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   158篇
  免费   8篇
  国内免费   4篇
教育   99篇
科学研究   42篇
各国文化   9篇
体育   5篇
综合类   11篇
文化理论   1篇
信息传播   3篇
  2022年   3篇
  2021年   6篇
  2020年   4篇
  2019年   1篇
  2018年   3篇
  2017年   3篇
  2016年   8篇
  2015年   11篇
  2014年   16篇
  2013年   10篇
  2012年   15篇
  2011年   16篇
  2010年   9篇
  2009年   5篇
  2008年   8篇
  2007年   10篇
  2006年   3篇
  2005年   4篇
  2004年   13篇
  2003年   10篇
  2002年   5篇
  2001年   1篇
  2000年   3篇
  1997年   1篇
  1993年   1篇
  1991年   1篇
排序方式: 共有170条查询结果,搜索用时 680 毫秒
11.
Hemoglobin (Hb) Grey Lynn is a Hb variant caused by a substitution of Phe for Leu at position 91 of α1-globin chain, originally described in individual of unknown ethnic background. This article addresses the interaction of Hb Grey Lynn with a non-deletional α+-thalassemia found in Thailand, a hitherto un-described condition. The proband was adult Thai woman referred for investigation of mild anemia with Hb 90 g/L. Hb analyses using low pressure liquid chromatography raised a suspicion of abnormal Hb presence, which was failed to demonstrate by cellulose acetate electrophoresis and capillary electrophoresis. DNA sequencing identified a CTT (Leu) to TTT (Phe) mutation at codon 91 corresponding to the Hb Grey Lynn (Vientiane) [α91(FG3)Leu>Phe (α1) on α1-globin gene and a C deletion between codons 36 and 37 on α2-globin gene causing α+-thalassemia. As compared to those observed in a compound heterozygote for Hb Grey Lynn / α0-thalassemia reported previously, higher MCV (81.7 fL) and MCH (26.3 pg) values with a lower level of Hb Grey Lynn (19.7%) were observed in the proband. The normochromic normocytic anemia observed could be due to the interaction of Hb Grey Lynn with α+-thalassemia. The two mutations could be identified using PCR-RFLP and allele-specific PCR assays developed.  相似文献   
12.
本文为方便中国用户在WINDOWS系统下做文字处理工作,用UCDOS 5.0系统中丰富的汉字词汇去充实WINDOWS的码表文件,提供了实用的转换程序。  相似文献   
13.
高校图书馆无线局域网的建设   总被引:17,自引:1,他引:16  
以厦门大学图书馆为例,结合高校图书馆特点、本馆建设经验和作者对无线局域网的认识,阐述以IEEE802.11b规范建立符合高校图书馆服务要求的无线局域网应注意的关键问题。  相似文献   
14.
E-commerce is growing rapidly in Brazil, led by information-intensive and transaction-intensive sectors such as finance, manufacturing, and retail/wholesale. However, Brazil's highly uneven income distribution is a major barrier for B2C diffusion. Government policies have emphasized promotional or enabling initiatives such as e-procurement, tax filings, and providing Internet access to social institutions. E-commerce legislation is just now being developed, and decisions on taxation are being negotiated in the context of international agreements. E-commerce raises issues for Brazil in terms of its relationship to the global economy. Although most online purchases involve imported goods, e-commerce also offers opportunities to participate in international value chains.  相似文献   
15.
陈思义  张德成 《科技通报》1993,9(5):319-321
通过对32例健康的中国白兔红细胞上C_(3b)受体和免疫复合物的检测,其红细胞上C_(3b)受体的花环率为8.86±1.42;免疫复合物的花环率为6.84±1.03.这一结果与恒河猴等动物相比,皆有一定的特异性,也充分表明中国白兔的红细胞在清除体内危害性极大的免疫复合物上起着重要的作用。  相似文献   
16.
The conditions for extracting polysaccharides from tea (Camellia sinensis L.) fruit peel (TFPPs) were studied. Three parameters (temperature, time, and liquid/solid ratio) affecting the extraction of TFPP were optimized using response surface methodology (RSM). Under the optimized conditions, the yield of TFPP was predicted to be 4.98%. The physicochemical properties, in vitro antioxidant activities, and inhibitory effects on α-glucosidase of fractionated TFPPs (TFPP-0, TFPP-20, TFPP-40, and TFPP-60) were investigated. We found that the TFPPs were all acid protein-bound heteropolysaccharides, although with different chemical compositions. They had not only remarkable scavenging activity on 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and reducing activity, but also excellent inhibitory potential against α-glucosidase in vitro. Our results suggest that tea fruit peel could be treated as a potential bioresource for the development of polysaccharide antioxidants.  相似文献   
17.
In this paper,we investigate the effect and the possible mechanism of high glucose levels on the calcification of human aortic smooth muscle cells (HASMCs).HASMCs were divided into four groups: normal glucose group (NG),osmolality control group (OC),high glucose group (HG,HASMCs culture medium containing 30 mmol/L glucose),and high glucose plus recombinant human Noggin protein (bone morphogenetic protein-2 (BMP-2) antagonist) group (HN).The mRNA levels and the protein expressions of BMP-2 and core binding factor alpha-1 (Cbfα-1) were measured by real-time quantitative polymerase chain reaction (PCR) and Western blot.After induced by 10 mmol/L β-glycerol phosphoric acid,cells were harvested for assessments of alkaline phosphatase (ALP) activities at Days 1,2,and 3,and intracellular calcium contents at Days 7 and 14,respectively.High glucose levels increased the mRNA levels and the protein expressions of BMP-2 and Cbfα-1 (P0.05).The expression of Cbfα-1 was partially blocked by Noggin protein (P0.05),while BMP-2 was not (P0.05).After being induced by β-glycerol phosphoric acid,high glucose levels increased the ALP activity [(48.63±1.03) vs.(41.42±2.28) U/mg protein,Day 3;P0.05] and the intracellular calcium content [(2.76±0.09) vs.(1.75±0.07) μmol/mg protein,Day 14;P0.05] in a time-dependent manner when compared with the NG group,while the ALP activity could not be blocked by Noggin protein [(48.63±1.03) vs.(47.37±0.97) U/mg protein,Day 3;P0.05].These results show that high glucose levels can evoke the calcification of HASMCs by inducing osteoblastic trans-differentiation and intracellular calcium deposition via the BMP-2/Cbfα-1 pathway,which can be partially blocked by Noggin protein.  相似文献   
18.
19.
Inrecent years ,IEEE802.11 wirelesslocal area net-work (WLAN) has emerged as a prevailing technology forthe (indoor) broadband wireless access to internet for themobile/portable devices . In IEEE 802.11 standards ,802.11b has become the most widely used v…  相似文献   
20.
Formalist conceptions of aesthetic goals began to give way from the 17th century on to rationalist accounts of experience. Beauty as described as essential by Renaissance thinkers was reconceived as just one possibility, with the sublime in Burke's account as another. In the early 20th century Clive Bell again asserted a formalist position with his argument for significant form. The weakness of the formality position, and the need for a richer, more contextual account of aesthetic goals and experience is argued with reference to the idea of thick and thin concepts as applied by Bernard Williams to ethics, Wittgenstein's attention to the way in which language is used in a specific context, and Scruton's emphasis on an informed conception of the object of aesthetic attention. Beauty, in Alberti's procedural account if not in his version of the Platonic ideal, can be seen to continue to have critical value. The idea of character, however, offers a broader range of possibilities for experience and of goals for design.  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