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   104461篇
  免费   8862篇
  国内免费   6100篇
耳鼻咽喉   1112篇
儿科学   1542篇
妇产科学   2304篇
基础医学   12381篇
口腔科学   1949篇
临床医学   14001篇
内科学   16584篇
皮肤病学   894篇
神经病学   5663篇
特种医学   3530篇
外国民族医学   42篇
外科学   11231篇
综合类   14796篇
现状与发展   23篇
一般理论   20篇
预防医学   6115篇
眼科学   2864篇
药学   10695篇
  56篇
中国医学   4821篇
肿瘤学   8800篇
  2024年   275篇
  2023年   1499篇
  2022年   3796篇
  2021年   4934篇
  2020年   3512篇
  2019年   3225篇
  2018年   3543篇
  2017年   2923篇
  2016年   2842篇
  2015年   4407篇
  2014年   5616篇
  2013年   5006篇
  2012年   7523篇
  2011年   8265篇
  2010年   4976篇
  2009年   3816篇
  2008年   5269篇
  2007年   5524篇
  2006年   5407篇
  2005年   5698篇
  2004年   3831篇
  2003年   3398篇
  2002年   3006篇
  2001年   2440篇
  2000年   2650篇
  1999年   2705篇
  1998年   1578篇
  1997年   1481篇
  1996年   1309篇
  1995年   1161篇
  1994年   982篇
  1993年   635篇
  1992年   998篇
  1991年   805篇
  1990年   684篇
  1989年   600篇
  1988年   593篇
  1987年   529篇
  1986年   420篇
  1985年   330篇
  1984年   208篇
  1983年   159篇
  1982年   85篇
  1981年   98篇
  1980年   83篇
  1979年   115篇
  1978年   54篇
  1977年   56篇
  1975年   44篇
  1974年   45篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Vitamin D is responsible for multiple metabolic functions in humans. Rickets are the most common disease caused by vitamin D deficiency. It is caused by poor calcium intake resulting in poor serum-ionized calcium. The purpose of this study is to develop a rapid, sensitive, and feasible method to determine the 25-hydroxy-vitamin D3 (25(OH)D3) levels in blood samples for clinical assessment. In this study, gas chromatography coupled mass spectrometry with trimethylsilyl derivatization (TMS-GC-MS) is the most suitable protocol for quantitative analyses of 25(OH)D3. Performance of method was evaluated and compared with liquid chromatography and immunoassay. Method validation has been carried out with plasma specimens. The limit of quantitation of TMS-GC-MS method is 1.5 ppb with good linear correlation. Furthermore, the dietary intake and nutritional status of vegetarian and non-vegetarians in Taiwan were assessed by our validated method. As a result, this vitamin D nutrition survey demonstrates that most Taiwanese people have insufficient vitamin D. Due to dietary habits; the male vegans may have the highest risk of vitamin D deficiency.  相似文献   
62.
63.
64.
65.
It has been suggested that tumour‐infiltrating lymphocytes (TILs) are associated with the progression of oral squamous cell carcinoma (OSCC). However, the prognostic value of TILs is inconclusive due to the heterogeneity of immune cells within the tumour microenvironment. In this meta‐analysis, we aimed to assess the prognostic value of TILs in OSCC. The PubMed, Cochrane, Embase, Scopus and Web of Science databases were searched up to April 20, 2019, and 33 studies were ultimately included in this meta‐analysis. Our pooled meta‐analysis showed that high infiltration of CD8+ TILs, CD45RO+ TILs and CD57+ TILs favoured better overall survival (OS). However, high infiltration of CD68+ macrophages and CD163+ macrophages was associated with poor prognosis in OSCC. These findings suggest that CD8+ TILs, CD45RO+ TILs, CD57+ TILs, CD68+ macrophages and CD163+ macrophages might serve as novel prognostic factors and therapeutic targets in OSCC.  相似文献   
66.
Abstract

Background and aim: Capsule retention is the most common adverse event associated with video capsule endoscopy. The use of double-balloon enteroscopy-assisted capsule endoscope retrieval has been increasingly reported in recent years. However, evidence is limited regarding its success rate, associated factors, and subsequent clinical outcomes.

Methods: A systematic review of relevant studies published before January 2019 was performed. Successful retrieval rate and associated factors, rate of endoscopic balloon dilation, and outcomes after double-balloon enteroscopy were summarized and pooled.

Results: Within 154 associated original articles, 12 including 150 cases of capsule retrieval by double-balloon enteroscopy were included. The estimated pooled successful retrieval rate was 86.5% (95% confidence interval, 75.6–95.1%). Anterograde approach and capsules retained in the jejunum or trapped by malignant strictures were associated with a higher successful retrieval rate than the retrograde approach (62/83 [74.7%] vs. 10/38 [26.3%], p?<?.001) and capsules retained in the ileum (41/41 [100.0%] vs. 43/58 [74.1%], p?<?.001) or trapped by benign strictures (21/21 [100.0%] vs. 65/83 [78.3%], p?=?.043). Endoscopic balloon dilation was performed in 38.8% (95% confidence interval, 22.3–56.3%) of patients with benign strictures. Two perforations (1.3%) were reported as severe adverse events after double-balloon enteroscopy. A significantly lower surgery rate was found among cases with successful video capsule removal compared with unsuccessful cases (7.2% vs. 38.5%, p?=?.002).

Conclusions: Double-balloon enteroscopy is feasible and safe for removing retained video capsule endoscopes, and its use could decrease the need for surgery in patients with benign strictures and facilitate subsequent surgery in patients with malignant strictures.  相似文献   
67.
68.
目的探讨治疗下肢静脉溃疡有效、简单的方法。方法清除下肢静脉溃疡分泌物及坏死组织,创面以胰岛素与庆大霉素混合液湿敷,创面清洁后行常规手术,术后继续用上述方法处理创面。结果全部溃疡创面在1 ̄6周内愈合,术后35例随诊最短4个月,最长6年无溃疡复发。结论下肢静脉性溃疡应早期手术,术前、术后用胰岛素和庆大霉素混合液湿敷溃疡创面是一种简单、安全、经济、治疗时间短的有效方法。  相似文献   
69.
实时三维超声对室间隔缺损的直视效果及影响因素分析   总被引:2,自引:0,他引:2  
目的探讨实时三维超声(RT3DE)对室间隔缺损(VSD)全貌的直视效果及其影响因素。 方法应用RT3DE对238例VSD患者进行检查,其中包括法洛四联症(TOF)36例、完全型心内膜垫缺损(TECD)2例和十字交叉心2例。获取并切割“全容积三维”图像,寻找最佳视角显示病变结构全貌。 结果RT3DE对中型和大型VSD(直径≥5mm)的直视效果优于小型VSD(〈5mm)。可显示缺损的形状、部位及毗邻结构。胸骨旁四腔位和心底短轴位RT3DE图像效果最佳,胸骨旁长轴位及心尖五腔位次之。 结论VSD的大小、部位及三维图像质量是决定RT3DE观察效果的主要因素。RT3DE可清晰直视中型及大型VSD的全貌。  相似文献   
70.
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