首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   62472篇
  免费   3153篇
  国内免费   68篇
耳鼻咽喉   623篇
儿科学   1795篇
妇产科学   1627篇
基础医学   8032篇
口腔科学   1512篇
临床医学   6016篇
内科学   9451篇
皮肤病学   2099篇
神经病学   6461篇
特种医学   3572篇
外科学   11951篇
综合类   132篇
一般理论   10篇
预防医学   2425篇
眼科学   1586篇
药学   3670篇
中国医学   123篇
肿瘤学   4608篇
  2023年   915篇
  2022年   1191篇
  2021年   1832篇
  2020年   2086篇
  2019年   1373篇
  2018年   1771篇
  2017年   1824篇
  2016年   1730篇
  2015年   1627篇
  2014年   2857篇
  2013年   2441篇
  2012年   2808篇
  2011年   2906篇
  2010年   2514篇
  2009年   2619篇
  2008年   2581篇
  2007年   2771篇
  2006年   2566篇
  2005年   2591篇
  2004年   2543篇
  2003年   2629篇
  2002年   2399篇
  2001年   2221篇
  2000年   2084篇
  1999年   1923篇
  1998年   773篇
  1997年   667篇
  1996年   669篇
  1995年   570篇
  1994年   527篇
  1993年   434篇
  1992年   988篇
  1991年   880篇
  1990年   807篇
  1989年   738篇
  1988年   660篇
  1987年   298篇
  1986年   164篇
  1985年   190篇
  1984年   171篇
  1983年   92篇
  1982年   155篇
  1981年   150篇
  1980年   132篇
  1979年   129篇
  1978年   99篇
  1977年   94篇
  1976年   91篇
  1973年   81篇
  1960年   50篇
排序方式: 共有10000条查询结果,搜索用时 293 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.
We present an automated approach to detect and longitudinally track skin lesions on 3D total-body skin surface scans. The acquired 3D mesh of the subject is unwrapped to a 2D texture image, where a trained objected detection model, Faster R-CNN, localizes the lesions within the 2D domain. These detected skin lesions are mapped back to the 3D surface of the subject and, for subjects imaged multiple times, we construct a graph-based matching procedure to longitudinally track lesions that considers the anatomical correspondences among pairs of meshes and the geodesic proximity of corresponding lesions and the inter-lesion geodesic distances.We evaluated the proposed approach using 3DBodyTex, a publicly available dataset composed of 3D scans imaging the coloured skin (textured meshes) of 200 human subjects. We manually annotated locations that appeared to the human eye to contain a pigmented skin lesion as well as tracked a subset of lesions occurring on the same subject imaged in different poses. Our results, when compared to three human annotators, suggest that the trained Faster R-CNN detects lesions at a similar performance level as the human annotators. Our lesion tracking algorithm achieves an average matching accuracy of 88% on a set of detected corresponding pairs of prominent lesions of subjects imaged in different poses, and an average longitudinal accuracy of 71% when encompassing additional errors due to lesion detection. As there currently is no other large-scale publicly available dataset of 3D total-body skin lesions, we publicly release over 25,000 3DBodyTex manual annotations, which we hope will further research on total-body skin lesion analysis.  相似文献   
3.
4.
  1. Download : Download high-res image (243KB)
  2. Download : Download full-size image
  相似文献   
5.
《Mucosal immunology》2022,15(5):896-907
Environmental microbial triggers shape the development and functionality of the immune system. Alveolar macrophages (AMs), tissue-resident macrophages of the lungs, are in constant and direct contact with inhaled particles and microbes. Such exposures likely impact AM reactivity to subsequent challenges by immunological imprinting mechanisms referred to as trained immunity. Here, we investigated whether a ubiquitous microbial compound has the potential to induce AM training in vivo. We discovered that intranasal exposure to ambient amounts of lipopolysaccharide (LPS) induced a pronounced AM memory response, characterized by enhanced reactivity upon pneumococcal challenge. Exploring the mechanistic basis of AM training, we identified a critical role of type 1 interferon signaling and found that inhibition of fatty acid oxidation and glutaminolysis significantly attenuated the training effect. Notably, adoptive transfer of trained AMs resulted in increased bacterial loads and tissue damage upon subsequent pneumococcal infection. In contrast, intranasal pre-exposure to LPS promoted bacterial clearance, highlighting the complexity of stimulus-induced immune responses, which likely involve multiple cell types and may depend on the local immunological and metabolic environment. Collectively, our findings demonstrate the profound impact of ambient microbial exposure on pulmonary immune memory and reveal tissue-specific features of trained immunity.  相似文献   
6.
7.
8.
BackgroundCholangiocarcinomas (CCA) are rare tumours originating from bile duct. Due to their asymptomatic nature they are usually diagnosed when the disease is advanced. Little data exists with respect to their incidence and treatment outcomes in low and middle income countries.MethodA retrospective analysis of a prospectively maintained database of all patients with perihilar (pCCA) and intrahepatic (iCCA) CCA registered between January 2012 and December 2018 was performed.ResultsA total of 760 patients, 427 (56.2%) diagnosed with pCCA and 333 (43.8%) of iCCA were included. Patients with localised, locally advanced and metastatic disease in pCCA were 45.5%, 25.9%, 8.5% and that in iCCA were 22.1%, 10.1% and 67.7% respectively. Only 141 (43.9%, 57 - iCCA, 84 -pCCA) of the total 321 patients started on some definitive cancer directed therapy could complete the intended treatment. The overall curative resection rate for all patients of iCCA was 14.5% whereas for patients of pCCA it was only 10.5%.ConclusionMore than half of CCA patients are not able to complete their intended treatment, being worse for pCCA as compared to iCCA. Early referral and centralisation of treatment for this complex disease might be the way forward to achieve optimal outcomes.  相似文献   
9.
10.
《Survey of ophthalmology》2022,67(3):659-674
The human eye has a unique immune architecture and behavior. While the conjunctiva is known to have a well-defined lymphatic drainage system, the cornea, sclera, and uveal tissues were historically considered “alymphatic” and thought to be immune privileged. The very fact that the aqueous outflow channels carry a clear fluid (aqueous humor) along the outflow pathway makes it hard to ignore its lymphatic-like characteristics. The development of novel lymphatic lineage markers and expression of these markers in aqueous outflow channels and improved imaging capabilities has sparked a renewed interest in the study of ocular lymphatics. Ophthalmic lymphatic research has had a directional shift over the last decade, offering an exciting new physiological platform that needs further in-depth understanding. The evidence of a presence of distinct lymphatic channels in the human ciliary body is gaining significant traction. The uveolymphatic pathway is an alternative new route for aqueous outflow and adds a new dimension to pathophysiology and management of glaucoma. Developing novel animal models, markers, and non-invasive imaging tools to delineate the core anatomical structure and physiological functions may help pave some crucial pathways to understand disease pathophysiology and help develop novel targeted therapeutic approaches for glaucoma.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号