首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   22602篇
  免费   758篇
  国内免费   11篇
  2019年   211篇
  2018年   319篇
  2017年   367篇
  2016年   365篇
  2015年   234篇
  2014年   306篇
  2013年   1670篇
  2012年   606篇
  2011年   663篇
  2010年   404篇
  2009年   382篇
  2008年   568篇
  2007年   550篇
  2006年   506篇
  2005年   455篇
  2004年   450篇
  2003年   405篇
  2002年   466篇
  2001年   731篇
  2000年   749篇
  1999年   559篇
  1998年   260篇
  1997年   218篇
  1996年   205篇
  1992年   454篇
  1991年   408篇
  1990年   447篇
  1989年   424篇
  1988年   403篇
  1987年   404篇
  1986年   407篇
  1985年   426篇
  1984年   335篇
  1983年   303篇
  1982年   239篇
  1981年   216篇
  1979年   390篇
  1978年   280篇
  1977年   255篇
  1976年   224篇
  1975年   345篇
  1974年   377篇
  1973年   355篇
  1972年   330篇
  1971年   289篇
  1970年   260篇
  1969年   326篇
  1968年   361篇
  1967年   322篇
  1966年   327篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
We tested the notion that better foster care adjustment would be observed when the temperaments of mothers and fathers were matched with those of adolescent foster children. We hypothesized that families in which foster parents and foster children had high (easy) scores on subscales of the Revised Dimensions of Temperament Scale (DOTS-R) would also report higher family functioning and higher foster care adjustment than parents and children from families in which one or both family members had low (difficult) scores on these scales. The hypotheses were supported when the mothers and fathers family assessments were used but rejected when the observations of the case managers and adolescents were tested. Methodological and substantive explanations for the findings are discussed and recommendation for foster care practice and continuing research are provided.  相似文献   
992.
This study investigated the prevalence of traumatic brain injury (TBI) in an inpatient psychiatric population. We hypothesized increased prevalence of TBI relative to the general population due to a variety of risk factors observed in psychiatric patients. One hundred (mean age = 34) psychiatric inpatients completed the revised Head Injury Questionnaire. Chart review of 17 subjects reporting injuries established whether injuries were documented in medical records. Sixty-eight percent of this psychiatric population reported one or more injuries in which they were unconscious or dazed. This number is higher than the prevalence in the general population. Injuries were generally of mild to moderate severity; multiple injuries were common. Chart review of 17 subjects reporting TBI indicated that histories of TBI had not been noted in the medical record. Finally, 63% of TBI subjects reported that their injury predated the onset of their psychiatric symptoms. These results suggest a possible role of TBI in psychiatric symptomatology and have implications for psychiatric treatment in this population.  相似文献   
993.
We investigated the ability of subjects to discriminate sugars with a whole-mouth forced-choice paradigm, in which a standard solution was compared with a test solution of varied concentration. Discrimination probabilities were U-shaped functions of test concentration: for 6 subjects and pairwise combinations of fructose, glucose, and sucrose, discriminability always declined to chance over a narrow range of test concentrations. At concentrations ≦ 100 mM, maltose was indiscriminable from fructose but discriminable at higher concentrations for 4 subjects. By analogy with themonochromacy of night vision, whereby any two lights are indiscriminable when their relative intensities are suitably adjusted, we call the gustatory indiscriminability of these sugarsmonogeusia. The simplest account of monogeusia is that all information about the indiscriminable sugars is represented by a single neural signal that varies only in magnitude. The discriminability of maltose from the other sugars at higher concentrations is consistent with the hypothesis that maltose also activates a second gustatory code.  相似文献   
994.
Groups of rats were administered either DSP4 (50 mg/kg, ip), xylamine (50 mg/kg, ip), or p-chloroamphetamine (2 X 10 mg/kg, ip), either 2 weeks or 1 week before the testing of two-way active avoidance. DSP4 and xylamine, the selective noradrenaline (NA) neurotoxins, caused a two-way avoidance impairment but p-chloroamphetamine, the selective 5-hydroxytryptamine (5-HT) neurotoxin, did not do so. Pretreatment with desipramine (20 mg/kg, ip) blocked the avoidance impairment caused by DSP4 and xylamine treatment. Neither DSP4 nor xylamine caused any alteration of passive avoidance retention. The biochemical analyses indicated severe NA, but not 5-HT, depletions in the DSP4 and xylamine conditions and drastic 5-HT, but not NA, depletions in the p-chloroamphetamine conditions. These results confirm and extend earlier findings concerning the role of NA in avoidance behavior.  相似文献   
995.
Fetal brain tissue from the occipital or the frontal cortex was implanted into the damaged occipital cortex of adult rats. The animals receiving grafts of embryonic frontal cortex showed partial restoration of brightness discrimination while recipients given homologous implants of occipital cortex were as impaired as those animals with lesions alone. Neither frontal nor occipital grafts aided in the performance of a pattern discrimination problem; both groups of brain-damaged animals were unable to learn the task. Nonetheless, both groups of animals had viable and enlarged grafts with similar neuronal and glial profiles.  相似文献   
996.
This study was designed to provide a detailed analysis of the parameters which interact to produce a field hockey drive. The drive was performed by an elite performer under two conditions of uncertainty (Blocked and Random). The subject was asked to drive a field hockey ball toward a specified target. In the Blocked condition the speed of the approaching ball remained constant (20, 30 and 40 m.p.h.) while in the Random condition these speeds were randomly assigned to each trial. Cine analysis of the subject's successful responses under the two experimental conditions led to an investigation of the kinematics, phasing, and timing of the stroke. The subject placed emphasis upon varying the initial phases of the stroke (i.e., backswing and preparatory phases) in order to produce a temporally consistent ballistic downswing to ball contact. It seemed likely that the subject appraised the ball speed that was being delivered and then incorporated additional stick movement to ‘mark time’ before initiating temporally consistent movement phases, as spatial uncertainty increased, the subject delayed her response initiation, but then tended to respond in intervals of one reaction time for each stroke phase. Consistency was evident for displacement and initiation point values, but to a lesser extent than existed for the other variables. However, as a result of this adjustment in spatial location and displacement of the stick end during the preliminary phases of the response, the subject was able to produce a consistent and accurate ballistic downswing.  相似文献   
997.
Inhibition of protein synthesis by anisomycin for a short duration impairs memory of a one-trial inhibitory avoidance task in rats. Memory of escape conditioning involving eight trials is disrupted only if the duration of protein synthesis is prolonged by repeated injections. In marked contrast, olfactory memory of rats trained on two odor discriminations is not affected by anisomycin even if the duration of inhibition is prolonged and the number of trials is reduced to a minimum. In previous work, leupeptin, a thiol proteinase inhibitor, was shown to impair olfactory discrimination learning, but left inhibitory and avoidance conditioning intact. Together, these results provide a pharmacological double dissociation of memory, and suggest that the same chemistries, or mixtures of chemistries, may not be involved in all types of memory.  相似文献   
998.
999.
Although vocational psychologists and sociologists have a long history of researching occupational choice, their theoretical postures have almost always been shaped in light of information on males, with little consideration for females. This article is an addition to others which attempt to correct this shortcoming in the literature. The article reviews the dominant conceptual schemes used to study occupational choice, considers potentially female-specific variables, and provides a typology for the analysis of women's marital-familial statuses and work modes.  相似文献   
1000.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号