收费全文 | 24757篇 |
免费 | 1405篇 |
国内免费 | 153篇 |
耳鼻咽喉 | 204篇 |
儿科学 | 596篇 |
妇产科学 | 579篇 |
基础医学 | 2940篇 |
口腔科学 | 960篇 |
临床医学 | 2085篇 |
内科学 | 6644篇 |
皮肤病学 | 601篇 |
神经病学 | 2115篇 |
特种医学 | 775篇 |
外科学 | 3787篇 |
综合类 | 113篇 |
一般理论 | 3篇 |
预防医学 | 1613篇 |
眼科学 | 303篇 |
药学 | 1233篇 |
中国医学 | 80篇 |
肿瘤学 | 1684篇 |
2024年 | 27篇 |
2023年 | 280篇 |
2022年 | 588篇 |
2021年 | 1061篇 |
2020年 | 533篇 |
2019年 | 837篇 |
2018年 | 1067篇 |
2017年 | 656篇 |
2016年 | 671篇 |
2015年 | 759篇 |
2014年 | 1084篇 |
2013年 | 1270篇 |
2012年 | 1937篇 |
2011年 | 2016篇 |
2010年 | 1074篇 |
2009年 | 973篇 |
2008年 | 1608篇 |
2007年 | 1505篇 |
2006年 | 1454篇 |
2005年 | 1412篇 |
2004年 | 1254篇 |
2003年 | 1042篇 |
2002年 | 957篇 |
2001年 | 231篇 |
2000年 | 202篇 |
1999年 | 200篇 |
1998年 | 163篇 |
1997年 | 131篇 |
1996年 | 125篇 |
1995年 | 103篇 |
1994年 | 84篇 |
1993年 | 70篇 |
1992年 | 95篇 |
1991年 | 71篇 |
1990年 | 64篇 |
1989年 | 60篇 |
1988年 | 56篇 |
1987年 | 45篇 |
1986年 | 57篇 |
1985年 | 45篇 |
1984年 | 43篇 |
1983年 | 41篇 |
1982年 | 41篇 |
1981年 | 29篇 |
1980年 | 33篇 |
1979年 | 23篇 |
1978年 | 22篇 |
1977年 | 21篇 |
1974年 | 23篇 |
1973年 | 32篇 |
Areas covered: This review provides an overview of microfluidic devices and materials used for their manufacturing, together with the flow patterns and regimes commonly used for nanoparticle preparation. Additionally, the different geometries used in droplet microfluidics are reviewed, with particular attention to the co-flow geometry used for the production of nanoparticles. Finally, this review summarizes the main and most recent nanoparticulate systems prepared using microfluidics, including drug nanosuspensions, polymeric, lipid, structured, and theranostic nanoparticles.
Expert opinion: The production of nanoparticles at industrial scale is still a challenge, but the microfluidic technologies bring exciting opportunities to develop drug delivery systems that can be engineered in an easy, cost-effective and reproducible manner. As a highly interdisciplinary research field, more efforts and general acceptance are needed to allow for the translation of nanoparticulate drug delivery systems from academic research to the clinical practice. 相似文献
The objective of this study is to determine the role of multimodal intraoperative neurophysiologic monitoring (IONM) in the overall outcome of intracranial aneurysms surgery, and the risk factors associated with ischemic complications. We grouped 268 ruptured and unruptured intracranial aneurysms surgically treated at our institution into 2 cohorts, based on the use of IONM (180; 67.16%) or non-use of IONM (88; 32.84%). The IONM technique used was multimodal: electroencephalogram (EEG), somatosensory evoked potentials (SSEPs), transcranial (TES), and direct cortical (DCS) stimulation motor evoked potentials (MEPs). There was a significant difference, with a reduction in perioperative strokes (p?=?0.011) and better motor surgery-related outcome in the IONM group (p?=?0.016). Independent risk factors identified for surgery ischemic complications were temporary clipping time?≥?6′05″ (odds ratio [OR]: 3.03; 95% CI: 1.068–8.601; p?=?0.037), aneurysm size?≥?7.5 mm (OR: 2.65; 95% CI: 1.127–6.235; p?=?0.026), and non-use of IONM (OR: 2.79; 95% CI: 1.171–6.636; p?=?0.021). Conversely, aneurysm rupture was not detected as an independent risk factor (OR: 2.5; 95% CI: 0.55–4.55; p?=?0.4). Longer temporary clipping time, larger aneurysm size, and the non-use of IONM could be considered as risk factors for ischemic complications during microsurgical clipping. A standardized designed protocol including multimodal IONM with DCS provides continuous information about blood supply and allows reduction of treatment-related morbidity. Multimodal IONM is a valuable technique in intracranial aneurysm surgery.
相似文献Malignant intraventricular meningiomas (IVMs) are very rare with only a few reported cases. A midline search up to December 2020 selected 40 articles for a total of 65 patients. The inclusion criteria were series and case reports in English language, as well as papers written in other languages, but with abstracts written in English. Malignant IVMs at the first diagnosis (group A, 50 patients) and those with anaplastic transformation from previous WHO grades I and II tumors (group B, 15 patients) were separately analyzed. The unique personal case among 1285 meningiomas (0.078%) is also added. Malignant IVMs mainly occur in women (61%) with a median age of 45 years and are mainly located in the lateral ventricle (93%) and trigonal region (74%), with no cases in the fourth ventricle. Irregular borders (80%), heterogeneous enhancement (83%), and perilesional edema (76%) are the most frequent radiological findings. The histology was mainly pure anaplastic (85%), whereas papillary (7%), rhabdoid (5%), and mixed forms (3%) are very rare. The CSF spread was found in 60% of the cases. The prognosis is very dismal, with an overall median survival of 17.5 months after surgery for the anaplastic forms. Malignant IVMs at initial diagnosis (group A) show better overall survival (25 months) than those occurring from anaplastic transformation of lower grade tumors (group B) (10.1 months).
相似文献![点击此处可从《The Journal of clinical investigation》网站下载免费的PDF全文](/ch/ext_images/free.gif)