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   335513篇
  免费   24907篇
  国内免费   8268篇
耳鼻咽喉   2426篇
儿科学   6186篇
妇产科学   4960篇
基础医学   32190篇
口腔科学   6299篇
临床医学   31596篇
内科学   44975篇
皮肤病学   4554篇
神经病学   18411篇
特种医学   11515篇
外国民族医学   48篇
外科学   40054篇
综合类   47898篇
一般理论   10篇
预防医学   20581篇
眼科学   4231篇
药学   38446篇
  157篇
中国医学   24415篇
肿瘤学   29736篇
  2024年   226篇
  2023年   4839篇
  2022年   6995篇
  2021年   12530篇
  2020年   12799篇
  2019年   11586篇
  2018年   11043篇
  2017年   12519篇
  2016年   12546篇
  2015年   11924篇
  2014年   18571篇
  2013年   25262篇
  2012年   18207篇
  2011年   20888篇
  2010年   15116篇
  2009年   14731篇
  2008年   15914篇
  2007年   17428篇
  2006年   16133篇
  2005年   14710篇
  2004年   12486篇
  2003年   11053篇
  2002年   8851篇
  2001年   7945篇
  2000年   6604篇
  1999年   5341篇
  1998年   4117篇
  1997年   3971篇
  1996年   3542篇
  1995年   3423篇
  1994年   3136篇
  1993年   2568篇
  1992年   2349篇
  1991年   2160篇
  1990年   1867篇
  1989年   1594篇
  1988年   1494篇
  1987年   1371篇
  1986年   1179篇
  1985年   1657篇
  1984年   1357篇
  1983年   999篇
  1982年   1020篇
  1981年   876篇
  1980年   802篇
  1979年   671篇
  1978年   443篇
  1977年   346篇
  1976年   352篇
  1975年   259篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
目的 探讨不同时期慢性阻塞性肺疾病(COPD)患者血清诱饵受体3(DcR3)、凋亡抑制蛋白(Survivin)表达水平及临床意义。方法 选取2018年9月—2019年12月本院收治的92名COPD患者为研究对象,其中稳定型COPD 50例,急性加重期COPD 42例;同期本院健康体检者88例为对照组。测定各组研究对象血清DcR3、Survivin水平及肺功能指标。 与对照组[DcR3(106.54±48.35)pg/mL,Survivin(98.85±26.59)pg/mL]比较,稳定期组和急性加重期组血清DcR3[(395.23±123.85)pg/mL,(1 248.81±213.59)pg/mL]、Survivin [(267.54±84.69)pg/mL,(1 233.95±307.26)pg/mL]水平升高;与稳定期组比较,急性加重期组血清DcR3、Survivin水平升高。与对照组比较,稳定期组和急性加重期组FEV1%、FEV1 /FVC、DLCO%水平降低(P<0.001);与稳定期组比较,急性加重期组FEV1%、FEV1 /FVC、DLCO%水平降低(P<0.001)。随着低氧血症严重程度的增加,COPD患者血清DcR3、Survivin水平逐渐增加(P<0.001)。多因素logistics回归分析显示,高水平DcR3、Survivin、IL-12、hs-CRP为COPD病情的危险因素(P<0.001)。DcR3、Survivin与FEV、FEV1 /FVC呈负相关,与IL-12、TNF-α、hs-CRP呈正相关(P<0.001)。 COPD稳定期、急性加重期患者血清DcR3、Survivin表达水平升高,且DcR3、Survivin与COPD病情严重程度呈正相关。  相似文献   
2.
3.
