全文获取类型
收费全文 | 183873篇 |
免费 | 16369篇 |
国内免费 | 8191篇 |
专业分类
耳鼻咽喉 | 2288篇 |
儿科学 | 3981篇 |
妇产科学 | 1843篇 |
基础医学 | 31845篇 |
口腔科学 | 5345篇 |
临床医学 | 15497篇 |
内科学 | 28854篇 |
皮肤病学 | 4450篇 |
神经病学 | 9618篇 |
特种医学 | 4695篇 |
外国民族医学 | 118篇 |
外科学 | 15710篇 |
综合类 | 28446篇 |
现状与发展 | 48篇 |
预防医学 | 5130篇 |
眼科学 | 3502篇 |
药学 | 14239篇 |
34篇 | |
中国医学 | 5569篇 |
肿瘤学 | 27221篇 |
出版年
2024年 | 369篇 |
2023年 | 2555篇 |
2022年 | 4605篇 |
2021年 | 6433篇 |
2020年 | 5757篇 |
2019年 | 5450篇 |
2018年 | 5705篇 |
2017年 | 5991篇 |
2016年 | 6298篇 |
2015年 | 7293篇 |
2014年 | 10901篇 |
2013年 | 11808篇 |
2012年 | 10345篇 |
2011年 | 11620篇 |
2010年 | 9756篇 |
2009年 | 9444篇 |
2008年 | 9902篇 |
2007年 | 10133篇 |
2006年 | 9290篇 |
2005年 | 8440篇 |
2004年 | 7381篇 |
2003年 | 6416篇 |
2002年 | 5284篇 |
2001年 | 4560篇 |
2000年 | 3802篇 |
1999年 | 3395篇 |
1998年 | 3167篇 |
1997年 | 2876篇 |
1996年 | 2539篇 |
1995年 | 2253篇 |
1994年 | 1971篇 |
1993年 | 1622篇 |
1992年 | 1329篇 |
1991年 | 1256篇 |
1990年 | 974篇 |
1989年 | 914篇 |
1988年 | 849篇 |
1987年 | 694篇 |
1986年 | 629篇 |
1985年 | 832篇 |
1984年 | 725篇 |
1983年 | 508篇 |
1982年 | 545篇 |
1981年 | 426篇 |
1980年 | 366篇 |
1979年 | 282篇 |
1978年 | 214篇 |
1977年 | 159篇 |
1976年 | 130篇 |
1975年 | 56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.
《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
3.
4.
5.
6.
《Cancer cell》2022,40(8):835-849.e8
- Download : Download high-res image (220KB)
- Download : Download full-size image
7.
《Revista portuguesa de cardiologia》2022,41(4):299-307
AimsMyocardial strain analysis enables more precise assessment of cardiac performance but is relatively load dependent. New tools have been developed with afterload adjustment. Our objective was to assess myocardial work (MW) in patients with repaired aortic coarctation (rACo).MethodsProspective study of consecutive patients with rACo who underwent a routine transthoracic echocardiogram in 2018 and 2019 at our center. Patients with significant aortic valve disease, pacemaker, or other congenital heart diseases (except for mild bicuspid aortic valve disease) were excluded. Global longitudinal strain with two dimensional speckle tracking analysis and MW were obtained (GWI:Global Work Index; GCW: Global Constructive Work; GWW: Global Wasted Work; GWE: Global Work Efficiency). Blood pressure was measured in the patient's right arm.ResultsWe included 42 patients in the analysis, mean age of 37±10 years, 38% males. In this group, 52% had hypertension and 64% had a concomitant bicuspid aortic valve. In comparison to previously published reference values, patients with rACo had significantly lower GWI (1807 vs. 1896 mmHg%) and GCW (2173 vs. 2232 mmHg%) (p<0.001), particularly in males. Systolic blood pressure is an independent predictor for GWI (β=0.432) and for GCW (β=0.534) and GLS an independent predictor of all MW parameters (β>0.594). Neither age nor gender were independent predictors.ConclusionsIn patients with rACo, there are some signs of left ventricular dysfunction with a reduction in GCW and GWI and with preserved GWE, despite normal ejection fraction and strain. 相似文献
8.
9.
《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
10.
《The British journal of oral & maxillofacial surgery》2022,60(7):890-895
Patients undergoing sentinel node biopsy (SLNB) for early oral squamous cell carcinoma (OSCC) who harbour occult metastases (pN+ve) may be at greater risk of mortality due to prolonged overall treatment times than those identified as pN+ve on elective neck dissection (ELND). A retrospective comparative survival analysis was therefore undertaken to test this hypothesis. Patients were identified from the South Glasgow multidisciplinary team (MDT) database. Group 1 comprised 38 patients identified as pN+ve, or who were false negative, on sentinel lymph node biopsy (SLNB). Group 2 comprised 146 patients staged pN+ve on ELND. The groups were compared with the Kaplan Meier method and Cox proportional hazards model. In addition, a matched-pair analysis was performed. A unique and specifically designed algorithm was deployed to optimise the pairings. No difference in disease-specific or overall survival was found between the groups. Patients undergoing SLNB as the initial neck staging modality in early OSCC and are identified as pN+ve do not appear to be at a survival disadvantage compared with those staged with ELND. 相似文献