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   18607篇
  免费   1671篇
  国内免费   492篇
耳鼻咽喉   105篇
儿科学   286篇
妇产科学   120篇
基础医学   2498篇
口腔科学   423篇
临床医学   2933篇
内科学   1468篇
皮肤病学   70篇
神经病学   3757篇
特种医学   703篇
外科学   896篇
综合类   2947篇
现状与发展   1篇
一般理论   16篇
预防医学   1814篇
眼科学   343篇
药学   1465篇
  126篇
中国医学   512篇
肿瘤学   287篇
  2024年   88篇
  2023年   863篇
  2022年   1147篇
  2021年   1526篇
  2020年   1261篇
  2019年   890篇
  2018年   670篇
  2017年   667篇
  2016年   580篇
  2015年   572篇
  2014年   1132篇
  2013年   1391篇
  2012年   945篇
  2011年   1097篇
  2010年   772篇
  2009年   778篇
  2008年   851篇
  2007年   771篇
  2006年   727篇
  2005年   556篇
  2004年   459篇
  2003年   397篇
  2002年   339篇
  2001年   267篇
  2000年   252篇
  1999年   182篇
  1998年   199篇
  1997年   192篇
  1996年   123篇
  1995年   96篇
  1994年   82篇
  1993年   88篇
  1992年   63篇
  1991年   56篇
  1990年   54篇
  1989年   33篇
  1988年   56篇
  1987年   33篇
  1986年   31篇
  1985年   54篇
  1984年   55篇
  1983年   37篇
  1982年   42篇
  1981年   34篇
  1980年   36篇
  1979年   32篇
  1978年   25篇
  1977年   36篇
  1976年   31篇
  1974年   31篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
非特异性言语学习障碍是具有明显的遗传倾向和遗传异质性的一类神经心理疾病,患者通常仅具有言语发育障碍这一认知缺陷.研究非特异性言语学习障碍的遗传易感位点和候选基因功能不仅可以从分子角度去认识和理解非特异性言语学习障碍的遗传和病理生理机制,同时也推动了神经心理学和认知遗传学等相关学科的发展.本文就目前常见非特异性言语学习障碍遗传易感位点和候选基因的研究现状及该研究领域所存在和面临的问题,以及发展前景作一综述.  相似文献   
82.
图片学习测验在识别老年人轻微认知功能损害中的作用   总被引:6,自引:2,他引:4  
目的 分析图片学习测验在识别老年人轻微认知功能损害 (MCI)中的作用。方法 选择符合MCI诊断标准的老年人 4 8例与正常对照组 5 6名完成图片学习测验、简易智能状态检查、听觉词语学习测验及多种非记忆测验。结果 图片学习测验的 3个记忆指标 (图片短时记忆、延迟记忆和学习记忆 )在MCI与正常对照组之间有非常显著的差异。已经给出这三个图片记忆指标区分MCI与正常老年人的划界分、敏感性和特异性。结论 图片记忆操作简便、信度和效度好 ,可以作为临床医师筛选MCI的有效工具  相似文献   
83.
Using a corticostriatal slice preparation, we have recently shown that tetanic stimulation of the corticostriatal pathway produces long-term depression (LTD) of striatal excitatory synaptic transmission. In the present study we have analysed the relationship between LTD and the striatal release of different endogenous transmitters. Samples of perfusate were collected via a small cannula placed just above the surface of the striatal slice close to the recording electrode, and were analysed by HPLC. The high-frequency stimulation (100 Hz, three trains, 3 s duration, 20 s intervals) used to induce LTD caused a significant but transient increase in the release of both excitatory (aspartate and glutamate) and inhibitory (glycine and GABA) amino acid transmitters. Tetanic stimulation also produced a significant, but transient increase in the release of endogenous dopamine. We conclude that the tetanic stimulation of the corticostriatal pathway is able to induce a large but transient release of excitatory amino acids and of dopamine, whose participation in the induction of striatal LTD has been demonstrated previously. Moreover, the maintenance of this form of synaptic plasticity does not seem to require a sustained change in transmitter release.  相似文献   
84.
