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   491篇
  免费   25篇
  2022年   2篇
  2021年   7篇
  2020年   2篇
  2019年   7篇
  2018年   8篇
  2017年   7篇
  2016年   12篇
  2015年   19篇
  2014年   14篇
  2013年   30篇
  2012年   28篇
  2011年   30篇
  2010年   18篇
  2009年   19篇
  2008年   25篇
  2007年   28篇
  2006年   25篇
  2005年   26篇
  2004年   21篇
  2003年   21篇
  2002年   25篇
  2001年   11篇
  2000年   7篇
  1999年   8篇
  1998年   4篇
  1997年   7篇
  1995年   6篇
  1994年   6篇
  1993年   2篇
  1992年   7篇
  1991年   4篇
  1990年   5篇
  1989年   8篇
  1988年   6篇
  1987年   2篇
  1986年   6篇
  1985年   5篇
  1984年   4篇
  1983年   5篇
  1982年   5篇
  1981年   4篇
  1979年   4篇
  1978年   3篇
  1974年   3篇
  1973年   5篇
  1972年   5篇
  1969年   1篇
  1968年   2篇
  1967年   2篇
  1966年   1篇
排序方式: 共有516条查询结果,搜索用时 15 毫秒
511.
Iron deficiency (ID) and iron deficiency anemia (IDA) are the most common iron disorders throughout the world. ID and IDA, particularly caused by increased iron requirements during pregnancy, represent a high risk for preterm delivery, fetal growth retardation, low birth weight, and inferior neonatal health. Oral administration of ferrous sulfate to cure ID and IDA in pregnancy often fails to increase hematological parameters, causes adverse effects and increases inflammation. Recently, we have demonstrated safety and efficacy of oral administration of 30% iron saturated bovine lactoferrin (bLf) in pregnant women suffering from ID and IDA. Oral administration of bLf significantly increases the number of red blood cells, hemoglobin, total serum iron and serum ferritin already after 30 days of the treatment. The increasing of hematological values by bLf is related to the decrease of serum IL-6 and the increase of serum hepcidin, detected as prohepcidin, whereas ferrous sulfate increases IL-6 and fails to increase hematological parameters and prohepcidin. bLf is a more effective and safer alternative than ferrous sulfate for treating ID and IDA in pregnant women.  相似文献   
512.
The effect of ethylisopropyl-amiloride (EIPA) and phenamil on sodium uptake in renal brush border membrane vesicles from prehypertensive rats of the Milan strain (MHS) and their normotensive controls (MNS) was investigated. In the presence of both a membrane potential and a pH gradient a differential effect of EIPA and phenamil was evidenced between the two rat strains. In the absence of a pH gradient, but in the presence of a membrane potential, EIPA was about two-fold more potent than phenamil in inhibiting sodium transport in both rat strains, excluding the presence of epithelial sodium channels in our BBMV preparations. Taken together these results support the hypothesis that a structurally different Na+/H+ exchanger located on the brush border membrane may be involved in the increased tubular sodium reabsorption observed in vivo in hypertensive rats.  相似文献   
513.

Background  

Backtranslation is the process of decoding a sequence of amino acids into the corresponding codons. All synthetic gene design systems include a backtranslation module. The degeneracy of the genetic code makes backtranslation potentially ambiguous since most amino acids are encoded by multiple codons. The common approach to overcome this difficulty is based on imitation of codon usage within the target species.  相似文献   
514.
Human and bovine lactoferrin (hLf and bLf) are multifunctional iron-binding glycoprotein constitutively synthesized and secreted by glandular epithelial cells and by neutrophils following induction. HLf and bLf possess very high similarity of sequence. Therefore, most of the in vitro and in vivo studies are carried out with commercial bLf (cbLf), available in large quantities and recognized by Food and Drug Administration (FDA, USA) as a safe substance. Physico-chemical heterogeneity of different cbLf preparations influences their effectiveness. CbLf iron-saturation affects thermal stability and resistance to proteolysis. Moreover, other metal ions such as Al(III), Cu(II), Mg(II), Mn(II), Zn(II) are chelated by cbLf, even if at lower affinity than Fe(III). Ca(II) is also sequestered by the carboxylate groups of sialic acid present on glycan chains of cbLf thus provoking the release of LPS, contributing to bactericidal activity. Similarly to more than 50% of eukaryotic proteins, cbLf possesses five N-glycosylation sites, also contributing to the resistance to proteolysis and, putatively, to the protection of intestinal mucosa from pathogens. CbLfs possess several functions as anti-microbial, anti-biofilm, anti-adhesive, anti-invasive and anti-inflammatory activities. They are also relevant modulators of iron and inflammatory homeostasis. However, the efficacy of cbLfs in exerting several functions can be erratic mainly depending from integrity, degree of iron and other metal ions saturation, N-glycosylation sites and chains, desialylated forms, Ca(II) sequestration, presence of contaminants and finally the ability to enter inside nucleus.  相似文献   
515.
516.
A simple fluorometric method for the determination of cAMP is presented. The fluorescent derivative is 1,N6-etheno cyclic 3,5-monophosphate (etheno-cAMP). Maximal formation of this derivative occurs after reacting cAMP with chloroacetaldehyde for 15 minutes at 100 degrees C. Fluorescent derivatives are also produced from compounds which contain a 6-amino purine. The specificity of the method resides in the use of a reverse phase/HPLC system. The derivatization as well as the fluorescent response of etheno-cAMP is linear between 2.5 and 700 picomoles of cAMP. Studies of brain adenylate cyclase by the fluorometric/HPLC method indicated that this method is comparable to the established radioenzymatic method. Thus, the present method provides a simple rapid nonradioactive means for the determination of adenylate cyclase activity.  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