全文获取类型
收费全文 | 202361篇 |
免费 | 18029篇 |
国内免费 | 8592篇 |
专业分类
耳鼻咽喉 | 2376篇 |
儿科学 | 4347篇 |
妇产科学 | 2124篇 |
基础医学 | 35308篇 |
口腔科学 | 5955篇 |
临床医学 | 15307篇 |
内科学 | 26346篇 |
皮肤病学 | 4642篇 |
神经病学 | 13010篇 |
特种医学 | 4609篇 |
外国民族医学 | 118篇 |
外科学 | 15736篇 |
综合类 | 28454篇 |
现状与发展 | 50篇 |
预防医学 | 8034篇 |
眼科学 | 3599篇 |
药学 | 22560篇 |
36篇 | |
中国医学 | 8479篇 |
肿瘤学 | 27892篇 |
出版年
2024年 | 196篇 |
2023年 | 2813篇 |
2022年 | 3586篇 |
2021年 | 7187篇 |
2020年 | 6480篇 |
2019年 | 6354篇 |
2018年 | 6504篇 |
2017年 | 6920篇 |
2016年 | 7116篇 |
2015年 | 7864篇 |
2014年 | 11724篇 |
2013年 | 13969篇 |
2012年 | 11098篇 |
2011年 | 12665篇 |
2010年 | 10178篇 |
2009年 | 10098篇 |
2008年 | 10529篇 |
2007年 | 10727篇 |
2006年 | 9631篇 |
2005年 | 8806篇 |
2004年 | 7804篇 |
2003年 | 6779篇 |
2002年 | 5621篇 |
2001年 | 4920篇 |
2000年 | 4000篇 |
1999年 | 3682篇 |
1998年 | 3530篇 |
1997年 | 3189篇 |
1996年 | 2500篇 |
1995年 | 2573篇 |
1994年 | 2258篇 |
1993年 | 1944篇 |
1992年 | 1656篇 |
1991年 | 1562篇 |
1990年 | 1261篇 |
1989年 | 1215篇 |
1988年 | 1118篇 |
1987年 | 949篇 |
1986年 | 894篇 |
1985年 | 1202篇 |
1984年 | 1072篇 |
1983年 | 748篇 |
1982年 | 845篇 |
1981年 | 662篇 |
1980年 | 613篇 |
1979年 | 457篇 |
1978年 | 394篇 |
1977年 | 296篇 |
1976年 | 297篇 |
1975年 | 117篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
BackgroundTo investigate perioperative complication rates at radical nephrectomy (RN) according to inferior vena cava thrombectomy (IVC-T) status and stage (metastatic vs non-metastatic) within kidney cancer patients.Materials and methodsWe ascertained perioperative complication rates within the National Inpatient Sample database (2016–2019). First, log-link linear Generalized Estimating Equation function (GEE) regression models (adjusted for hospital clustering and weighted for discharge disposition) tested complication rates in IVC-T patients, according to metastatic stage. Subsequently, a subgroup analysis relied on RN patients with or without IVC-T. Here, multivariable logistic regression models tested complication rates in RN patients according to IVC-T status, after propensity score matching including metastatic stage.ResultsOf 26,299 RN patients, 461 (2%) patients underwent IVC-T. Of those, 252 (55%) were non-metastatic vs 209 (45%) were metastatic. Rates of acute kidney injury (AKI), transfusion, cardiac, thromboembolic and other medical complications in non-metastatic vs metastatic patients were 40 vs 40%, 25 vs 22%, 21 vs 23%, 19 vs 14% and 38 vs 40%, respectively (all p ≥ 0.2). Metastatic stage in IVC-T patients did not predict differences in complications in log-link linear GEE regression models (all p > 0.1). However, in logistic regression models with propensity score matching, relying on the overall cohort of RN patients, IVC-T status was associated with higher complication rates (all p < 0.001): AKI (Odds ratio [OR]:2.60; 95%-CI [95%-Confidence interval: 1.97–3.44), transfusions (OR:2.40; 95%-CI: 1.72–3.36), cardiac (OR:2.27; 95%-CI: 1.49–3.47), thromboembolic (OR:9.07; 95%-CI: 5.21–16.58) and other medical complications (OR:2.01; 95%-CI: 1.52–2.66).ConclusionsThe current analyses indicate that presence of concomitant IVC-T is associated with higher complication rate at RN. Conversely, metastatic stage has no effect on recorded complication rates. 相似文献
2.
内生菌由细菌、真菌、古菌和原生生物组成,它们生活在植物的活体组织中,具有丰富的次级代谢产物多样性。人参内生菌在人参的生长发育、次级代谢产物的生成和环境适应等方面均有重要的促进作用,对人参的产量和品质有较大影响。随着人们在微生物领域研究的深入,高通量测序技术已经成为研究植物内生菌的重要方法。文章主要从人参内生菌分离与鉴定研究方法、人参内生菌的多样性、人参内生菌及其次级代谢产物的活性、人参内生菌对宿主的影响等4个方面对人参内生菌近年来的研究进展进行讨论,并对其发展方向提出展望,以期为药用植物内生菌研究和品质改良提供新思路、新方法。 相似文献
3.
