全文获取类型
收费全文 | 881篇 |
免费 | 2篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 3篇 |
机械仪表 | 2篇 |
轻工业 | 4篇 |
石油天然气 | 1篇 |
无线电 | 1篇 |
一般工业技术 | 7篇 |
冶金工业 | 861篇 |
自动化技术 | 2篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 1篇 |
1999年 | 10篇 |
1998年 | 174篇 |
1997年 | 118篇 |
1996年 | 94篇 |
1995年 | 54篇 |
1994年 | 58篇 |
1993年 | 49篇 |
1992年 | 13篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 16篇 |
1980年 | 19篇 |
1978年 | 4篇 |
1977年 | 97篇 |
1976年 | 127篇 |
1975年 | 3篇 |
1954年 | 1篇 |
1899年 | 1篇 |
排序方式: 共有883条查询结果,搜索用时 31 毫秒
831.
Faecal concentrations and output of short chain fatty acids (SCFA) were assessed on successive days by gas-liquid chromatography in 24 patients with acute watery diarrhoea. Absorption of water and sodium from the rectum was also measured by a dialysis technique in 17 of these patients and in nine normal subjects in the presence and absence of luminal SCFA. Faecal SCFA concentrations were low on the first day of diarrhoea (mean (SEM) 9.9 (5.8) mmol/kg) and increased to 94.8 (16.4) mmol/kg by the fifth day. Faecal output of SCFA corresponded to these figures. Net water absorption, in the absence of luminal SCFA, was stopped in patients with acute diarrhoea (-59 (81) nl/cm2/min) compared with healthy controls (+322 (63) nl/cm2/min) (p < 0.01). Luminal SCFA restored net water absorption to +184 (67) nl/cm2/min in patients with acute diarrhoea (p < 0.01). Net absorption of sodium decreased in patients with acute diarrhoea in the absence of luminal SCFA, but returned to normal with luminal SCFA. Net secretion of potassium increased in acute diarrhoea, and did not change in the presence of SCFA. Defective absorption from the rectum in acute diarrhoea is reversed by luminal SCFA. The reduction of luminal SCFA in acute diarrhoea treated conventionally may be a factor contributing to colonic dysfunction. 相似文献
832.
833.
SG Gasanov OA Buianovskaia EB Nechaeva VI Trubnikov 《Canadian Metallurgical Quarterly》1981,92(7):98-100
Effect of splenin (1 ml) and its fractions (0.5 ml) on adrenocortical function was studied after a single intramuscular injection of the preparations into rats. Splenin and its fractions containing water-soluble substances reduced the content of ascorbic acid in the rat adrenals thereby indicating the increased synthesis of adrenocortical hormones. Adenosine-5-monophosphate is one of the basic biological substances contained by splenin and its water-soluble fractions. It produces a stimulant effect on the synthesis of adrenocortical hormones. 相似文献
834.
835.
Individual peculiarities of 90Sr skeleton deposition in voles M. gregalis and M. arvalis inhabiting at the territory of East Ural Radioactive Trace were investigated. More high accumulation of radionuclide in the organism of M. gregalis was registered. Considerable variations (3-6 times more, than in linear mice ones) of individual indices of radionuclide accumulation exceeding interspecies level are found. Possible reasons of both interspecies differences and an individual deposition' variability were discussed. 相似文献
836.
We have identified and characterized mutants of the yeast Yarrowia lipolytica that are deficient in protein secretion, in the ability to undergo dimorphic transition from the yeast to the mycelial form, and in peroxisome biogenesis. Mutations in the SEC238, SRP54, PEX1, PEX2, PEX6, and PEX9 genes affect protein secretion, prevent the exit of the precursor form of alkaline extracellular protease from the endoplasmic reticulum, and compromise peroxisome biogenesis. The mutants sec238A, srp54KO, pex2KO, pex6KO, and pex9KO are also deficient in the dimorphic transition from the yeast to the mycelial form and are affected in the export of only plasma membrane and cell wall-associated proteins specific for the mycelial form. Mutations in the SEC238, SRP54, PEX1, and PEX6 genes prevent or significantly delay the exit of two peroxisomal membrane proteins, Pex2p and Pex16p, from the endoplasmic reticulum en route to the peroxisomal membrane. Mutations in the PEX5, PEX16, and PEX17 genes, which have previously been shown to be essential for peroxisome biogenesis, affect the export of plasma membrane and cell wall-associated proteins specific for the mycelial form but do not impair exit from the endoplasmic reticulum of either Pex2p and Pex16p or of proteins destined for secretion. Biochemical analyses of these mutants provide evidence for the existence of four distinct secretory pathways that serve to deliver proteins for secretion, plasma membrane and cell wall synthesis during yeast and mycelial modes of growth, and peroxisome biogenesis. At least two of these secretory pathways, which are involved in the export of proteins to the external medium and in the delivery of proteins for assembly of the peroxisomal membrane, diverge at the level of the endoplasmic reticulum. 相似文献
837.
838.
839.
840.
VI Ursulenko AP Slabchenko AA Krikunov AV Gabrielian GV Knyshov 《Canadian Metallurgical Quarterly》1993,(6):21-24
The authors analyze 144 surgeries in patients with single and multiple valvular defects combined with multiple involvement of the coronary arteries; multiple (3-4) coronary artery shunting was carried out in 21 patients, the mortality being 19.4%. Recovery of the blood stream in all involved coronary arteries and correction of defective valves were found conducive to reduction of incidence of myocardial infarction and acute heart failure. Retrograde blood cardioplegia to a considerable measure shortened the duration of aorta clamping and improved myocardial protection. Such methods and improvement of surgical technique helped us reduce the mortality rate by 2-3 times. 相似文献