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   118篇
  免费   12篇
  国内免费   1篇
耳鼻咽喉   4篇
儿科学   4篇
妇产科学   12篇
基础医学   26篇
口腔科学   1篇
临床医学   26篇
内科学   15篇
皮肤病学   2篇
神经病学   15篇
外科学   2篇
综合类   2篇
预防医学   8篇
眼科学   5篇
药学   4篇
肿瘤学   5篇
  2023年   1篇
  2021年   6篇
  2020年   3篇
  2019年   8篇
  2018年   5篇
  2017年   5篇
  2016年   2篇
  2015年   6篇
  2014年   2篇
  2013年   9篇
  2012年   4篇
  2011年   9篇
  2010年   2篇
  2009年   5篇
  2008年   5篇
  2007年   4篇
  2006年   4篇
  2005年   9篇
  2004年   7篇
  2003年   5篇
  2002年   4篇
  2001年   3篇
  2000年   7篇
  1999年   5篇
  1998年   1篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1991年   1篇
  1986年   1篇
  1985年   1篇
  1975年   1篇
  1933年   1篇
  1923年   1篇
排序方式: 共有131条查询结果,搜索用时 15 毫秒
51.

Aims/hypothesis  

Pregnancies complicated by diabetes have a higher risk of adverse outcomes for mothers and children, including predisposition to disease later in life, e.g. metabolic syndrome and hypertension. We hypothesised that adverse outcomes from diabetic pregnancies may be linked to compromised placental function, and sought to identify cellular and molecular abnormalities in diabetic placenta.  相似文献   
52.
Pittet CL  Newcombe J  Antel JP  Arbour N 《Glia》2011,59(5):841-856
Central nervous system (CNS) cells locally modulate immune responses using numerous molecules that are not fully elucidated. Engagement of programmed death-1 (PD-1), expressed on activated T cells, by its ligands (PD-L1 or PD-L2) suppresses T-cell responses. Enhanced CNS PD-1 and PD-L1 expression has been documented in inflammatory murine models; however, human CNS data are still incomplete. We determined that human primary cultures of astrocytes, microglia, oligodendrocytes, or neurons expressed low or undetectable PD-L1 under basal conditions, but inflammatory cytokines significantly induced such expression, especially on astrocytes and microglia. Blocking PD-L1 expression in astrocytes using specific siRNA led to significantly increased CD8 T-cell responses (proliferation, cytokines, lytic enzyme). Thus, our results establish that inflamed human glial cells can express sufficient and functional PD-L1 to inhibit CD8 T cell responses. Extensive immunohistochemical analysis of postmortem brain tissues demonstrated a significantly greater PD-L1 expression in multiple sclerosis (MS) lesions compared with control tissues, which colocalized with astrocyte or microglia/macrophage cell markers. However, more than half of infiltrating CD8 T lymphocytes in MS lesions did not express PD-1, the cognate receptor. Thus, our results demonstrate that inflamed human CNS cells such as in MS lesions express significantly elevated PD-L1, providing a means to reduce CD8 T cell responses, but most of these infiltrating immune cells are devoid of PD-1 and thus insensitive to PD-L1/L2. Strategies aimed at inducing PD-1 on deleterious activated human CD8 T cells that are devoid of this receptor could provide therapeutic benefits since PD-L1 is already increased in the target organ.  相似文献   
53.
54.
Harlequin ichthyosis, (MIM 242500), is a rare, autosomal recessive skin disorder due to an inborn error of epidermal keratinization. The gene for this condition has not been localized. We present a case of HI in which there was a de novo deletion of chromosome 18q: the karyotype was 46, XY, del(18)(q21.3). We postulate that the gene for HI may lie at, or distal to 18q21.3 and that the deletion observed in this case may have unmasked this autosomal recessive disorder. © 2001 Wiley‐Liss, Inc.  相似文献   
55.
The phenomenon of paradoxical nasal obstruction is described. An understanding of this phenomenon is made possible by the knowledge of the nasal cycle and of the concept of total nasal airway resistance. These topics are reviewed and two patients with paradoxical nasal obstruction are described. Direct observation, rhinomanometric tests and serial tomograms were utilized to substantiate these findings.  相似文献   
56.

