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   8895篇
  免费   540篇
  国内免费   334篇
耳鼻咽喉   198篇
儿科学   153篇
妇产科学   254篇
基础医学   558篇
口腔科学   173篇
临床医学   583篇
内科学   1494篇
皮肤病学   40篇
神经病学   320篇
特种医学   160篇
外科学   1561篇
综合类   677篇
预防医学   613篇
眼科学   39篇
药学   403篇
中国医学   79篇
肿瘤学   2464篇
  2024年   6篇
  2023年   146篇
  2022年   341篇
  2021年   483篇
  2020年   413篇
  2019年   424篇
  2018年   460篇
  2017年   344篇
  2016年   315篇
  2015年   362篇
  2014年   711篇
  2013年   611篇
  2012年   456篇
  2011年   557篇
  2010年   359篇
  2009年   477篇
  2008年   514篇
  2007年   450篇
  2006年   336篇
  2005年   256篇
  2004年   234篇
  2003年   164篇
  2002年   135篇
  2001年   139篇
  2000年   121篇
  1999年   130篇
  1998年   75篇
  1997年   74篇
  1996年   59篇
  1995年   53篇
  1994年   49篇
  1993年   51篇
  1992年   48篇
  1991年   30篇
  1990年   38篇
  1989年   45篇
  1988年   35篇
  1987年   31篇
  1986年   28篇
  1985年   35篇
  1984年   25篇
  1983年   24篇
  1982年   29篇
  1981年   17篇
  1980年   21篇
  1979年   17篇
  1978年   6篇
  1977年   11篇
  1976年   10篇
  1973年   6篇
排序方式: 共有9769条查询结果,搜索用时 15 毫秒
1.
2.
This review provides a practical guide to the essentials of survival analysis and their reporting in cardiovascular studies, although most of its key content can be extrapolated to other medical fields. This is the first in a series of 2 educational articles laying the groundwork to address the most relevant statistical issues in survival analyses, which will smoothly drive the reader from the most basic analyses to the most complex situations. The focus will be on the type and shape of survival data, and the most common statistical methods, such as nonparametric, parametric and semiparametric models. Their adequacy, interpretation, advantages and disadvantages are illustrated by examples from the field of cardiovascular research. This article ends with a set of recommendations to guide the strategy of survival analyses for a randomized clinical trial and observational studies. Other topics, such as competing risks, multistate models and recurrent-event methods will be addressed in the second article.  相似文献   
3.
ObjectiveThere is a paucity of data concerning the use of granulocyte colony-stimulating factors (G-CSFs) in pediatric patients with acute lymphoblastic leukemia (ALL). The aim of the present study was to evaluate the effect of G-CSF use on relapse-free and overall survival in 358 consecutive, newly diagnosed pediatric ALL patients uniformly treated at the same institution between April 2012 and April 2020.Materials and MethodsPatients were evaluated in two separate periods, based on the G-CSF treatment approach. All patients who underwent ALL treatment between April 2012 and December 2016 received G-CSF (G-CSF+ arm; n: 245) in the course of the protocol for reducing the risk of febrile neutropenia and/or inducing neutrophil recovery to prevent any treatment delay. No patients after December 2016 received G-CSF, even if they belonged to the high-risk group, and these were included in the G-CSF? arm (n: 113).ResultsEstimated mean relapse-free (106.5 months; 95 % CI 102?110.8 vs 82 months 95 % CI 75.2?88.9; p: 0.794) and overall survival (111.4 months; 95 % CI 108?114.8 vs 85 months 95 % CI 80.4?89.8; p: 0.431) rates were similar between the G-CSF+ and G-CSF? groups.ConclusionsOur findings indicate that G-CSF use during ALL treatment had no effect on relapse rates or overall survival.  相似文献   
4.
PurposeGlioblastoma multiforme (GBM) is the most common malignant brain tumor. Moreover, GBM recurs in nearly all patients. Although a standard STUPP protocol has been widely used for newly diagnosed GBM, no standard regimen has been established for recurrent patients. Here we evaluated the clinical value of recurrent GBM reoperation by comparing overall survival and quality of life (QoL) in patients with recurrent GBM undergoing repeat surgery or conservative treatment.MethodsThis was a prospective study of 165 patients with GBM receiving first operations for their disease between 2011 and 2013 at two tertiary neurosurgery centers in Poland. Thirty-five eligible patients were re-operated for recurrence (the study group), and 35 patients were selected as the control group using propensity score matching. A model was created to determine advantageous prognostic factors for longer survival of patients qualifying for reoperation using stepwise linear regression.ResultsThe mean overall survival of patients undergoing repeat surgery was 528 days compared to 297 days in patients who did not undergo repeat surgery. Reoperation did not result in a significant deterioration in performance status as measured by the Karnofsky Performance Scale. Older age, the presence of symptoms of increased intracranial pressure, and a shorter period between initial operation and reoperation were independent predictors of a worse outcome.ConclusionIn selected patients, reoperation for recurrent GBM prolongs survival with no significant deteriorations in performance status.  相似文献   
5.
