全文获取类型
收费全文 | 160389篇 |
免费 | 2723篇 |
国内免费 | 1538篇 |
专业分类
耳鼻咽喉 | 1639篇 |
儿科学 | 6061篇 |
妇产科学 | 2625篇 |
基础医学 | 18934篇 |
口腔科学 | 4128篇 |
临床医学 | 10504篇 |
内科学 | 31297篇 |
皮肤病学 | 2872篇 |
神经病学 | 9561篇 |
特种医学 | 3245篇 |
外国民族医学 | 1篇 |
外科学 | 25736篇 |
综合类 | 8887篇 |
一般理论 | 4篇 |
预防医学 | 8455篇 |
眼科学 | 3212篇 |
药学 | 17009篇 |
8篇 | |
中国医学 | 5944篇 |
肿瘤学 | 4528篇 |
出版年
2022年 | 1027篇 |
2021年 | 2028篇 |
2020年 | 888篇 |
2019年 | 12428篇 |
2018年 | 12073篇 |
2017年 | 5257篇 |
2016年 | 842篇 |
2015年 | 862篇 |
2014年 | 2207篇 |
2013年 | 3934篇 |
2012年 | 2367篇 |
2011年 | 2379篇 |
2010年 | 2065篇 |
2009年 | 2052篇 |
2008年 | 2522篇 |
2007年 | 3611篇 |
2006年 | 3904篇 |
2005年 | 3846篇 |
2004年 | 2994篇 |
2003年 | 3084篇 |
2002年 | 3016篇 |
2001年 | 3010篇 |
2000年 | 3257篇 |
1999年 | 2944篇 |
1998年 | 3017篇 |
1997年 | 2375篇 |
1996年 | 2232篇 |
1995年 | 2588篇 |
1994年 | 2417篇 |
1993年 | 1881篇 |
1992年 | 1481篇 |
1991年 | 1476篇 |
1990年 | 1227篇 |
1989年 | 971篇 |
1988年 | 1012篇 |
1987年 | 976篇 |
1986年 | 816篇 |
1985年 | 5396篇 |
1984年 | 7269篇 |
1983年 | 5817篇 |
1982年 | 6252篇 |
1981年 | 5704篇 |
1980年 | 4901篇 |
1979年 | 4958篇 |
1978年 | 4061篇 |
1977年 | 3047篇 |
1976年 | 3522篇 |
1975年 | 2732篇 |
1974年 | 2523篇 |
1973年 | 2226篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
Ngai-Yin Chan Chi-Chung Choy Ho-Chuen Yuen Hoi-Fan Chow Ho-Fai Fong 《The Canadian journal of cardiology》2019,35(4):396-404
Background
Persistent iatrogenic atrial septal defect (iASD) is a common but poorly characterized complication after cryoballoon (CB) pulmonary vein isolation (PVI) procedures. We therefore investigate its prevalence, evolution, risk factors, and clinical outcomes in a prospective longitudinal study.Methods
A total of 108 patients (41 women, mean age 57 ± 11.3) underwent CB PVI for AF. Serial transesophageal echocardiography (TEE) was performed 9 months and then annually until 6 years after the procedure to study the characteristics of persistent iASD.Results
Persistent iASD occurred in 33 (30.6%) patients 9 months after CB PVI. Spontaneous closure of iASD was found in 6 (22.2%) and 3 (15.8%) patients 2 and 3 years after the procedures, respectively. No spontaneous closure was observed on 4, 5, and 6-year TEE follow-up. The projected long-term persistence rate of iASD after CB PVI was therefore 20% (30.6% × 0.778 × 0.842). Using multivariate logistic regression, a higher number of cryoapplications (≥ 2 minutes) was the only independent predictor of persistent iASD 9 months after CB PVI (odds ratio [OR] 1.207; 95% confidence interval [CI], 1.033-1.411, P = 0.018). Two (1.9%) patients with significantly larger iASD size than the others (long diameter 12.6 ± 0.8 vs 3.7 ± 1.5 mm, P < 0.001; short diameter 10.9 ± 0.2 vs 3 ± 1.1 mm, P < 0.001) required percutaneous closure because of exertional dyspnea and right ventricular enlargement. Over 129.7 patient-years follow-up, during which iASD persisted, there was no occurrence of neurologic events.Conclusions
Approximately one fifth of patients undergoing CB PVI will have permanently persistent iASD. Patients with defect sizes of greater than 10 mm may need percutaneous closure due to significant left-to-right shunting. 相似文献14.
15.
16.
Pavan Brahmamdam Stephen L. Carveth Mary Smyth Brian S. Gendelman M. Jeffrey Maisels 《Journal of pediatric surgery》2019,54(9):1800-1803
PurposeTo examine what proportion of caregivers, if given a choice, would choose medical versus surgical treatment of appendicitis and what factors would be important in their decision.MethodsA survey was devised and given to the caregivers of children presenting to the pediatrician for a routine visit in community and academic pediatric clinics. The survey presented a summary of outcomes after medical (non-operative) and surgical treatment of uncomplicated appendicitis. Participants were then asked to choose medical versus surgical treatment if their child were to develop appendicitis. They were also asked to rate the importance of certain factors in their decision ? 1 being “not important” and 5 being “very important”.ResultsFour hundred surveys were distributed with an 86.2% (345/400) response rate. Six percent (21/342) of respondents reported a history of appendicitis and 49.4% (168/340) reported having known someone who had appendicitis. The majority of respondents, 85.3% (284/333), were mothers. A minority of respondents, 41.7% (95% CI: 36.7, 47.0), chose medical treatment over surgery for appendicitis. There was no statistical difference in the proportion of mothers (41.6%) versus fathers who chose medical treatment (41.3%). Caregivers who chose medical treatment were more likely to rate time in hospital (p = .008) and time out of school (p = 05) as important in decision making when compared with those who chose surgery. Those who chose surgical treatment were more likely to rate risk of recurrent appendicitis (p < .001) as important to decision making. In the multivariate analysis, those who rated time in hospital as very important had more than twice the odds of choosing medical therapy (OR 2.20, p = 0.02) when compared with those who rated it as less important. Not knowing someone who has had appendicitis was significantly associated with choosing medical therapy when compared with those who do know someone who has had appendicitis, OR 2.3, p = .002. Rating pain as very important was also significantly associated with choosing medical therapy, when compared to those rating pain 1–3, OR 3.38, p = .03.ConclusionsIn this survey of caregivers of children presenting for routine care, 41.7% would choose medical, or non-operative, therapy for their children with acute appendicitis. The risk of recurrence, time in hospital, and time out of school, pain, and knowing someone who has had appendicitis were all important factors that families may consider when making a decision. These data may be useful for surgeons counseling patients on which treatment to pursue. 相似文献
17.
