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   11418篇
  免费   592篇
  国内免费   52篇
耳鼻咽喉   88篇
儿科学   207篇
妇产科学   189篇
基础医学   1874篇
口腔科学   228篇
临床医学   1029篇
内科学   2268篇
皮肤病学   237篇
神经病学   1358篇
特种医学   572篇
外科学   1918篇
综合类   51篇
一般理论   2篇
预防医学   352篇
眼科学   210篇
药学   731篇
中国医学   25篇
肿瘤学   723篇
  2023年   63篇
  2022年   75篇
  2021年   224篇
  2020年   132篇
  2019年   183篇
  2018年   208篇
  2017年   189篇
  2016年   236篇
  2015年   291篇
  2014年   367篇
  2013年   472篇
  2012年   720篇
  2011年   747篇
  2010年   441篇
  2009年   439篇
  2008年   689篇
  2007年   717篇
  2006年   670篇
  2005年   669篇
  2004年   625篇
  2003年   597篇
  2002年   574篇
  2001年   101篇
  2000年   82篇
  1999年   84篇
  1998年   127篇
  1997年   106篇
  1996年   77篇
  1995年   77篇
  1994年   76篇
  1993年   64篇
  1992年   45篇
  1991年   33篇
  1990年   31篇
  1989年   34篇
  1988年   30篇
  1937年   33篇
  1936年   34篇
  1935年   36篇
  1933年   47篇
  1932年   75篇
  1931年   35篇
  1930年   45篇
  1929年   35篇
  1928年   61篇
  1927年   57篇
  1926年   39篇
  1925年   34篇
  1924年   43篇
  1922年   31篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
The comparative in vitro activities of 11 iodonium salt compounds, 0.12% chlorhexidine, and four antimicrobial agents against 322 anaerobic and fastidious potential dental and periodontal bacterial pathogens were studied. Iodonium salts 3, 4, 5, 9, and 10 had in vitro activities comparable to that of chlorhexidine against most isolates. These compounds may be suitable for incorporation into an oral mouthwash.  相似文献   
992.
Congenital mirror movements (CMM) are involuntary movements of one side of the body that mirror intentional movements of the other side. Heterozygous missense, frameshift and nonsense variants and small intragenic deletions in DCC cause CMM, isolated agenesis of the corpus callosum (ACC) or both. We report here the clinical phenotype and natural history of ten individuals with CMM carrying five different monoallelic DCC variants, including the missense variant p.(Trp273Arg), two duplications, one deletion and one deletion-insertion; all are novel and absent from databases. We re-evaluated the 15 known disease-associated DCC missense variants by determining minor allele frequency (MAF) and pathogenicity using four in silico tools combining previous pathogenicity scores and the ACMG/AMP standards and guidelines and classified them in three groups. Group I contains three DCC missense variants that are rather unlikely to be associated with a higher risk to CMM and/or ACC. The five variants in group II may represent susceptibility factors to altered midline crossing in the central nervous system. Group III includes seven variants absent in publically available databases and representing possible pathogenic alleles, with four predicted to have a severe impact on protein function. Based on this data and the variable expressivity and incomplete penetrance present in heterozygous carriers of a DCC variant, classification and clinical interpretation of missense variants is challenging in the absence of evidence of pathogenicity originated from functional studies. Evaluation of missense variants by MAF and a weighted combination of several computational algorithms is recommended.  相似文献   
993.
Congenital disorders of glycosylation (CDG) are genetic defects in the glycoconjugate biosynthesis. > 100 types of CDG are known, most of them cause multi-organ diseases. Here we describe a boy whose leading symptoms comprise cutis laxa, pancreatic insufficiency and hepatosplenomegaly. Whole exome sequencing identified the novel hemizygous mutation c.542 T > G (p.L181R) in the X-linked ATP6AP1, an accessory protein of the mammalian vacuolar H+-ATPase, which led to a general N-glycosylation deficiency. Studies of serum N-glycans revealed reduction of complex sialylated and appearance of truncated diantennary structures. Proliferation of the patient's fibroblasts was significantly reduced and doubling time prolonged. Additionally, there were alterations in the fibroblasts' amino acid levels and the acylcarnitine composition. Especially, short-chain species were reduced, whereas several medium- to long-chain acylcarnitines (C14-OH to C18) were elevated. Investigation of the main lipid classes revealed that total cholesterol was significantly enriched in the patient's fibroblasts at the expense of phophatidylcholine and phosphatidylethanolamine. Within the minor lipid species, hexosylceramide was reduced, while its immediate precursor ceramide was increased. Since catalase activity and ACOX3 expression in peroxisomes were reduced, we assume an ATP6AP1-dependent impact on the β-oxidation of fatty acids. These results help to understand the complex clinical characteristics of this new patient.  相似文献   
994.
Approximately 10-20% of patients will not tolerate cross-clamping of the common carotid artery for carotid endarterectomy procedures. The most frequent causes of neurological deficits are either embolization of particulate matter or cerebral hypoperfusion. Insufficient blood flow through primary collaterals of the circle of Willis is the main reason for hypoperfusion that requires immediate shunt placement. Although excessive preoperative imaging is not indicated in many patients undergoing disobliteration of a stenosed internal carotid artery, there are some patients with particular anatomic constellations who would benefit from a more detailed preoperative work-up. In these cases, the specific risk should be evaluated prior to surgery in order to make plans for appropriate intraoperative management regarding neurologic monitoring and shunt insertion. As regional anesthesia permits early detection of ischemic symptoms, it is advantageous in these patients. We report a case where regional anesthesia allowed early detection of rapidly progressing signs of bi-hemispheric brain ischemia in a patient with diabetes and with at that time unknown severe abnormalities of the circle of Willis. Lack of adequate collateralization was detected only after surgery, in a combined perfusion-magnetic resonance imaging study. In symptomatic diabetics with low-grade stenosis of the internal carotid artery, preoperative assessment of the function of the circle of Willis may therefore be helpful in predicting any increased risk for intraoperative cerebral ischemia.  相似文献   
995.
Summary Thrombocyte glycoprotein IIb/IIIa inhibitors prevent fibrinogen binding and thereby thrombocyte aggregation. The inhibition of thrombocyte activation at the damaged coronary plaque is the target of the new therapeutic strategies in treating acute coronary syndrome. This reduces the ischemic complications associated with the non-STelevation myocardial infarction (NSTEMI) and percutaneous coronary intervention (PCI). Thrombocytopenia is a known complication of glycoprotein (GP) IIb/IIIa inhibitors. Although, in general, GP IIb/IIIa inhibitor-induced thrombocytopenia is a harmless side effect which responds readily to thrombocyte transfusion, it can occasionally be a very serious complication associated with serious bleeding. In addition patients developing thrombocytopenia have unfavorable outcome (e.g., death, myocardial infarction, bypass surgery or additional PCI) in comparison to patients without thrombocytopenia. Advanced age (> 65 years), low BMI and a low initial thrombocyte count (<180 000/μl) are independent risk factors of thrombocytopenia. The risk of bleeding is higher with this form of thrombocytopenia not only due to the low thrombocyte count but also to the impaired function of the remaining thrombocytes. It is important to closely monitor platelet count during GP IIb/IIIa antagonist treatment. Platelet count monitoring two, six, twelve and 24 hour after starting the treatment reveals most cases of acute thrombocytopenia. Side effects can be avoided by the early discontinuation of the GP IIb/IIIa antagonist treatment. This article reviews the diagnosis and treatment of glycoprotein IIb/IIIa inhibitor-induced thrombocytopenia and summarizes the differential diagnosis from heparin-induced thrombocytopenia and laboratory-related pseudothrombocytopenia.  相似文献   
996.
997.

