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   118551篇
  免费   7156篇
  国内免费   690篇
耳鼻咽喉   1122篇
儿科学   3791篇
妇产科学   2758篇
基础医学   17256篇
口腔科学   4360篇
临床医学   10628篇
内科学   26835篇
皮肤病学   2973篇
神经病学   11628篇
特种医学   2775篇
外国民族医学   3篇
外科学   10704篇
综合类   445篇
一般理论   52篇
预防医学   11779篇
眼科学   2030篇
药学   8401篇
中国医学   494篇
肿瘤学   8363篇
  2024年   90篇
  2023年   1029篇
  2022年   1963篇
  2021年   3996篇
  2020年   2506篇
  2019年   3404篇
  2018年   3917篇
  2017年   2910篇
  2016年   3421篇
  2015年   3809篇
  2014年   4992篇
  2013年   6492篇
  2012年   9872篇
  2011年   10282篇
  2010年   5556篇
  2009年   4728篇
  2008年   8152篇
  2007年   8215篇
  2006年   7527篇
  2005年   6978篇
  2004年   6246篇
  2003年   5643篇
  2002年   5074篇
  2001年   771篇
  2000年   575篇
  1999年   759篇
  1998年   899篇
  1997年   727篇
  1996年   626篇
  1995年   512篇
  1994年   486篇
  1993年   416篇
  1992年   402篇
  1991年   271篇
  1990年   270篇
  1989年   266篇
  1988年   236篇
  1987年   199篇
  1986年   227篇
  1985年   164篇
  1984年   184篇
  1983年   163篇
  1982年   180篇
  1981年   148篇
  1980年   151篇
  1979年   102篇
  1978年   96篇
  1977年   84篇
  1976年   72篇
  1974年   76篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
PurposeTo compare the clinical presentation, treatment receipt, and oncologic outcomes between human immunodeficiency virus-seropositive (HIV+) and seronegative (HIV?) men with prostate cancer (CaP) matched by age, clinical stage, and race.Materials and methodsA retrospective review of 3,135 men treated for CaP from 2000 to 2016 was performed. HIV+ patients (N = 46) were matched 1:2 to 3 to HIV? men (N = 137) by age, race, and clinical stage. Clinicopathologic features and primary treatment received were compared between cohorts. Associations between HIV status and progression-free, cancer-specific, and overall survival were compared by HIV status using the Kaplan-Meier method and Cox proportional hazards analysis.ResultsAfter matching, men with and without HIV were similar with respect initial prostate-specific antigen, Gleason Sum, and Eastern Cooperative Oncology Group (ECOG) performance status. Among HIV+ men, 67.4% had a history of acquired immune deficiency syndrome, and 91.3% were on highly active antiretroviral therapy at CaP diagnosis. Among men with localized disease, HIV+ men were more likely to receive radiation (59.5% vs. 44.8%) or no therapy (13.5% vs. 4.3%) and less likely to receive surgery (16.2% vs. 30.2%), or to initiate active surveillance (10.8% vs. 16.4%; P = 0.04 overall). There were no differences in rates of clinical progression, development of castration resistance, or CaP death by HIV status. However, HIV+ status was associated with inferior overall survival (hazard ratio 2.89, P = 0.04).ConclusionsWhile most HIV+ patients had a history of acquired immune deficiency syndrome; HIV was well controlled in the majority of patients at the time of CaP diagnosis. While oncologic outcomes were similar between HIV+ and HIV? men, significant differences in treatment selection were observed. Further research is necessary to understand differences in treatment election by HIV status and to define optimal CaP treatment selection in men with HIV.  相似文献   
992.
