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   35560篇
  免费   2693篇
  国内免费   1247篇
耳鼻咽喉   349篇
儿科学   275篇
妇产科学   225篇
基础医学   7144篇
口腔科学   1079篇
临床医学   3019篇
内科学   4568篇
皮肤病学   218篇
神经病学   4966篇
特种医学   1654篇
外国民族医学   1篇
外科学   4177篇
综合类   3920篇
现状与发展   6篇
预防医学   1787篇
眼科学   1334篇
药学   3261篇
  5篇
中国医学   1066篇
肿瘤学   446篇
  2024年   75篇
  2023年   461篇
  2022年   906篇
  2021年   1430篇
  2020年   1183篇
  2019年   1027篇
  2018年   1055篇
  2017年   1006篇
  2016年   965篇
  2015年   1089篇
  2014年   1739篇
  2013年   2112篇
  2012年   1645篇
  2011年   1875篇
  2010年   1552篇
  2009年   1541篇
  2008年   1556篇
  2007年   1611篇
  2006年   1464篇
  2005年   1333篇
  2004年   1218篇
  2003年   1175篇
  2002年   990篇
  2001年   851篇
  2000年   707篇
  1999年   663篇
  1998年   739篇
  1997年   754篇
  1996年   679篇
  1995年   578篇
  1994年   517篇
  1993年   471篇
  1992年   454篇
  1991年   458篇
  1990年   376篇
  1989年   344篇
  1988年   313篇
  1987年   285篇
  1986年   250篇
  1985年   315篇
  1984年   271篇
  1983年   166篇
  1982年   232篇
  1981年   228篇
  1980年   177篇
  1979年   148篇
  1978年   140篇
  1977年   112篇
  1976年   109篇
  1975年   45篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
2.
3.
4.
Cutaneous leiomyomas are rare benign smooth‐muscle tumors. These lesions are distinguished based on their cell of origin and are subclassified as pilar leiomyoma, angioleiomyoma, and genital‐type leiomyoma. Nipple leiomyoma is the least common genital‐type leiomyoma, arising from the dartoic muscle cell of the nipple. Histologic examination of the lesion is necessary for definitive diagnosis, and these uncommon tumors can pose a diagnostic challenge. We describe herein a series of six nipple leiomyomas with a spectrum of histologic appearances.  相似文献   
5.
Despite orientation and mobility (O&M) being a significant factor determining quality of life of people with low vision or blindness, there are no gold standard measures or agreement on how to measure O&M performance. In the first part of this systematic review, an inventory of O&M outcome measures used by recent studies to assess the performance of orientation and/or mobility of adults with vision impairment (low vision and blindness) is presented. A wide variety of O&M outcome measures have been implemented in different fields of study, such as epidemiologic research and interventional studies evaluating training, assistive technology, vision rehabilitation and vision restoration. The most frequent aspect of outcome measures is efficiency such as time, distance, speed and percentage of preferred walking speed, followed by obstacle contacts and avoidance, and dis/orientation and veering. Other less commonly used aspects are target identification, safety and social interaction and self-reported outcome measures. Some studies employ sophisticated equipment to capture and analyse O&M performance in a laboratory setting, while others carry out their assessment in real-world indoor or outdoor environments. In the second part of this review, the appropriateness of implementing the identified outcome measures to assess O&M performance in clinical and functional O&M practice is evaluated. Nearly a half of these outcome measures meet all four criteria of face validity (either clinical or functional), responsiveness, reliability and feasibility and have the potential to be implemented in clinical or functional O&M practice. The findings of this review confirm the complicated and dynamic nature of O&M. Multiple measures are required in any evaluation of O&M performance to facilitate holistic assessment of O&M abilities and limitations of each individual.  相似文献   
6.
