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   1409886篇
  免费   90430篇
  国内免费   2195篇
耳鼻咽喉   20416篇
儿科学   46400篇
妇产科学   40867篇
基础医学   205524篇
口腔科学   38746篇
临床医学   117827篇
内科学   273609篇
皮肤病学   29792篇
神经病学   111527篇
特种医学   56570篇
外国民族医学   390篇
外科学   218116篇
综合类   27311篇
现状与发展   1篇
一般理论   334篇
预防医学   98673篇
眼科学   32311篇
药学   106575篇
  19篇
中国医学   2773篇
肿瘤学   74730篇
  2018年   13948篇
  2016年   12545篇
  2015年   14317篇
  2014年   18841篇
  2013年   28324篇
  2012年   39723篇
  2011年   41687篇
  2010年   24679篇
  2009年   22877篇
  2008年   40748篇
  2007年   44252篇
  2006年   44880篇
  2005年   44343篇
  2004年   42535篇
  2003年   41595篇
  2002年   40978篇
  2001年   62270篇
  2000年   63764篇
  1999年   54269篇
  1998年   15359篇
  1997年   13738篇
  1996年   13773篇
  1995年   12925篇
  1994年   12298篇
  1993年   11373篇
  1992年   42603篇
  1991年   41954篇
  1990年   41452篇
  1989年   40149篇
  1988年   37325篇
  1987年   36584篇
  1986年   34873篇
  1985年   33267篇
  1984年   24813篇
  1983年   21502篇
  1982年   12874篇
  1981年   11370篇
  1979年   23583篇
  1978年   16573篇
  1977年   14338篇
  1976年   13505篇
  1975年   14985篇
  1974年   17492篇
  1973年   16806篇
  1972年   16054篇
  1971年   14924篇
  1970年   13830篇
  1969年   13313篇
  1968年   12554篇
  1967年   11004篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
72.
73.
74.
Brain Structure and Function - Accumulating evidence suggests that besides its function in early facial feature processing, the role of the right occipital face area (rOFA) extends to higher level,...  相似文献   
75.
Allogeneic stem cell transplantation (SCT) as primary treatment for aplastic anemia (AA) is being increasingly used. Yet, age, stem cell source, and donor type are important outcome factors. We have recently performed a nationwide cohort study of all patients with AA in Sweden diagnosed from 2000 to 2011 and now present outcome data on SCT patients. In total, 68 patients underwent SCT, and 63% of them had failed immunosuppressive therapy. We found that, with a median follow-up of 109 months (range, 35 to 192 months), 5-year overall survival (OS) for all patients was 86.8%, whereas graft-versus-host disease-free, relapse/rejection-free survival (GRFS) at 5 years was 69.1%. There was no survival impact regarding the donor type or stem cell source. Patients aged ≥40 years had a higher transplant-related mortality (29.4% versus 7.8%; P = .023), which translated into a lower 5-year OS: 70.6% versus 92.2% (P = .022) and a trend of lower GRFS (52.9% versus 74.5%; P = .069). In conclusion, we found in this real-world setting that both OS and GRFS were high, but SCT for patients with AA aged ≥40 years is problematic, and clinical trials addressing this issue are warranted.  相似文献   
76.
77.
Cerebral adrenoleukodystrophy (CALD) is a rapidly progressing, often fatal neurodegenerative disease caused by mutations in the ABCD1 gene, resulting in deficiency of ALD protein. Clinical benefit has been reported following allogeneic hematopoietic stem cell transplantation (HSCT). We conducted a large multicenter retrospective chart review to characterize the natural history of CALD, to describe outcomes after HSCT, and to identify predictors of treatment outcomes. Major functional disabilities (MFDs) were identified as having the most significant impact on patients’ abilities to function independently and were used to assess HSCT outcome. Neurologic function score (NFS) and Loes magnetic resonance imaging score were assessed. Data were collected on 72 patients with CALD who did not undergo HSCT (untreated cohort) and on 65 patients who underwent transplantation (HSCT cohort) at 5 clinical sites. Kaplan-Meier (KM) estimates of 5-year overall survival (OS) from the time of CALD diagnosis were 55% (95% confidence interval [CI], 42.2% to 65.7%) for the untreated cohort and 78% (95% CI, 64% to 86.6%) for the HSCT cohort overall (P?=?.01). KM estimates of 2-year MFD-free survival for patients with gadolinium-enhanced lesions (GdE+) were 29% (95% CI, 11.7% to 48.2%) for untreated patients (n?=?21). For patients who underwent HSCT with GdE+ at baseline, with an NFS ≤1 and Loes score of 0.5 to ≤9 (n?=?27), the 2-year MFD-free survival was 84% (95% CI, 62.3% to 93.6%). Mortality rates post-HSCT were 8% (5 of 65) at 100days and 18% (12 of 65) at 1 year, with disease progression (44%; 7 of 16) and infection (31%; 5 of 16) listed as the most common causes of death. Adverse events post-HSCT included infection (29%; 19 of 65), acute grade II-IV graft-versus-host disease (GVHD) (31%; 18 of 58), and chronic GVHD (7%; 4 of 58). Eighteen percent of the patients (12 of 65) experienced engraftment failure after their first HSCT. Positive predictors of OS in the HSCT cohort may include donor-recipient HLA matching and lack of GVHD, and early disease treatment was predictive of MFD-free survival. GdE+ status is a strong predictor of disease progression in untreated patients.? This study confirms HSCT as an effective treatment for CALD when performed early. We propose survival without MFDs as a relevant treatment goal, rather than solely assessing OS as an indicator of treatment success.  相似文献   
78.
