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   9488篇
  免费   693篇
  国内免费   282篇
耳鼻咽喉   92篇
儿科学   176篇
妇产科学   128篇
基础医学   835篇
口腔科学   554篇
临床医学   901篇
内科学   1504篇
皮肤病学   173篇
神经病学   1265篇
特种医学   697篇
外国民族医学   4篇
外科学   1063篇
综合类   1397篇
现状与发展   1篇
预防医学   323篇
眼科学   123篇
药学   428篇
  4篇
中国医学   214篇
肿瘤学   581篇
  2024年   17篇
  2023年   159篇
  2022年   286篇
  2021年   408篇
  2020年   358篇
  2019年   318篇
  2018年   290篇
  2017年   317篇
  2016年   305篇
  2015年   309篇
  2014年   558篇
  2013年   506篇
  2012年   469篇
  2011年   466篇
  2010年   411篇
  2009年   460篇
  2008年   485篇
  2007年   529篇
  2006年   450篇
  2005年   380篇
  2004年   304篇
  2003年   268篇
  2002年   275篇
  2001年   235篇
  2000年   183篇
  1999年   156篇
  1998年   132篇
  1997年   161篇
  1996年   131篇
  1995年   115篇
  1994年   117篇
  1993年   90篇
  1992年   93篇
  1991年   65篇
  1990年   65篇
  1989年   54篇
  1988年   55篇
  1987年   50篇
  1986年   65篇
  1985年   89篇
  1984年   51篇
  1983年   31篇
  1982年   37篇
  1981年   40篇
  1980年   31篇
  1979年   14篇
  1978年   14篇
  1976年   13篇
  1975年   14篇
  1973年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
PurposeTears involving the myotendinous junction (MTJ) of the infraspinatus (IS) have been recently described on MRI. These occur centrally in the muscle belly, and are not associated with full thickness tears of the distal infraspinatus tendon. They also induce a rapidly progressive fatty infiltration of the muscles and amyotrophy. The purpose of this study is to assess the accuracy of ultrasonography in diagnosing MTJ tears of the infraspinatus and to describe the usual ultrasonographic appearance compared with MRI.Materials and methodsRetrospective study of 2403 US examinations of the shoulder (over 5 years). Fifteen patients with a reported suspicion of infraspinatus MTJ tears were included. MRI examination was available in all cases, CT arthrography in 13 cases, and one patient underwent surgical confirmation.ResultsAll patients were sent for an ultrasound for suspect lesion of the tendons of the rotator cuff, with posterior pain in the infraspinatus fossa. All cases seen on ultrasonography were confirmed on MRI. CT arthrography confirmed the absence of tear of the IS tendon in all cases and did not reveal the MTJ tears. Two signs appeared to us as being of special interest: the “tadpole sign” on longitudinal views, and the “black eye sign” on sagittal views. The proximal retraction of the tendon at the MTJ is the anatomical explanation of both signs.ConclusionTears at the myotendinous junction of the infraspinatus are rare but can be diagnosed on US examination, provided that the sonographer pays attention to the infraspinatus fossa especially in cases of normality of the distal tendinous cuff.  相似文献   
12.
神经导航系统在神经外科显微手术中的应用   总被引:1,自引:1,他引:0  
目的探讨神经导航系统在神经外科显微手术中的应用价值。方法我科在2004年10月至2005年6月应用美国Stryker神经导航系统辅助进行显微神经外科手术治疗颅内病变104例。结果在85例病灶切除术中,病灶全切除71例(83.53%),次全切除13例(15.29%),部分切除1例(1.18$);侧脑室-腹腔分流术16例,成功15例,1例改常规手术完成;3例脑脓肿穿刺成功率100%。本组术后死亡1例,其余术后恢复良好。104例平均注册误差(1.3±0.7)mm。结论神经导航系统在神经外科手术中提供术中动态跟踪、实时导航,准确、直观,有助于提高手术疗效,降低手术并发症的发生。  相似文献   
13.
The aim of this pilot study was to examine the role of the striatum and cerebellum in the adaptation to a novel movement within a sequence of practiced movements using a motor learning paradigm. The performance of patients in the early or advanced stages of Parkinson's disease (PD) and of patients with damage to the cerebellum (CE) was compared, respectively to a group of aged and young matched controls on an adapted version of the Mirror-Tracing Test. In this task, subjects were required to trace a series of complex figures in two conditions: (1) a Practiced condition, in which the figures were composed of the juxtaposition of three simple designs that were extensively practiced before; and (2) a Mixed condition in which triads were created by replacing the last simple figure of the triads in the Practiced condition by a new simple figure that had never been traced individually before. Results showed that all clinical groups were slower than controls at tracing the Practiced triads. Most interestingly, however, only patients in the advanced stages of PD showed increased completion time to trace the triads in the Mixed condition. This suggests that a bilateral striatal dysfunction affects the ability to adapt to a novel motion within a sequence of practiced movements. Although exploratory, these results support a functional dissociation between the striatum and cerebellum in acquiring visuomotor skilled behaviors.  相似文献   
14.
