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   330篇
  免费   26篇
耳鼻咽喉   1篇
儿科学   6篇
妇产科学   1篇
基础医学   36篇
口腔科学   17篇
临床医学   34篇
内科学   129篇
皮肤病学   7篇
神经病学   5篇
特种医学   16篇
外科学   29篇
综合类   6篇
一般理论   1篇
预防医学   26篇
药学   19篇
中国医学   5篇
肿瘤学   18篇
  2023年   7篇
  2022年   7篇
  2021年   4篇
  2020年   7篇
  2019年   4篇
  2018年   9篇
  2017年   10篇
  2016年   10篇
  2015年   10篇
  2014年   15篇
  2013年   14篇
  2012年   20篇
  2011年   21篇
  2010年   8篇
  2009年   16篇
  2008年   20篇
  2007年   12篇
  2006年   10篇
  2005年   15篇
  2004年   19篇
  2003年   21篇
  2002年   20篇
  2001年   16篇
  2000年   9篇
  1999年   5篇
  1998年   4篇
  1997年   7篇
  1996年   8篇
  1995年   4篇
  1993年   4篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1986年   1篇
  1984年   1篇
  1983年   3篇
  1982年   1篇
  1980年   1篇
  1978年   3篇
  1977年   1篇
  1976年   1篇
  1975年   2篇
排序方式: 共有356条查询结果,搜索用时 15 毫秒
51.
52.

Objectives

The aim of the present study was to assess the short term prognostic significance of N-terminal pro BNP (NT-proBNP), 3D left atrial volume (LAV) and left ventricular (LV) dyssynchrony in patients of acute ST-elevation myocardial infarction (STEMI) who underwent primary Percutaneous intervention (PCI).

Background

NT-proBNP, LV dyssynchrony and LAV in patients with acute coronary syndrome have been associated with PCI outcomes and predict the short and long-term prognosis.

Methods

This study consisted of 142 patients with a first STEMI who underwent primary PCI. Baseline echocardiographic data was collected at admission and at 6 months follow up. Left ventricular dyssynchrony was measured by tissue Doppler imaging and LAV by real time 3D-echocardiography, plasma NT-proBNP levels were estimated between 72 and 96 h of admission.

Results

During study period 3 patients expired and 4 developed congestive heart failure (CHF). Baseline NT-proBNP and LV dyssynchrony correlated with LV size and LV ejection fraction (LVEF) at baseline and during follow up. Patients with higher NT-proBNP levels and higher LV dyssynchrony showed significant increase in LV size with decrease in LVEF during follow-up. Baseline Left atrial volume index (LAVI) showed significant correlation with LV size but no association with LVEF at baseline and during follow-up.

