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   9107篇
  免费   609篇
  国内免费   328篇
耳鼻咽喉   10篇
儿科学   282篇
妇产科学   38篇
基础医学   1093篇
口腔科学   25篇
临床医学   890篇
内科学   2987篇
皮肤病学   32篇
神经病学   441篇
特种医学   298篇
外国民族医学   2篇
外科学   1213篇
综合类   1033篇
现状与发展   1篇
预防医学   223篇
眼科学   38篇
药学   785篇
  6篇
中国医学   175篇
肿瘤学   472篇
  2024年   17篇
  2023年   129篇
  2022年   253篇
  2021年   322篇
  2020年   275篇
  2019年   285篇
  2018年   241篇
  2017年   243篇
  2016年   304篇
  2015年   303篇
  2014年   460篇
  2013年   538篇
  2012年   408篇
  2011年   485篇
  2010年   430篇
  2009年   428篇
  2008年   413篇
  2007年   432篇
  2006年   431篇
  2005年   373篇
  2004年   365篇
  2003年   305篇
  2002年   273篇
  2001年   231篇
  2000年   207篇
  1999年   172篇
  1998年   158篇
  1997年   157篇
  1996年   168篇
  1995年   131篇
  1994年   130篇
  1993年   94篇
  1992年   99篇
  1991年   83篇
  1990年   84篇
  1989年   65篇
  1988年   71篇
  1987年   55篇
  1986年   51篇
  1985年   87篇
  1984年   55篇
  1983年   34篇
  1982年   43篇
  1981年   35篇
  1980年   31篇
  1979年   23篇
  1978年   20篇
  1977年   16篇
  1976年   9篇
  1975年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
Background and AimsPrimary biliary cholangitis (PBC) and autoimmune hepatitis (AIH) are hepatobiliary diseases of presumed immune-mediated origin that have been shown to overlap. The aim of this retrospective trial was to use national data to examine the characteristics and outcomes of patients hospitalized with overlapping PBC and AIH (PBC/AIH).MethodsThe National Inpatient Sample was used to identify hospitalized adult patients with PBC, AIH, and PBC/AIH from 2010 to 2014 by International Classification of Diseases-Ninth Edition Revision codes; patients with hepatitis B virus and hepatitis C virus infection were excluded. Primary outcomes measures were in-hospital outcomes that included mortality, respiratory failure, septic shock, length of stay, and total hospital charges. Secondary outcomes were the clinical characteristics of PBC/AIH, including the comorbid extrahepatic autoimmune disease pattern and complications of cirrhosis.ResultsA total of 3,478 patients with PBC/AIH were included in the study. PBC/AIH was associated with higher rates of Sjögren’s syndrome (p<0.001; p<0.001), lower rates of Crohn’s disease (p<0.05; p<0.05), and higher rates of cirrhosis-related complications when compared to PBC or AIH alone. There were similar rates of mortality between the PBC/AIH, PBC, and AIH groups. The PBC/AIH group had higher rates of septic shock when compared to the PBC group (p<0.05) and AIH group (p<0.05) after adjusting for possible confounders.ConclusionsPBC/AIH is associated with a lower rate of Crohn’s disease, a higher rate of Sjögren’s syndrome, higher rates of cirrhosis-related complications, and significantly increased risk of septic shock compared to PBC and AIH individually.  相似文献   
972.
Delayed recovery (DR) is very commonly seen in the patients undergoing laparoscopic radical biliary surgery, we aimed to investigate the potential risk factors of DR in the patients undergoing radical biliary surgery, to provide evidences into the management of DR.Patients who underwent radical biliary surgery from January 1, 2018 to August 31, 2020 were identified. The clinical characteristics and treatment details of DR and no-DR patients were compared and analyzed. Multivariable logistic regression analyses were conducted to identify the potential influencing factors for DR in patients with laparoscopic radical biliary surgery.We included a total of 168 patients with laparoscopic radical biliary surgery, the incidence of postoperative DR was 25%. There were significant differences on the duration of surgery, duration of anesthesia, and use of intraoperative combined sevoflurane inhalation (all P < .05), and there were not significant differences on American Society of Anesthesiologists, New York Heart Association, tumor-lymph node- metastasis, and estimated blood loss between DR group and control group (all P > .05). Multivariable logistic regression analyses indicated that age ≥70 years (odd ratio [OR] 1.454, 95% confidence interval [CI] 1.146–1.904), body mass index ≥25 kg/m2 (OR 1.303, 95% CI 1.102–1.912), alcohol drinking (OR 2.041, 95% CI 1.336–3.085), smoking (OR 1.128, 95% CI 1.007–2.261), duration of surgery ≥220 minutes (OR 1.239, 95% CI 1.039–1.735), duration of anesthesia ≥230 minutes (OR 1.223, 95% CI 1.013–1.926), intraoperative combined sevoflurane inhalation (OR 1.207, 95% CI 1.008–1.764) were the independent risk factors for DR in patients with radical biliary surgery (all P < .05).It is clinically necessary to take early countermeasures against various risk factors to reduce the occurrence of DR, and to improve the prognosis of patients.  相似文献   
973.
