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   99098篇
  免费   9369篇
  国内免费   5760篇
耳鼻咽喉   847篇
儿科学   1492篇
妇产科学   1269篇
基础医学   9143篇
口腔科学   1742篇
临床医学   11755篇
内科学   13413篇
皮肤病学   1108篇
神经病学   3645篇
特种医学   4141篇
外国民族医学   34篇
外科学   10553篇
综合类   19729篇
现状与发展   27篇
一般理论   16篇
预防医学   8394篇
眼科学   1817篇
药学   11342篇
  98篇
中国医学   6999篇
肿瘤学   6663篇
  2024年   361篇
  2023年   1376篇
  2022年   3303篇
  2021年   4306篇
  2020年   3356篇
  2019年   2580篇
  2018年   2798篇
  2017年   2810篇
  2016年   2629篇
  2015年   3925篇
  2014年   5007篇
  2013年   5540篇
  2012年   7944篇
  2011年   8268篇
  2010年   6315篇
  2009年   5440篇
  2008年   6520篇
  2007年   6375篇
  2006年   5777篇
  2005年   5100篇
  2004年   4047篇
  2003年   3525篇
  2002年   2949篇
  2001年   2573篇
  2000年   2288篇
  1999年   1717篇
  1998年   834篇
  1997年   835篇
  1996年   678篇
  1995年   568篇
  1994年   495篇
  1993年   336篇
  1992年   518篇
  1991年   427篇
  1990年   410篇
  1989年   361篇
  1988年   289篇
  1987年   279篇
  1986年   219篇
  1985年   172篇
  1984年   125篇
  1983年   87篇
  1982年   68篇
  1981年   75篇
  1980年   39篇
  1979年   73篇
  1978年   39篇
  1974年   36篇
  1973年   33篇
  1972年   41篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
The current model for delivery of prenatal care was developed more than 100 years ago. Evidence suggests that this model is no longer appropriate for meeting national health objectives or for meeting the needs of a diverse population of pregnant women. This article provides a historical overview of prenatal care; describes the current system for care delivery and problems associated with it; and suggests strategies for transforming care into an effective, comprehensive model. JOGNN, 25, 17–23; 1996.  相似文献   
82.
北京市东城区和平里社区居民慢性病防治探讨   总被引:3,自引:0,他引:3  
为探索慢性病的防治方法,我们于1989 ̄1994年社区居民中开展了以高血压为主的循环系统慢性病防治课题,经过5年的干预,观察组与对照组居民及接受管理的高血压病人在减少吸烟,饮酒,控制食盐摄入,掌握慢性病防治知识等方面有显著性差异,取得了满意的结果,从而为今后全面开展慢性病防治积累了经验。  相似文献   
83.
Spinal cord/brainstem preparations from 5- to 8-day-old rats, maintained in vitro, were used to determine the cells of origin and regions of termination of fibers in the superficial ventrolateral funiculus (VLF) at a site from which rhythmic locomotor-like activity can be induced. Rhythmic locomotor-like activity was recorded from lumbar ventral roots after short trains of stimuli (50 Hz for 0.5-2 seconds) delivered to the VLF. Field potential mapping revealed that single VLF stimuli elicited responses in the ipsilateral ventrolateral medulla. Tract-tracing experiments by using biocytin, pressure-injected into the VLF, showed that only a small number of brainstem neurons were labeled and these were scattered bilaterally in the ventrolateral and lateral medulla. Dense concentrations of nerve terminals were found in the lateral reticular nucleus ipsilateral to the stimulation site. Labeled spinal cord neurons included a primary population of large cells distributed bilaterally in lamina VII from T13 to L4, with peak numbers in L2 ipsilaterally and in L3 contralaterally. Intracellular recordings revealed that some L2 and L3 neurons with rhythmic responses to VLF stimulation could be activated antidromically from the VLF, with latencies of less than 1.0 msec. These observations led us to speculate that the superficial VLF carries a locomotor-related tract originating bilaterally in lumbar lamina VII and terminating in the ipsilateral medulla, including the lateral reticular nucleus. This pathway may be part of the spinoreticular or spinoreticulotectal pathway that has been described in many species, the function of which has only loosely been ascribed.  相似文献   
84.