目的:探讨食管癌高、低发区无症状居民食管上皮固有膜血管乳头(简称乳头)增生特征(乳头密度和高度)及其与病变分布的关系,加深对食管癌变早期形态学变化特征的了解。方法:2480例无症状人群食管粘膜活检组织,采用食管癌高低发区食管纤维内镜检查,粘膜活检,组织病理学检查和形态学测量技术对食管乳头的分布特征及其与病变的关系进行分析。结果:食管癌高低发区居民食管中、下段乳头升高(≥上皮厚度的1/2)发生率之间差异并不明显(P>0.05),但是,高发区居民食管中段乳头密度(乳头数目/mm)明显高于下段,并高于低发区居民食管中段的乳头密度(P<0.05);高发区居民食管上皮乳头升高伴基底细胞过度增生患者明显高于正常人(P<0.05),而低发区未观察到类似情况。结论:乳头增生表现为乳头数目增多和乳头升高是食管癌高发区人群食管上皮特征性形态学变化,高分区居民上皮乳头升高伴明显基底细胞过度增生,提示乳头增生可能是食管癌变极早期阶段的重要形态学变化,反映了上皮细胞的增生状态。  相似文献   
15.
应用常规内镜技术难以发现大肠平坦型病变和凹陷型病变。近年来染色内镜和放大内镜技术已经发展成熟,在国外已获广泛应用,可以发现大肠微小病变和早期大肠癌。应用腺管开口分型方法可以预测肿瘤病变的组织学类型及肿瘤的浸润深度,据此可确定行内镜下粘膜剥离术或分片粘膜剥离术将肿瘤切除,抑或行外科手术治疗。在当前我国的胃肠内镜医疗界,应广泛开展染色内镜和放大内镜的临床应用,以早期发现大肠病变,提高我国大肠癌的内镜诊治水平。  相似文献   
16.
17.
Alzheimer's disease (AD) generally begins with mild memory problems which occur in an insidious manner and progresses to the development of multiple cognitive impairments. There is a ‘gray’ area between what is classified as ‘normal’ and what is classified as ‘dementia’, currently called mild cognitive impairment (MCI). In this article, a case of MCI is described, and the diagnosis, assessment, subclassification (pre‐Alzheimer type and white matter lesion type) and future therapeutic plans for MCI are reviewed.  相似文献   
18.
目的探讨多层螺旋CT(MSCT)肺密度测定对结缔组织病(CTD)肺间质病变(ILL)早期诊断的临床意义。方法对222例CTD患者及50名正常对照者,应用MSCT附带的Pulmo自动评估软件进行上、中、下肺区的密度测定,并同时进行肺高分辨扫描(}-IR(_1、),分析二者的变化与CTD伴ILL的关系。结果222例cm患者中197例平均肺密度有不同程度的增高,25例平均肺密度正常。157例HRCT有不同程度的肺间质病变,65例HRCT正常。50名正常对照者HRCT均正常,8名平均肺密度有不同程度的增高,42名平均肺密度正常。结论采用MSCT与HRCT对CTD伴ILL的检测结果差异有统计学意义,P=0.000(双侧),因此MSCT平均肺密度测定对早期诊断CTD伴ILL比HRCT更敏感,更有临床意义。  相似文献   
19.
应用自动化图象分析仪对131个胃粘膜肠型病灶(单纯性肠化27个;异型增生:轻度30,中度35个,重度20个;肠型胃癌19个)进行定量分析。以单个腺管内细胞核总面积与细胞面积之比(ING)作为反映细胞核大小、数量及覆层排列程度的客观定量指标。结果发现:单纯性肠化(对照组)0.165±0.025,轻度异型增生0.21±0.023,中度异型增生0.259±0.026,重度异型增生0.32±0.028,分化型胃癌0.371±0.052,各组ING值呈正态,各组间的均值有非常显著的差异(P<0001)。因而,ING可作为胃粘膜癌前病变诊断的指标。  相似文献   
20.
Naloxone, an opioid peptide antagonist, has been reported to facilitate voiding in neurologic bladder disorders, but its effects on the neural micturition reflex arc are poorly understood. We studied the effect of naloxone in 34 male adult cats, spinalized at C5-C6 level 7 to 119 days previously. Each cat served as its own control. The following tests were performed: Urethral pressure profiles, cystosphincterograms with the urethro-vesical junction opened and closed and mechanograms of the detrusor, and the circular and longitudinal urethral muscles. The study included (1) the effects of anesthesia of the bladder and pelvic nerve, as well as that of the urethral and pudendal nerves; (2) the action of naloxone; and (3) the action of oxymorphone. Our results demonstrated that naloxone (1) increased somatic (osteotendinous and nociceptive) reflexes and aggravated spasticity; (2) increased vegetative micturitional and sexual reflexes, in particular the urethra-urethral contraction reflex, aggravating the spasmodic contractions of the external sphincter; and (3) increased the frequency and intensity of the mass reflex. In consequence, we suggest that naloxone is contraindicated in cases of spinal cord lesions with detrusor-sphincter dyssynergia syndrome.  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