ObjectivesWe sought to investigate the safety and potential benefit of administrating glycoprotein IIb‐IIIa inhibitors (GPIs) on top of more potent P2Y12 inhibitors.BackgroundA number of clinical trials, performed at a time when pretreatment and potent platelet inhibition was not part of routine clinical practice, have documented clinical benefits of GPI in ST‐segment elevation myocardial infarction (STEMI) patients at the cost of a higher risk of bleeding.MethodsWe used the data of a prospective, ongoing registry of patients admitted for STEMI in our center. For the purpose of this study only patients presenting for primary percutaneous coronary intervention and pretreated with new P2Y12 inhibitors (prasugrel or ticagrelor) were included. We compared patients who received GPI with those who did not.ResultsEight hundred twenty‐four STEMI patients were included in our registry; GPIs were used in 338 patients (41%). GPI patients presented more often with cardiogenic shock and Thrombolysis in myocardial infarction (TIMI) flow grade <3. GPI use was not associated with an increase in in‐hospital or 3‐month mortality. Bleeding endpoints were similar in both groups.ConclusionsOur study suggests that GPI may be used safely in combination with recent P2Y12 inhibitors in STEMI patients in association with modern primary percutaneous coronary intervention strategies (radial access and anticoagulation with enoxaparin) with similar bleeding and mortality rates at hospital discharge and 3‐month follow‐up.  相似文献   
974.
Background: Strain-specific antibodies to human cytomegalovirus (HCMV) glycoproteins B and H (gB and gH) have been proposed as a potential diagnostic tool for identifying reinfection. We investigated genotype-specific IgG antibody responses in parallel with defining the gB and gH genotypes of the infecting viral strains. Methods: Subjects with primary (n = 20) or non-primary (n = 25) HCMV infection were studied. The seven gB (gB1-7) and two gH (gH1-2) genotypes were determined by real-time PCR and whole viral genome sequencing, and genotype-specific IgG antibodies were measured by a peptide-based enzyme-linked immunosorbent assay (ELISA). Results: Among subjects with primary infection, 73% (n = 8) infected by gB1-HCMV and 63% (n = 5) infected by gB2/3-HCMV had genotype-specific IgG antibodies to gB (gB2 and gB3 are similar in the region tested). Peptides from the rarer gB4-gB7 genotypes had nonspecific antibody responses. All subjects infected by gH1-HCMV and 86% (n = 6) infected by gH2-HCMV developed genotype-specific responses. Among women with non-primary infection, gB and gH genotype-specific IgG antibodies were detected in 40% (n = 10) and 80% (n = 20) of subjects, respectively. Conclusions: Peptide-based ELISA is capable of detecting primary genotype-specific IgG responses to HCMV gB and gH, and could be adopted for identifying reinfections. However, about half of the subjects did not have genotype-specific IgG antibodies to gB.  相似文献   
975.
Genetically diverse influenza A viruses (IAVs) circulate in wild aquatic birds. From this reservoir, IAVs sporadically cause outbreaks, epidemics, and pandemics in wild and domestic avians, wild land and sea mammals, horses, canines, felines, swine, humans, and other species. One molecular trait shown to modulate IAV host range is the stability of the hemagglutinin (HA) surface glycoprotein. The HA protein is the major antigen and during virus entry, this trimeric envelope glycoprotein binds sialic acid-containing receptors before being triggered by endosomal low pH to undergo irreversible structural changes that cause membrane fusion. The HA proteins from different IAV isolates can vary in the pH at which HA protein structural changes are triggered, the protein causes membrane fusion, or outside the cell the virion becomes inactivated. HA activation pH values generally range from pH 4.8 to 6.2. Human-adapted HA proteins tend to have relatively stable HA proteins activated at pH 5.5 or below. Here, studies are reviewed that report HA stability values and investigate the biological impact of variations in HA stability on replication, pathogenicity, and transmissibility in experimental animal models. Overall, a stabilized HA protein appears to be necessary for human pandemic potential and should be considered when assessing human pandemic risk.  相似文献   
976.
BACKGROUND: Acute cholangitis in old people is a cause of mortality and prolonged hospital stay. We evaluated the effects of methods and timing of biliary drainage on the outcomes of acute cholangitis in elderly and very elderly patients.METHODS: We analyzed 331 patients who were older than 75 years and were diagnosed with acute calculous cholangitis. They were admitted to our hospital from 2009 to 2014. Patients' demographics, severity grading, methods and timing of biliary drainage, mortality, and hospital stay were retrospectively obtained from medical records. Clinical parameters and outcomes were compared between elderly(75-80 years, n=156) and very elderly(≥81 years, n=175) patients. We analyzed the effects of methods [none, endoscopic retrograde cholangiopancreatography(ERCP), percutaneous transhepatic biliary drainage, or failure] and timing(urgent or early) of biliary drainage on mortality and hospital stay in these patients.RESULTS: Acute cholangitis in older patients manifested as atypical symptoms characterized as infrequent Charcot's triad(4.2%) and comorbidity in one-third of the patients. Patients were graded as mild, moderate, and severe cholangitis in 104(31.4%), 175(52.9%), and 52(15.7%), respectively. Urgent biliary drainage(≤24 hours) was performed for 80.5%(247/307) of patients. Very elderly patients tended to have more severe grades and were treated with sequential procedures of transient biliary drainage and stone removal at different sessions. Hospital stay was related to methods and timing of biliary drainage. Mortality was very low(1.5%) and not related to patient age but rather to the success or failure of biliary drainage and severity grading of the acute cholangitis.CONCLUSIONS: The methods and timing used for biliary drainage and severity of cholangitis are the major determinants of mortality and hospital stay in elderly and very elderly patients with acute cholangitis. Urgent successful ERCP is mandatory for favorable prognosis in these patients.  相似文献   
977.