目的探究面肌痉挛患者微血管减压术(MVD)中异常肌反应(AMR)的变化特点与术后疗效的关系。方法回顾性分析73例MVD术中采用AMR全程定量化监测患者的AMR变化特点,减压操作前AMR阈值较基础阈值升高≥1倍为A1组、1倍为A2组,手术结束时AMR完全消失为B1组、未消失为B2组,B2组中AMR阈值较基础阈值升高≥1倍为B2a组、1倍为B2b组,对各组的术后疗效进行对比分析。结果 A1组21例中,19例立即治愈,1例延迟治愈,1例未愈; A2组52例中,35例立即治愈,9例延迟治愈,8例未愈。A1组较A2组疗效好(P=0. 046)。B1组50例中,42例立即治愈,5例延迟治愈,3例未愈; B2组23例中,12例立即治愈,5例延迟治愈,6例未愈。B1组较B2组疗效好(P=0. 003)。B2 a组的治愈比例较B2 b组高(分别为14/16、3/7),差异有统计学意义(P=0. 045)。结论 AMR在术中的变化特点对术者有重要参考意义,AMR在减压前升高、在手术结束时完全消失、未消失但升高较基础阈值≥1倍者术后疗效相对较好。  相似文献   
7.
8.
《Clinical neurophysiology》2020,131(1):259-264
ObjectivesFasciculation potentials (FP) are an important consideration in the electrophysiological diagnosis of ALS. Muscle ultrasonography (MUS) has a higher sensitivity in detecting fasciculations than electromyography (EMG), while in some cases, it is unable to detect EMG-detected fasciculations. We aimed to investigate the differences of FP between the muscles with and without MUS-detected fasciculations (MUS-fas).MethodsThirty-one consecutive patients with sporadic ALS were prospectively recruited and in those, both needle EMG and MUS were performed. Analyses of the amplitude, duration, and number of phases of EMG-detected FPs were performed for seven muscles per patient, and results were compared between the muscles with and without MUS-fas in the total cohort.ResultsThe mean amplitude and phase number of FP were significantly lower in patients with EMG-detected FP alone (0.39 ± 0.25 mV and 3.21 ± 0.88, respectively) than in those with both FP and MUS-fas (1.22 ± 0.92 mV and 3.74 ± 1.39, respectively; p < 0.0001 and p = 0.017, Welch’s t-test).ConclusionSmall FP may be undetectable with MUS. MUS cannot replace EMG in the diagnostic approach for ALS.SignificanceClinicians should use a combination of EMG and MUS for the detection and quantitative analysis of fasciculation in ALS.  相似文献   
9.
Controlling cellular alignment is critical in engineering intestines with desired structure and function. Although previous studies have examined the directional alignment of cells on the surface (x–y plane) of parallel fibers, quantitative analysis of the cellular alignment inside implanted scaffolds with oriented fibers has not been reported. This study examined the cellular alignment in the x–z and y–z planes of scaffolds made with two layers of orthogonally oriented fibers. The cellular orientation inside implanted scaffolds was evaluated with immunofluorescence. Quantitative analysis of coherency between cell orientation and fiber direction confirmed that cells aligned along the fibers not only on the surface (x–y plane) but also inside the scaffolds (x–z & y–z planes). Our study demonstrated that two layers of orthogonally aligned scaffolds can generate the histological organization of cells similar to that of intestinal circular and longitudinal smooth muscle.  相似文献   
10.
目的 研究主、被动最大张口度(AMMO、PMMO)与颞下颌关节强直严重程度的关系。方法 选取28只健康雄性绵羊随机分为实验组和对照组,每组各14只。实验组绵羊双侧颞下颌关节模拟髁突矢状骨折,其中左侧翼外肌被切断以阻断其功能;对照组绵羊未进行手术。于术前及术后12、24周对所有绵羊体重、AMMO、PMMO、颞下颌关节形态学特点进行测量评估。结果 实验组只有右侧保留翼外肌功能的颞下颌关节发生了骨强直。术后12、24周,实验组绵羊AMMO、PMMO、极限距离均显著低于对照组,差异均有统计学意义(均P < 0.05)。实验组绵羊AMMO和PMMO与骨融合区宽度、长度、面积及钙化程度均呈负相关(均P < 0.05),其中骨融合区面积为主要影响因素(术后12、24周相关系数r分别为-0.94、-0.95)。结论 颞下颌关节强直动物模型中阻断翼外肌功能可阻止骨强直的发生;对于早期髁突矢状骨折,可通过牙合垫或牙合板进行张口训练,进而阻断翼外肌功能。当颞下颌关节发生骨强直时,骨融合区面积越大,张口受限越明显。  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