全文获取类型
收费全文 | 2133篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
综合类 | 1篇 |
化学工业 | 10篇 |
金属工艺 | 1篇 |
机械仪表 | 38篇 |
建筑科学 | 5篇 |
能源动力 | 2篇 |
轻工业 | 41篇 |
水利工程 | 1篇 |
无线电 | 5篇 |
一般工业技术 | 5篇 |
冶金工业 | 2015篇 |
自动化技术 | 7篇 |
出版年
2021年 | 5篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2013年 | 3篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 5篇 |
2009年 | 6篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 7篇 |
2002年 | 7篇 |
2001年 | 7篇 |
2000年 | 15篇 |
1999年 | 74篇 |
1998年 | 603篇 |
1997年 | 353篇 |
1996年 | 222篇 |
1995年 | 139篇 |
1994年 | 99篇 |
1993年 | 119篇 |
1992年 | 12篇 |
1991年 | 18篇 |
1990年 | 15篇 |
1989年 | 17篇 |
1988年 | 23篇 |
1987年 | 13篇 |
1986年 | 16篇 |
1985年 | 17篇 |
1984年 | 1篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 19篇 |
1980年 | 27篇 |
1978年 | 7篇 |
1977年 | 67篇 |
1976年 | 161篇 |
1975年 | 3篇 |
1973年 | 1篇 |
1964年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有2134条查询结果,搜索用时 15 毫秒
11.
Obesity is a major risk factor for cardiovascular disease. However, a direct link between these two states is difficult to establish, since obesity frequently occurs with other disease states such as diabetes, hypertension and atherosclerosis. Clinical studies have clearly shown that uncorrected obesity is associated with cardiac hypertrophy and compromised ventricular function. A number of rodent models of obesity have been studied in terms of cardiovascular adaptations. Cardiac function of the obese Zucker rat appears to be normal at a younger age. Only after several months is depression in cardiac function discernable. These animals are mildly hypertensive, but do not exhibit the characteristic increase in cardiac output associated with human obesity. A unique characteristic of JCR:LA-cp rat is that they develop atherosclerotic and myocardial lesions. Hearts from these animals will maintain normal function when perfused with physiological levels of calcium. At higher calcium concentrations, however, mechanical function becomes impaired. Dietary-induced obese rats exhibit many of the hemodynamic alterations associated with human obesity, but there is no evidence to-date that these animals will develop severe cardiac depression. Short-term weight reduction apparently has beneficial cardiovascular effects, but weight cycling may be harmful. Given the widespread occurrence of obesity, further studies are warranted to characterize the cardiac manifestations of this condition. 相似文献
12.
13.
14.
15.
16.
17.
We report a case of typical chronic eosinophilic pneumonia (CEP), in a female of 27 years-old suffering bronchial asthma light. Although the initial answer to the treatment with steroids was satisfactory, the patient develop difficult to control asthma (DCA). DCA is a clinical situation which requires careful investigation of several potential factors which can be solved. We suggest a protocol of treatment for patients affected with DCA. 相似文献
18.
GS Wengler A Lanfranchi T Frusca R Verardi A Neva D Brugnoni S Giliani M Fiorini P Mella F Guandalini E Mazzolari S Pecorelli LD Notarangelo F Porta AG Ugazio 《Canadian Metallurgical Quarterly》1996,348(9040):1484-1487
BACKGROUND: X-linked severe combined immunodeficiency (SCIDXI) is an inherited immune defect which leads to death in infancy from severe infections. The defect is caused by mutations of the IL-2RG gene that encodes for the common gamma chain shared by several cytokine receptors. The disease is characterised by lack of T and NK cells with normal numbers of B cells. SCIDXI can be cured by bone marrow transplantation (BMT) or prevented by abortion after prenatal diagnosis. METHODS: A male fetus was diagnosed as having SCIDXI by molecular, immunophenotypic, and functional analyses. The fetus was injected intraperitoneally under ultrasound guidance with CD34 haematopoietic progenitor cells purified from paternal bone marrow and T-cell depleted by E rosetting. Chimerism analysis was by HLA-DQ alpha typing and gamma-chain staining on cord blood. FINDINGS: A healthy 3.6 kg boy was delivered by caesarean section at 38 weeks of gestation with no clinical or laboratory signs of graft-versus-host disease. Engraftment of donor-derived CD2 cells was found at birth. At 3.5 months of age the infant is well and his T-cell counts and function are normal. INTERPRETATION: In-utero transplantation of haematopoietic progenitor cells allowed immune reconstitution of a fetus with SCIDXI and may be an alternative to elective abortion. Our report should encourage applications of this method to other inherited disorders curable by BMT. 相似文献
19.
Two forms of mitochondrial adrenodoxin reductase from bovine adrenals and recombinant bovine adrenodoxin and adrenodoxin reductase expressed in Escherichia coli were isolated, purified to homogeneity and biochemically characterized. Recombinant adrenodoxin reductase was expressed as a single polypeptide; its retention time on DEAE-Fractogel coincides with the second form (F2) of the mitochondrial reductase. Two enzyme forms have similar adrenodoxin reductase activities in two types of systems comprising either cytochrome c or cytochrome P-450 (11 beta) as the terminal electron acceptor. Adrenodoxin and each of two reductase forms were cross-linked using 1-ethyl-3-(dimethyl-amino-propyl)carbodiimide. An effective two-step method for the purification of the active heterologous cross-linked complexes is suggested that enables purification of the functional complexes to homogeneity. The cross-linked bimolecular complex of adrenodoxin and adrenodoxin reductase was crystallized for the first time. 相似文献
20.