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   809篇
  免费   40篇
  国内免费   4篇
耳鼻咽喉   7篇
儿科学   12篇
妇产科学   13篇
基础医学   147篇
口腔科学   5篇
临床医学   89篇
内科学   203篇
皮肤病学   12篇
神经病学   58篇
特种医学   24篇
外科学   91篇
综合类   5篇
预防医学   49篇
眼科学   30篇
药学   37篇
  1篇
中国医学   5篇
肿瘤学   65篇
  2024年   13篇
  2023年   15篇
  2022年   29篇
  2021年   67篇
  2020年   44篇
  2019年   66篇
  2018年   60篇
  2017年   27篇
  2016年   33篇
  2015年   27篇
  2014年   39篇
  2013年   43篇
  2012年   89篇
  2011年   56篇
  2010年   25篇
  2009年   14篇
  2008年   35篇
  2007年   30篇
  2006年   27篇
  2005年   16篇
  2004年   16篇
  2003年   8篇
  2002年   10篇
  2001年   6篇
  2000年   5篇
  1999年   2篇
  1998年   2篇
  1996年   3篇
  1991年   2篇
  1979年   3篇
  1973年   3篇
  1972年   2篇
  1971年   3篇
  1969年   3篇
  1968年   1篇
  1966年   1篇
  1961年   1篇
  1939年   1篇
  1933年   1篇
  1931年   1篇
  1927年   1篇
  1926年   1篇
  1924年   1篇
  1923年   2篇
  1920年   1篇
  1917年   1篇
  1915年   1篇
  1914年   3篇
  1913年   1篇
  1910年   1篇
排序方式: 共有853条查询结果,搜索用时 0 毫秒
11.
Tight coordination of cell proliferation and differentiation is central to red blood cell formation. Erythropoietin controls the proliferation and survival of red blood cell precursors, while variations in GATA-1/FOG-1 complex composition and concentrations drive their maturation. However, clear evidence of cross-talk between molecular pathways is lacking. Here, we show that erythropoietin activates AKT, which phosphorylates GATA-1 at Ser310, thereby increasing GATA-1 affinity for FOG-1. In turn, FOG-1 displaces pRb/E2F-2 from GATA-1, ultimately releasing free, proproliferative E2F-2. Mice bearing a Gata-1S310A mutation suffer from fatal anemia when a compensatory pathway for E2F-2 production involving insulin-like growth factor-1 (IGF-1) signaling is simultaneously abolished. In the context of the GATA-1V205G mutation resulting in lethal anemia, we show that the Ser310 cannot be phosphorylated and that constitutive phosphorylation at this position restores partial erythroid differentiation. This study sheds light on the GATA-1 pathways that synchronize cell proliferation and differentiation for tissue homeostasis.  相似文献   
12.
We report that daily administration of the diuretic NKCC1 chloride co‐transporter, bumetanide, reduces the severity of autism in a 10‐year‐old Fragile X boy using CARS, ADOS, ABC, RDEG and RRB before and after treatment. In keeping with extensive clinical use of this diuretic, the only side effect was a small hypokalaemia. A double‐blind clinical trial is warranted to test the efficacy of bumetanide in FRX. Conclusion: This single case report showed an improvement of the scores of each test used after 3 months of treatment. Double‐blind clinical trials are warranted to test the efficacy of bumetanide in FRX.  相似文献   
13.
Try a different breed of security officer to improve safety and boost morale in your facility.  相似文献   
14.
BACKGROUND: Starting a surgical internship is a stressful experience. We developed a web and simulation-based curriculum to ease this transition. METHODS: We created an educational website containing a curriculum of commonly encountered on call situations. After match day in 2003, we contacted all of our new surgical interns. We performed a confidence assessment using a Likert-scale questionnaire, and the trainees were given access to the curriculum. In June 2003, we performed human patient simulator sessions. The participants were asked to provide feedback regarding the simulator experience. During the first week of residency, they were again asked to answer the confidence questionnaire. RESULTS: Sixteen residents (94%) used the web curriculum, and 17 (100%) participated in the simulations. Eleven (65%) filled out both questionnaires. The confidence score improved from 5.4 to 6.7 (P < .0001). CONCLUSIONS: A web and simulation-based curriculum for incoming house staff is feasible. Studies are underway to validate this novel method and to expand its use for surgical education.  相似文献   
15.
Takayasu arteritis (TA) is a large vessel vasculitis that usually affects young female patients during the second and third decades of life, but has been reported in children as young as 24 months of age. Aim of this report was to describe four children (two girls) with TA, as well as summarizing main published studies. The mean age at presentation of our cases was 11 years (range 8–15). Three patients were Caucasians and one Asian. Arterial hypertension was the commonest mode of presentation followed by systemic symptoms. Other related symptoms were due to ischemia and consisted of abdomen, chest, and limb pain. An abdominal bruit was noted in only one patient. Inflammation markers were always abnormal. Angiography was performed in all cases; left subclavian artery and common carotid artery were more frequently involved. Renal artery stenosis was observed in two patients. One boy was diagnosed as having an associated immune deficiency (Wiskott-Aldrich syndrome). Treatment modalities included prednisone (n = 4), methotrexate (n = 3), and mycophenolate mofetil (MMF) (n = 1). Surgery was required in two patients. Follow-up ranged from 3 to 10 years since diagnosis. In three cases antihypertensive drugs and methotrexate were stopped, and prednisone was reduced to 7.5 mg/day.  相似文献   
16.
Safe and effective cell delivery remains one of the main challenges in cell-based therapy of neurodegenerative disorders. Graft survival, sufficient enrichment of therapeutic cells in the brain, and avoidance of their distribution throughout the peripheral organs are greatly influenced by the method of delivery. Here we demonstrate for the first time noninvasive intranasal (IN) delivery of mesenchymal stem cells (MSCs) to the brains of unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats. IN application (INA) of MSCs resulted in the appearance of cells in the olfactory bulb, cortex, hippocampus, striatum, cerebellum, brainstem, and spinal cord. Out of 1?×?10? MSCs applied intranasally, 24% survived for at least 4.5 months in the brains of 6-OHDA rats as assessed by quantification of enhanced green fluorescent protein (EGFP) DNA. Quantification of proliferating cell nuclear antigen-positive EGFP-MSCs showed that 3% of applied MSCs were proliferative 4.5 months after application. INA of MSCs increased the tyrosine hydroxylase level in the lesioned ipsilateral striatum and substantia nigra, and completely eliminated the 6-OHDA-induced increase in terminal deoxynucleotidyl transferase (TdT)-mediated 2'-deoxyuridine, 5'-triphosphate (dUTP)-biotin nick end labeling (TUNEL) staining of these areas. INA of EGFP-labeled MSCs prevented any decrease in the dopamine level in the lesioned hemisphere, whereas the lesioned side of the control animals revealed significantly lower levels of dopamine 4.5 months after 6-OHDA treatment. Behavioral analyses revealed significant and substantial improvement of motor function of the Parkinsonian forepaw to up to 68% of the normal value 40-110 days after INA of 1?×?10? cells. MSC-INA decreased the concentrations of inflammatory cytokines-interleukin-1β (IL-1β), IL-2, -6, -12, tumor necrosis factor (TNF), interferon-γ (IFN-γ, and granulocyte-macrophage colony-stimulating factor (GM-CSF)-in the lesioned side to their levels in the intact hemisphere. IN administration provides a highly promising noninvasive alternative to the traumatic surgical procedure of transplantation and allows targeted delivery of cells to the brain with the option of chronic application.  相似文献   
17.
18.
19.
20.
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