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   2022篇
  免费   103篇
  国内免费   16篇
耳鼻咽喉   21篇
儿科学   17篇
妇产科学   141篇
基础医学   176篇
口腔科学   26篇
临床医学   153篇
内科学   507篇
皮肤病学   27篇
神经病学   149篇
特种医学   41篇
外科学   355篇
综合类   9篇
预防医学   67篇
眼科学   61篇
药学   174篇
中国医学   3篇
肿瘤学   214篇
  2023年   23篇
  2022年   28篇
  2021年   57篇
  2020年   46篇
  2019年   62篇
  2018年   66篇
  2017年   51篇
  2016年   61篇
  2015年   66篇
  2014年   95篇
  2013年   127篇
  2012年   203篇
  2011年   190篇
  2010年   100篇
  2009年   82篇
  2008年   161篇
  2007年   131篇
  2006年   140篇
  2005年   127篇
  2004年   96篇
  2003年   94篇
  2002年   55篇
  2001年   8篇
  2000年   8篇
  1999年   6篇
  1998年   10篇
  1997年   6篇
  1996年   3篇
  1995年   2篇
  1994年   10篇
  1993年   2篇
  1992年   3篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   3篇
  1987年   3篇
  1986年   1篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1972年   1篇
  1961年   1篇
排序方式: 共有2141条查询结果,搜索用时 203 毫秒
1.
Immunologic Research - EBV infection has long been suspected to play a role in the development of autoimmune diseases. Interestingly, a recently published study has provided the strongest evidence...  相似文献   
2.
3.
Bone vasculature and bone marrow vascular niches supply oxygen, nutrients, and secrete angiocrine factors required for the survival, maintenance, and self-renewal of stem and progenitor cells. In the skeletal system, vasculature creates nurturing niches for bone and blood-forming stem cells. Blood vessels regulate hematopoiesis and drive bone formation during development, repair, and regeneration. Dysfunctional vascular niches induce skeletal aging, bone diseases, and hematological disorders. Recent cellular and molecular characterization of the bone marrow microenvironment has provided unprecedented insights into the complexity, heterogeneity, and functions of the bone vasculature and vascular niches. The bone vasculature is composed of distinct vessel subtypes that differentially regulate osteogenesis, hematopoiesis, and disease conditions in bones. Further, bone marrow vascular niches supporting stem cells are often complex microenvironments involving multiple different cell populations and vessel subtypes. This review provides an overview of the emerging vascular cell heterogeneity in bone and the new roles of the bone vasculature and associated vascular niches in health and disease. © 2020 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).  相似文献   
4.
Background/objectivesTo investigate the association between optical coherence tomography (OCT) markers of lesion activity and changes in visual acuity (VA) during anti-vascular endothelial growth factor (anti-VEGF) therapy of eyes diagnosed with neovascular age-related macular degeneration (nAMD); and how VA and OCT markers are considered in physicians’ decision to retreat with anti-VEGFs.Subjects/methodsRetrospective, non-comparative, non-randomised cohort study involving electronic medical record data collected from 1190 patient eyes with nAMD diagnosis at two sites in the United Kingdom. Two sub-cohorts consisting of 321 and 301 eyes, respectively, were selected for analyses.ResultsIn 321 eyes, absence of IRF or SRF at ≥2 clinic visits resulted in a gain of five ETDRS letters from baseline, compared with two letters gained in eyes with <2 clinic visits with absence of IRF (p = 0.006) or SRF (p = 0.042). Anti-VEGF treatment was administered at 421 clinic visits, and 308 visits were without treatment. Comparing treatment visits with non-treatment visits, the maximum difference in frequency of OCT markers of lesion activity were for intraretinal fluid (IRF; 24% versus 5%) and subretinal fluid (SRF; 32% versus 5%). Pigment epithelial detachment (PED) was reported in 58% of treatment visits compared with 36% in non-treatment visits. VA loss was not a consistent trigger for retreatment as it was present in 63% of injection visits and in 49% of non-injection visits.ConclusionsRetreatment decision making is most strongly influenced by the presence of IRF and SRF and less by the presence of PED or VA loss.Subject terms: Outcomes research, Macular degeneration  相似文献   
5.
6.
Psoriasis is characterized by keratinocyte proliferation and chronic inflammation, but the pathogenesis is still unclear. Dysregulated mitochondria (mt) could lead to reduced apoptosis and extracellular secretion of mtDNA, acting as “innate pathogen” triggering inflammation. Serum was obtained from healthy volunteers and psoriatic patients. Mitochondrial DNA was extracted from the serum and amplified with quantitative PCR (qPCR). Punch biopsies were obtained from lesional and non‐lesional psoriatic skin (10 cm apart) and from healthy volunteers, were placed in RNA later and were stored at ?80°C until RNA was extracted and cDNA was synthesized; gene expression of uncoupling protein 2 (UCP2), Dynamin‐related protein 1 (Drp1) and calcineurin, involved in the regulation of mitochondria function, was detected with qPCR. Mitochondrial DNA was significantly increased (7s, P = 0.0496 and Cytochrome B, CytB, P = 0.0403) in the serum of psoriatic patients (n = 63) as compared to controls (n = 27). Gene expression was significantly reduced for UCP2 (P = 0.0218), Drp1 (P = 0.0001) and calcineurin (P = 0.0001) in lesional psoriatic skin, as compared to non‐lesional or control skin. Increased serum extracellular mtDNA in psoriatic patients and decreased expression of mitochondrial regulatory proteins in psoriatic skin suggest increased inflammation and reduced keratinocyte apoptosis, respectively. Inhibitors of mtDNA secretion and/or UCP2 stimulants may be potential treatment options.  相似文献   
7.
Abstract

Aim: Sex differences have long been reported in schizophrenia leading to the hypothesis that sex hormones may be implicated in the pathophysiology of the disorder. We assessed gonadal hormones during the fasted state in drug-naïve patients with psychosis.

Method: Fasting serum concentrations of follicular-stimulating hormone (FSH) and luteinizing hormone (LH), testosterone, free-testosterone, Sex Hormone Binding Globulin (SHBG) and oestradiol (E2) were compared between a group of 55 newly diagnosed, drug-naïve, first-episode men with psychosis and a group of 55 healthy controls, matched for age, smoking status and BMI. Testosterone, free-testosterone and SHBG were compared between a group of 32 drug-naïve, first-episode females with psychosis and a group of 32 healthy controls matched for age, smoking status and BMI.

Results: Testosterone and free-testosterone levels were significantly lower in the patients’ group and SHBG levels significantly higher in the patients’ group compared to those in healthy controls. The two female groups had similar values in the hormones which were measured.

Conclusion: Our findings provide evidence of lower testosterone and free-testosterone levels and increased SHBG levels in drug-naïve, first-episode males with psychosis.
  • KEY POINTS
  • Reduced testosterone and free-testosterone levels in drug-naive, first-episode males with psychosis.

  • Increased SHBG levels in drug-naive first-episode males with psychosis.

  • No difference in FSH, LH and E2 levels between drug-naive first episode males with psychosis and controls.

  • No difference in testosterone, free-testosterone and SHBG levels between drug-naive, first-episode women with psychosis and controls.

  相似文献   
8.
9.
ABSTRACT

Introduction

Type 1 diabetes mellitus (T1DM) is a chronic, autoimmune disease that is characterized by total absence of insulin production. Hypertension is a common comorbidity in T1DM with complex pathophysiology, while it is also a well-recognized risk factor for the development of cardiovascular disease (CVD), as well as other microvascular diabetic complications.  相似文献   
10.
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