全文获取类型
收费全文 | 82689篇 |
免费 | 5490篇 |
国内免费 | 1603篇 |
专业分类
耳鼻咽喉 | 452篇 |
儿科学 | 2138篇 |
妇产科学 | 1452篇 |
基础医学 | 9206篇 |
口腔科学 | 2043篇 |
临床医学 | 6804篇 |
内科学 | 12770篇 |
皮肤病学 | 1502篇 |
神经病学 | 5020篇 |
特种医学 | 2964篇 |
外国民族医学 | 9篇 |
外科学 | 9061篇 |
综合类 | 9065篇 |
现状与发展 | 6篇 |
预防医学 | 6563篇 |
眼科学 | 803篇 |
药学 | 10884篇 |
28篇 | |
中国医学 | 3557篇 |
肿瘤学 | 5455篇 |
出版年
2023年 | 871篇 |
2022年 | 1366篇 |
2021年 | 2864篇 |
2020年 | 2118篇 |
2019年 | 5491篇 |
2018年 | 4996篇 |
2017年 | 3083篇 |
2016年 | 2126篇 |
2015年 | 2443篇 |
2014年 | 4750篇 |
2013年 | 4440篇 |
2012年 | 3495篇 |
2011年 | 3719篇 |
2010年 | 3377篇 |
2009年 | 3985篇 |
2008年 | 2984篇 |
2007年 | 3744篇 |
2006年 | 3373篇 |
2005年 | 2702篇 |
2004年 | 1683篇 |
2003年 | 1816篇 |
2002年 | 1395篇 |
2001年 | 1207篇 |
2000年 | 1091篇 |
1999年 | 928篇 |
1998年 | 802篇 |
1997年 | 698篇 |
1996年 | 642篇 |
1995年 | 534篇 |
1994年 | 480篇 |
1993年 | 347篇 |
1992年 | 323篇 |
1991年 | 315篇 |
1990年 | 241篇 |
1989年 | 236篇 |
1988年 | 198篇 |
1987年 | 215篇 |
1985年 | 1381篇 |
1984年 | 2177篇 |
1983年 | 1393篇 |
1982年 | 1499篇 |
1981年 | 1396篇 |
1980年 | 1177篇 |
1979年 | 1019篇 |
1978年 | 880篇 |
1977年 | 764篇 |
1976年 | 861篇 |
1975年 | 612篇 |
1974年 | 562篇 |
1973年 | 588篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
31.
32.
Mayuko Kinoshita Haruka Kaneko Lizu Liu Masashi Nagao Ryo Sadatsuki 《Modern rheumatology / the Japan Rheumatism Association》2019,29(1):157-164
Objectives: To examine the factors associated with increase in lumbar spine bone mineral density (LS-BMD) by bisphosphonates (BPs) with active vitamin D analog (aVD).Methods: Two independent postmenopausal osteoporotic patients treated by BPs with aVD for 24 months (Study 1: n?=?93, Study 2: n?=?99) were retrospectively analyzed.Results: In Study 1, LS-BMD of the patients significantly increased for 24 m (5.4%, p?.001). A multiple regression analysis among baseline characteristics revealed that serum calcium (sCa: 8.5–10.5?mg/dL) was associated with an increased LS-BMD by treatment (r2: 0.088, p?=?.02). While average sCa of the patients was 9.2?mg/dL before treatment, it increased time-dependently to 9.6?mg/dL for 24 m by treatment. As each patient had their LS-BMD five times during the study, there were four instances of %LS-BMD in each patient, resulting in 372 instances of %LS-BMD in Study 1. The smallest Akaike’s information criterion value for the most appropriate cut-off levels of sCa for %LS-BMD by treatment every 6 m was 9.3?mg/dL. The %LS-BMD by treatment for 6 m during 24 m period in patients with sCa ≥9.3?mg/dL (1.5%) was significantly higher than that in patients with sCa <9.3?mg/dL (0.8%, p?=?.038). The results of Study 2 were similar to those of Study 1, confirming the phenomena observed.Conclusion: sCa was associated with an increased LS-BMD by BPs with aVD. 相似文献
33.