Conclusions

Higher levels of NT-proBNP and higher LV dyssynchrony can predict patients with increase in LV size, worsening of LV systolic and diastolic function during follow-up. Patients with higher NT-proBNP levels at baseline developed CHF during follow-up.  相似文献   
53.
Dewald  GW; Pierre  RV; Phyliky  RL 《Blood》1982,59(1):100-105
Structural abnormalities of the X chromosome are rarely found in neoplastic disorders. We describe three patients with a history of idiopathic acquired sideroblastic anemia (IASA); each one had an abnormal clone of cells in the bone marrow, characterized by a structurally abnormal X chromosome. In two of these patients, the predominant karyotype was 47,X,2idic(X)(q13); in the other patient, it was 46,X,t(X;11)(q13;p15). Inasmuch as all three of these cases involved chromosome band Xq13, as did two previously published cases, we suggest that band Xq13 may be more prone to structural rearrangement than other X chromosome bands in hematologic disorders. The common Xq13 chromosome breakpoint and clinical presentation (IASA) among these three patients and the occurrence of an X-linked type of sideroblastic anemia may suggest that an association exists between X chromosome abnormalities and IASA. Perhaps alteration of a gene or chromosome structure in or near band Xq13 predisposes to development of IASA. The fact that two of these patients had preleukemia and the third had overt acute leukemia may imply that patients with IASA and X chromosome abnormalities have a poor prognosis. Cases of IASA without associated X chromosome abnormalities are known; thus, if an association between IASA and an abnormal X chromosome does exist, most likely it involves only some patients with IASA.  相似文献   
54.
Datta  R; Banach  D; Kojima  H; Talanian  RV; Alnemri  ES; Wong  WW; Kufe  DW 《Blood》1996,88(6):1936-1943
The response of human myeloid leukemia cells to treatment with 1-beta- arabinofuranosylcytosine (ara-C) includes the induction of apoptosis. Ara-C induced apoptosis is associated with proteolytic cleavage of poly(ADP-ribose) polymerase (PARP) and protein kinase C (PKC) delta. However, the signals involved in this response are unknown. The present studies show that ara-C treatment of U-937 cells is associated with induction of a protease activity that cleaves the tetrapeptides Ac-DEVD- pNA and Ac-DMOD-pNA found at the cleavage sites of PARP and PKC delta, respectively. The ara-C-induced protease activity was sensitive to overexpression of the anti-apoptotic protein Bcl-xL and the baculovirus protein p35. By contrast, overexpression of the cowpox virus protein CrmA blocked apoptosis induced by engagement of the Fas receptor but not that induced by ara-C. CrmA overexpression also had no detectable effect on ara-C-induced cleavage of PKC delta. The results further show that ara-C induces activation of the CPP32 protease by a CrmA- insensitive and p35-sensitive mechanism. Similar results were obtained with cisplatinum, etoposide, and camptothecin. These findings indicate that ara-C and other DNA-damaging agents activate a CrmA-insensitive apoptotic pathway involving CPP32 and that these signals differ from those associated with apoptosis induced by the Fas receptor.  相似文献   
55.
56.
57.
58.
(+)-Lariciresinol 3a-acetate [(+)-(3S)-acetyloxymethyl-(2S)-(4-hydroxy-3-methoxyphenyl)-(4R)-[(4-hydroxy-3-methoxyphenyl)methyl]tetrahydrofuran] (1), a metabolite of A. elaeagnoidea was synthesized starting from (-)-lariciresinol (2) in three steps with an overall yield of 66%.  相似文献   
59.
目的构建并鉴定靶向人ERRα基因的小分子干扰RNA的慢病毒载体。方法针对ERRαmRNA设计了4条si RNA,并构建pGCSIL-GFP-siERRα慢病毒质粒,PCR扩增阳性克隆并测序鉴定。用pGCSIL-GFP-siERRα、pHelp-er1.0和pHelper2.0质粒共转染293T细胞包装产生慢病毒,测定病毒滴度。将慢病毒干扰RNA及含有ERRα过表达载体共转染293T细胞,Western-blot检测ERRα表达,观察蛋白表达抑制效果。结果 PCR和测序结果与设计的干扰序列一致,病毒滴度达2×109TU/ml。转染细胞中ERRα蛋白表达显著降低。结论成功构建高表达、高效率的人ERRα基因小分子干扰RNA慢病毒载体,为进一步研究ERRα在细胞核内转导中的作用机制和靶向ERRα治疗奠定基础。  相似文献   
60.
Cadmium (Cd) toxicity was studied in broilers, and efficacy of Emblica officinalis (500 ppm in feed), vitamin E (300 ppm in feed), and stressroak (1 g/kg feed) were evaluated for prophylactic and therapeutic management of Cd toxicity. One-day-old male broiler chicks were randomly divided into eight groups consisting of 10 chicks in each. Groups 1 and 2 were maintained as plain control and Cd (100 ppm in feed) toxic control (for six weeks). Groups 3, 4, and 5 were maintained on a combination of Cd (100 ppm in feed) and Emblica officinalis, vitamin E, and stressroak for six weeks. Groups 6, 7, and 8 were maintained with Cd for the first four weeks and on Emblica officinalis, vitamin E, and stressroak during the subsequent two weeks without Cd. Body weights, feed consumed, Feed conversion ratio (FCR), and glulathione (GSH) were significantly (P<0.05) decreased, whereas the activities of antioxidant enzymes (catalase and Superoxide dismutase (SOD)) and concentration of Thiobarbituric acid reacting substances (TBARS) were significantly (P<0.05) increased in toxic control group. After treatment with Emblica officinalis, vitamin E, and stressroak in groups 6, 7, and 8 during last two weeks and discontinuation of Cd, the parameters revealed improvement. From this study, it is concluded that Cd induces toxicity by oxidative stress, and supplementing Emblica officinalis, vitamin E, and stressroak in feed is useful in preventing and treating the toxicity.  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