ObjectiveTo identify in which cases after cytological diagnosis, the Bladder EpiCheck test could represent an effective tool in non-muscle invasive bladder carcinoma or an useless expence.Materials and methods375 patients diagnosed with non-muscle invasive bladder cancer, 269 with high grade urothelial carcinoma and 106 with carcinoma in situ, were treated and followed for 1 year. The treatment was an intravesical instillation of Bacillus Calmette-Guerin in 305 patients and Mitomycin-C in 70 patients.During the follow-up patients were evaluated by voided urine cytology and white-light cystoscopy, according to the European Association of Urology Guidelines. Bladder EpiCheck test was performed together with cytology in all cases.ResultsAnalyzing Bladder Epicheck results for each category defined by the Paris System for Reporting Urinary Cytology, we found that the Episcore >60 correlates with histological diagnosis of high grade urothelial carcinoma (HGUC) in atypical urothelial cells and Suspicious for High Grade Urothelial Carcinoma (P = 0.0002 Odds Ratio 0.05926 95% Confidence Interval from 0.01127 to 0.3116 and P = 0.0009 Odds Ratio 0.0315595% Confidence Interval from 0.001683 to 0.5914, Fisher's exact test, respectively), while in Negative for high grade urothelial carcinoma and HGUC patients Episcore is not helpful to identify cases with histological diagnosis of HGUC (P = 0.101 and P = 0.58 Fisher's exact test, respectively). Considering an Episcore ≥ 90 in the HGUC cytological group, this seems not to be correlated with a histological diagnosis of HGUC (P = 0.090 Fisher's exact test).ConclusionsCytology and Bladder EpiCheck test in combination may have the potential to reduce cystoscopies in the follow-up of non-muscle invasive bladder cancer only for cytological diagnoses of atypical urothelial cells and Suspicious for High Grade Urothelial Carcinoma . Moreover, in patients with a cytological diagnosis of Negative for high grade urothelial carcinoma or HGUC, cytology alone seems to be safe and cost-effective.  相似文献   
993.
Objective: Intravesical Bacillus Calmette-Guèrin (BCG) is an effective treatment in non––muscle-invasive bladder cancer, however, extravesical BCG infection may occur in remote organs as a potentially serious complication. Researchers aimed to assess whether a different timing of BCG infection after intravesical administration of BCG could be identified and estimated for each single involved organ. Methods: We performed a systematic literature review over systemic and genitourinary BCG infection case reports, including 271 published case reports for a total of 307 patients. Demographic data, clinical features, and timing of BCG infection development were collected and analyzed for each patient. Results: BCG infection developed with a different timing from last instillation, depending on the involved organ. Among the genitourinary complications, penile lesions occurred as early as 1 (1;3) weeks, while orchiepididymitis occurred as late as 56 (6.25;156) weeks. At the same time, granulomatous hepatitis and lungs involvement such as miliary pulmonary BCG infection occurred earlier, with a median time of 1 (1;4) and 1 (1;6) weeks respectively, whereas vascular, osteoarticular, and muscular complications developed with a median timing from last instillation of 52 (20;104), 68 (14;156), and 93 (29;156) weeks, respectively. The analysis detected a cluster between lungs, liver, and bone marrow complications on one side and muscular and osteoarticular or vascular complications on the other side was also observed. Conclusions: BCG infection after intravesical BCG for bladder cancer may develop even several months or years after the last instillation, depending on the involved organs. When BCG infection interests one or more organ, 2 main associative patterns are common: one involving lungs, liver, and bone marrow, with earlier occurrence but lower rates of microbiological diagnosis achievement, and one involving muscular and osteoarticular or vascular districts, with later occurrence but higher rates of microbiological evidence.  相似文献   
994.
Background: The prompt identification of patients with poor prognosis is essential in order to improve the treatment outcomes in prostate cancer (CaP); as a novel approach, several molecular markers, including integrins, have been discussed as prognostic biomarkers. Our aim was to comprehensively examine aberrant expression of integrins in correlation with clinicopathological features and prognosis in CaP by synthesizing all available evidence, in a systematic review and meta-analysis. Methods: A systematic review and meta-analysis was performed in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. Scientific literature databases (Pubmed, Embase, and Scopus) were systematically searched until May 10, 2020. Random-effects (DerSimonian-Laird) models were used to estimate pooled odds ratios (ORs) for cross-sectional correlations with clinicopathological characteristics and relative risks for longitudinal associations with prognosis. Results: Fourteen studies were included with a total number of 3,194 CaP cases examined (13 cross-sectional and four longitudinal cohort study arms). Correlation of low expression of α6 (pooled OR = 0.10, 95% confidence interval [CI]: 0.04–0.28, P < 0.001) and β1 (pooled OR = 0.45; 95% CI: 0.21–1.00, P = 0.049) integrin with high Gleason score was noted. A borderline trend between reduced expression of α6 integrin and an advanced clinical stage of CaP (pooled OR = 0.48; 95% CI: 0.22-1.03, P = 0.06) was observed. No associations with biochemical recurrence and survival were documented. Conclusions: Evidence on the association of low expression of integrins α6 and β1 and more advanced CaP exist, whereas significant results on survival were not documented; further studies are warranted.  相似文献   
995.
