 | 449篇 |
2003年 | 435篇 |
2002年 | 457篇 |
2001年 | 754篇 |
2000年 | 726篇 |
1999年 | 552篇 |
1998年 | 224篇 |
1997年 | 205篇 |
1996年 | 227篇 |
1992年 | 452篇 |
1991年 | 446篇 |
1990年 | 427篇 |
1989年 | 403篇 |
1988年 | 421篇 |
1987年 | 381篇 |
1986年 | 389篇 |
1985年 | 394篇 |
1984年 | 313篇 |
1983年 | 281篇 |
1982年 | 206篇 |
1981年 | 207篇 |
1979年 | 356篇 |
1978年 | 256篇 |
1977年 | 215篇 |
1975年 | 281篇 |
1974年 | 355篇 |
1973年 | 367篇 |
1972年 | 290篇 |
1971年 | 283篇 |
1970年 | 281篇 |
1969年 | 253篇 |
1968年 | 351篇 |
1967年 | 309篇 |
1966年 | 286篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
261.
Dating experiences, especially the type or stage of dating, have consistently been found to be related to premarital sexual behavior. Findings regarding the age at 1st date and sexual behavior have been less consistent. This paper examined the age at which dating began and the type of dating relationship as correlates of premarital sexual attitudes and behavior among mid-teen adolescents. The analyses were based on a sample of high school students (n=836), most of whom were between the ages of 15 and 18 when the surveys were conducted. Early dating, especially early steady dating, was related to permissive attitudes and to premarital sexual experience among both males and females. The relationship between early dating and intercourse experience was particulary strong among Mormons, a religious group which has institutionalized age 16 as the legitimate age to begin dating. 相似文献
262.
J K O'Hanlon B D Sachs 《Journal of comparative psychology (Washington, D.C. : 1983)》1986,100(2):178-187
Three experiments with rats (Rattus norvegicus) were conducted to examine the roles of the male's penile spines and penile cups (flaring of the distal glans) in the induction of luteal activity in the female, and in the removal of copulatory plugs from the vaginal tract. The results of Experiment 1 revealed no role for the cup in luteal induction but did suggest that elements of the ejaculatory reflex apart from cup formation contribute to the elicitation of this neuroendocrine response. The origin of this stimulatory effect was not directly determined, but indirect evidence suggested a role for penile spines. In Experiments 2 and 3, features of the glans penis that might help effect plug removal were investigated, and the experiments demonstrated that penile spines, perhaps in conjunction with penile cups, contribute to the extraction of plugs from the vagina. 相似文献
263.
Sex difference trends in completed suicide 总被引:1,自引:0,他引:1
The recent suicide literature increasingly has contained statements suggesting that the differences in completed suicide between the sexes are lessening. A compilation of official suicide data for 1933-1980 verifies such a trend from the 1950s through 1971. However, increased differences (as measured by the ratio of male to female rates) were consistently observed from 1971 to 1980. These trends were found for data for the nation, for whites and nonwhites, for numbers of suicides, for crude rates, and for age-adjusted rates. Decreased sex differences were obtained for those 35-44, 45-54, 55-64, and for 65+ years of age, but increased sex differences were observed for those aged 15-24 and 25-34. Possible explanations for these findings are presented. 相似文献
264.
Younger adult students between 19 and 24 years of age (M = 21.3 years), older adult students between 61 and 76 years of age (M = 67.9 years), and older adult nonstudents between 62 and 76 years of age (M = 68.5 years) were assessed for health (self-ratings of physical and mental health), social functioning (self-ratings of physical and mental activity, perceived role activity level, perceived roles, locus of control, and age-norm expectations), and cognitive functioning (Wechsler Adult Intelligence Scale-Revised vocabulary and block design, and paired associate memory). Age differences were observed in self-ratings of health, social roles, intellectual performance, and memory. No student status differences were observed. The results are discussed in terms of plasticity of intellectual function and characteristics of student status in later adulthood. 相似文献
265.
Fluid intelligence belongs to that cluster of intellectual abilities evincing aging loss. To examine further the range of intellectual reserve available to aging individuals and the question of replicability in a new cultural and laboratory setting, 204 healthy older adults (mean age = 72 years; range = 60-86) participated in a short-term longitudinal training study. For experimental subjects, 10 sessions consisted of cognitive training involving two subability tests (Figural Relations, Induction) of fluid intelligence. The pattern of outcomes replicates and expands on earlier studies. Older adults have the reserve to evince substantial increases in levels of performance in fluid intelligence tests. Transfer of training, however, is narrow in scope. Training also increases accuracy of performance and the ability to solve more difficult test items. Difficulty level was estimated in a separate study, with a comparable sample of N = 112 elderly adults. Future research is suggested to examine whether intellectual reserve extends to near-maximum levels of performance. 相似文献
266.
Christie B. Gardiner Margaret M. Beaumont J. Graham Eason Ken Davidoff Jules B. Richardson John T. E. Messer David Newstead Steve 《Current psychology (New Brunswick, N.J.)》1986,5(2):205-216
Current Psychology - 相似文献
267.
Frederick J. Fuoco Barry J. Naster Janice B. Vernon Robert T. Morley Betty L. Smith Andy E. B. Cancelliere 《Behavioral Interventions》1986,1(3):169-182
The purpose of the present experiment was to investigate the efficacy of a goal orientation procedure in their treatment of apathy, isolation, and insufficient goal setting skills in chronic psychiatric residents. The experiment was conducted in a behaviorally-oriented deinstitutionalization program in a state psychiatric hospital. Three male and four female chronic psychiatric residents served as research participants. A group repeated measures design with four within-participant phases (ABA‘B’) was utilized. The goal orientation procedure included a written schedule that was completed by each research participant daily. This Daily Living Schedule required that a behavior be specified by the participant for every half-hour period during the day (8:30 a.m. to 9:00 p.m.). During all four phases of the experiment, research participants were observed on the ward from 8:30 a.m. to 12:00 noon and 1:00 p.m. to 5:00 p.m. for engagement in scheduled target behaviors. The daily scheduling procedure produced substantial increases in appropriate behavior such as social activities, ward jobs, and participation in treatment programs, whereas decrease were produced in inappropriate behavior such as isolation and day time sleeping. 相似文献
268.
Douglas B. Eamon 《Behavior research methods》1984,16(2):168-171
The need for common pedagogical and design features in courseware is discussed. A particularly useful feature would allow use of courseware in either of two “modes”: as an “electronic chalkboard” for the instructor who wishes to take advantage of the computer in a traditional lecture setting, or as an “electronic study guide” in which students interact individually with the programs. Development of programs using these two modes can be facilitated using Author-Assist, a set of routines and a program skeleton being developed by CONDUIT (1983). Author-Assist provides procedures for use of several types of automatic menu generation, automatic text formatting in “text ports,” mixed text and graphics, protected input routines, lowercase characters in text, automatic scaling of graphic displays using “graphports,” on-screen calculator functions, and a variety of other features. 相似文献
269.
B. J. Kennedy M.D. 《The Journal of medical humanities》1984,5(1):27-32
The concepts of informed consent and surveillance of human research designed to protect human subjects is commendable. The regulations of the Institutional Review Board (IRB) are having a major impact on clinical cancer research. There is greater administrative time needed of the investigator, the mechanisms of patient care have become cumbersome and some patients reject optional medical management that could be life saving. IRB regulations must be flexible to meet the needs of human subjects as well as those of the clinical investigator. 相似文献
270.