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   2115篇
  免费   142篇
  国内免费   10篇
耳鼻咽喉   67篇
儿科学   93篇
妇产科学   21篇
基础医学   202篇
口腔科学   43篇
临床医学   155篇
内科学   524篇
皮肤病学   41篇
神经病学   115篇
特种医学   63篇
外科学   400篇
综合类   51篇
一般理论   6篇
预防医学   96篇
眼科学   52篇
药学   175篇
中国医学   4篇
肿瘤学   159篇
  2023年   13篇
  2022年   42篇
  2021年   132篇
  2020年   68篇
  2019年   71篇
  2018年   101篇
  2017年   62篇
  2016年   61篇
  2015年   65篇
  2014年   93篇
  2013年   104篇
  2012年   171篇
  2011年   151篇
  2010年   80篇
  2009年   78篇
  2008年   125篇
  2007年   117篇
  2006年   110篇
  2005年   109篇
  2004年   67篇
  2003年   48篇
  2002年   55篇
  2001年   22篇
  2000年   36篇
  1999年   22篇
  1998年   23篇
  1997年   12篇
  1993年   4篇
  1992年   15篇
  1991年   15篇
  1990年   15篇
  1989年   14篇
  1988年   12篇
  1987年   15篇
  1986年   17篇
  1985年   11篇
  1984年   14篇
  1983年   10篇
  1980年   3篇
  1979年   10篇
  1977年   8篇
  1976年   4篇
  1975年   6篇
  1974年   3篇
  1973年   8篇
  1972年   6篇
  1971年   10篇
  1970年   4篇
  1969年   3篇
  1966年   3篇
排序方式: 共有2267条查询结果,搜索用时 582 毫秒
61.
62.
BACKGROUND: We established the biochemical and hematological reference intervals among a south Indian healthy adult population attending an HIV referral centre in Chennai, southern India. METHODS: In a cross sectional study, 213 study subjects (129 male and 84 female) were studied between March and August 2005. All of the parameters were analyzed using standard hematological and biochemical techniques. RESULTS: Certain biochemical (viz. total bilirubin, alanine transaminase, albumin, creatinine, total protein, lipid profile, creatine phosphokinase, uric acid and lactate) and hematological (mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration and lymphocyte levels) parameters presented higher upper limits. In addition, the upper limits of white blood cell count, platelet count, hematocrit, red blood cell count and hemoglobin level were low in comparison to the currently reported ranges. CONCLUSION: Ethnic variation in reference intervals was observed in certain biochemical and hematological analytes in a south Indian adult population.  相似文献   
63.
Occlusion and its relationship to the function of the stomatognathic system have been widely studied in dentistry since many decades. This series of articles describe about occlusion in the complete denture, fixed partial denture, and implants. Part I and II of this articles series describe concepts and philosophies of occlusion in complete denture. So far, available research has not concluded a superior tooth form or occlusal scheme to satisfy the requirements of completely edentulous patients with respect to comfort, mastication, phonetics, and esthetics. Since then, several balanced and nonbalanced articulation concepts were proposed in the literature. A balanced articulation appears to be most appropriate because of tooth contacts observed during nonfunctional activities of patients. This article discusses about evolution of different concepts of occlusion and occlusal schemes in complete denture occlusion.Key Words: Articulation, complete denture, occlusion  相似文献   
64.
Inclusion body myositis is a rare sporadic inflammatory‐degenerative myopathy of the elderly. Despite being the commonest type of acquired myopathy after the age of 50, misdiagnosis is extremely common. The most frequent hurdle in identifying new cases is the wrong diagnosis of polymyositis or motor neuron disease. Novel insights into pathogenic mechanisms have heralded the quest for newer therapeutics as well as drug repurposing in this otherwise progressive disorder.  相似文献   
65.
