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   36篇
  免费   1篇
  国内免费   1篇
电工技术   5篇
化学工业   6篇
机械仪表   2篇
轻工业   1篇
无线电   2篇
一般工业技术   12篇
冶金工业   8篇
自动化技术   2篇
  2020年   1篇
  2018年   1篇
  2015年   1篇
  2014年   1篇
  2013年   2篇
  2011年   5篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2007年   1篇
  2006年   1篇
  2005年   1篇
  2004年   1篇
  2002年   1篇
  2000年   3篇
  1999年   3篇
  1998年   2篇
  1996年   3篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1991年   2篇
  1990年   1篇
  1984年   1篇
  1977年   1篇
排序方式: 共有38条查询结果,搜索用时 15 毫秒
1.
This report describes a 5-year-old girl with congenital tricuspid regurgitation associated with an atrial septal defect and peripheral pulmonary stenosis. The girl was diagnosed with the heart murmur at birth and recently developed the cardiomegaly. Cardiac echocardiography and catheterization showed severe tricuspid regurgitation, an atrial septal defect of the secundum type and peripheral pulmonary stenosis. In the operative findings, the tricuspid annulus was dilated to 33 mm in diameter, and leaflets were attached normally to the antomic annulus. There was a large cleft of the anterior leaflet of the tricuspid valve. Suture of the cleft and annuloplasty of the tricuspid valve, suture closure of the atrial septal defect and patch dilatation of peripheral pulmonary stenosis were successfully performed. Including this case, 19 other cases with congenital tricuspid regurgitation undergoing surgery were reported to date.  相似文献   
2.
BaTiO3-Cu composite powders were prepared via an alkoxide-mediated synthesis approach. As-synthesized BaTiO3 nanoparticles were as small as 40 nm and coated partially larger Cu particles of approximately 1 μm in size. Thermogravimetric analysis (TGA) and dilatometry revealed a gradual increase in weight loss and retarded shrinkage with the increase of Cu addition. BaTiO3-Cu composites were successfully densified by spark plasma sintering (SPS). The microstructures show an average grain-size for BaTiO3 of around 100 nm and a crystallite size of about 1 μm for the Cu inclusions. The AC conductivity of the BaTiO3-Cu composites increased with increasing Cu content or with temperature. The dominant electrical conduction mechanism in SPSed BaTiO3-Cu composites changed from migration of oxygen vacancies to band conduction of trapped electrons in oxygen vacancies with the increase of Cu content.  相似文献   
3.
Recent studies have shown that various tumor cells accumulate ubiquitin (Ub)-conjugated proteins, the profiles of which differ from those of normal cells. To identify the Ub-conjugated proteins accumulated specifically by human carcinoma cells, a two-dimensional immunoblot analysis of 31 surgically resected human primary colorectal carcinoma tissues was performed using an anti-Ub monoclonal antibody, KM691. Two distinct Mr 42,000 and 45,000 proteins in the Triton X-insoluble fractions of carcinoma tissues reacted with this antibody, whereas only one Mr 45,000 protein reacted in normal tissues. The Mr 42,000 Ub-conjugated proteins were specific to carcinoma tissues from 25 patients (80.6%). One of the purified Mr 42,000 proteins was digested with Achromobacter protease I. This protein was identified as a cytokeratin 8 (CK 8) fragment based on both molecular mass determination and molecular mass searching of Achromobacter protease I-digested fragments of proteins registered in a protein sequence data base. Two-dimensional immunoblot analysis with an anti-CK 8 antibody confirmed that all of the Mr 42,000 proteins were CK 8 degradation products. These results demonstrate that human colorectal carcinomas specifically accumulate Mr 42,000 Ub-conjugated CK 8 fragments. This accumulation was observed frequently not only in advanced (18/22, 81.8%), but also in early stage cases (7/9, 77.8%), suggesting that it occurs even in the early stages of colorectal carcinoma progression.  相似文献   
4.