Objectives

To optimize the 3D printing of a dental material for provisional crown and bridge restorations using a low-cost stereolithography 3D printer; and compare its mechanical properties against conventionally cured provisional dental materials.

Methods

Samples were 3D printed (25 × 2 × 2 mm) using a commercial printable resin (NextDent C&B Vertex Dental) in a FormLabs1+ stereolithography 3D printer. The printing accuracy of printed bars was determined by comparing the width, length and thickness of samples for different printer settings (printing orientation and resin color) versus the set dimensions of CAD designs. The degree of conversion of the resin was measured with FTIR, and both the elastic modulus and peak stress of 3D printed bars was determined using a 3-point being test for different printing layer thicknesses. The results were compared to those for two conventionally cured provisional materials (Integrity®, Dentsply; and Jet®, Lang Dental Inc.).

Results

Samples printed at 90° orientation and in a white resin color setting was chosen as the most optimal combination of printing parameters, due to the comparatively higher printing accuracy (up to 22% error), reproducibility and material usage. There was no direct correlation between printing layer thickness and elastic modulus or peak stress. 3D printed samples had comparable modulus to Jet®, but significantly lower than Integrity®. Peak stress for 3D printed samples was comparable to Integrity®, and significantly higher than Jet®. The degree of conversion of 3D printed samples also appeared higher than that of Integrity® or Jet®.

Significance

Our results suggest that a 3D printable provisional restorative material allows for sufficient mechanical properties for intraoral use, despite the limited 3D printing accuracy of the printing system of choice.  相似文献   
57.
Women's health care in the United States is at a critical juncture. There is increased demand for primary care providers, including women's health specialists such as certified nurse‐midwives/certified midwives, women's health nurse practitioners, and obstetrician‐gynecologists, yet shortages in numbers of these providers are expected. This deficit in the number of women's health care providers could have adverse consequences for women and their newborns when women have to travel long distances to access maternity health care. Online education using innovative technologies and evidence‐based teaching and learning strategies have the potential to increase the number of health care providers in several disciplines, including midwifery. This article reviews 3 innovative uses of online platforms for midwifery education: virtual classrooms, unfolding case studies, and online return demonstrations of clinical skills. These examples of innovative teaching strategies can promote critical and creative thinking and enhance competence in skills. Their use in online education can help enhance the student experience. More students, including those who live in rural and underserved regions and who otherwise might be unable to attend a traditional onsite campus, are provided the opportunity to complete quality midwifery education through online programs, which in turn may help expand the women's health care provider workforce. This article is part of a special series of articles that address midwifery innovations in clinical practice, education, interprofessional collaboration, health policy, and global health.  相似文献   
58.
59.
60.
The archaic definition and registration processes for stillbirth currently prevalent in Canada impede both clinical care and public health. The situation is fraught because of definitional problems related to the inclusion of induced abortions at ≥20 weeks’ gestation as stillbirths: widespread uptake of prenatal diagnosis and induced abortion for serious congenital anomalies has resulted in an artefactual temporal increase in stillbirth rates in Canada and placed the country in an unfavourable position in international (stillbirth) rankings. Other problems with the Canadian stillbirth definition and registration processes extend to the inclusion of fetal reductions (for multi-fetal pregnancy) as stillbirths, and the use of inconsistent viability criteria for reporting stillbirth. This paper reviews the history of stillbirth registration in Canada, provides a rationale for updating the definition of fetal death and recommends a new definition and improved processes for fetal death registration. The recommendations proposed are intended to serve as a starting point for reformulating issues related to stillbirth, with the hope that building a consensus regarding a definition and registration procedures will facilitate clinical care and public health.  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