全文获取类型
| 收费全文 | 1439288篇 |
| 免费 | 107214篇 |
| 国内免费 | 4643篇 |
专业分类
| 耳鼻咽喉 | 18177篇 |
| 儿科学 | 46266篇 |
| 妇产科学 | 38013篇 |
| 基础医学 | 210965篇 |
| 口腔科学 | 38019篇 |
| 临床医学 | 140261篇 |
| 内科学 | 279914篇 |
| 皮肤病学 | 27917篇 |
| 神经病学 | 122087篇 |
| 特种医学 | 51644篇 |
| 外国民族医学 | 370篇 |
| 外科学 | 198848篇 |
| 综合类 | 30508篇 |
| 现状与发展 | 2篇 |
| 一般理论 | 615篇 |
| 预防医学 | 123895篇 |
| 眼科学 | 31487篇 |
| 药学 | 106156篇 |
| 36篇 | |
| 中国医学 | 3354篇 |
| 肿瘤学 | 82611篇 |
出版年
| 2021年 | 12861篇 |
| 2019年 | 13295篇 |
| 2018年 | 18230篇 |
| 2017年 | 13747篇 |
| 2016年 | 14874篇 |
| 2015年 | 17188篇 |
| 2014年 | 23663篇 |
| 2013年 | 36482篇 |
| 2012年 | 50488篇 |
| 2011年 | 53592篇 |
| 2010年 | 30900篇 |
| 2009年 | 28635篇 |
| 2008年 | 49127篇 |
| 2007年 | 52061篇 |
| 2006年 | 52027篇 |
| 2005年 | 50688篇 |
| 2004年 | 48295篇 |
| 2003年 | 46065篇 |
| 2002年 | 44480篇 |
| 2001年 | 61822篇 |
| 2000年 | 63320篇 |
| 1999年 | 53291篇 |
| 1998年 | 16000篇 |
| 1997年 | 14418篇 |
| 1996年 | 14042篇 |
| 1995年 | 13391篇 |
| 1994年 | 12412篇 |
| 1993年 | 11675篇 |
| 1992年 | 42189篇 |
| 1991年 | 41317篇 |
| 1990年 | 39966篇 |
| 1989年 | 37856篇 |
| 1988年 | 35059篇 |
| 1987年 | 34153篇 |
| 1986年 | 32599篇 |
| 1985年 | 31195篇 |
| 1984年 | 23714篇 |
| 1983年 | 20257篇 |
| 1982年 | 12680篇 |
| 1981年 | 11144篇 |
| 1979年 | 21179篇 |
| 1978年 | 15302篇 |
| 1977年 | 12515篇 |
| 1976年 | 12231篇 |
| 1975年 | 12448篇 |
| 1974年 | 15112篇 |
| 1973年 | 14715篇 |
| 1972年 | 13538篇 |
| 1971年 | 12536篇 |
| 1970年 | 11609篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
61.
Partha Sardar Deepak L. Bhatt Ajay J. Kirtane Kevin F. Kennedy Saurav Chatterjee Jay Giri Peter A. Soukas William B. White Sahil A. Parikh Herbert D. Aronow 《Journal of the American College of Cardiology》2019,73(13):1633-1642
Background
There are conflicting data regarding the relative effectiveness of renal sympathetic denervation (RSD) in patients with hypertension.Objectives
The purpose of this study was to evaluate the blood pressure (BP) response after RSD in sham-controlled randomized trials.Methods
Databases were searched through June 30, 2018. Randomized trials (RCTs) with ≥50 patients comparing catheter-based RSD with a sham control were included. The authors calculated summary treatment estimates as weighted mean differences (WMD) with 95% confidence intervals (CIs) using random-effects meta-analysis.Results
The analysis included 977 patients from 6 trials. The reduction in 24-h ambulatory systolic blood pressure (ASBP) was significantly greater for patients treated with RSD than sham procedure (WMD ?3.65 mm Hg, 95% CI: ?5.33 to ?1.98; p < 0.001). Compared with sham, RSD was also associated with a significant decrease in daytime ASBP (WMD ?4.07 mm Hg, 95% CI: ?6.46 to ?1.68; p < 0.001), office systolic BP (WMD ?5.53 mm Hg, 95% CI: ?8.18 to ?2.87; p < 0.001), 24-h ambulatory diastolic BP (WMD ?1.71 mm Hg, 95% CI: ?3.06 to ?0.35; p = 0.01), daytime ambulatory diastolic BP (WMD ?1.57 mm Hg, 95% CI: ?2.73 to ?0.42; p = 0.008), and office diastolic BP (WMD ?3.37 mm Hg, 95% CI: ?4.86 to ?1.88; p < 0.001). Compared with first-generation trials, a significantly greater reduction in daytime ASBP was observed with RSD in second-generation trials (6.12 mm Hg vs. 2.14 mm Hg; p interaction = 0.04); however, this interaction was not significant for 24-h ASBP (4.85 mm Hg vs. 2.23 mm Hg; p interaction = 0.13).Conclusions
RSD significantly reduced blood pressure compared with sham control. Results of this meta-analysis should inform the design of larger, pivotal trials to evaluate the long-term efficacy and safety of RSD in patients with hypertension. 相似文献62.
