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   6072篇
  免费   433篇
  国内免费   19篇
耳鼻咽喉   49篇
儿科学   180篇
妇产科学   154篇
基础医学   867篇
口腔科学   82篇
临床医学   633篇
内科学   1333篇
皮肤病学   117篇
神经病学   630篇
特种医学   118篇
外科学   587篇
综合类   52篇
一般理论   3篇
预防医学   762篇
眼科学   93篇
药学   417篇
中国医学   32篇
肿瘤学   415篇
  2024年   12篇
  2023年   90篇
  2022年   136篇
  2021年   280篇
  2020年   167篇
  2019年   229篇
  2018年   245篇
  2017年   177篇
  2016年   154篇
  2015年   217篇
  2014年   243篇
  2013年   349篇
  2012年   533篇
  2011年   492篇
  2010年   306篇
  2009年   253篇
  2008年   399篇
  2007年   365篇
  2006年   357篇
  2005年   340篇
  2004年   315篇
  2003年   249篇
  2002年   231篇
  2001年   34篇
  2000年   33篇
  1999年   43篇
  1998年   38篇
  1997年   20篇
  1996年   32篇
  1995年   30篇
  1994年   17篇
  1993年   15篇
  1992年   11篇
  1991年   16篇
  1990年   7篇
  1989年   7篇
  1988年   11篇
  1987年   7篇
  1986年   9篇
  1984年   6篇
  1983年   5篇
  1982年   3篇
  1981年   3篇
  1980年   4篇
  1979年   4篇
  1976年   4篇
  1974年   5篇
  1973年   5篇
  1971年   3篇
  1970年   3篇
排序方式: 共有6524条查询结果,搜索用时 10 毫秒
81.
82.
Studies show a link between neighborhoods and depression. Multiple social processes may contribute to this relationship. This study examines multiple neighborhood social factors simultaneously and how each may contribute to depression. 717 individuals were recruited from high‐drug‐use areas in Baltimore, Maryland to be interviewed. Participants reported perceptions of their neighborhood and depressive symptoms. The influence of four neighborhood factors (social disorder, institutional control, individual control, and future risk) on presence of depression was assessed using logistic regression. Higher levels of social disorder (OR:1.36) and perceived future risk of crime (OR:1.41) were associated with greater odds of depression. These relationships remained even when accounting for other neighborhood and individual factors. These results suggest perceived social disorder and future risk of being a victim of crime may be particularly salient in exacerbating depressive symptoms. This research may be beneficial for individual and community‐based interventions for prevention and treatment of depression.  相似文献   
83.
Inflammation stimulates new lymphatic vessel growth (inflammatory lymphangiogenesis). One key question is how recurrent inflammation, a common clinical condition, regulates lymphatic vessel remodeling. We show here that recurrent inflammation accelerated the development a functional lymphatic vessel network. This observation suggests a novel program of lymphangiogenesis and identifies a property of lymphatic vessel memory in response to recurrent inflammation. A brief episode of initial inflammation regressed lymphatic vessels, and a significant increase in CD11b+ macrophages were associated with the development of lymphatic vessel memory. These vessels had major differences in the structure and the spatial distribution of specialized lymphatic vessel features. Surprisingly, we found that the lymphatic vessel memory response did not depend on the vascular endothelial growth factor C or A pathway, indicating that different molecular pathways regulate inflammatory lymphangiogenesis and lymphatic vessel memory. These findings uncover a priming mechanism to facilitate a rapid lymphatic vessel memory response: a potential important component of peripheral host defense.The lymphatic vasculature is one component of the inflammatory response that is remarkably understudied. The lymphatic system can be broadly classified into the lymphoid tissue (tonsils, lymph nodes, and spleen) and the conduit system or lymphatic vasculature. The focus of these studies is the lymphatic capillaries which literally are the most peripheral extension of the immune system and reside intimately in the diseased tissue. Aside from the classic functions of the lymphatic vasculature described many years ago (transport of extracellular fluid, cells, antigens, and lipid), surprisingly little is known about the normal physiology of this system and how it regulates inflammation and wound recovery. Multiple lines of evidence have shown that the lymphatic vasculature proliferates in response to inflammatory conditions, suggesting an active, perhaps essential, role during the inflammatory response.1–6 Inflammatory lymphangiogenesis is thought to be a physiological mechanism that develops to meet the increased demands of fluid, antigen, and cellular transport during an inflammatory response. New lymphatic vessel growth has been associated with beneficial effects in several different preclinical models of acute or chronic inflammatory disease.3,7–9 It is well recognized that vascular endothelial growth factor (VEGF)-C-VEGF receptor (VEGFR)-3 and