全文获取类型
收费全文 | 3458篇 |
免费 | 423篇 |
国内免费 | 751篇 |
专业分类
4632篇 |
出版年
2024年 | 16篇 |
2023年 | 69篇 |
2022年 | 97篇 |
2021年 | 108篇 |
2020年 | 149篇 |
2019年 | 114篇 |
2018年 | 161篇 |
2017年 | 167篇 |
2016年 | 151篇 |
2015年 | 122篇 |
2014年 | 130篇 |
2013年 | 296篇 |
2012年 | 216篇 |
2011年 | 291篇 |
2010年 | 253篇 |
2009年 | 244篇 |
2008年 | 275篇 |
2007年 | 351篇 |
2006年 | 341篇 |
2005年 | 252篇 |
2004年 | 173篇 |
2003年 | 110篇 |
2002年 | 97篇 |
2001年 | 55篇 |
2000年 | 58篇 |
1999年 | 49篇 |
1998年 | 30篇 |
1997年 | 34篇 |
1996年 | 20篇 |
1995年 | 24篇 |
1994年 | 19篇 |
1993年 | 21篇 |
1992年 | 17篇 |
1991年 | 5篇 |
1990年 | 20篇 |
1989年 | 19篇 |
1988年 | 9篇 |
1987年 | 10篇 |
1986年 | 4篇 |
1985年 | 14篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 10篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1973年 | 4篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有4632条查询结果,搜索用时 15 毫秒
21.
The present study compared the moderating effect of social support on parental stress variables and mental health among three groups of parents: parents of HBV (Hepatitis B Virus) children who attended the special health kindergarten, parents of HBV children who stayed at home, and parents of healthy children who attended the ordinary kindergarten. These families resided in the city of Guangzhou. A set of questionnaires measuring parental stress and social support were given to the mothers after a one-hour interview. Results showed that parents of HBV children were significantly more stressed and psychologically at risk than parents of healthy children. They also sought help from social resources more often than the parents of healthy children. Parents of healthy children who attended the ordinary kindergarten reported the highest levels of overall social support, i.e. the number of very close friends and relatives with whom they could form close emotional attachments. Although they reported a lower number of acquaintances available, they also reported the most satisfactory relationships with the support provided by their acquaintances, lower levels of stress, fewer somatic problems, more adequate general health, and more perceived meaning in life than did parents of HBV children, and social support is one of the main influences on stress or parental health. The findings call for further research to focus on parents' well-being and social support that is helpful in addressing the needs of the family. 相似文献
22.
23.
Stimulus control in the use of landmarks by pigeons in a touch-screen task 总被引:2,自引:1,他引:1 下载免费PDF全文
Pigeons were tested in a search task on the surface of a monitor on which their responses were registered by a touch-sensitive device. A graphic landmark array was presented consisting of a square outline (the frame) and a colored “landmark.” The unmarked goal, pecks at which produced reward, was located near the center of one edge of the frame, and the landmark was near it. The entire array was displaced without rotation on the monitor from trial to trial. On occasional no-reward tests, the following manipulations were made to the landmark array: (a) either the frame or the landmark was removed; (2) either one edge of the frame or the landmark was shifted; and (3) two landmarks were presented with or without the frame present. On these two-landmark tests, the frame, when present, defined which was the “correct” landmark. When the frame was absent, the “correct” landmark was arbitrarily determined. Results showed that pecks of 2 pigeons were controlled almost solely by the landmark, pecks of 3 were controlled primarily by the landmark but the frame could distinguish the correct landmark, and 1 bird's behavior was controlled primarily by the frame. Stimulus control in this search task is thus selective and differs across individuals. Comparisons to other search tasks and to other stimulus control experiments are made. 相似文献
24.
Manuel Barrera Jr. Susan A. Li Laurie Chassin 《American journal of community psychology》1995,23(4):479-507
Investigated ethnicity and parental alcoholism as factors that might influence the stress vulnerability of adolescents. It
extended an initial cross-sectional study of this same sample by adding two annual assessments which allowed for additional
cross-sectional analyses and longitudinal tests. Hispanic and Caucasian adolescents (N=306 at Time 1) completed measures of their own life stress, family conflict, and alcohol use. Their parents reported on adolescents'
internalizing and externalizing symptoms. Cross-sectional analyses at Time 2, and prospective analyses involving Time 1 and
Time 2 measures were, for the most part, consistent with the original study's results. Caucasian adolescents and children
of alcoholic parents appeared to be more vulnerable to stress than Hispanic adolescents and children of nonalcoholic parents.
Family conflict was a partial explanation for this increased vulnerability.