The discussion paper will focus on continuity of care relating to previous NZ research, specifically to transitioning complex preterm infants from NICU to home based on parent experiences, and on the practice developments that have occurred, to ensure optimal health outcomes. Previous NZ research discovered parent desire a consistent service delivery for the entire transition journey from NICU and at home.An informative and comprehensive opportunity has occurred for reflective professional practice, evaluation, development and implementation which have transpired in positive change through innovative practice developments and support change implementation in Wellington, NZ. This has resulted in the articulation of a model of care that has both embraced and integrated parental desires for a continuity of care process for complex preterm infants. This has been achieved by having the same Discharge Facilitator/Key Case Manager present within the NICU and external to the NICU for Home-based infants for the entire transition journey.The paper will focus and emphasis additional practice development changes and furthermore, will present a real purpose, for other countries to learn of such practice developments that have exemplified a celebratory success for families of Wellington, NZ.  相似文献   
4.
Since their inception in the 1960s–70s, mesenchymal stem/stromal cells (MSCs) have gained interest because of their differentiation potential, anti-inflammatory effects, and immune-modulating properties. Both cell-based and cell-free MSC treatments show healing capacity in injured tissues. Cell-based treatment comprises MSCs and all secreted products, whereas cell-free treatments include only the secreted products. MSCs are therapeutically administered to many damaged organs owing to their efficacy. Specifically, the eye is a unique organ system to study the effects of MSCs, as treatment is easily applied and measured owing to its external location. The eye holds an immune-privileged status, wherein inflammation and immune responses are innately down-regulated. As excessive inflammation in the cornea often leads to fibrosis and irreversible corneal hazing, many studies have investigated the anti-inflammatory and immune-modulating capacities of MSCs. Decades of research suggest that MSCs modulate the immune response by secreting cytokines, growth factors, and extracellular matrix proteins that inhibit the infiltration of inflammatory cells following injury and promote a healing phenotype via M2 macrophage polarization. MSCs have also shown trans-differentiation potential into cornea-specific cell types during the wound healing process, such as corneal epithelial, stromal, or endothelial cells. This review discusses recent investigations of MSC treatment in the cornea, focusing on therapeutic efficacy, mechanisms, and future directions.  相似文献   
5.
目的 评价多功能套针浮刺疗法对神经根型颈椎病的临床疗效。方法 选取256例神经根型颈椎病患者,按随机数字表法分为观察组与对照组各128例。观察组应用多功能套针浮刺疗法进行干预,对照组为常规针刺治疗。两组患者均治疗7天。分别于治疗前后观察两组患者的简化McGill疼痛问卷(SF-MPQ)、国际标准颈椎功能障碍指数(NDI)和田中靖久颈椎病症状20分法量表评分,并于治疗结束后3个月观察复发率。结果 两组患者治疗后的SF-MPQ量表评分、NDI量表评分及田中靖久颈椎病症状20分法评分与治疗前相比均有改善(P<0.05),且观察组优于对照组(P<0.05);两组患者于治疗后3个月随访,SF-MPQ量表评分与治疗后相比均有改善,且观察组优于对照组(P<0.05);观察组临床疗效总有效率为96.88%,愈显率为81.25%;对照组总有效率为78.13%,愈显率为46.88%,观察组优于对照组(P<0.05)。结论 应用多功能套针浮刺疗法治疗神经根型颈椎病临床疗效显著,见效较快,可有效降低其复发率,且作用稳定,效果持久,值得临床推广应用。  相似文献   
6.
Barrett's esophagus (BE) is the precursor to esophageal adenocarcinoma (EAC). Progression to cancer typically occurs in a stepwise fashion through worsening dysplasia and ultimately, invasive neoplasia. Established EAC with deep involvement of the esophageal wall and/or metastatic disease is invariably associated with poor long-term survival rates. This guides the rationale of surveillance of Barrett’s in an attempt to treat lesions at an earlier, and potentially curative stage. The last two decades have seen a paradigm shift in management of Barrett’s with rapid expansion in the role of endoscopic eradication therapy (EET) for management of dysplastic and early neoplastic BE, and there have been substantial changes to international consensus guidelines for management of early BE based on evolving evidence. This review aims to assist the physician in the therapeutic decision-making process with patients by comprehensive review and summary of literature surrounding natural history of Barrett’s by histological stage, and the effectiveness of interventions in attenuating the risk posed by its natural history. Key findings were as follows. Non-dysplastic Barrett’s is associated with extremely low risk of progression, and interventions cannot be justified. The annual risk of cancer progression in low grade dysplasia is between 1%-3%; EET can be offered though evidence for its benefit remains confined to highly select settings. High-grade dysplasia progresses to cancer in 5%-10% per year; EET is similarly effective to and less morbid than surgery and should be routinely performed for this indication. Risk of nodal metastases in intramucosal cancer is 2%-4%, which is comparable to operative mortality rate, so EET is usually preferred. Submucosal cancer is associated with nodal metastases in 14%-41% hence surgery remains standard of care, except for select situations.  相似文献   
7.