6.
《Clinical neurophysiology》2021,132(9):2003-2011
ObjectiveA large N20 and P25 of the median nerve somatosensory evoked potential (SEP) predicts short survival in amyotrophic lateral sclerosis (ALS). We investigated whether high frequency oscillations (HFOs) over N20 are enlarged and associated with survival in ALS.MethodsA total of 145 patients with ALS and 57 healthy subjects were studied. We recorded the median nerve SEP and measured the onset-to-peak amplitude of N20 (N20o-p), and peak-to-peak amplitude between N20 and P25 (N20p-P25p). We obtained early and late HFO potentials by filtering SEP between 500 and 1 kHz, and measured the peak-to-peak amplitude. We followed up patients until endpoints (death or tracheostomy) and analyzed the relationship between SEP or HFO amplitudes and survival using a Cox analysis.ResultsPatients showed larger N20o-p, N20p-P25p, and early and late HFO amplitudes than the control values. N20p-P25p was associated with survival periods (p = 0.0004), while early and late HFO amplitudes showed no significant association with survival (p = 0.4307, and p = 0.6858, respectively).ConclusionsThe HFO amplitude in ALS is increased, but does not predict survival.SignificanceThe enlarged HFOs in ALS might be a compensatory phenomenon to the hyperexcitability of the sensory cortex pyramidal neurons.  相似文献   
7.
8.
9.
AimLung metastases are a negative prognostic factor in Ewing sarcoma, however, the incidence and significance of sub-centimetre pulmonary nodules at diagnosis is unclear. The aims of this study were to (1): determine the incidence of indeterminate pulmonary nodules (IPNs) in patients diagnosed with Ewing sarcoma (2); establish the impact of IPNs on overall and metastasis-free survival and (3) identify patient, oncological and radiological factors that correlate with poorer prognosis in patients that present with IPNs on their staging chest CT.Materials & methodsBetween 2008 and 2016, 173 patients with a first presentation of Ewing sarcoma of bone were retrospectively identified from an institutional database. Staging and follow-up chest CTs for all patients with IPN were reviewed by a senior radiologist. Clinical and radiologic course were examined to determine overall- and metastasis-free survival for IPN patients and to identify demographic, oncological or nodule-specific features that predict which IPN represent true lung metastases.ResultsFollowing radiologic re-review, IPN were found in 8.7% of patients. Overall survival for IPN patients was comparable to those with a normal staging chest CT (2-year overall survival of 73.3% [95% CI 43.6–89] and 89.4% [95% CI 81.6–94], respectively; p = 0.34) and was significantly better than for patients with clear metastases (46.0% [95% CI 31.9–59]; p < 0.0001). Similarly, there was no difference in metastasis-free survival between ‘No Metastases’ and ‘IPN’ patients (p = 0.16). Lung metastases developed in 40% of IPN patients at a median 9.6 months. Reduction of nodule size on neoadjuvant chemotherapy was associated with worse overall survival in IPN patients (p = 0.0084).ConclusionIPN are not uncommon in patients diagnosed with Ewing sarcoma. In this study, we were unable to detect a difference in overall- or metastasis-free survival between patients with IPN at diagnosis and patients with normal staging chest CTs.  相似文献   
10.
目的探究肾透明细胞癌不同CT影像学征象对患者术后康复情况的影响。方法选取2010年1月到2014年4月我院收治的50例肾透明细胞癌患者的CT征象,进行T分期,并分析不同CT征象与患者预后关系。结果利用CT征象进行T分期区别主要在T3a期,T3a期分为T3a-CT(10例)和T3a-仅病理(6例),T3a-仅病理CT分期可分为T1期2例,T2期4例;单因素分析显示,肿瘤大小、肿瘤是否侵及肾被膜外、是否侵及肾窦集合系统、是否侵及肾静脉及分支、是否侵及下腔静脉、有无广泛性坏死、是否存在囊性改变、瘤周是否受侵、瘤周是否存在新生血管与5年生存率具有一定相关性(P<0.05);多因素回归分析显示,肿瘤≥7cm、肿瘤穿透肾被膜、肾静脉及分支受侵、下腔静脉受侵、肿瘤无囊变、瘤周受侵及瘤周新生血管是影响肾透明细胞癌预后的独立危险因素(P<0.05)。结论肾透明细胞瘤患者肿瘤大于7cm、肿瘤穿透肾被膜、肾静脉及分支受侵、下腔静脉受侵、肿瘤无囊变、瘤周受侵及瘤周新生血管是影响肾透明细胞癌预后的独立危险因素,肿瘤周围受侵及瘤周新生血管形成可降低患者5年生存率,而肿瘤囊变可作为预测术后康复情况较好的标志之一。  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