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   7551篇
  免费   417篇
  国内免费   93篇
耳鼻咽喉   101篇
儿科学   108篇
妇产科学   110篇
基础医学   796篇
口腔科学   242篇
临床医学   668篇
内科学   2211篇
皮肤病学   76篇
神经病学   869篇
特种医学   495篇
外科学   1079篇
综合类   9篇
预防医学   250篇
眼科学   74篇
药学   415篇
中国医学   10篇
肿瘤学   548篇
  2024年   13篇
  2023年   112篇
  2022年   206篇
  2021年   337篇
  2020年   240篇
  2019年   261篇
  2018年   285篇
  2017年   186篇
  2016年   266篇
  2015年   270篇
  2014年   315篇
  2013年   422篇
  2012年   609篇
  2011年   594篇
  2010年   322篇
  2009年   270篇
  2008年   369篇
  2007年   422篇
  2006年   368篇
  2005年   349篇
  2004年   344篇
  2003年   277篇
  2002年   235篇
  2001年   104篇
  2000年   82篇
  1999年   76篇
  1998年   59篇
  1997年   43篇
  1996年   37篇
  1995年   31篇
  1994年   24篇
  1993年   35篇
  1992年   54篇
  1991年   52篇
  1990年   53篇
  1989年   51篇
  1988年   41篇
  1987年   27篇
  1986年   27篇
  1985年   21篇
  1984年   25篇
  1983年   16篇
  1982年   8篇
  1979年   10篇
  1978年   9篇
  1974年   10篇
  1973年   10篇
  1971年   8篇
  1968年   7篇
  1966年   7篇
排序方式: 共有8061条查询结果,搜索用时 31 毫秒
71.
The determinants of the susceptibility to severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection and severe coronavirus disease 2019 (COVID-19) manifestations are yet not fully understood. Amino-bisphosphonates (N-BPs) have anti-inflammatory properties and have been shown to reduce the incidence of lower respiratory infections, cardiovascular events, and cancer. We conducted a population-based retrospective observational cohort study with the primary objective of determining if oral N-BPs treatment can play a role in the susceptibility to development of severe COVID-19. Administrative International Classification of Diseases, Ninth Revision, Clinical ModificationI (ICD-9-CM) and anatomical-therapeutic chemical (ATC) code data, representative of Italian population (9% sample of the overall population), were analyzed. Oral N-BPs (mainly alendronate and risedronate) were included in the analysis, zoledronic acid was excluded because of the low number of patients at risk. Incidence of COVID-19 hospitalization was 12.32 (95% confidence interval [CI], 9.61–15.04) and 11.55 (95% CI, 8.91–14.20), of intensive care unit (ICU) utilization because of COVID-19 was 1.25 (95% CI, 0.38–2.11) and 1.42 (95% CI, 0.49–2.36), and of all-cause death was 4.06 (95% CI, 2.50–5.61) and 3.96 (95% CI, 2.41–5.51) for oral N-BPs users and nonusers, respectively. Sensitivity analyses that excluded patients with prevalent vertebral or hip fragility fractures and without concomitant glucocorticoid treatment yielded similar results. In conclusion, we found that the incidence of COVID-19 hospitalization, intensive care unit (ICU) utilization, and COVID-19 potentially related mortality were similar in N-BPs–treated and nontreated subjects. Similar results were found in N-BPs versus other anti-osteoporotic drugs. We provide real-life data on the safety of oral N-BPs in terms of severe COVID-19 risk on a population-based cohort. Our results do not support the hypothesis that oral N-BPs can prevent COVID-19 infection and/or severe COVID-19; however, they do not seem to increase the risk. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).  相似文献   
72.
BackgroundThe occurrence of early graft failure (EGF) after heart transplantation (Htx) often requires a mechanical circulatory support (MCS) therapy. The aims of our study were to identify risk factors of mechanically supported severe EGF and evaluate their impact on both early and late outcomes.MethodsBetween January 2000 and December 2019, 499 consecutive adult patients underwent Htx at our institution. Severe EGF was defined as the need for extracorporeal life support (ECLS) within 24 hours after surgery. All available recipient and donor variables were retrospectively analyzed.ResultsOverall, EGF occurred in 58 (11.6%) patients. Post-Htx peripheral or central ECLS was necessary in 32 (6.4%) cases. Independent predictors of severe EGF were, in the recipient group, preoperative transpulmonary gradient (TPG) >12 mm Hg (odds ratio [OR] 4.1, P = .013), preoperative inotropic score >10 (OR 7.3, P = .0001), and pre-Htx ECLS support (OR 5.2, P = .015), while in the donors, a Eurotransplant donor score ≥17 (OR 8.5, P = .005). The absence of EGF was related with a better survival at 1 year and 5 years (94% and 85%, respectively) compared with EGF requiring ECLS population (36% and 28% at 1 year and 5 years, respectively; P < .001). A five-year conditional survival rate did not differ significantly (85% no EGF vs 83% EGF requiring ECLS).ConclusionBoth donor and recipient factors may influence EGF occurrence. Post-Htx ECLS may impact negatively early; however, patients weaned from ECLS eventually benefit from such a rescue treatment with outcomes comparable with Htx patients who did not suffer EGF.  相似文献   
73.
74.
75.
76.
77.
78.
The authors report a case of primary plasma cell leukemia and two cases of multiple myeloma with a large number of circulating plasma cells. The display of Technicon H-1 shows a very high "cloud" in the area of large unstained cells. A massive invasion of the basophil area was not found. Differences between these results and those found in different lymphoid leukemias are discussed.  相似文献   
79.
The main features and the present position of tetracyclines are reviewed. The mechanism of their action, bacterial resistance and the most recent findings are reported. Their decreased use is due to the availability of new, active, better-tolerated antibiotics. However, tetracyclines still have a place in the treatment of chlamydial and rickettsial infections, brucellosis and Lyme disease. In respiratory infections, they can be employed when necessary in infections caused by Chlamydia psittaci, C. pneumoniae, Mycoplasma pneumoniae, and also by Streptococcus pneumoniae and Haemophilus influenzae, whose rates of resistance now seem lower than in the past when tetracyclines were more largely prescribed.  相似文献   
80.
Experimental animal studies carried out over the past 40 years have unequivocally shown that neurogenic mechanisms are involved in the pathogenesis of hypertension. The results of these studies also suggest that neural factors are important not only in the development but also in the maintenance of the high blood pressure condition. Whether this is the case also for human hypertension has been matter of debate for several decades. However, recent studies in man by employing sophisticated techniques for assessing sympathetic tone, i.e. the norepinephrine radiolabelled technique and microneurographic recording of sympathetic nerve traffic, support the hypothesis that alterations in sympathetic modulation of the cardiovascular system take place in hypertension and may have a pathogenetic relevance in age-related blood pressure increase.  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