外泌体是一类直径为30~100 nm的圆盘囊泡,其内包含许多组分,诸如复杂RNA和蛋白质等,主要参与细胞间的信号转导。肿瘤相关巨噬细胞(tumor-associated macrophages,TAMs)是肿瘤微环境中普遍存在的巨噬细胞,通过对肿瘤生长、免疫逃逸、侵袭和转移、耐药性等多方面的作用影响肿瘤进程。外泌体在肿瘤相关巨噬细胞的招募、极化及抗肿瘤免疫调控等方面发挥着重要的调节功能。同时,TAMs以外泌体为媒介作用于肿瘤细胞,从而构成了外泌体、TAMs与肿瘤细胞之间相互作用的调控通路。综上所述,本文旨在阐明肿瘤细胞与TAMs之间,以外泌体为“桥梁”相互影响的潜在机制,以及靶向肿瘤细胞和TAMs来源的外泌体在恶性肿瘤治疗中的展望。  相似文献   
8.
BackgroundRepairing crowns with defective margins is minimally invasive and cost-effective compared with replacement. The authors’ objectives were to examine the survival trajectory of crown margin repairs and to determine the factors associated with survival.MethodsRecords of adult patients from January 2008 through August 2019 were reviewed for crown margin repairs completed at University of Iowa College of Dentistry. A total of 1,002 crown margin repairs were found. Each repair was followed through the end of study in 2019 or until an event (for example, additional repair, endodontic treatment, crown replacement, or extraction). A Cox proportional hazards model was used to study the relationship between selected covariates and time to event.ResultsDuring the follow-up period, 32.8% of the repairs needed reintervention. In the final model, repair material was the only significant covariate. No difference was found between the survival of repairs done with resin-modified glass ionomer and amalgam. However, the repairs done with resin-based composite and conventional glass ionomer were more likely (1.5 times: 95% CI, 1.02 to 2.10 times; and 2 times: 95% CI, 1.40 to 2.73 times, respectively) to need reintervention than were those done with amalgam.ConclusionsMedian survival time of crown margin repairs was 5.1 years (95% CI, 4.48 to 5.72 years). Median survival times for amalgam, resin-modified glass ionomer, resin-based composite, and glass ionomer repair materials were 5.7 years (95% CI, 4.80 to 6.25 years), 5.3 years (95% CI, 4.73 to 6.34 years), 3.2 years (95% CI, 2.51 to 6.19 years), and 3.0 years (95% CI, 2.53 to 3.62 years), respectively.Practical ImplicationsWhen considering crown margin repairs, resin-modified glass ionomer or amalgam is preferable to resin-based composite or glass ionomer.  相似文献   
9.
《Orthopaedics and Trauma》2022,36(3):166-174
Shoulder replacement surgery has become the gold standard treatment for end-stage glenohumeral arthropathies in patients who are fit for surgical treatment. The options include anatomic total shoulder replacement, reverse total shoulder replacement and humeral hemiarthroplasty procedures. Whilst for some patients and some indications there is little debate, decision-making for older patients with osteoarthritis remains one of the hot topics in shoulder surgery. In this article we will explore the treatment options, outcomes, and controversies.  相似文献   
10.
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