全文获取类型
收费全文 | 163937篇 |
免费 | 33777篇 |
国内免费 | 2416篇 |
专业分类
耳鼻咽喉 | 5280篇 |
儿科学 | 5684篇 |
妇产科学 | 2721篇 |
基础医学 | 5326篇 |
口腔科学 | 1758篇 |
临床医学 | 27993篇 |
内科学 | 49717篇 |
皮肤病学 | 7637篇 |
神经病学 | 16140篇 |
特种医学 | 6909篇 |
外科学 | 43089篇 |
综合类 | 769篇 |
现状与发展 | 72篇 |
一般理论 | 56篇 |
预防医学 | 8621篇 |
眼科学 | 3794篇 |
药学 | 2051篇 |
中国医学 | 14篇 |
肿瘤学 | 12499篇 |
出版年
2024年 | 695篇 |
2023年 | 4855篇 |
2022年 | 1317篇 |
2021年 | 3371篇 |
2020年 | 6177篇 |
2019年 | 2433篇 |
2018年 | 7669篇 |
2017年 | 7530篇 |
2016年 | 8595篇 |
2015年 | 8664篇 |
2014年 | 15813篇 |
2013年 | 16074篇 |
2012年 | 6078篇 |
2011年 | 6148篇 |
2010年 | 10692篇 |
2009年 | 14532篇 |
2008年 | 6367篇 |
2007年 | 4581篇 |
2006年 | 6934篇 |
2005年 | 4260篇 |
2004年 | 3538篇 |
2003年 | 2457篇 |
2002年 | 2539篇 |
2001年 | 4267篇 |
2000年 | 3481篇 |
1999年 | 3659篇 |
1998年 | 3822篇 |
1997年 | 3629篇 |
1996年 | 3517篇 |
1995年 | 3372篇 |
1994年 | 2093篇 |
1993年 | 1698篇 |
1992年 | 1723篇 |
1991年 | 1764篇 |
1990年 | 1389篇 |
1989年 | 1542篇 |
1988年 | 1296篇 |
1987年 | 1157篇 |
1986年 | 1180篇 |
1985年 | 1057篇 |
1984年 | 805篇 |
1983年 | 726篇 |
1982年 | 628篇 |
1981年 | 492篇 |
1980年 | 472篇 |
1979年 | 496篇 |
1978年 | 461篇 |
1977年 | 502篇 |
1975年 | 394篇 |
1972年 | 433篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
43.
44.
Breast Elastography: How to Perform and Integrate Into a “Best-Practice” Patient Treatment Algorithm
Breast elastography has been available for more than 15 years but is not widely incorporated into clinical practice. Many publications report extremely high accuracy for various breast elastographic techniques. However, results in the literature are extremely variable. This variability is most likely due to variations in technique, a relatively steep learning curve, and variability in methods between vendors. This article describes our protocol for performing breast elastography using both strain elastography and shear wave elastography, which produces high sensitivity and specificity. Additionally, we will describe the most commonly known false-positive and false-negative lesions as well as how to detect them. 相似文献
45.
46.
47.
48.
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
49.
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
Background
The purpose of the study was to evaluate the association between fetal echocardiographic measurements and the need for intervention (primary coarctation repair, staged coarctation repair, or catheter intervention) in prenatally diagnosed coarctation of the aorta.Methods
A single-centre retrospective cohort study (2005-2015) of 107 fetuses diagnosed with suspected coarctation of the aorta in the setting of an apex-forming left ventricle and antegrade flow across the mitral and aortic valves.Results
Median gestational age at diagnosis was 32 weeks (interquartile range, 23-35 weeks). Fifty-six (52%) did not require any neonatal intervention, 51 patients (48%) underwent a biventricular repair. In univariable analysis, an increase in ascending aorta (AAo) peak Doppler flow velocity (odds ratio [OR], 1.40 [95% confidence interval [CI], 1.05-1.91] per 20 cm/s; P = 0.03) was associated with intervention. No intervention was associated with larger isthmus size (OR, 0.23; P < 0.001), transverse arch diameter (OR, 0.23; P < 0.001), and aortic (OR, 0.72; P = 0.02), mitral (OR, 0.58; P = 0.001), and AAo (OR, 0.53; P < 0.001) z-scores. In multivariable analysis, higher peak AAo Doppler (OR, 2.51 [95% CI, 1.54-4.58] per 20 cm/s; P = 0.001) and younger gestational age at diagnosis (OR, 0.81 [95% CI, 0.70-0.93] per week; P = 0.005) were associated with intervention, whereas a higher AAo z-score (OR, 0.65 [95% CI, 0.43-0.94] per z; P = 0.029) and transverse arch dimension (OR, 0.44 [95% CI, 0.18-0.97]; P = 0.05) decreased the risk of intervention.Conclusions
In prenatally suspected coarctation, the variables associated with intervention comprised smaller AAo and transverse arch size, earlier gestational age at diagnosis, and the additional finding of a higher peak AAo Doppler. 相似文献50.
Marie V. Plaisime PhD MPH Marie Jipguep-Akhtar PhD Joseph J. Locascio PhD Harolyn M. E. Belcher MD MHS Rachel R. Hardeman PhD MPH Katherine Picho-Kiroga PhD Sylvia P. Perry PhD Sean M. Phelan PhD MPH Michelle van Ryn PhD LMFT MPH John F. Dovidio PhD 《Health services research》2023,58(Z2):229-237