Hanna Lee Mary K. Tan Andrew T. Yan Paul Angaran Paul Dorian Claudia Bucci Jean C. Gregoire Alan D. Bell Martin S. Green Peter L. Gross Allan Skanes Charles R. Kerr L. Brent Mitchell Jafna L. Cox Vidal Essebag Brett Heilbron Krishnan Ramanathan Carl Fournier Shaun G. Goodman 《The Canadian journal of cardiology》2019,35(2):160-168
Background
Physicians treating nonvalvular atrial fibrillation (AF) assess stroke and bleeding risks when deciding on anticoagulation. The agreement between empirical and physician-estimated risks is unclear. Furthermore, the association between patient and physician sex and anticoagulation decision-making is uncertain.Methods
We pooled data from 2 national primary care physician chart audit databases of patients with AF (Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation and Coordinated National Network to Engage Physicians in the Care and Treatment of Patients with Atrial Fibrillation Chart Audit) with a combined 1035 physicians (133 female, 902 male) and 10,927 patients (4567 female and 6360 male).Results
Male physicians underestimated stroke risk in female patients and overestimated risk in male patients. Female physicians estimated stroke risk well in female patients but underestimated the risk in male patients. Risk of bleeding was underestimated in all. Despite differences in risk assessment by physician and patient sex, > 90% of patients received anticoagulation across all subgroups. There was modest agreement between physician estimated and calculated (ie, CHADS2 score) stroke risk: Kappa scores were 0.41 (0.35-0.47) for female physicians and 0.34 (0.32-0.36) for male physicians.Conclusions
Our study is the first to examine the association between patient and physician sex influences and stroke and bleeding risk estimation in AF. Although there were differences in agreement between physician estimated stroke risk and calculated CHADS2 scores, these differences were small and unlikely to affect clinical practice; further, despite any perceived differences in the accuracy of risk assessment by sex, most patients received anticoagulation. 相似文献63.
Kyle L. Thompson Mei Chung Deepa Handu Melissa Gutschall Sarah T. Jewell Laura Byham-Gray J. Scott Parrott 《Journal of the Academy of Nutrition and Dietetics》2019,119(5):799-817.e43
Background
Nutrition specialists are considered key members of multicomponent pediatric weight management intervention teams, but to date, their contribution has not been quantified.Objective
The purpose of this systematic review was to estimate the effectiveness of interventions provided by treatment teams that include a nutrition specialist on pediatric weight management outcomes, including body mass index (BMI), BMI z score, and waist circumference when compared with treatment teams that do not include a nutrition specialist.Methods
The results of a comprehensive literature search and a systematic and more targeted update of that search were included in the meta-analyses: a search of controlled trials published between July 2005 and April 2012, conducted during the 2015 Pediatric Weight Management Update Project of the Academy of Nutrition and Dietetics Evidence Analysis Library, and an update search of controlled trials published between May 2012 and December 2015 focusing on a more specific topic within the previous search. Studies included overweight and/or obese patients aged 6 to 18 years receiving outpatient weight management treatment. Data extraction of all studies identified was performed using a standardized tool. The resulting data from the search and the systematic update were merged. Ninety-nine studies and 209 study arms were included in the analysis. An exploratory meta-analysis using alternative meta-analytic methods designed for complex, heterogenous interventions was conducted to identify relative contributions by intervention provider category at selected time points. Meta-regression analyses were used to evaluate significant differences from the reference category for each provider category.Results
The nutrition specialist-only condition resulted in increased reductions in BMI z score compared with behavioralist-only, combined nutrition specialist and behavioralist, and neither nutrition specialist or behavioralist category (reference) throughout the analysis. Meta-regression analysis indicated that the difference in BMI z score between the nutrition specialist-only category and the reference category was significant at 3 to <6 months, 6 months to <1 year, and 1-year to 2-year time points (P=0.01, P=0.05, and P=0.01, respectively). There were smaller increases in BMI over time for the nutrition specialist-only provider category compared with reference categories, and this difference was significant at the 3 to <6 months and 1-year to 2-years time points (P=0.001 and P=0.05, respectively). There were no significant differences among provider categories for waist circumference at any time point.Conclusions
Indirect evidence indicated that pediatric weight management outcomes for BMI z score and BMI at selected time points appeared to be better when a nutrition specialist was involved in delivering care. 相似文献64.
