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   43188篇
  免费   2787篇
  国内免费   132篇
耳鼻咽喉   569篇
儿科学   1422篇
妇产科学   1092篇
基础医学   6576篇
口腔科学   1053篇
临床医学   3908篇
内科学   8633篇
皮肤病学   791篇
神经病学   4201篇
特种医学   2102篇
外国民族医学   14篇
外科学   6413篇
综合类   313篇
一般理论   19篇
预防医学   2514篇
眼科学   996篇
药学   2392篇
中国医学   37篇
肿瘤学   3062篇
  2023年   223篇
  2022年   389篇
  2021年   859篇
  2020年   536篇
  2019年   717篇
  2018年   875篇
  2017年   691篇
  2016年   869篇
  2015年   964篇
  2014年   1314篇
  2013年   1626篇
  2012年   2487篇
  2011年   2576篇
  2010年   1383篇
  2009年   1410篇
  2008年   2250篇
  2007年   2401篇
  2006年   2154篇
  2005年   2119篇
  2004年   1862篇
  2003年   1757篇
  2002年   1535篇
  2001年   1184篇
  2000年   1196篇
  1999年   1009篇
  1998年   488篇
  1997年   378篇
  1996年   305篇
  1995年   272篇
  1994年   241篇
  1993年   241篇
  1992年   594篇
  1991年   623篇
  1990年   593篇
  1989年   493篇
  1988年   474篇
  1987年   496篇
  1986年   460篇
  1985年   469篇
  1984年   363篇
  1983年   272篇
  1982年   200篇
  1979年   350篇
  1978年   244篇
  1977年   214篇
  1976年   201篇
  1975年   205篇
  1974年   228篇
  1973年   214篇
  1972年   196篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
1.
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   
2.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Akteure der öffentlichen Gesundheit (Public Health) tragen wesentlich zu Gesundheitsschutz, -förderung und...  相似文献   
3.
Background Immune checkpoint blockers (ICBs) activate CD8+ T cells, eliciting both anti-cancer activity and immune-related adverse events (irAEs). The relationship of irAEs with baseline parameters and clinical outcome is unclear.Methods Retrospective evaluation of irAEs on survival was performed across primary (N = 144) and secondary (N = 211) independent cohorts of patients with metastatic melanoma receiving single agent (pembrolizumab/nivolumab—sICB) or combination (nivolumab and ipilimumab—cICB) checkpoint blockade. RNA from pre-treatment and post-treatment CD8+ T cells was sequenced and differential gene expression according to irAE development assessed.Results 58.3% of patients developed early irAEs and this was associated with longer progression-free (PFS) and overall survival (OS) across both cohorts (log-rank test, OS: P < 0.0001). Median survival for patients without irAEs was 16.6 months (95% CI: 10.9–33.4) versus not-reached (P = 2.8 × 10−6). Pre-treatment monocyte and neutrophil counts, but not BMI, were additional predictors of clinical outcome. Differential expression of numerous gene pathway members was observed in CD8+ T cells according to irAE development, and patients not developing irAEs demonstrating upregulated CXCR1 pre- and post-treatment.Conclusions Early irAE development post-ICB is associated with favourable survival in MM. Development of irAEs is coupled to expression of numerous gene pathways, suggesting irAE development in-part reflects baseline immune activation.Subject terms: Immunotherapy, Melanoma  相似文献   
4.
5.
6.
A typical time series in functional magnetic resonance imaging (fMRI) exhibits autocorrelation, that is, the samples of the time series are dependent. In addition, temporal filtering, one of the crucial steps in preprocessing of functional magnetic resonance images, induces its own autocorrelation. While performing connectivity analysis in fMRI, the impact of the autocorrelation is largely ignored. Recently, autocorrelation has been addressed by variance correction approaches, which are sensitive to the sampling rate. In this article, we aim to investigate the impact of the sampling rate on the variance correction approaches. Toward this end, we first derived a generalized expression for the variance of the sample Pearson correlation coefficient (SPCC) in terms of the sampling rate and the filter cutoff frequency, in addition to the autocorrelation and cross‐covariance functions of the time series. Through simulations, we illustrated the importance of the variance correction for a fixed sampling rate. Using the real resting state fMRI data sets, we demonstrated that the data sets with higher sampling rates were more prone to false positives, in agreement with the existing empirical reports. We further demonstrated with single subject results that for the data sets with higher sampling rates, the variance correction strategy restored the integrity of true connectivity.  相似文献   
7.
8.
9.
Hawi  N.  von Falck  C.  Krettek  C.  Meller  R. 《Der Unfallchirurg》2019,122(12):944-949
Die Unfallchirurgie - Zur Diagnostik von Schultergelenkerkrankungen wird routinemäßig die Magnetresonanztomographie (MRT) durchgeführt. Diese kann entsprechend der klinischen...  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