996.
997.
Background ContextSmartphone-based applications enable new prospects to monitor symptoms and assess functional outcome in patients with lumbar degenerative spinal disorders. However, little is known regarding patient acceptance and preference towards new modes of digital objective outcome assessment.PurposeTo assess patient preference of an objective smartphone-based outcome measure compared to conventional paper-based subjective methods of outcome assessment.Study designProspective observational cohort study.Patient sampleFourty-nine consecutive patients undergoing surgery for lumbar degenerative spinal disorder.Outcome measuresPatients completed a preference survey to assess different methods of outcome assessment. A 5-level Likert scale ranged from strong disagreement (2 points) over neutral (6 points) to strong agreement (10 points) was used.MethodsPatients self-determined their objective functional impairment using the 6-minute Walking Test application (6WT-app) and completed a set of paper-based patient-reported outcome measures (PROMs) before and 6 weeks after surgery. Patients were then asked to rate the methods of outcome assessment in terms of suitability, convenience, and responsiveness to their symptoms.ResultsThe majority of patients considered the 6WT-app a suitable instrument (median 8.0, interquartile range [IQR] 4.0). Patients found the 6WT more convenient (median 10.0, IQR 2.0) than the Zurich Claudication Questionnaire (ZCQ; median 8.0, IQR 4.0, p=.019) and Core Outcome Measure Index (COMI; median 8.0, IQR 4.0, p=.007). There was good agreement that the 6WT-app detects change in physical performance (8.0, IQR 4.0). 78 % of patients considered the 6WT superior in detecting differences in symptoms (vs. 22% for PROMs). Seventy-six percent of patients would select the 6WT over the other, 18% the ZCQ and 6% the COMI. Eighty-two percent of patients indicated their preference to use a smartphone app for the assessment and monitoring of their spine-related symptoms in the future.ConclusionsPatients included in this study favored the smartphone-based evaluation of objective functional impairment over paper-based PROMs. Involving patients more actively by means of digital technology may increase patient compliance and satisfaction as well as diagnostic accuracy.  相似文献   
998.
BackgroundBariatric surgery is currently the most effective long-term treatment for severe obesity. However, interindividual variation in surgery outcome has been observed, and research suggests a moderating effect of several factors including baseline co-morbidities (e.g., type 2 diabetes [T2D] and genetic factors). No data are currently available on the interaction between T2D and variants in brain derived neurotrophic factor (BDNF) and its effect on weight loss after surgery.ObjectivesTo examine the role of the BDNF Val66Met polymorphism (rs6265) and the influence of T2D and their interaction on weight loss after bariatric surgery in a cohort of patients with severe obesity.SettingUniversity hospital in Spain.MethodsThe present study evaluated a cohort of 158 patients with obesity submitted to bariatric surgery (Roux-en-Y gastric bypass or sleeve gastrectomy) followed up for 24 months (loss to follow-up: 0%). During the postoperative period, percentage of excess body mass index loss (%EBMIL), percentage of excess weight loss (%EWL), and total weight loss (%TWL) were evaluated.ResultsLongitudinal analyses showed a suggestive effect of BDNF genotype on the %EWL (P = .056) and indicated that individuals carrying the methionine (Met) allele may experience a better outcome after bariatric surgery than those with the valine/valine (Val/Val) genotype. We found a negative effect of a T2D diagnosis at baseline on %EBMIL (P = .004). Additionally, we found an interaction between BDNF genotype and T2D on %EWL and %EBMIL (P = .027 and P = .0004, respectively), whereby individuals with the Met allele without T2D displayed a greater %EWL and greater %EBMIL at 12 months and 24 months than their counterparts with T2D or patients with the Val/Val genotype with or without T2D.ConclusionOur data showed an association between the Met variant and greater weight loss after bariatric surgery in patients without T2D. The presence of T2D seems to counteract this positive effect.  相似文献   
999.