M. Tobias Heinrichs George L. Drusano David L. Brown Michael S. Maynard Sherwin K.B. Sy Kenneth H. Rand Charles A. Peloquin Arnold Louie Hartmut Derendorf 《International journal of antimicrobial agents》2019,53(3):275-283
Introduction
There is an urgent need for new anti-tuberculosis (TB) drugs and optimization of current TB treatment. Moxifloxacin and linezolid are valuable options for the treatment of drug-resistant TB; however, it is crucial to find a dose at which these drugs not only show high efficacy but also suppress the development of further drug resistance.Methods
Activity of moxifloxacin and linezolid against Mycobacterium tuberculosis was studied in the hollow-fiber infection model system in log-phase growth under neutral pH and slow growth in an acidic environment. Doses that achieved maximum bacterial kill while suppressing the emergence of drug resistance were determined. Through Monte Carlo simulations the quantitative output of this in vitro study was bridged to the human patient population to inform optimal dosage regimens while accounting for clinical minimum inhibitory concentration (MIC) distributions.Results and Discussion
Moxifloxacin activity was significantly decreased in an acidified environment. The loss of activity was compensated by accumulation of the drug in TB lung lesions; therefore, moderate efficacy can be expected. Moxifloxacin 800 mg/day is the dose that most likely leads to resistance suppression while exerting maximum bacterial kill. Linezolid demonstrated very good activity even at a reduced pH. Linezolid 900 mg once-daily (QD) is likely to achieve a maximum killing effect and prevent the emergence of drug resistance; 600 mg QD in a robust drug regimen may have similar potential. 相似文献65.
Background and purpose — No difference in outcome has been demonstrated comparing cemented taper-slip and composite beam designs in short-term randomised trials; we assessed outcome differences using a registry analysis.
Patients and methods — All cemented stems with > 100 implantations were identified in the National Joint Registry of England and Wales from April 1, 2003 to September 31, 2013 and categorised as taper-slip or composite beam. Survival analyses using Kaplan–Meier and Cox regression were performed.
Results — We identified 292,987 cemented arthroplasties, of which 16% (47,586) were composite beam stems, with taper-slip stems making up the remainder (n = 245,401). There was a statistically significant increased chance of revision in the composite beam group compared with the taper-slip group (1.7% vs 1.3%, p < 0.001) but statistically no significant differences of survival estimates (p = 0.06). When the 2 groups were segregated to delineate the most implanted model in each category, the differences became more profound with the most implanted taper-slip stem (Exeter V40) showing statistically and clinically significant superior 8-year survival: 97.9% compared with 97.6% for all other taper-slip; 97.5% for the most implanted composite beam (Charnley cemented stem); and 97.7% for all other composite beam.
Interpretation — There was an increased incidence of revision for composite beam stems. The most implanted taper-slip stem demonstrated significant survival advantage vs. all other stems. 相似文献
66.
V. Jenkins I. Solis-Trapala H. Payne M. Mason L. Fallowfield S. May L. Matthews S. Catt 《Clinical oncology (Royal College of Radiologists (Great Britain))》2019,31(2):99-107
Aims
Delaying progression, ameliorating symptoms and maintaining quality of life (QoL) are primary aims of treatment for metastatic castrate-resistant prostate cancer (mCRPC). Real-world rather than clinical trial data about symptoms and side-effects are sparse. In EXTREQOL, patients' QoL, pain and information needs were recorded during treatment.Material and methods
Men with mCRPC from 20 UK cancer centres starting various systemic mCRPC treatments completed QoL, pain and information needs questionnaires at baseline, 3 and 6 months.Results
In total, 132 patients were recruited. Overall QoL declined significantly by 6 months (Functional Assessment of Cancer Therapy-Prostate [FACT-P] mean = –3.89, 95% confidence interval –6.7 to –1.05, P = 0.007; Trial Outcome Index [TOI] analysis mean = –3.10, 95% confidence interval –5.34 to –0.83, P = 0.007). Those who came off novel therapy and remained on luteinising hormone-releasing hormone agonist therapy alone had worse scores than patients receiving concomitant chemotherapy (Prostate Concerns Subscale mean difference = –4.45, 95% confidence interval –7.06 to –1.83, P = 0.001; TOI mean difference = –5.62, 95% confidence interval –10.97 to –0.26, P = 0.040). At 3 and 6 months, men who reported pain at baseline improved (43%, 40%), but for others pain levels remained the same (45%, 42%) or worsened (13%, 18%). Information regarding supportive care was lacking throughout the period of time on the study.Conclusion
Most mCRPC treated patients experience reduced QoL and inadequate pain control. More help with pain management and better information provision regarding supportive care is warranted. 相似文献67.