T‐cell migration across the blood‐brain barrier is a crucial step in the pathogenesis of EAE, an animal model for MS. Live cell imaging studies demonstrated that P‐selectin glycoprotein ligand‐1 (PSGL‐1) and its endothelial ligands E‐ and P‐selectin mediate the initial rolling of T cells in brain vessels during EAE. As functional absence of PSGL‐1 or E/P‐selectins does not result in ameliorated EAE, we speculated that T‐cell entry into the spinal cord is independent of PSGL‐1 and E/P‐selectin. Performing intravital microscopy, we observed the interaction of WT or PSGL‐1?/? proteolipid protein‐specific T cells in inflamed spinal cord microvessels of WT or E/P‐selectin?/? SJL/J mice during EAE. T‐cell rolling but not T‐cell capture was completely abrogated in the absence of either PSGL‐1 or E‐ and P‐selectin, resulting in a significantly reduced number of T cells able to firmly adhere in the inflamed spinal cord microvessels, but did not lead to reduced T‐cell invasion into the CNS parenchyma. Thus, PSGL‐1 interaction with E/P‐selectin is essential for T‐cell rolling in inflamed spinal cord microvessels during EAE. Taken together with previous observations, our findings show that T‐cell rolling is not required for successful T‐cell entry into the CNS and initiation of EAE.  相似文献   
66.
Polymer based solid electrolytes (SEs) are envisaged as futuristic components of safer solid state energy devices. But the semi-crystalline nature and slow dynamics of the host polymer matrix are found to hamper the ion transport through the solid polymer network and hence solid state devices are still far beyond the scope of practical application. In this study, we unravel the synergistic roles of Li salt (LiClO4) and two different polymers – polyethylene oxide (PEO) and polydimethyl siloxane (PDMS), in the Li ion transport through their solid blend based electrolyte. A detailed study using dielectric spectroscopy and thermo-mechanical analysis is conducted to understand the tunability of the PEO chain dynamics with LiClO4 and the mechanism of hopping of Li ions by forming ion pairs with oxygen dipoles on the PEO backbone is established. Despite the lack of PDMS''s capability to solvate ions and promote ion transport directly, its proper mixing within the PEO host matrix is demonstrated to enhance ion transport due to the influence of PDMS on the segmental dynamics of PEO. A detailed molecular dynamics study supported by experimental validation suggests that even inert polymers can affect the dynamics of the active host matrix and increase ion transport, leading to next generation high ionic conductivity solid matrices, and opens new avenues in designing polymer based transparent electrolytes.

The studies shown here prove that both the Li salt and ‘inert-polymer’ mixing have paramount importance in the tunability of Li ion conductivity in solid electrolytes for batteries.  相似文献   
67.
Ocean barrier layers' effect on tropical cyclone intensification   总被引:5,自引:0,他引:5  
Improving a tropical cyclone's forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone's path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are "quasi-permanent" features in the upper tropical oceans. When tropical cyclones pass over regions with barrier layers, the increased stratification and stability within the layer reduce storm-induced vertical mixing and sea surface temperature cooling. This causes an increase in enthalpy flux from the ocean to the atmosphere and, consequently, an intensification of tropical cyclones. On average, the tropical cyclone intensification rate is nearly 50% higher over regions with barrier layers, compared to regions without. Our finding, which underscores the importance of observing not only the upper-ocean thermal structure but also the salinity structure in deep tropical barrier layer regions, may be a key to more skillful predictions of tropical cyclone intensities through improved ocean state estimates and simulations of barrier layer processes. As the hydrological cycle responds to global warming, any associated changes in the barrier layer distribution must be considered in projecting future tropical cyclone activity.  相似文献   
68.
69.
Magnetic resonance imaging (MRI) is the imaging modality of choice in the evaluation of internal derangement of the temporomandibular joint (TMJ). Dynamic MRI including the open and close mouth views in sagittal plane determine the exact position of articular disk and thus help to evaluate the joint for internal derangement. We also highlight the role of dynamic MRI of TMJ in diagnosis of stuck disk in a 17-year-old male who presented with symptoms of pain and difficulty in opening the mouth.  相似文献   
70.
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