Objective

The overall therapeutic goal of venoarterial extracorporeal membrane oxygenation (ECMO) in patients with postcardiotomy shock is bridging to myocardial recovery. However, in patients with irreversible myocardial damage prolonged ECMO treatment would cause a delay or even withholding of further permanent potentially life-saving therapeutic options. We therefore assessed the prognostic effect of duration of ECMO support on survival in adult patients after cardiovascular surgery.

Methods

We enrolled into our single-center registry a total of 354 patients who underwent venoarterial ECMO support after cardiovascular surgery at a university-affiliated tertiary care center.

Results

Through a median follow-up period of 45 months (interquartile range, 20-81 months), 245 patients (69%) died. We observed an increase in mortality with increasing duration of ECMO support. The association between increased duration of ECMO support and mortality persisted in patients who survived ECMO support with a crude hazard ratio of 1.96 (95% confidence interval, 1.40-2.74; P < .001) for 2-year mortality compared with the third tertile and the second tertile of ECMO duration. This effect was even more pronounced after multivariate adjustment using a bootstrap-selected confounder model with an adjusted hazard ratio of 2.30 (95% confidence interval, 1.52-3.48; P < .001) for 2-year long-term mortality.

Conclusions

Prolonged venoarterial ECMO support is associated with poor outcome in adult patients after cardiovascular surgery. Our data suggest reevaluation of therapeutic strategies after 7 days of ECMO support because mortality disproportionally increases afterward.  相似文献   
998.
Background: Up to now, little is known about higher order cognitive abilities like social cognition and social problem solving abilities in alcohol-dependent patients. However, impairments in these domains lead to an increased probability for relapse and are thus highly relevant in treatment contexts. Method: This cross-sectional study assessed distinct aspects of social cognition and social problem solving in 31 hospitalized patients with alcohol use disorder (AUD) and 30 matched healthy controls (HC). Three ecologically valid scenario-based tests were used to gauge the ability to infer the mental state of story characters in complicated interpersonal situations, the capacity to select the best problem solving strategy among other less optimal alternatives, and the ability to freely generate appropriate strategies to handle difficult interpersonal conflicts. Standardized tests were used to assess executive function, attention, trait empathy, and memory, and correlations were computed between measures of executive function, attention, trait empathy, and tests of social problem solving. Results: AUD patients generated significantly fewer socially sensitive and practically effective solutions for problematic interpersonal situations than the HC group. Furthermore, patients performed significantly worse when asked to select the best alternative among a list of presented alternatives for scenarios containing sarcastic remarks and had significantly more problems to interpret sarcastic remarks in difficult interpersonal situations.

Conclusions: These specific patterns of impairments should be considered in treatment programs addressing impaired social skills in individuals with AUD.  相似文献   

999.
1000.
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