Megan L. Robbins Robert C. Wright Ana María López Karen Weihs 《Journal of psychosocial oncology》2019,37(2):160-177
AbstractObjectives: This study examined word use as an indicator of interpersonal positive reframing in daily conversations of couples coping with breast cancer and as a predictor of stress.Design: The Electronically Activated Recorder (EAR) and Linguistic Inquiry and Word Count (LIWC) were used to examine naturally occurring word use conceptually linked to positive reframing (positive emotion, negative emotion, and cognitive processing words).Sample: Fifty-two couples coping with breast cancer.Methods: Couples wore the EAR, a device participants wear, that audio-recorded over one weekend (>16,000 sound files), and completed self-reports of positive reframing (COPE) and stress (Perceived Stress Scale). LIWC, a software program, measured word use.Findings: Both partners’ word use (i.e., positive emotion and cognitive processing words) was associated with their own reported positive reframing, and spouses’ word use was also indicative of patients’ positive reframing. Results also revealed that, in general, words indicating positive reframing predicted lower levels of stress.Conclusions: Findings supported the hypothesis that partners—and particularly spouses of breast cancer patients—may assist each other’s coping by positively reframing the cancer experience and other negative experiences in conversation. 相似文献
68.
K.A. Lee M.T.A. Sharabiani D. Tumino J. Wadsley V. Gill G. Gerrard R. Sindhu M.N. Gaze L. Moss K. Newbold 《Clinical oncology (Royal College of Radiologists (Great Britain))》2019,31(6):385-390
Aims
To obtain an overview of the management and outcomes of children aged 18 years or younger diagnosed with differentiated thyroid carcinoma of follicular cell origin across the UK, by collecting and analysing data from the limited number of centres treating these patients. This multicentre data might provide a more realistic perspective than single-institution series.Materials and methods
Six centres submitted data extracted from historical records on patients aged 18 years or younger, diagnosed between 1964 and 2017. The univariate and multivariable Cox proportional hazard model was used to identify potential predictors of progression-free survival, using national data as a control.Results
Data on 166 patients were available for analysis. Females (74%) were predominant, and the age ranged from 3 to 19 years at diagnosis, mean 14.1 years. Nodal metastases were present in 51%; 12% had distant metastases. After surgery, 95% received radioactive iodine (39% on more than one occasion) and 4% received external beam radiotherapy. With a median follow-up duration of 5 years, 69% are alive with no evidence of disease; 20% are alive with a raised thyroglobulin level as the only evidence of residual disease; 6% have residual structural disease detectable on imaging; 2% have died, from cerebral metastases.Conclusion
Despite most patients having advanced disease at presentation, outcomes are very good. A national prospective registry should allow systematic collection of good-quality data and may facilitate research to further improve outcomes. 相似文献69.
Annette E Hay Nicole Mittmann Michael Crump Matthew C Cheung Jessica Sleeth Judy Needham Mike Broekhoven Marina Djurfeldt Lois E Shepherd Ralph M Meyer Bingshu E Chen Joseph L Pater 《Current oncology (Toronto, Ont.)》2021,28(2):1153
In a prospective study, we sought to determine acceptability of linkage of administrative and clinical trial data among Canadian patients and Research Ethics Boards (REBs). The goal is to develop a more harmonized approach to data, with potential to improve clinical trial conduct through enhanced data quality collected at reduced cost and inconvenience for patients. On completion of the original LY.12 randomized clinical trial in lymphoma (NCT00078949), participants were invited to enrol in the Long-term Innovative Follow-up Extension (LIFE) component. Those consenting to do so provided comprehensive identifying information to facilitate linkage with their administrative data. We prospectively designed a global assessment of this innovative approach to clinical trial follow-up including rates of REB approval and patient consent. The pre-specified benchmark for patient acceptability was 80%. Of 16 REBs who reviewed the research protocol, 14 (89%) provided approval; two in Quebec declined due to small patient numbers. Of 140 patients invited to participate, 115 (82%, 95% CI 76 to 88%) from across 9 Canadian provinces provided consent and their full name, date of birth, health insurance number and postal code to facilitate linkage with their administrative data for long-term follow-up. Linkage of clinical trial and administrative data is feasible and acceptable. Further collaborative work including many stakeholders is required to develop an optimized secure approach to research. A more coordinated national approach to health data could facilitate more rapid testing and identification of new effective treatments across multiple jurisdictions and diseases from diabetes to COVID-19. 相似文献
70.
Molly K. McCann Todd A. Jusko Courtney M. C. Jones Christopher L. Seplaki Jeremy T. Cushman 《Prehospital emergency care》2021,25(1):82-90
Abstract