4.
《Saudi Pharmaceutical Journal》2022,30(6):849-855
The emergence of carbapenem-resistant organisms posed considerable threat to global health while only limited treatment options are available and led to efforts to discover a novel way to treat them. To evaluate in vitro synergistic activity of meropenem plus ertapenem, a total of 203 carbapenem-resistant strains, collected from 12 provinces and municipalities in China, were examined with a dual carbapenem combination therapy. The statistical software R was used for analysis. Two hundred and one (201) of carbapenem-resistant strains mainly produced four types of carbapenemase: KPC-2 (n = 142, 69.95%), OXA-232 (n = 7, 3.45%), NDM (n = 38, 18.72%; 36 NDM-1, 1 NDM-4, 1 NDM-5), and IMP (n = 15, 7.39%; 1 IMP-26, 10 IMP-30, 4 IMP-4). Fifty-one out of two hundred and three (51/203 or 25.12%) of the examined strains showed a synergistic effect for the meropenem plus ertapenem combination throughout the checkerboard method, while only three isolates showed potential clinically relevant synergy (3/203, 1.48%). An additive effect was observed in 55/203 (27.09%) of the examined strains. Ninety-seven of the examined isolates (47.78%) showed fractional inhibitory concentration (FIC) greater or equal to 2 (indicating antagonism). The synergistic activity of meropenem plus ertapenem combination suggests this combination can be a possible way to treat the infection caused by the carbapenem-resistant organisms, especially for IMP or NDM producer with a lesser minimum inhibitory concentration (MIC) and the infected individual who was not recommended to use colistin or tigecycline. 相似文献
5.
《Journal of pediatric surgery》2023,58(9):1613-1617
BackgroundThe goal of this study was to characterize contemporary performance benchmarks and risk factors associated with negative appendectomy (NA) in children with suspected appendicitis.MethodsA multicenter retrospective cohort analysis of children undergoing appendectomy for suspected appendicitis was performed using data from the 2016–2021 NSQIP-Pediatric Appendectomy Targeted Public Use Files. Multivariable regression was used to evaluate the influence of year, age, sex, and WBC count on NA rate, and to generate rate estimates for NA based on different combinations of demographic characteristics and WBC profiles.Results100,322 patients were included from 140 hospitals. The overall NA rate was 2.4%, and rates decreased significantly during the study period (2016: 3.1% vs. 2021: 2.3%, p < 0.001). In adjusted analyses, the highest risk for NA was associated with a normal WBC (<9000/mm3; OR 5.31 [95% CI: 4.87–5.80]), followed by female sex (OR 1.55 [95% CI: 1.42–1.68]) and age <5 years (OR 1.64 [95% CI 1.39, 1.94]). Model-estimated risk for NA varied significantly across demographic and WBC strata, with a 14.4-fold range in rates between subgroups with the lowest and highest predicted risk (males 13–17 years with elevated WBC [1.1%] vs. females 3–4 years with normal WBC [15.8%]).ConclusionsContemporary NA rates have decreased over time, however NA risk remains high in children without a leukocytosis, particularly for girls and children <5 years of age. These data provide contemporary performance benchmarks for NA in children with suspected appendicitis and identify high-risk populations where further efforts to mitigate NA risk should be targeted.Level of EvidenceIII. 相似文献
6.
7.
8.
9.
10.
《Transfusion and apheresis science》2022,61(1):103368
The endothelium is a single-layered structure that responds to physical and chemical signals with various factors it synthesizes. In the early days of its discovery, as the inner wall of the vessels, the endothelium was thought to be a simple barrier that lays on the surface. Over time it is discovered that endothelium maintains body homeostasis with the molecules it synthesizes, despite its simple single-layer structure. It has been accepted as an important organ that contributes to the maintenance of vascular tone, cell adhesion, inflammation, vascular permeability and coagulation. Any imbalance in these physiological and pathological events causes endothelial dysfunction. This can cause many diseases such as atherosclerosis, hypertension, diabetes, or it can occur because of these. Endothelial related disorders may also complicate hematopoietic stem cell transplantation (HSCT), which is used to treat various hematologic and neoplastic diseases. These life-threatening complications include graft-versus-host disease, hepatic veno-occlussive disease, transplant-associated thrombotic microangiopathy and diffuse alveolar hemorrhage. They share a similar pathophysiology involving endothelial cells with different clinical presentations. Therefore, current researche on the issue is putting the endothelium under the spotlight for novel markers and treatment options that should be used to monitor or treat at least some of these complications following HSCT. 相似文献