The diversity of human immunodeficiency virus (HIV) in vivo has been reported. In this article, we propose a cellular automata (CA) model describing the interactions between the immune system and HIV, and examine the effect of the diversity of these interactions. The novel aspects of our CA model are that it not only considers four states (HIV, virgin, dead, infect) but also the diversity exhibited by both HIV and T cells. We simulated maximum diversities for these states by simulating CA on a computer. The model revealed that increased diversity had the effect of increasing the HIV population and simulation steps. In addition, we observed that the CA model accurately reflects the occurrence of infection, incubation period, and the development of AIDS. The CA model demonstrated that the diversity of the virus is the major factor affecting the success rate of the escape of HIV from the immune response. This work was presented in part at the 10th International Symposium on Artificial Life and Robotics, Oita, Japan, February 4–6, 2005  相似文献   
5.
There have been few reports on lymph node swelling in human parvovirus (HPV) B19 infection. A report of a 42-year-old female, who developed HPV B19-associated transient red cell aplasia with lymphadenopathy, is presented. The lymph node swelling began with the appearance of atypical lymphocytes in the peripheral blood and it disappeared as the patient recovered from the aplasia. Microscopically, the patient's bone marrow showed characteristic giant proerythroblasts with no maturation of the erythroid series. An excised inguinal lymph node showed florid, reactive follicular hyperplasia with paracortex expansion, and neutrophil infiltration and hemophagocytosis in the medullary sinus. These findings were compatible with the histology of a viral infection. A polymerase chain reaction study revealed HPV B19 in her serum and lymph node, but an immunohistochemical study failed to demonstrate HPV B19 capsid antigen in the lymph node or bone marrow. Although the present case suggests that reactive lymphadenopathy is associated with HPV B19 infection, the mechanism of the lymph node swelling still remains to be elucidated.  相似文献   
6.
7.
A series of regioisomeric bis-methanofullerenes (diethyl [60]fullerenobisacetate) were prepared by reaction of the sulfonium ylide with C60. Seven stable resultant regioisomers were completely isolated on a preparative HPLC and identified by FT-IR, UV-vis, TOF-MS, and 1H and 13C NMR measurements. The structures of these bisadducts were assigned based on 1) the relationship of the polarities of the regioisomers with the elution order from HPLC; 2) a comparison of their UV-vis spectra with those of corresponding Bingel-Hirsch bisadducts; and 3) the identification of their molecular symmetries by their 1H and 13C NMR spectra. The electrochemical properties of the resultant regioisomeric bismethanofullerene, derivatives were investigated through cyclic voltammetry (CV). The bisadducts exhibited more negative reduction potential than the pristine C60. Trans-2- and cis-3- bisadducts had the least negative potential E11/2 of all the other bisadducts.  相似文献   
8.
Carbohydrates, fats, and proteins are the underlying energy sources for animals and are catabolized through specific biochemical cascades involving numerous enzymes. The catabolites and metabolites in these metabolic pathways are crucial for many cellular functions; therefore, an imbalance and/or dysregulation of these pathways causes cellular dysfunction, resulting in various metabolic diseases. Bone, a highly mineralized organ that serves as a skeleton of the body, undergoes continuous active turnover, which is required for the maintenance of healthy bony components through the deposition and resorption of bone matrix and minerals. This highly coordinated event is regulated throughout life by bone cells such as osteoblasts, osteoclasts, and osteocytes, and requires synchronized activities from different metabolic pathways. Here, we aim to provide a comprehensive review of the cellular metabolism involved in bone development and homeostasis, as revealed by mouse genetic studies.  相似文献   
9.
High-performance reactive sputter-deposition of magnesium oxide (MgO) thin films is investigated. In this research, planar magnetron (PM) sputtering of Mg target in argon/oxygen mixture is assisted by an inductively coupled plasma (ICP) that is located between the target and the substrate and is driven by an internal RF coil antenna at 13.56 MHz. The changes in deposition rates and X-ray diffraction patterns due to the independent power control of PM and ICP are investigated. As a result, we found that deposition rate of MgO films was predominantly controlled by the PM discharge power and that the crystallinity of deposited MgO films was controlled by the ICP-RF power.  相似文献   
10.
We measured the complex surface impedance Z s = R s +iX s of optimally- and over-doped Bi 2 Sr 2 CaCu 2 O y single crystals around the vortex-phase boundaries. In both doping states, the surface reactance X s increased rapidly just above the first-order melting transition field and the so-called second magnetization peak field, while no obvious anomalies were observed in the surface resistance R s . From the analysis of the relationship between X s and R s , we showed that the origin of this anomaly is not the loss of pinning but the reduction of the superfluid density above the transition.  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