Kidneys from donation after circulatory death (DCD) donors are utilized variably worldwide, in part due to high rates of delayed graft function (DGF) and putative associations with adverse longer-term outcomes. We aimed to determine whether the presence of DGF and its duration were associated with poor longer-term outcomes after kidney transplantation from DCD donors. Using the UK transplant registry, we identified 4714 kidney-only transplants from controlled DCD donors to adult recipients between 2006 and 2016; 2832 recipients (60·1%) had immediate graft function and 1882 (39·9%) had DGF. Of the 1847 recipients with DGF duration recorded, 926 (50·1%) had DGF < 7 days, 576 (31·2%) had DGF 7–14 days, and 345 (18·7%) had DGF >14 days. After risk adjustment, the presence of DGF was not associated with inferior long-term graft or patient survivals. However, DGF duration of >14 days was associated with an increased risk of death-censored graft failure (hazard ratio 1·7, p = ·001) and recipient death (hazard ratio 1·8, p < ·001) compared to grafts with immediate function. This study suggests that shorter periods of DGF have no adverse influence on graft or patient survival after DCD donor kidney transplantation and that DGF >14 days is a novel early biomarker for significantly worse longer-term outcomes.  相似文献   
1000.
Aránzazu Caballero-Marcos  Magdalena Salcedo  Roberto Alonso-Fernández  Manuel Rodríguez-Perálvarez  María Olmedo  Javier Graus Morales  Valentín Cuervas-Mons  Alba Cachero  Carmelo Loinaz-Segurola  Mercedes Iñarrairaegui  Lluís Castells  Sonia Pascual  Carmen Vinaixa-Aunés  Rocío González-Grande  Alejandra Otero  Santiago Tomé  Javier Tejedor-Tejada  José María Álamo-Martínez  Luisa González-Diéguez  Flor Nogueras-Lopez  Gerardo Blanco-Fernández  Gema Muñoz-Bartolo  Francisco Javier Bustamante  Emilio Fábrega  Mario Romero-Cristóbal  Rosa Martin-Mateos  Julia Del Rio-Izquierdo  Ana Arias-Milla  Laura Calatayud  Alberto A. Marcacuzco-Quinto  Víctor Fernández-Alonso  Concepción Gómez-Gavara  Jordi Colmenero  Patricia Muñoz  José A. Pons  the Spanish Society of Liver Transplantation 《American journal of transplantation》2021,21(8):2876-2884
The protective capacity and duration of humoral immunity after SARS-CoV-2 infection are not yet understood in solid organ transplant recipients. A prospective multicenter study was performed to evaluate the persistence of anti-nucleocapsid IgG antibodies in liver transplant recipients 6 months after coronavirus disease 2019 (COVID-19) resolution. A total of 71 liver transplant recipients were matched with 71 immunocompetent controls by a propensity score including variables with a well-known prognostic impact in COVID-19. Paired case–control serological data were also available in 62 liver transplant patients and 62 controls at month 3 after COVID-19. Liver transplant recipients showed a lower incidence of anti-nucleocapsid IgG antibodies at 3 months (77.4% vs. 100%, < .001) and at 6 months (63.4% vs. 90.1%, < .001). Lower levels of antibodies were also observed in liver transplant patients at 3 (= .001) and 6 months (< .001) after COVID-19. In transplant patients, female gender (OR = 13.49, 95% CI: 2.17–83.8), a longer interval since transplantation (OR = 1.19, 95% CI: 1.03–1.36), and therapy with renin–angiotensin–aldosterone system inhibitors (OR = 7.11, 95% CI: 1.47–34.50) were independently associated with persistence of antibodies beyond 6 months after COVID-19. Therefore, as compared with immunocompetent patients, liver transplant recipients show a lower prevalence of anti-SARS-CoV-2 antibodies and more pronounced antibody levels decline.  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