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   64439篇
  免费   6353篇
  国内免费   2417篇
耳鼻咽喉   435篇
儿科学   525篇
妇产科学   665篇
基础医学   4889篇
口腔科学   3501篇
临床医学   9193篇
内科学   4987篇
皮肤病学   554篇
神经病学   2157篇
特种医学   3010篇
外国民族医学   8篇
外科学   5900篇
综合类   13617篇
现状与发展   6篇
一般理论   3篇
预防医学   6959篇
眼科学   1051篇
药学   6819篇
  47篇
中国医学   6126篇
肿瘤学   2757篇
  2024年   158篇
  2023年   1609篇
  2022年   2801篇
  2021年   3619篇
  2020年   3526篇
  2019年   1941篇
  2018年   1930篇
  2017年   1442篇
  2016年   1816篇
  2015年   2273篇
  2014年   4963篇
  2013年   4723篇
  2012年   6684篇
  2011年   6400篇
  2010年   4540篇
  2009年   3970篇
  2008年   2653篇
  2007年   3275篇
  2006年   2680篇
  2005年   1793篇
  2004年   1645篇
  2003年   1510篇
  2002年   1354篇
  2001年   1305篇
  2000年   806篇
  1999年   842篇
  1998年   603篇
  1997年   587篇
  1996年   371篇
  1995年   219篇
  1994年   207篇
  1993年   204篇
  1992年   235篇
  1991年   194篇
  1990年   176篇
  1989年   68篇
  1988年   42篇
  1987年   26篇
  1986年   9篇
  1985年   5篇
  1984年   3篇
  1982年   2篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
81.
82.
While the lung is frequently involved by systemic lymphoma, primary pulmonary lymphoma accounts for less than 1% of all extranodal ymphomas. In particular, T-cell lymphoma is very rare in the lung, as a primary or secondary lesion. Patients with pulmonary T-cell lymphoma usually present with cough, dyspnea, pain, fever, recurrent infections, and hemoptysis. Typical radiologic features include pulmonary nodules, consolidation, solid pulmonary opacities, cystic changes, hilar adenopathy, and pleural effusions. Patients with these clinical and radiologic findings are frequently presumed to have pneumonia and initially treated with empirical antibiotics. Therefore, CT-guided needle biopsy, bronchoscopic examination, or even wedge biopsy should be considered when clinical symptoms show deterioration despite adequate antibiotic therapy. Precise pathologic diagnosis and molecular characterization are recommended in all cases, following the World Health Organization (WHO) classification. Principles of treatment typically vary with the different histologic types of T-cell lymphoma.  相似文献   
83.
目的对膝关节前外侧韧带(anterolateral ligament,ALL)的研究进展进行综述,为临床诊治提供参考。方法广泛查阅近年来国内外有关 ALL 损伤诊断及治疗的文献,总结膝关节 ALL 解剖形态、生物力学以及 ALL 损伤机制、治疗现状。结果膝关节 ALL 具有限制胫骨内旋及前移作用,影响膝关节轴移。ALL 损伤后可结合患者体征和 MRI 检查诊断。膝关节 ALL 手术指征尚未统一,但多数学者倾向于对需进行前交叉韧带(anterior cruciate ligament,ACL)重建或翻修且伴有高度轴移试验阳性的患者进行 ALL 重建。目前 ALL 重建方式较多,但尚无最佳治疗术式。此外,由于缺乏高质量的术后长期随访研究,远期临床疗效仍不明确。结论ALL 在维持膝关节稳定性方面具有一定作用,但 ALL 重建技术及临床疗效仍待进一步研究。  相似文献   
84.
益母草是著名的经产良药,具有"调经"功效,自古以来是治疗妇人"经产带下"之良药。子宫是益母草"调经"功效的重点靶器官。本文通过对益母草对子宫的药理作用研究进行梳理,显示益母草对子宫有双向调节子宫收缩活动、调节子宫肌电、保护子宫内膜和促进子宫内膜复旧、抗子宫内膜炎等多种作用,其作用的发挥与益母草的入药品种与炮制、提取成分和子宫状态密切相关。本文对指导益母草质量提升和临床应用有参考意义。  相似文献   
85.
  1. Download : Download high-res image (376KB)
  2. Download : Download full-size image
  相似文献   
86.