Background and aimsLow serum albumin (SA) is associated with an increased risk of long-term adverse events (AEs) among patients with chronic coronary syndromes. Its prognostic role in patients with ST-elevation myocardial infarction (STEMI) is less clear. To investigate the association between low SA and in-hospital AEs in STEMI patients.Methods and resultsMulticenter retrospective cohort study of 220 STEMI patients undergoing primary percutaneous coronary intervention within 12 h from the onset of symptoms. Hypoalbuminemia was defined by serum SA <35 g/L. SA. In-hospital AEs were defined as cardiogenic shock, resuscitated cardiac arrest and death. Median SA was 38 (IQR 35.4–41.0) g/L and 37 (16.8%) patients showed hypoalbuminemia (<35 g/L) on admission. Patients with hypoalbuminemia were older, more frequently women and diabetics, prior CAD and HF. Furthermore, they showed lower hemoglobin levels and impaired renal function. At multivariable logistic regression analysis, diabetes (odds ratio [OR]:4.59, 95% confidence interval [CI] 1.71–12.28, p = 0.002) and haemoglobin (OR:0.52, 95%CI 0.37–0.72, p < 0.001) were associated with low SA. In a subgroup of 132 patients, SA inversely correlated with D-Dimer (rS −0.308, p < 0.001). Globally, twenty-eight (14.6%) AEs were recorded. Hypoalbuminemia (OR:3.43, 95%CI 1.30–9.07, p = 0.013), high-sensitive (HS)-Troponin peak above median (OR:5.41, 95%CI 1.99–14.7, p = 0.001), C-reactive protein (CRP) peak above median (OR:6.03, 95%CI 2.02–18.00, p = 0.001), and in-hospital infection (OR:3.61, 95%CI 1.21–10.80, p = 0.022) were associated with AEs.ConclusionLow SA levels are associated with worse in-hospital AEs in STEMI patients, irrespective of HS-troponin and CRP plasma levels. Our findings suggest that low SA may contribute to the pro-thrombotic phenotype of these patients.  相似文献   
978.
AIM:To determine the risk factors of biliary intervention using magnetic resonance cholangiopancreatography(MRCP) after living donor liver transplantation(LDLT).METHODS: We retrospectively enrolled 196 patients who underwent right lobe LDLT between 2006 and 2010 at a single liver transplantation center. Direct duct-to-duct biliary anastomosis was performed in all 196 patients. MRCP images routinely taken 1 mo after LDLT were analyzed to identify risk factors for biliary intervention during follow-up, such as retrograde cholangiopancreatography or percutaneous transhepatic biliary drainage. Two experienced radiologists evaluated the MRCP findings, including the anastomosis site angle on three-dimensional images, the length of the filling defect on maximum intensity projection, bile duct dilatation, biliary stricture, and leakage.RESULTS: Eighty-nine patients underwent biliary intervention during follow-up. The anastomosis site angle [hazard ratio(HR) = 0.48; 95% confidence interval(CI), 0.30-0.75, P 0.001], a filling defect in the anastomosis site(HR = 2.18, 95%CI: 1.41-3.38,P = 0.001), and biliary leakage(HR = 2.52, 95%CI: 1.02-6.20, P = 0.048) on MRCP were identified in the multivariate analysis as significant risk factors for biliary intervention during follow-up. Moreover, a narrower anastomosis site angle(i.e., below the median angle of 113.3°) was associated with earlier biliary intervention(38.5 ± 4.2 mo vs 62. 1 ± 4.1 mo, P 0.001). Kaplan-Meier analysis comparing biliary intervention-free survival according to the anastomosis site angle revealed that lower survival was associated with a narrower anastomosis site angle(36.3% vs 62.0%, P 0.001).CONCLUSION: The biliary anastomosis site angle in MRCP after LDLT may be associated with the need for biliary intervention.  相似文献   
979.
An 84-year-old man was admitted with epigastralgia. Computed tomography showed contrast-enhanced wall thickness in the cystic duct. An endoscopic examination revealed short irregular stricture in the cystic duct, and per-oral cholangioscopy revealed a reddish papillary tumor at the stricture site. Surgical resection revealed high-grade biliary intraepithelial neoplasia (BilIN) at the stricture site of the cystic duct. To our knowledge, this is the first case of a solitary high-grade BilIN epithelium in the cystic duct detected by per-oral cholangioscopy.  相似文献   
980.
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