全文获取类型
收费全文 | 16187篇 |
免费 | 1771篇 |
国内免费 | 162篇 |
专业分类
耳鼻咽喉 | 50篇 |
儿科学 | 811篇 |
妇产科学 | 1225篇 |
基础医学 | 722篇 |
口腔科学 | 74篇 |
临床医学 | 1264篇 |
内科学 | 4598篇 |
皮肤病学 | 71篇 |
神经病学 | 870篇 |
特种医学 | 110篇 |
外国民族医学 | 1篇 |
外科学 | 2230篇 |
综合类 | 1068篇 |
一般理论 | 1篇 |
预防医学 | 3005篇 |
眼科学 | 29篇 |
药学 | 620篇 |
2篇 | |
中国医学 | 40篇 |
肿瘤学 | 1329篇 |
出版年
2023年 | 461篇 |
2022年 | 341篇 |
2021年 | 945篇 |
2020年 | 872篇 |
2019年 | 899篇 |
2018年 | 856篇 |
2017年 | 730篇 |
2016年 | 727篇 |
2015年 | 680篇 |
2014年 | 1076篇 |
2013年 | 1371篇 |
2012年 | 755篇 |
2011年 | 857篇 |
2010年 | 618篇 |
2009年 | 700篇 |
2008年 | 739篇 |
2007年 | 706篇 |
2006年 | 663篇 |
2005年 | 527篇 |
2004年 | 491篇 |
2003年 | 381篇 |
2002年 | 323篇 |
2001年 | 277篇 |
2000年 | 205篇 |
1999年 | 178篇 |
1998年 | 155篇 |
1997年 | 141篇 |
1996年 | 139篇 |
1995年 | 145篇 |
1994年 | 126篇 |
1993年 | 128篇 |
1992年 | 110篇 |
1991年 | 86篇 |
1990年 | 76篇 |
1989年 | 63篇 |
1988年 | 74篇 |
1987年 | 62篇 |
1986年 | 76篇 |
1985年 | 76篇 |
1984年 | 76篇 |
1983年 | 39篇 |
1982年 | 33篇 |
1981年 | 24篇 |
1980年 | 17篇 |
1979年 | 24篇 |
1978年 | 16篇 |
1977年 | 10篇 |
1976年 | 12篇 |
1974年 | 7篇 |
1973年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
《Journal d'obstetrique et gynecologie du Canada》2022,44(8):901-907
ObjectivePregnancies complicated by fetal heart defects often undergo a planned delivery prior to term by either induction of labour or cesarean delivery to ensure optimal availability of neonatal care. We aimed to assess whether such planned deliveries achieve their goal of better perinatal care.MethodsWe conducted a retrospective case-control study of pregnancies complicated by isolated fetal cardiac defects, without other fetal comorbidities, managed at a single fetal medicine unit over a 10-year period. Only pregnancies delivered past 37 weeks gestation were included. Patients undergoing elective delivery for care planning reasons only were compared with patients in whom planned delivery was clinically indicated and patients who laboured spontaneously. Obstetric and perinatal outcomes were recorded.ResultsOf the 180 pregnancies included in the study, 59 (32.8%) were in the elective group, 49 (27.2%), in the indicated group, and 72 (40%), in the spontaneous group. Mean gestational age at delivery was 39.0 ± 1.1 weeks overall and did not differ between the groups. For the elective group, only 35.6% of deliveries occurred during office hours, which was similar to the 2 other groups. The rate of adverse obstetric or postnatal outcomes was not statistically significantly different between groups.ConclusionTimed delivery at term does not seem to be associated with an increased risk of poor perinatal outcomes. It may improve perinatal care by providing proximity to a neonatal intensive care unit and convenience for patients and providers. 相似文献
2.
3.
Matthew C. Phillips Laura Sarff Josh Banerjee Chase Coffey Paul Holtom Steve Meurer Noah Wald-Dickler Brad Spellberg 《Journal of medical virology》2022,94(1):318-326
When hospitals first encountered coronavirus disease 2019 (COVID-19), there was a dearth of therapeutic options and nearly 1 in 3 patients died from the disease. By the summer of 2020, as deaths from the disease declined nationally, multiple single-center studies began to report declining mortality of patients with COVID-19. To evaluate the effect of COVID-19 on hospital-based mortality, we searched the Vizient Clinical Data Base for outcomes data from approximately 600 participating hospitals, including 130 academic medical centers, from January 2017 through December 2020. More than 32 million hospital admissions were included in the analysis. After an initial spike, mortality from COVID-19 declined in all regions of the country to under 10% by June 2020 and remained constant for the remainder of the year. Despite this, inpatient, all-cause mortality has increased since the beginning of the pandemic, even those without respiratory failure. Inpatient mortality has particularly increased in elderly patients and in those requiring intubation for respiratory failure. Since June 2020, COVID-19 kills one in every 10 patients admitted to the hospital with this diagnosis. The addition of this new disease has raised overall hospital mortality especially those who require intubation for respiratory failure. 相似文献
4.