目的 探讨营养风险与腹膜后肿瘤患者住院时间的相关性。方法 采用回顾性研究,选取2012年1月至2018年12月四川大学华西医院血管外科新入院腹膜后肿瘤患者60例,采用营养风险筛查表评估患者营养风险,收集患者体质指数、围术期血红蛋白和白蛋白水平、住院天数、术后恶心呕吐发生情况、术后排气、排便时间和首次进食时间。采用单因素分析比较不同患者住院时间,采用多重线性逐步回归分析患者住院时间的影响因素。结果 纳入的60例腹膜后肿瘤患者中,40例患者(66.7%)术前存在营养风险,52例患者(86.7%)术后存在营养风险;单因素分析显示,患者术前、术后营养风险 (术前P<0.001,术后P=0.043)、术前白蛋白 (P=0.019)、术后血红蛋白 (P=0.019)、术后白蛋白(P=0.025) 水平以及术后恶心呕吐 (P=0.001) 均会影响患者的住院时间;患者住院时间与围术期营养风险筛查工具评分、术后首次进食时间、术后排气时间和排便时间具有相关性,且相关性强(r=0.759~0.770; P<0.01);多因素分析显示术前营养风险是腹膜后肿瘤患者住院时间的重要预测因素(β=0.399)。结论 术前营养风险是腹膜后肿瘤患者住院时间的预测因子。  相似文献   
87.
88.
89.
Sorafenib provides survival benefits in patients with advanced renal cell carcinoma (RCC), but its use is hampered by acquired drug resistance. It is important to fully clarify the molecular mechanisms of sorafenib resistance, which can help to avoid, delay or reverse drug resistance. Extracellular vesicles (EVs) can mediate intercellular communication by delivering effector molecules between cells. Here, we studied whether EVs are involved in sorafenib resistance of RCC and its possible molecular mechanisms. Using differential centrifugation, EVs were isolated from established sorafenib-resistant RCC cells (786-0 and ACHN), and EVs derived from sorafenib-resistant cells were uptaken by sensitive parental RCC cells and thus promoted drug resistance. Elevated exogenous miR-31-5p within EVs effectively downregulated MutL homolog 1 (MLH1) expression and thus promoted sorafenib resistance in vitro. Mice experiments also confirmed that miR-31-5p could mediate drug sensitivity in vivo. In addition, low expression of MLH1 was observed in sorafenib-resistant RCC cells and upregulation of MLH1 expression restored the sensitivity of resistant cell lines to sorafenib. Finally, miR-31-5p level in circulating EVs of RCC patients with progressive disease (PD) during sorafenib therapy was higher when compared to that in the pretherapy status. In conclusion, EVs shuttled miR-31-5p can transfer resistance information from sorafenib-resistant cells to sensitive cells by directly targeting MLH1, and thus magnify the drug resistance information to the whole tumor. Furthermore, miR-31-5p and MLH1 could be promising predictive biomarkers and therapeutic targets to prevent sorafenib resistance.  相似文献   
90.
The neuropeptide galanin is widely expressed in both the central and peripheral nervous systems. However there is limited understanding of how individual galanin receptor (GalR1, 2, and 3) subtypes mediate the physiological activity of galanin in vivo. To address this issue we utilized NAX-5055, a systemically available, metabolically stable galanin analog. NAX-5055 displays a preference for GalR1 receptors and possesses potent anticonvulsant activity in vivo, suggesting that NAX-5055 engages central galanin receptors. To determine if NAX-5055 also modulates the activity of peripheral galanin receptors, we evaluated the effect of NAX-5055 on blood glucose and insulin levels in mice. Acute and repeated (once daily for four days) systemic administration of NAX-5055 (4 mg/kg) significantly increased blood glucose levels compared to vehicle treated mice. However, a hyperglycemic response was not observed following systemic administration of NAX-805-1, a scrambled analog of NAX-5055, with critical receptor binding residues, Trp2 and Tyr9, reversed. These results suggest that chemical modifications independent of the galanin backbone of NAX-5055 are not responsible for the hyperglycemic response. The effect of NAX-5055 on glucose homeostasis was further evaluated with a glucose tolerance test (GTT). Mice administered either acute or repeated (once daily for four days) injections of NAX-5055 (4 mg/kg) displayed impaired glucose handling and reduced insulin response to an acute glucose (1g/kg) challenge. Here we have shown that systemic administration of a centrally active GalR1-preferring galanin analog produces acute hyperglycemia and an inhibition of insulin release in vivo and that these effects are not attenuated with repeated administration. NAX-5055 thus provides a new pharmacological tool to further the understanding of function of both central and peripheral GalR1 receptors in vivo.  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