煤烟型大气污染对儿童肺功能的影响   总被引:4,自引:1,他引:3  
为观察煤烟型大气污染对儿童健康的影响 ,选择了太原市 3个污染程度不同地区的 45 0名儿童进行肺功能测试和问卷调查。研究结果显示 ,儿童呼吸功能表现为重度污染区 <中度污染区 <相对清洁区 ;肺通气功能阻塞性异常率表现为重度污染区 >中度污染区 >相对清洁区 ;Logistic回归分析发现肺通气功能阻塞性异常率与小学生家庭的取暖方式、厨房和卧室是否分开以及污染物的水平有关 ;多元线性回归分析显示重度污染区儿童的FVC、FEF5 0与相对清洁区相比分别减少了 65 80ml、119 2 7ml,中度污染区儿童的FVC、FEF5 0与相对清洁区相比分别减少了 5 7 2 8ml和 114 2 9ml;Ln(SO2 )每升高一个单位 ,FVC和FEF5 0分别减少69 10ml和 119 79ml,Ln(PM1 0 )每升高一个单位 ,FVC、FEF5 0等分别减少了 193 5 0ml和 171 69ml。结果提示 ,太原市煤烟型大气污染对儿童呼吸系统产生了危害。  相似文献   
85.
Research shows that clients with automatic thoughts (dysfunctional thinking) often do not think of alternative explanations in relation to negative events. Furthermore, these automatic thoughts are characterized by a broad global, self-evaluative and ambiguous nature that could make disputing (or changing the ways they think) the most difficult part of the therapeutic process. This paper proposes a two-stage practise-based disputing model, guided by research, that aims to 'bring' an automatic thought to a specific, objective, quantifiable and concrete level at which not only is the particular aspect(s) of the automatic thought that causes emotional disturbances finely focused, but the disputing is also likely to be effective and manageable. Furthermore, it will also generate alternative explanations that are helpful in reducing emotional disturbances and in facilitating problem solving approach. In this paper, the authors use a case example to discuss the rationale that underpins the conceptualization of the model and to illustrate the process in which the strategies of the model are effectively used.  相似文献   
86.
87.
Summary: The involvement of the IgA immune system and complement components in IgA glomerulonephritis (IgAGN) has prompted the use of immunosuppressive drugs in therapy, but none has so far been shown to alter the natural course of the disease. Because most patients with IgAGN present during the chronic phase of their illness, at the time when the initiating immune events may no longer be active, nonimmune therapy which targets the common pathway of progressive renal injury is likely to be more useful. There is increasing evidence that angiotensin-converting enzyme inhibitors (ACEI) reduce proteinuria and renal injury in patients with IgAGN, and this effect may be observed in both normotensive and hypertensive patients. Yet to be determined is whether this effect is specific for ACEI and whatever other effective antihypertensive drugs may achieve a similar result. Fish oil has recently been shown to retard the progression of renal failure in patients with aggressive IgAGN, but a narrow therapeutic window appears to exist for this form of treatment. Antiplatelet agents on their own appear to be ineffective but in combination with anticoagulation (low dose warfarin) have been shown to have an antiproteinuric effect and may preserve renal function in patients with progressive disease. Future directions of non-immune therapy of IgAGN include evaluation of the renoprotective effect of angiotensin II receptor antagonists, free-radical scavengers and antilipid drugs. More work should also be done to identify factors which put the patients at risk of developing progressive disease and which predict therapeutic response, as has been done recently with the identification of the deletion polymorphism of the angiotensin-converting enzyme gene as a marker of progressive disease and therapeutic response to ACEI in patients with IgAGN.  相似文献   
88.
89.
Nine cases of endometrial stromal tumors were examined by light microscopy and a battery of immunostains for diagnostic purposes. Eight of the cases were originally classified as endometrial stromal tumors and one as an epithelioid leiomyoma. Three of six (50%) endometrial stromal sarcomas stained positively for keratin/cytokeratin. All of these same tumors stained for vimentin. One case originally considered an epithelioid leiomyoma on light microscopy was later diagnosed as a uterine tumor with sex cord features following strong positive immunostaining with keratin/cytokeratin antibodies and negative staining with antidesmin. These results show that immunoreactivity for epithelial differentiation may be present in endometrial stromal tumors. The diverse immunostaining patterns of the stromal tumors reflect the probable histogenesis of these neoplasms from primitive totipotential stem cells which may differentiate along epithelial and various mesenchymal cell lines.  相似文献   
90.
1980年12月至1993年12月,我科经前方入路治疗颈椎病并获随访183例,其中37例(20.2%)术后恢复不满意,JOA恢复率小于60%。根据主诉与症状,我们把这些病人分成4组。(1)术后症状立即加重,1年内仍无改善者4例。(2)术后症状无明显改善,1年后仍无进步者11例。(3)术后症状减轻,但经过一段时间后,原症状又复出现者8例。(4)双下肢症状好转,但又出现新的上肢症状或上肢原症状加重者14例。结合术后X线、CT、MRI和椎管造影等检查所见,我们将发现的主要问题归纳为手术操作、病情发展演变、原有胸腰椎病和脊髓受压变性等情况。本文对以上发生的问题进行了分析,提出在以后的手术中应特别注意的事项。  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