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   7505篇
  免费   503篇
  国内免费   12篇
耳鼻咽喉   51篇
儿科学   185篇
妇产科学   197篇
基础医学   937篇
口腔科学   157篇
临床医学   802篇
内科学   1435篇
皮肤病学   67篇
神经病学   722篇
特种医学   187篇
外科学   866篇
综合类   75篇
一般理论   8篇
预防医学   979篇
眼科学   300篇
药学   679篇
中国医学   3篇
肿瘤学   370篇
  2023年   71篇
  2022年   89篇
  2021年   185篇
  2020年   106篇
  2019年   189篇
  2018年   239篇
  2017年   150篇
  2016年   169篇
  2015年   180篇
  2014年   257篇
  2013年   381篇
  2012年   599篇
  2011年   711篇
  2010年   329篇
  2009年   337篇
  2008年   529篇
  2007年   551篇
  2006年   499篇
  2005年   502篇
  2004年   442篇
  2003年   341篇
  2002年   317篇
  2001年   79篇
  2000年   51篇
  1999年   72篇
  1998年   61篇
  1997年   55篇
  1996年   36篇
  1995年   33篇
  1994年   31篇
  1993年   36篇
  1992年   38篇
  1991年   19篇
  1990年   17篇
  1989年   13篇
  1987年   21篇
  1986年   16篇
  1984年   11篇
  1983年   13篇
  1982年   17篇
  1981年   17篇
  1980年   14篇
  1979年   14篇
  1978年   11篇
  1977年   12篇
  1976年   10篇
  1968年   10篇
  1967年   10篇
  1923年   10篇
  1922年   28篇
排序方式: 共有8020条查询结果,搜索用时 12 毫秒
51.
BackgroundThis is the first-in-human study of icenticaftor, an oral potentiator of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) channel. Restoration of CFTR activity has shown significant clinical benefits, but more studies are needed to address all CFTR mutations.MethodsSafety, pharmacodynamics/pharmacokinetics of icenticaftor were evaluated in a randomized, double-blind, placebo-controlled study in healthy volunteers. Efficacy was assessed in adult CF patients with ≥1 pre-specified CFTR Class III or IV mutation (150 and 450 mg bid), or homozygous for F508del mutation (450 mg bid). Primary efficacy endpoint was change from baseline in lung clearance index (LCI2.5). Secondary endpoints included %predicted FEV1 and sweat chloride level.ResultsClass IV mutations were present in 22 patients, Class III in 2 (both S549N), and 25 were homozygous for F508del. Icenticaftor was well-tolerated in healthy and CF subjects with no unexpected events or discontinuations in the CF groups. The most frequent study-drug related adverse events in CF patients were nausea (12.2%), headache (10.2%), and fatigue (6.1%). Icenticaftor 450 mg bid for 14 days showed significant improvements in all endpoints versus placebo in patients with Class III and IV mutations; mean %predicted FEV1 increased by 6.46%, LCI2.5 decreased by 1.13 points and sweat chloride decreased by 8.36 mmol/L. No significant efficacy was observed in patients homozygous for a single F508del.ConclusionsIcenticaftor was safe and well-tolerated in healthy volunteers and CF patients, and demonstrated clinically meaningful changes in lung function and sweat chloride level in CF patients with Class III and IV CFTR mutations.ClinicalTrials.gov: NCT02190604  相似文献   
52.
BackgroundMolecular diagnostics have led to the identification of a broad range of bacterial species in cystic fibrosis (CF) including Inquilinus. The clinical significance of Inquilinus in CF has not been thoroughly characterized.MethodsRetrospective, case-control study of persons with CF from two CF centers with at least one respiratory culture positive for Inquilinus spp. compared with age-matched CF controls with chronic Pseudomonas aeruginosa. Percent predicted forced expiratory volume in one second (ppFEV1) and body mass index percentile (BMI) were modeled from time of first positive culture up to 5 years later. Rates of pulmonary exacerbations were compared. Inquilinus isolates were genotyped to evaluate strain diversity.ResultsSeventeen patients with Inquilinus infection were identified with a mean age of 13 years at first positive culture. Most cases had multiple cultures positive for Inquilinus. ppFEV1 was not different between cases versus controls (80.2% vs 81.6%, p = 0.97 at baseline, 67.5% vs. 73.3%, p = 0.82 at 5 years). Patients were undernourished and BMI percentiles did not differ between groups (30.7% vs 43.4%, p = 0.32 at baseline, 37.9% vs. 37.6%, p = 0.98 at 5 years). There was no difference in the pulmonary exacerbation rate (3.0/year vs 2.5/year, p = 0.34). Genotyping showed diverse genetic strains between patients.ConclusionsInquilinus can present in childhood and is often associated with chronic infection in CF. Lung function and nutrition status at time of detection, lung function decline, and pulmonary exacerbation rates in Inquilinus cases were similar to those with chronic P. aeruginosa, a well-established CF pathogen.  相似文献   
53.
Wound‐dressing performances are affected by exudate viscosity, resistance to flow because of gravity, and bodyweight loads, the level of which is related to the body position. Here, we focussed on two dressing properties: (a) Sorptivity—the ability of dressings to transfer exudate away from the wound bed by capillary action—and (b) Durability—the capacity of dressings to maintain their integrity over time and during their removal. Both properties are critically important for avoiding further tissue damage but require the development of new laboratory tests for their measurement. A computer‐controlled phantom of an exuding sacral pressure ulcer has therefore been developed and used to compare the performances of Exufiber (Mölnlycke Health Care) vs an alternative market‐leading dressing. Sorptivity was determined using weight tests, and durability was measured through tensile tests of the used dressings. For a supine configuration, the Exufiber dressing demonstrated ~three times higher sorptivity and better durability, withstanding ~five times greater strain energy than the other product before failure occurred. This work paves the way for quantitative, standardised testing of dressings in all aspects of exudate management. The reported tests are further suitable for testing dressing combinations or how dressings interact with negative pressure wound therapy.  相似文献   
54.
Ectomesenchymal chondromyxoid tumor is a rare neoplasm of uncertain histogenesis that typically occurs in the anterior dorsal tongue. Recent reports in the literature have described rare examples of gingival, palatal and tonsillar lesions. Histologically, ectomesenchymal chondromyxoid tumors are typically well-circumscribed, lacking overtly aggressive features. Herein we report a tumor arising in the right mandible that is morphologically and molecularly consistent with ectomesenchymal chondromyxoid tumor. This case furthers awareness of the extra-glossal distribution of this neoplasm; moreover, it suggests that a subset of these tumors have the potential for locally aggressive behaviour.Electronic supplementary materialThe online version of this article (10.1007/s12105-020-01169-5) contains supplementary material, which is available to authorized users.  相似文献   
55.
56.
57.
58.
59.
60.
A total of 872 children aged up to 14 years, who were diagnosed withleukemia in Greece during the decade 1980-89, were allocated by place ofresidence to the 601 administrative districts of the country. Evaluation ofspatial clustering was done using the Potthoff-Whittinghill method, whichvalidly assesses heterogeneity of leukemia risk among districts with variableexpected numbers of cases. There was highly significant evidence for spatialclustering occurring particularly among children living in urban and, to alesser extent, semi-urban areas. The evidence was stronger for childrenyounger than 10 years old, applied also to children in different five-yearage groups, and persisted when cases of acute lymphoblastic leukemia wereanalyzed separately. These findings provide support to the hypothesis thatlocalized environmental exposures could contribute to the etiology ofchildhood leukemia, but they cannot distinguish between exposures of physicalor chemical nature, nor can they exclude socially conditioned patterns ofexposure to infectious agents.  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