This research was supported by National Institute on Drug Abuse Grant DA05227 to Laurie Chassin (pricipal investigator) and
Manuel Barrera, Jr. (coprincipal investigator). Susan Li was supported by an American Psychological Association Minority Fellowship
Award. Portions of this research were presented at the conference, “Resiliency in Families: Racial and Ethnic Minority Families
in America” that was held at the University of Wisconsin, May 31–June 2, 1994. 相似文献
25.
临床经验对诊断的双重作用及改造 总被引:1,自引:0,他引:1
文中用辩证唯物主义的观点,阐述了临床经验的定义、来源及指导实践过程中的意义,指出其具有促进诊断和引起误诊的双重作用,并用临床病历例子详细说明其双重作用的形式、导致结果及产生的原因。指出临床经验的双重作用在临床工作中的重要性及局限性,提出对经验的改造完善途径,以能充分表现出其促进诊断的作用,而最大限度降低其导致误诊的程度,发挥在临床工作中的良性作用。 相似文献
26.
Li FP 《Ethics & behavior》1995,5(2):193-196
Case vignette: sharing unanticipated genetic information. The Questor family has experienced an unusual number of malignancies in the past two generations and has been advised by an oncologist that the p53 oncogene known as Li-Fraumeni Syndrome may be present in the family genome. The option of predictive genetic testing has been raised and several branches of the family have chosen to undergo screening to determine whether they are at risk for cancer because of the gene. Roger and Liz Questor have arranged for screening of themselves and their three children, ages 12, 10, and 7. The couple has, by all appearances, been happily married for 14 years. None of the family members are found to carry the oncogene; however, the geneticist conducting the analyses has made an interesting incidental discovery. The 10-year-old child is not the biological progeny of Roger Questor. Although the 12- and 7-year-olds are clearly the biological children of the couple, it is evident that the 10-year-old born to Liz Questor was fathered by a person other than Roger. What are the ethical obligations of the geneticist with respect to any sharing or disclosure of the information that has been discovered incidentally? What course of action, if any, do you recommend? 相似文献
27.
合作学习对小学生同伴关系、成就动机和成就影响的研究 总被引:12,自引:0,他引:12
旨在探讨在我国开展合作学习教学的可行性,以及合作学习对小学生同伴关系、成就动机和成就水平的影响,运用自然实验和测量相结合的方法,选择了北京师范大学实验小学三年级两个班进行实验研究,其中一个班为实验班(n=35),另一个班为控制班(n=37).实验为期三个月。结果表明:合作学习在小学教学中不但是可行的,而且效果较为显著;合作学习对同伴关系的改善有着积极的影响,学生间的接纳度和被接纳度都有普遍的提高;合作学习在较大程度上激发了学生的成就动机水平,学生对合作学习的课程兴趣明显提高.成绩较差的学生表现得更为明显;合作学习对提高学生的学习成绩有一定的促进作用。 相似文献
28.
The visual field exerts powerful effects on egocentric spatial localization along both horizontal and vertical dimensions. Thus, (1) prism-produced visual pitch and visual slant generate similar mislocalizations of visually perceived eye level (VPEL) and visually perceived straight ahead (VPSA) and (2) in darkness curare-produced extraocular muscle paresis under eccentric gaze generates similar mislocalizations in VPEL and VPSA that are essentially eliminated by introducing a normal visual field. In the present experiments, however, a search for influences of real visual slant on VPSA to correspond to the influences of visual pitch on VPEL failed to find one. Although the elevation corresponding to VPEL changes linearly with the pitch of a visual field consisting of two isolated 66.5°-long pitched-from-vertical lines, the corresponding manipulation of change in the slant of either a horizontal two-line or a horizontal four-line visual field on VPSA did not occur. The average slope of the VPEL-versus-pitch function across 5 subjects was +0.40 over a ±30° pitch range, but was indistinguishable from 0.00 for the VPSA-versus-slant function over a ±30° slant range. Possible contributions to the difference between susceptibility of VPEL and VPSA to visual influence from extraretinal eye position information, gravity, and several retinal gradients are discussed. 相似文献
29.
30.
成人脑涨落图年龄变化特点的研究 总被引:13,自引:0,他引:13
该工作研究了120名20-79岁正常成人脑涨落图的年龄变化特点。结果表明:(1)从20岁到50岁,S系谱线活动向低频方向集中,60岁后谱线又向高频方向有所移动;(2)部分谐振系的随龄变化表现明显,其中以S17系变化最为敏感;(3)脑区间相干活动和各脑区的连频活动随年龄增强,脑能量分布的有序性逐渐破坏;(4)增龄性变化主要反映在优势脑区(左前脑)和优势脑轴(左前/右后脑)上,与脑高级机能活动密切相关的左前脑的退行性变化最为明显。上述结果反映了脑功能的减退是一个非线性的多层次的复杂过程。 相似文献