K. Miura S. Yamaoka K. Arizono S. Ohba T. Koga T. Kawasaki N. Yoshida I. Asahina 《The British journal of oral & maxillofacial surgery》2019,57(6):529-535
Our aim was to evaluate the long-term skeletal stability of the mandible in 21 patients after orthognathic surgery with physiological positioning. The measurement points SNB, B point (X, Y), Pog (X, Y), and the angle of the ramus were measured on cephalometric photographs to assess skeletal stability preoperatively, immediately after operation, and one and two years postoperatively. In addition, we evaluated the clinical symptoms of disorders of the temporomandibular joint (TMJ). The analysis of the cephalometric photographs showed that SNB, B point X, and Pog X showed no significant differences among the postoperative time points. On the other hand, B point Y and Pog Y showed no significant differences throughout the study period. We compared the angle of the ramus before operation and two years postoperatively, and no significant difference was found. In addition, no cases showed any pathological symptoms of disorders of the TMJ two years postoperatively. The long-term stability after orthognathic surgery with physiological positioning was confirmed, and it seems to be a reliable orthognathic treatment in patients with mandibular prognathism. 相似文献
34.
Sadahiro Hijikata Igen Hongo Shu-ichi Nakayama Tetsuo Yamaguchi Yoshiyuki Sekikawa Toshihiro Nozato Takashi Ashikaga 《The Canadian journal of cardiology》2019,35(1):104.e9-104.e11
Syphilis is a sexually transmitted disease caused by Treponema pallidum. Syphilitic aortitis might coexist in a dysfunctional aortic valve, but the etiology remains unclear, because microbiological diagnosis is difficult. A 62-year-old man with low-grade fever was diagnosed with aortitis and infective endocarditis, due to Treponema pallidum infection, using polymerase chain reaction analysis. This case suggests that syphilis might cause infective endocarditis. 相似文献
35.
Alexander C. Egbe Rosalyn Adigun Vidhu Anand Collin P. West Victor M. Montori Hassan M. Murad Emmanuel Akintoye Karim Osman Heidi M. Connolly 《The Canadian journal of cardiology》2019,35(12):1784-1790
BackgroundAlthough there are robust data about the pathophysiology and prognostic implications of left ventricular (LV) systolic dysfunction in patients with acquired heart disease, similar prognostic data about LV systolic dysfunction are sparse in the tetralogy of Fallot (TOF) population. The purpose of this study was to perform a meta-analysis of all studies that assessed the relationship between LV ejection fraction (LVEF) and cardiovascular adverse events (CAEs) defined as death, aborted sudden death, or sustained ventricular tachycardia.MethodsWe used random-effects models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).ResultsOf the 1,809 citations, 7 studies with 2,854 patients (age 28 ± 4 years) were included. During 5.6 ± 3.4 years' follow-up, there were 82 deaths, 17 aborted sudden cardiac deaths, and 56 sustained ventricular tachycardia events. Overall, CAEs occurred in 5.1% (144 patients). As a continuous variable, LVEF was a predictor of CAE (HR 1.29, 95% CI, 1.09-1.53, P = 0.001) per 5% decrease in LVEF. Similarly, LVEF < 40% was also a predictor of CAE (HR 3.22, 95% CI, 2.16-4.80, P < 0.001).ConclusionsLV systolic dysfunction was an independent predictor of CAE, and we observed a 30% increase in the risk of CAE for every 5% decrease in LVEF, and a 3-fold increase in the risk of CAE in patients with LVEF <40% compared with other patients. These findings underscore the importance of incorporating LV systolic function in clinical risk stratification of patients with TOF and the need to explore new treatment options to address this problem. 相似文献
36.