5.
6.
7.
8.
《Journal of the American Medical Directors Association》2022,23(1):161-164
ObjectivesAs more countries are implementing measures to address Alzheimer’s disease (AD), it is essential to update the available knowledge on the relationship between economic status and mortality in patients with AD. This study examined the influence of economic status on mortality in Japanese individuals with AD using a medical claims dataset.DesignThis was a retrospective cohort study.Setting and ParticipantsMedical claims data from April 2014 to March 2019 were obtained from 13 local cities participating in the Longevity Improvement and Fair Evidence study. The inclusion criteria were patients aged 65 years and older who were newly diagnosed with AD during the study period.MethodsThe outcome was death during the follow-up period. We assessed economic status by household income (middle to high income and low income); data were obtained from the use of the Medical Expenditure Ceiling Application and Standard Copayment Reduction Card (fee reduction card) when receiving an AD diagnosis, as an indicator of low-income status. We performed multivariate Cox proportional hazards analyses to examine the relationship between economic status and mortality; the model was adjusted for age, sex, the Charlson comorbidity index, and antidementia drug use.ResultsWe identified 39,081 newly diagnosed patients with AD from the Longevity Improvement and Fair Evidence study database (mean age, 83.6 years; female, 67.1%). Of these, 3189 individuals were identified as having a low-income status. After adjusting for possible confounders, low-income status was associated with mortality (hazard ratio, 1.95; 95% confidence interval, 1.84–2.07).Conclusions and ImplicationsLow-income status was associated with substantially poorer prognoses in new AD cases, indicating a need for a thorough examination of medical and nursing care services utilized by low-income individuals with AD and to explore improvement strategies. 相似文献
9.
《The Journal of thoracic and cardiovascular surgery》2023,165(2):591-604.e3
ObjectivesGuidelines suggest aortic valve replacement (AVR) for low-risk asymptomatic patients. Indications for transcatheter AVR now include low-risk patients, making it imperative to understand state-of-the-art surgical AVR (SAVR) in this population. Therefore, we compared SAVR outcomes in low-risk patients with those expected from Society of Thoracic Surgeons (STS) models and assessed their intermediate-term survival.MethodsFrom January 2005 to January 2017, 3493 isolated SAVRs were performed in 3474 patients with STS predicted risk of mortality <4%. Observed operative mortality and composite major morbidity or mortality were compared with STS-expected outcomes according to calendar year of surgery. Logistic regression analysis was used to identify risk factors for these outcomes. Patients were followed for time-related mortality.ResultsWith 15 observed operative deaths (0.43%) compared with 55 expected (1.6%), the observed:expected ratio was 0.27 for mortality (95% confidence interval [CI], 0.14-0.42), stroke 0.65 (95% CI, 0.41-0.89), and reoperation 0.50 (95% CI, 0.42-0.60). Major morbidity or mortality steadily declined, with probabilities of 8.6%, 6.7%, and 5.2% in 2006, 2011, and 2016, respectively, while STS-expected risk remained at approximately 12%. Mitral valve regurgitation, ventricular hypertrophy, pulmonary, renal, and hepatic failure, coronary artery disease, and earlier surgery date were residual risk factors. Survival was 98%, 91%, and 82% at 1, 5, and 9 years, respectively, superior to that predicted for the US age-race-sex–matched population.ConclusionsSTS risk models overestimate contemporary SAVR risk at a high-volume center, supporting efforts to create a more agile quality assessment program. SAVR in low-risk patients provides durable survival benefit, supporting early surgery and providing a benchmark for transcatheter AVR. 相似文献
10.
Matthias Knefel PhD Elisabeth L. Zeilinger PhD Simone Lubowitzki PhD Katharina Krammer MSc Matthias Unseld MD Rupert Bartsch MD Thorsten Fuereder MD Ulrich Jäger MD Barbara Kiesewetter MD Maria Krauth MD Markus Raderer MD Philipp B. Staber MD Peter Valent MD Alexander Gaiger MD 《Cancer》2023,129(21):3466-3475