ObjectivesThis study was conducted to compare clinical outcomes of fidaxomicin versus oral vancomycin in the management of severe Clostridium difficile infection (CDI).MethodsThe investigation was a retrospective, multicentre, propensity score-matched analysis using a national clinical administrative database. Veterans treated for severe CDI from any Veterans Affairs Medical Center between 1 June 2011 and 30 June 2017 were included if they received fidaxomicin or an oral vancomycin regimen for treatment. The two groups were matched by the nearest-neighbour method from a propensity score derived from independent variables associated with the selection of a fidaxomicin course.ResultsPropensity score matching resulted in two well-matched cohorts consisting of 213 fidaxomicin and 639 oral vancomycin courses. No statistically-significant difference was found for the primary outcome of combined clinical failure or recurrence (68/213 (31.9%) versus 163/639 (25.5%), respectively, p 0.071). Additionally, no statistically significant differences were found for the secondary outcomes of 30-day (23/213 (10.8%) versus 75/639 (11.7%), respectively, p 0.71), 90-day (48/213 (22.5%) versus 140/639 (21.9%), respectively, p 0.85), and 180-day mortality (62/213 (29.1%) versus 186/639 (29.1%), respectively, p 1.0) between the two treatment groups.ConclusionsCourses of fidaxomicin or oral vancomycin for severe CDI resulted in similar treatment outcomes. Study findings are consistent with current treatment guideline recommendations for the use of either agent in the management of severe CDI.  相似文献   
79.
ObjectivesThe rise in carbapenem resistance among Gram-negative bacteria has renewed interest in colistin. Recently, the EUCAST-CLSI Polymyxin Breakpoints Working Group declared that broth microdilution (BMD) is the only valid method for colistin susceptibility testing. BMD is not easily incorporated into the routine work of clinical laboratories, and usually this test is incorporated serially, resulting in delayed susceptibility reporting. We tested a strategy of combining VITEK® 2 with a 2 μg/mL colistin agar dilution (VITEK® 2/AD) screening plate to improve performance and time to reporting of colistin susceptibility.MethodsColistin susceptibility for 364 clinical isolates was determined by VITEK® 2/AD and compared with the reference standard BMD according to the ISO 20776-1:2007 and CLSI guidelines. The EUCAST colistin susceptibility breakpoint of ≤2 μg/mL was used. Escherichia coli NCTC 13846 served as quality control strain. Agreement, very major error (VME) and major error rates were determined using ISO 20776-2:2007.ResultsThe VME rate for VITEK® 2 alone was 30.6% (15/49, 95% CI 18.3–45.4%), and was reduced to 10.2% (5/49, 95% CI 3.4–22.2%) using the VITEK® 2/AD combined testing. The combined testing had categorical agreement with BMD of 97% (354/364, 95% CI 95.0–98.7%), and a major error (ME) rate of 1.6% (5/315, 95% CI 0.5–3.7%). Using the combined testing, even against challenging strains, 349 (95.8%, 95% CI 93.3–97.7%) colistin susceptibility results could be reported, and only 15 isolates required further analysis by BMD.DiscussionOur method is simple to apply and allows rapid reporting of colistin susceptibility.  相似文献   
80.
ObjectivesParapneumonic pleural effusions/empyema (PPE/PE) are severe complications of community-acquired pneumonia. We investigated the bacterial aetiology and incidence of paediatric PPE/PE in Germany after the introduction of universal pneumococcal conjugate vaccine (PCV) immunization for infants.MethodsChildren <18 years of age hospitalized with pneumonia-associated PPE/PE necessitating pleural drainage or persisting >7 days were reported to the German Surveillance Unit for Rare Diseases in Childhood between October 2010 and June 2017. All bacteria detected in blood or pleural fluid (by culture/PCR) were included, with serotyping for Streptococcus pneumoniae.ResultsThe median age of all 1447 PPE/PE patients was 5 years (interquartile range 3–10). In 488 of the 1447 children with PPE/PE (34%), 541 bacteria (>40 species) were detected. Aerobic gram-positive cocci accounted for 469 of 541 bacteria detected (87%); these were most frequently Streptococcus pneumoniae (41%), Streptococcus pyogenes (19%) and Staphylococcus aureus (6%). Serotype 3 accounted for 45% of 78 serotyped S. pneumoniae strains. Annual PPE/PE incidence varied between 14 (95%CI 12–16) and 18 (95%CI 16–21) PPE/PE per million children. Incidence of S. pneumoniae PPE/PE decreased from 3.5 (95%CI 2.5–4.6) per million children in 2010/11 to 1.5 (95%CI 0.9–2.4) in 2013/14 (p 0.002), followed by a re-increase to 2.2 (95%CI 1.5–3.2) by 2016/17 (p 0.205).ConclusionsIn the era of widespread PCV immunization, cases of paediatric PPE/PE were still caused mainly by S. pneumoniae and, increasingly, by S. pyogenes. The re-increase in the incidence of PPE/PE overall and in S. pneumoniae-associated PPE/PE indicates ongoing changes in the bacterial aetiology and requires further surveillance.  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