VEGF-A-VEGFR-2 pathways are important in inflammatory lymphangiogenesis.10 The most accepted model of inflammatory lymphangiogenesis is that vessels sprout and elongate from pre-existing lymphatic vessels. In contrast, is some evidence is available that circulating endothelial progenitors or macrophages differentiate into lymphatic endothelial cells to comprise newly synthesized lymphatic vessels.11,12Clinically, two general outcomes occur after an initial episode of inflammatory disease: wound recovery or recurrent inflammation. We developed a mouse model of wound recovery and recurrent inflammation to simulate these clinical outcomes and to study the lymphatic vasculature during these conditions. We recently demonstrated that lymphatic vessel regression developed during wound recovery in the cornea.13 Fragmented lymphatic vessels that persisted over time were visualized in wound recovery conditions.In contrast to wound recovery, recurrent inflammation is a common clinical outcome after an initial episode of inflammation. We studied the effects of recurrent inflammation in corneal tissue recovered from an initial inflammatory response. This approach is different from earlier studies in that it features wound recovery followed by recurrent inflammation rather than an acute or chronic unrelenting pathogen or tumor-based inflammatory stimuli.3,4,7,14 We induced recurrent inflammation in recovered corneal tissue by placing a subsequent suture in the cornea (re-suturing). Here, we show that one feature of recurrent inflammation was the accelerated localized development of a functional lymphatic vessel network. The rapid kinetics and memory response were reminiscent of an immunological memory response; for this reason we describe this process as lymphatic vessel memory. This response appeared to stimulate the anastomosis of fragmented lymphatic vessels. Unlike inflammatory lymphangiogenesis induced by initial inflammation, we showed that lymphatic vessel memory was independent of the VEGF-C and VEGF-A pathways. Thus, these studies reveal a novel program of lymphatic vessel memory.  相似文献   
84.
85.
In the early 21st century, a new way to classify breast cancer appeared, based on their gene expression profiles. Various classifications have been proposed in an attempt to subrogate these molecular groups to an immunohistochemical expression of estrogen and progesterone receptors, HER2 and Ki67. We compared the three major molecular classifications (MCs) of 374 infiltrating breast carcinomas with the assumption that one is better than the others to discriminate the prognosis of patients that are classified by it. We found that [1] there was a significant statistical association with tumor grade and presence of associated HG-DCIS, but with differences in kappa indices [2]; MC3 showed a significant relationship with pathological tumor stage (p = 0.012, CI95% of 0.012–0.017); [3] only MC3 showed convincingly that the observed differences in OS were not due to chance in the univariate analysis (p = 0.04); [4] only MC3 is an independent prognostic factor of OS. In conclusion, these three classifications are not interchangeable; MC3, the only one that includes Ki67 expression in their defining criteria, is better in predicting prognosis than the others.  相似文献   
86.
87.
88.
89.
Autoimmune neurological disorders, including neuromyelitis optica spectrum disorder, anti-N-methyl-D-aspartate receptor encephalitis, anti-MOG antibody-associated disorders, and myasthenia gravis, are clearly defined by the presence of autoantibodies against neurological antigens. Although these autoantibodies have been heavily studied for their biological activities, given the heterogeneity of polyclonal patient samples, the characteristics of a single antibody cannot be definitively assigned. This review details the findings of polyclonal serum and CSF studies and then explores the advances made by single-cell technologies to the field of antibody-mediated neurological disorders. High-resolution single-cell methods have revealed abnormalities in the tolerance mechanisms of several disorders and provided further insight into the B cells responsible for autoantibody production. Ultimately, several factors, including epitope specificity and binding affinity, finely regulate the pathogenic potential of an autoantibody, and a deeper appreciation of these factors may progress the development of targeted immunotherapies for patients.  相似文献   
90.
The International Journal of Cardiovascular Imaging - Recent studies show that microvascular injury consists of microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH). In patients...  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