Marta López-Fauqued Laura Campora Frédérique Delannois Mohamed El Idrissi Lidia Oostvogels Ferdinandus J. De Looze Javier Diez-Domingo Thomas C. Heineman Himal Lal Janet E. McElhaney Shelly A. McNeil Wilfred Yeo Fernanda Tavares-Da-Silva 《Vaccine》2019,37(18):2482-2493
Background
The ZOE-50 (NCT01165177) and ZOE-70 (NCT01165229) phase 3 clinical trials showed that the adjuvanted recombinant zoster vaccine (RZV) was ≥90% efficacious in preventing herpes zoster in adults. Here we present a comprehensive overview of the safety data from these studies.Methods
Adults aged ≥50 (ZOE-50) and ≥70 (ZOE-70) years were randomly vaccinated with RZV or placebo. Safety analyses were performed on the pooled total vaccinated cohort, consisting of participants receiving at least one dose of RZV or placebo. Solicited and unsolicited adverse events (AEs) were collected for 7 and 30?days after each vaccination, respectively. Serious AEs (SAEs) were collected from the first vaccination until 12?months post-last dose. Fatal AEs, vaccination-related SAEs, and potential immune-mediated diseases (pIMDs) were collected during the entire study period.Results
Safety was evaluated in 14,645 RZV and 14,660 placebo recipients. More RZV than placebo recipients reported unsolicited AEs (50.5% versus 32.0%); the difference was driven by transient injection site and solicited systemic reactions that were generally seen in the first week post-vaccination. The occurrence of overall SAEs (RZV: 10.1%; Placebo: 10.4%), fatal AEs (RZV: 4.3%; Placebo: 4.6%), and pIMDs (RZV: 1.2%; Placebo: 1.4%) was balanced between groups. The occurrence of possible exacerbations of pIMDs was rare and similar between groups. Overall, except for the expected local and systemic symptoms, the safety results were comparable between the RZV and Placebo groups irrespective of participant age, gender, or race.Conclusions
No safety concerns arose, supporting the favorable benefit-risk profile of RZV. 相似文献37.
Understanding why persons with human immunodeficiency virus (HIV) have accelerated atherosclerosis and its sequelae, including coronary artery disease (CAD) and myocardial infarction, is necessary to provide appropriate care to a large and aging population with HIV. In this review, we delineate the diverse pathophysiologies underlying HIV-associated CAD and discuss how these are implicated in the clinical manifestations of CAD among persons with HIV. Several factors contribute to HIV-associated CAD, with chronic inflammation and immune activation likely representing the primary drivers. Increased monocyte activation, inflammation, and hyperlipidemia present in chronic HIV infection also mirror the pathophysiology of plaque rupture. Furthermore, mechanisms central to plaque erosion, such as activation of toll-like receptor 2 and formation of neutrophil extracellular traps, are also abundant in HIV. In addition to inflammation and immune activation in general, persons with HIV have a higher prevalence than uninfected persons of traditional cardiovascular risk factors, including dyslipidemia, hypertension, insulin resistance, and tobacco use. Antiretroviral therapies, although clearly necessary for HIV treatment and survival, have had varied effects on CAD, but newer generation regimens have reduced cardiovascular toxicities. From a clinical standpoint, this mix of risk factors is implicated in earlier CAD among persons with HIV than uninfected persons; whether the distribution and underlying plaque content of CAD for persons with HIV differs considerably from uninfected persons has not been definitively studied. Furthermore, the role of cardiovascular risk estimators in HIV remains unclear, as does the role of traditional and emerging therapies; no trials of CAD therapies powered to detect clinical events have been completed among persons with HIV. 相似文献
38.
目的:通过3D打印的方法制备的不同重量比例的纳米羟基磷灰石/聚乳酸/聚乙烯醇(n-HA/PLA/PVA)复合膜,并对其相关性能检测。方法:采用3D打印技术制备不同重量比例的n-HA/PLA/PVA复合膜,分别为PLA/PVA复合膜、15%n-HA/PLA/PVA复合膜、50%n-HA/PLA/PVA复合膜、75%n-HA/PLA/PVA复合膜。扫描电镜下观察各组膜形态,对其力学性能、细胞毒性及动物实验相应指标进行检测。结果:扫描电镜下观察,n-HA/PLA/PVA复合膜呈现三维网状结构,各材料间相互结合,孔隙分布不均,大小不一。随着n-HA质量浓度的提高,电镜下见各材料间孔隙逐渐减小,形成结构均匀的复合膜。力学性能及吸水率检测中,随着nHA含量的增加,n-HA/PLA/PVA复合膜的拉伸强度及吸水率呈下降趋势;细胞毒性检测,不同比例复合膜的细胞增殖率无明显差别,无细胞毒性。动物实验测量牙周菌斑指数及龈沟出血指数未发现不同比例n-HA/PLA/PVA复合膜有统计学差异。结论:3D打印不同比例的n-HA/PLA/PVA复合膜具有良好的物理性能和细胞生物相容性,n-HA比例更高的复合膜可能具有更好的物理性能及良好的生物相容性。 相似文献
39.
40.