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   301461篇
  免费   24434篇
  国内免费   8651篇
耳鼻咽喉   3116篇
儿科学   10382篇
妇产科学   6737篇
基础医学   38197篇
口腔科学   5221篇
临床医学   30850篇
内科学   44229篇
皮肤病学   4230篇
神经病学   18167篇
特种医学   6806篇
外国民族医学   41篇
外科学   33916篇
综合类   44189篇
现状与发展   29篇
一般理论   25篇
预防医学   18214篇
眼科学   6848篇
药学   23465篇
  157篇
中国医学   18962篇
肿瘤学   20765篇
  2024年   524篇
  2023年   4388篇
  2022年   7414篇
  2021年   12619篇
  2020年   11472篇
  2019年   10359篇
  2018年   10290篇
  2017年   10269篇
  2016年   10467篇
  2015年   10255篇
  2014年   18004篇
  2013年   19233篇
  2012年   15579篇
  2011年   18044篇
  2010年   14863篇
  2009年   14574篇
  2008年   14569篇
  2007年   15684篇
  2006年   14299篇
  2005年   13217篇
  2004年   11549篇
  2003年   10231篇
  2002年   7470篇
  2001年   7113篇
  2000年   5881篇
  1999年   5428篇
  1998年   4152篇
  1997年   3707篇
  1996年   3686篇
  1995年   3507篇
  1994年   3116篇
  1993年   2804篇
  1992年   2455篇
  1991年   2071篇
  1990年   1766篇
  1989年   1617篇
  1988年   1558篇
  1987年   1267篇
  1986年   1010篇
  1985年   1240篇
  1984年   1166篇
  1983年   721篇
  1982年   921篇
  1981年   792篇
  1980年   668篇
  1979年   563篇
  1978年   423篇
  1977年   349篇
  1976年   344篇
  1975年   207篇
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
11.
ObjectiveSpinal cord stimulation (SCS) is an effective treatment in failed back surgery syndrome (FBSS). We studied the effect of preimplantation opioid use on SCS outcome and the effect of SCS on opioid use during a two-year follow-up period.Materials and methodsThe study cohort included 211 consecutive FBSS patients who underwent an SCS trial from January 1997 to March 2014. Participants were divided into groups, which were as follows: 1) SCS trial only (n = 47), 2) successful SCS (implanted and in use throughout the two-year follow-up period, n = 131), and 3) unsuccessful SCS (implanted but later explanted or revised due to inadequate pain relief, n = 29). Patients who underwent explantation for other reasons (n = 4) were excluded. Opioid purchase data from January 1995 to March 2016 were retrieved from national registries.ResultsHigher preimplantation opioid doses associated with unsuccessful SCS (ROC: AUC = 0.66, p = 0.009), with 35 morphine milligram equivalents (MME)/day as the optimal cutoff value. All opioids were discontinued in 23% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.004). Strong opioids were discontinued in 39% of patients with successful SCS, but in none of the patients with unsuccessful SCS (p = 0.04). Mean opioid dose escalated from 18 ± 4 MME/day to 36 ± 6 MME/day with successful SCS and from 22 ± 8 MME/day to 82 ± 21 MME/day with unsuccessful SCS (p < 0.001).ConclusionsHigher preimplantation opioid doses were associated with SCS failure, suggesting the need for opioid tapering before implantation. With continuous SCS therapy and no explantation or revision due to inadequate pain relief, 39% of FBSS patients discontinued strong opioids, and 23% discontinued all opioids. This indicates that SCS should be considered before detrimental dose escalation.  相似文献   
12.
13.
14.
15.
16.
17.
IntroductionPregnancy in spinal cord injured patients has specific issues that must be carefully addressed. However, guidelines for their management are scarce.MethodsA systematic review of the literature regarding the anaesthetic management during delivery of pregnant patients with cervical spinal cord injury was performed on the electronic databases of PubMed (Medline) and Cochrane.ResultsA higher incidence of preterm birth and caesarean delivery were seen. Anaesthetic management was diverse, although most pregnant patients received epidural analgesia. Autonomic dysreflexia symptoms were present in 51% of pregnancies.ConclusionTimely management of these patients could possibly reduce caesarean and preterm delivery rates, avoid or minimize common complications, as well as reduce costs. An early reference to anaesthesiology consultation and a multidisciplinary approach is recommended.  相似文献   
18.
19.
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   
20.
Cantharidin (CTD) is an effective antitumor agent. However, it exhibits significant hepatotoxicity, the mechanism of which remains unclear. In this study, biochemical and histopathological analyses complemented with ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS)-based targeted metabolomic analysis of bile acids (BAs) were employed to investigate CTD-induced hepatotoxicity in rats. Sixteen male and female Sprague–Dawley rats were randomly divided into two groups: control and CTD (1.0 mg/kg) groups. Serum and liver samples were collected after 28 days of intervention. Biochemical, histopathological, and BA metabolomic analyses were performed for all samples. Further, the key biomarkers of CTD-induced hepatotoxicity were identified via multivariate and metabolic pathway analyses. In addition, metabolite–gene–enzyme network and Kyoto Encyclopedia of Genes and Genomes pathway analyses were used to identify the signaling pathways related to CTD-induced hepatotoxicity. The results revealed significantly increased levels of biochemical indices (alanine aminotransferase, aspartate aminotransferase, and total bile acid). Histopathological analysis revealed that the hepatocytes were damaged. Further, 20 endogenous BAs were quantitated via UHPLC-MS/MS, and multivariate and metabolic pathway analyses of BAs revealed that hyocholic acid, cholic acid, and chenodeoxycholic acid were the key biomarkers of CTD-induced hepatotoxicity. Meanwhile, primary and secondary BA biosynthesis and taurine and hypotaurine metabolism were found to be associated with the mechanism by which CTD induced hepatotoxicity in rats. This study provides useful insights for research on the mechanism of CTD-induced hepatotoxicity.  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