18.
《JACC: Cardiovascular Interventions》2022,15(7):741-750
ObjectivesThe aim of this study was to report 1-year clinical outcomes following commercial transcatheter left atrial appendage occlusion (LAAO) in the United States.BackgroundThe National Cardiovascular Data Registry LAAO Registry was initiated to meet a condition of Medicare coverage and allow the assessment of clinical outcomes. The 1-year rates of thromboembolic events after transcatheter LAAO in such a large cohort of “real-world” patients have not been previously reported.MethodsPatients entered into the National Cardiovascular Data Registry LAAO Registry for a Watchman procedure between January 1, 2016, and December 31, 2018, were included. The primary endpoint was ischemic stroke. Key secondary endpoints included the rate of ischemic stroke or systemic embolism, mortality, and major bleeding. Major bleeding was defined as any bleeding requiring hospitalization, and/or causing a decrease in hemoglobin level > 2g/dL, and/or requiring blood transfusion that was not hemorrhagic stroke. The Kaplan-Meier method was used for 1-year estimates of cumulative event rates.ResultsThe study population consisted of 36,681 patients. The mean age was 76.0 ± 8.1 years, the mean CHA2DS2-VASc score was 4.8 ± 1.5, and the mean HAS-BLED score was 3.0 ± 1.1. Prior stroke was present in 25.5%, clinically relevant bleeding in 69.5%, and intracranial bleeding in 11.9%. Median follow-up was 374 days (IQR: 212-425 days). The Kaplan-Meier–estimated 1-year rate of ischemic stroke was 1.53% (95% CI: 1.39%-1.69%), the rate of ischemic stroke or systemic embolism was 2.19% (95% CI: 2.01%-2.38%), and the rate of mortality was 8.52% (95% CI: 8.19%-8.87%). The 1-year estimated rate of major bleeding was 6.93% (95% CI: 6.65%-7.21%). Most bleeding events occurred between discharge and 45 days following the procedure.ConclusionsThis study characterizes important outcomes in a national cohort of patients undergoing transcatheter LAAO in the United States. Clinicians and patients can integrate these data in shared decision making when considering this therapy. 相似文献
19.
Y. Ermias I.A. Morgan K.M. Curtis M.K. Whiteman L.G. Horton L.B. Zapata 《Contraception》2019,99(5):300-305
ObjectiveIdentify factors associated with healthcare providers' frequency of depot medroxyprogesterone acetate (DMPA) provision to adolescents.Study designWe analyzed data from surveys mailed to a nationally representative sample of public-sector providers and office-based physicians (n=1984). We estimated adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of factors associated with frequent DMPA provision to adolescents in the past year.ResultsAlthough most providers (>95%) considered DMPA safe for adolescents, fewer reported frequent provision (89% of public-sector providers; 64% of office-based physicians). Among public-sector providers, factors associated with lower odds of frequent provision included working in settings without Title X funding (aOR 0.44, 95% CI 0.30–0.64), reporting primary care as their primary clinical focus versus reproductive or adolescent health (aOR 0.42, 95% CI 0.28–0.61), and providing fewer patients with family planning services. Among office-based physicians, factors associated with lower odds of frequent provision included specializing in obstetrics/gynecology (aOR 0.50, 95% CI 0.27–0.91) and family medicine (aOR 0.21, 95% CI 0.09–0.47) versus adolescent medicine, completing training ≥15 versus <5 years ago (aOR 0.27, 95% CI 0.09–0.83), and reporting that 0–24% of patients pay with Medicaid or other government healthcare assistance versus ≥50% (aOR 0.23, 95% CI 0.09–0.61). The reason most commonly reported by providers for infrequent DMPA provision was patient preference for another method.ConclusionsWhile most providers reported frequently providing DMPA to adolescents, training on evidence-based recommendations for contraception, focused on subgroups of providers with lower odds of frequent DMPA provision, may increase adolescents' access to contraception.ImplicationsAlthough >95% of providers considered depot medroxyprogesterone (DMPA) a safe contraceptive for adolescents, only 89% of public-sector providers and 64% of office-based physicians reported frequently providing DMPA to adolescents. Provider training on evidence-based recommendations for contraception counseling and provision may increase adolescents' access to DMPA and all methods of contraception. 相似文献
20.
Conall T. Morgan Brigitte Mueller Varsha Thakur Vitor Guerra Callaghan Jull Luc Mertens Mark Friedberg Fraser Golding Mike Seed Steven E.S. Miner Edgar T. Jaeggi Cedric Manlhiot Lynne E. Nield 《The Canadian journal of cardiology》2019,35(4):453-461