The present study was designed to examine patterns of regional cerebral blood flow (CBF) associated with the learning of a repeated visuomotor sequence both in the early and late phases of the acquisition process. In addition, changes in blood flow related to the implicit versus explicit aspects of learning such a skill were investigated. Fourteen normal control subjects were scanned while performing the task (i) in both early and advanced learning stages of the visuomotor sequence; (ii) after having acquired explicit knowledge of the sequences; and (iii) in two control conditions (perceptual and random sequence). Subtraction of the random condition from the highly learned condition revealed specific areas of activity in the right ventral striatum and dentate nucleus of the cerebellum. Blood flow changes in the right hemisphere were also seen in the medial posterior parietal and prestriate regions, as well as in the anterior cingulate cortex. Finally, once the subjects had acquired explicit knowledge of the embedded sequence that was presented in the highly learned condition, increased CBF activity was observed only in the mid-ventrolateral frontal area in the right hemisphere. These findings confirm that both the striatum and the cerebellum are involved in the implicit acquisition of a visuomotor skill, especially in the advanced stages of the learning process, and furthermore that the ventrolateral prefrontal cortex contributes preferentially to the declarative aspect of this task.  相似文献   
85.
86.
Since Samuel Orton's (1937) assertion that dyslexia reflects abnormal brain organization, the relationship of learning disabilities to brain dysfunction has been the topic of considerable debate. Recently, learning-disabled individuals have been studied in conjunction with those known to have neurological dysfunction, in a search for common subtypes. In the present study, a population of 177 children, ages 9-0 to 14-0, were assessed on an augmented version of the Children's Halstead-Reitan Battery. One hundred twenty-nine Ss were learning-disabled, 37 of whom also had verified brain damage. The remaining 48 children had neither learning disabilities nor evidence of brain damage. Patterns of neuropsychological performance were determined using Tryon's clustering methods. The procedure yielded six subject clusters: (A) and (B)—children with low general intellectual ability; (C) children who are clumsy and lethargic; (D) children with language dysfunction; (E) children with faulty spatial orientation; and (F) children with no detectable neuropsychological deficits. These clusters were similar to those identified by investigators who have used other subject-clustering methods. Brain-damaged individuals were more prevalent in some clusters (e.g., A and B) than in others (e.g., E and F), and substantial numbers of learning disabled subjects were also found in clusters where brain-damaged individuals tended to cluster, indicating similar neuropsychological profiles. The cluster structure was validated by comparison with subtypes identified by other investigators, as well as by tests of association between clusters with exogenous factors (e.g., history of prematurity; seizures).  相似文献   
87.
88.
The validity of a hinged constant force probe (0.25 N) was compared with that of a similar but immobilised instrument, using the same interchangeable tip for both (0.64 mm diameter; 2 mm divisions). 60 sites were measured on teeth which were extracted subsequently, in patients with untreated periodontal disease, and the connective tissue attachment level was used as validity criterion. The clinical measurements of both probes correlated well with each other, but they differed significantly from the post-extraction connective tissue attachment level measurements, indicating a point 1.2 mm coronally to this, on average. A companion investigation of intra-operator probing depth reproducibility with the 2 probes, was undertaken in 14 patients, at 2 visits separated by 1 week in each case. All patients had untreated periodontal disease. A difference between probes was found at the first visit, but not at the second; the immobilised probe showed a difference between visits, reducing mean probing depth slightly at the second; when the immobilised probe was used first, there was a difference between probes. Further analysis of the results indicated that there was greatest agreement between probes when the constant force probe had been used before the immobilised probe at the second visit. The results suggested that these probes indicated a point above the connective tissue attachment level, related to pocket morphology, and that there was a moderate learning effect due to operator use of the constant force probe, which modified use of the immobilised probe.  相似文献   
89.
Remodeling Adult Nursing   总被引:1,自引:0,他引:1  
This article describes a nursing education experience in which a critical thinking approach was planned and implemented. Background discussion on critical thinking concepts and related research provides a foundation for presentation of the Mackie teaching model. The model uses a community-based, family-centered scenario as the basis for developing problemfocused nursing intervention skills from a holistic viewpoint. Role expectations of students and faculty are outlined, and related implementation difficulties, together with their resolution strategies, are described. Evaluation methods and outcomes are reviewed in the conclusion.  相似文献   
90.
以问题为中心的病案教学法在临床核医学中的实践   总被引:8,自引:0,他引:8  
目的 设计以问题为中心的病案小组讨论教学法,在临床核医学核素治疗见习的教学实践中进行验证和评价。方法 总结近几年在临床核医学见习带教中的问题与缺陷;以病案引入问题,教师引导,进行小组讨论;评价教学效果。结果 临床核医学及其教学具有不同于其它临床学科的鲜明特点和规律;经改革的教案,收到学生和教师的良好反馈。结论 以问题为中心的病案小组讨论教学法,切合临床核医学见习实际,有效可行。  相似文献   
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