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   1415344篇
  免费   116524篇
  国内免费   3343篇
耳鼻咽喉   18428篇
儿科学   46839篇
妇产科学   41188篇
基础医学   201663篇
口腔科学   37950篇
临床医学   126791篇
内科学   285426篇
皮肤病学   33447篇
神经病学   117556篇
特种医学   54068篇
外国民族医学   464篇
外科学   211661篇
综合类   32989篇
现状与发展   3篇
一般理论   515篇
预防医学   110565篇
眼科学   31597篇
药学   99147篇
  1篇
中国医学   3351篇
肿瘤学   81562篇
  2021年   10927篇
  2019年   11765篇
  2018年   16690篇
  2017年   12755篇
  2016年   14346篇
  2015年   16095篇
  2014年   22741篇
  2013年   33651篇
  2012年   45709篇
  2011年   48262篇
  2010年   28350篇
  2009年   27252篇
  2008年   44647篇
  2007年   47206篇
  2006年   47740篇
  2005年   46232篇
  2004年   44096篇
  2003年   42001篇
  2002年   40466篇
  2001年   73255篇
  2000年   74749篇
  1999年   61766篇
  1998年   17092篇
  1997年   15498篇
  1996年   15657篇
  1995年   14861篇
  1994年   13466篇
  1993年   12656篇
  1992年   46020篇
  1991年   43649篇
  1990年   41655篇
  1989年   39718篇
  1988年   36341篇
  1987年   35524篇
  1986年   33019篇
  1985年   31442篇
  1984年   23946篇
  1983年   20120篇
  1982年   12288篇
  1981年   10849篇
  1979年   20788篇
  1978年   14640篇
  1977年   12141篇
  1976年   11437篇
  1975年   11678篇
  1974年   14055篇
  1973年   13609篇
  1972年   12708篇
  1971年   11520篇
  1970年   10947篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
261.
262.
Background Although prostate cancer is a leading cause of cancer death, its aetiology is not well understood. We aimed to identify novel biochemical factors for prostate cancer incidence and mortality in UK Biobank.Methods A range of cardiovascular, bone, joint, diabetes, renal and liver-related biomarkers were measured in baseline blood samples collected from up to 211,754 men at recruitment and in a subsample 5 years later. Participants were followed-up via linkage to health administrative datasets to identify prostate cancer cases. Hazard ratios (HRs) and 95% confidence intervals were calculated using multivariable-adjusted Cox regression corrected for regression dilution bias. Multiple testing was accounted for by using a false discovery rate controlling procedure.Results After an average follow-up of 6.9 years, 5763 prostate cancer cases and 331 prostate cancer deaths were ascertained. Prostate cancer incidence was positively associated with circulating vitamin D, urea and phosphate concentrations and inversely associated with glucose, total protein and aspartate aminotransferase. Phosphate and cystatin-C were the only biomarkers positively and inversely, respectively, associated with risk in analyses excluding the first 4 years of follow-up. There was little evidence of associations with prostate cancer death.Conclusion We found novel associations of several biomarkers with prostate cancer incidence. Future research will examine associations by tumour characteristics.Subject terms: Predictive markers, Prostate cancer, Risk factors  相似文献   
263.
The amphibian micronucleus test has been widely used during the last 30 years to test the genotoxic properties of several chemicals and as a tool for ecogenotoxic monitoring. The vast majority of these studies were performed on peripheral blood of urodelan larvae and anuran tadpoles and to a lesser extent adults were also used. In this study, we developed protocols for measuring micronuclei in adult shed skin cells and larval gill cells of the Italian crested newt (Triturus carnifex). Amphibians were collected from ponds in two protected areas in Italy that differed in their radon content. Twenty‐three adult newts and 31 larvae were captured from the radon‐rich pond, while 20 adults and 27 larvae were taken from the radon‐free site. The animals were brought to the laboratory and the micronucleus test was performed on peripheral blood and shed skins taken from the adults and on larval gills. Samples from the radon‐rich site showed micronucleus frequencies higher than those from the radon‐free site and the difference was statistically significant in gill cells (P < 0.00001). Moreover, the larval gills seem to be more sensitive than the adult tissues. This method represents an easy (and noninvasive in the case of the shed skin) application of the micronucleus assay that can be useful for environmental studies in situ. Environ. Mol. Mutagen. 56:412–417, 2015. © 2014 Wiley Periodicals, Inc.  相似文献   
264.
265.
266.
267.
268.
Postoperative pulmonary complications are associated with an increase in mortality, morbidity and healthcare utilisation. The Agency for Healthcare Research and Quality recommends risk assessment for postoperative respiratory complications in patients undergoing surgery. In this hospital registry study of adult patients undergoing non-cardiac surgery between 2005 and 2017 at two independent healthcare networks, a prediction instrument for early postoperative tracheal re-intubation was developed and externally validated. This was based on the development of the Score for Prediction Of Postoperative Respiratory Complications. For predictor selection, stepwise backward logistic regression and bootstrap resampling were applied. Development and validation cohorts were represented by 90,893 patients at Partners Healthcare and 67,046 patients at Beth Israel Deaconess Medical Center, of whom 699 (0.8%) and 587 (0.9%) patients, respectively, had their tracheas re-intubated. In addition to five pre-operative predictors identified in the Score for Prediction Of Postoperative Respiratory Complications, the final model included seven additional intra-operative predictors: early post-tracheal intubation desaturation; prolonged duration of surgery; high fraction of inspired oxygen; high vasopressor dose; blood transfusion; the absence of volatile anaesthetic use; and the absence of lung-protective ventilation. The area under the receiver operating characteristic curve for the new score was significantly greater than that of the original Score for Prediction Of Postoperative Respiratory Complications (0.84 [95%CI 0.82–0.85] vs. 0.76 [95%CI 0.75–0.78], respectively; p < 0.001). This may allow clinicians to develop and implement strategies to decrease the risk of early postoperative tracheal re-intubation.  相似文献   
269.
270.
Psoriasis is a chronic disease that requires long‐term treatment. Consequently, understanding the safety and tolerability of any potential treatment over time is critical to effective prescribing. The biologic agents currently available for the treatment of psoriasis target a number of different inflammatory cytokines involved in psoriasis disease pathogenesis. The monoclonal antibodies tildrakizumab, guselkumab and risankizumab target the p19 subunit that is specific to interleukin (IL)‐23. This article reviews published data on the safety of these IL‐23p19 inhibitors in patients with psoriasis compared with other currently available biologic therapies. Data from randomized, placebo‐ and active‐controlled phase 3 clinical trials show tildrakizumab, guselkumab and risankizumab to have a favourable risk–benefit profile in patients with moderate to severe psoriasis. No significant safety concerns have been observed for any of these IL‐23p19 inhibitors in the data published to date. The most commonly reported adverse events (AEs) associated with these agents in phase 3 studies were upper respiratory tract infections. No increase was seen in rates of serious infections, malignancies or major adverse cardiovascular events, with no signals suggestive of an elevated risk of opportunistic infections, active tuberculosis or reactivation of latent tuberculosis infection, mucocutaneous Candida infections, triggering or worsening of inflammatory bowel disease, demyelinating disorders or suicidal ideation. Selectively targeting IL‐23p19 may help avoid AEs that have been associated with biologic agents with other mechanisms of action. Data from long‐term extension studies and patient registries will further establish the safety profile of IL‐23p19 inhibitors for the treatment of moderate to severe psoriasis in routine practice.  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