全文获取类型
收费全文 | 2002篇 |
免费 | 8篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 16篇 |
机械仪表 | 1篇 |
建筑科学 | 2篇 |
能源动力 | 4篇 |
轻工业 | 9篇 |
无线电 | 1篇 |
一般工业技术 | 32篇 |
冶金工业 | 1932篇 |
自动化技术 | 7篇 |
出版年
2023年 | 1篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 1篇 |
2016年 | 7篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 6篇 |
2012年 | 2篇 |
2011年 | 7篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 1篇 |
2007年 | 6篇 |
2006年 | 1篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2000年 | 2篇 |
1999年 | 53篇 |
1998年 | 617篇 |
1997年 | 315篇 |
1996年 | 197篇 |
1995年 | 139篇 |
1994年 | 123篇 |
1993年 | 127篇 |
1992年 | 24篇 |
1991年 | 25篇 |
1990年 | 15篇 |
1989年 | 21篇 |
1988年 | 21篇 |
1987年 | 19篇 |
1986年 | 19篇 |
1985年 | 20篇 |
1983年 | 5篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1980年 | 28篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 42篇 |
1976年 | 101篇 |
1975年 | 5篇 |
1964年 | 1篇 |
排序方式: 共有2010条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
The behavioral disturbances of 16 nursing home patients with a history of sundowning behaviour and dementia were treated with light therapy instead of psychopharmacological medication. After the withdrawal of the before established medication a very individual, heterogenous deterioration of the symptoms was noted. A significant improvement of the behaviour was not found by light therapy in any patient. The problems in practical handling and possible consequences of further investigation are discussed. 相似文献
105.
106.
1. Animal studies have shown that angiotensin II has a biphasic effect on urinary sodium excretion. To examine whether this is also true in man, we studied seven salt-replete male subjects in a single-blind placebo-controlled manner. 2. While undergoing maximum diuresis, subjects were infused with 0, 1, 2, 5 or 10 ng of angiotensin II min-1 kg-1 over 80 min. Subjects were studied while seated, and stood every 20 min for urine collection. 3. Angiotensin II produced a dose-dependent antidiuretic effect. The urine flow rate, in ml/min expressed as the change from baseline with increasing dose of angiotensin, was: +3.4 +/- 1.77, -1.26 +/- 0.49 (P < 0.05), -2.75 +/- 1.23 (P < 0.05), -4.21 +/- 0.82 (P < 0.05) and -6.51 +/- 1.07 (P < 0.01). 4. In contrast, the effect of angiotensin II on sodium excretion showed a flat dose-response curve beyond 5 ng min-1 kg-1. The urinary sodium excretion, in mumol/min expressed as the change from baseline with increasing dose of angiotensin, was: 9.5 +/- 21.2, -18.9 +/- 29.6, -37.0 +/- 11.6 (P < 0.05), -67.7 +/- 19.6 (P < 0.01) and -63.8 +/- 14.3 (P < 0.01). 5. The fractional distal reabsorption of sodium, determined by using the lithium clearance technique, showed a rise with all doses of angiotensin II used and reached statistical significance with the top two doses. 6. Unlike antidiuresis, antinatriuresis after graded doses of angiotensin II in human subjects showed a flat dose-response curve beyond 5 ng min-1 kg-1. Pressor doses of angiotensin II also have a significant effect on the distal tubule in promoting sodium reabsorption. 相似文献
107.
108.
C Lupu CA Goodwin AD Westmuckett JJ Emeis MF Scully VV Kakkar F Lupu 《Canadian Metallurgical Quarterly》1997,17(11):2964-2974
Tissue factor pathway inhibitor (TFPI), the main downregulator of the procoagulant activity of tissue factor.factor VIIa complex, locates in human endothelial cells (EC) in culture as well-defined clusters uniformly distributed both on the cell surface and intracellularly. We here demonstrate by immunofluorescence that TFPI colocalizes in EC with caveolin, urokinase-type plasminogen activator receptor, and glycosphingolipids. The localization of TFPI in caveolae in resting endothelium is proved by double immunogold electron microscopy for TFPI and caveolin. After ultracentrifugation of rat lung or EC homogenates through density gradients of Nycodenz, TFPI was highly enriched at densities of 1.05 to 1.08 g/mL, together with caveolin and alkaline phosphatase. By ELISA, more than half of the cellular TFPI was detected in Triton X-100-insoluble extracts of EC. TFPI incorporates [1-3H]ethanolamine and is cleaved from the cell surface by phosphatidylinositol-phospholipase C, indicating a specific glycosylphosphatidylinositol-anchorage mechanism for TFPI in the plasma membrane. Clustering of TFPI and its localization in caveolae are dependent on the presence of cholesterol in the membrane. Agonist-induced stimulation of EC caused marked changes of distribution for both TFPI and caveolin at subcellular level, with subsequent increase of the cell surface-associated inhibitory activity toward tissue factor.factor VIIa. Our findings suggest that, beside their function in transcytosis, potocytosis, cell surface proteolysis, and regulation of signal transduction, caveolae also play a direct role in the regulation of EC anticoagulant properties. 相似文献
109.
SC Langley GW Rickett A Hunt FJ Kelly AD Postle DA York 《Canadian Metallurgical Quarterly》1993,45(3):543-551
The biochemical maturation of the lung in late gestation and in the young animal is regulated by glucocorticoids. The present study was aimed at dissociating the different glucocorticoid receptor sites involved in these regulatory functions. The obese Zucker rat was selected as a model for this study as it exhibits hypersensitivity to glucocorticoid hormone action by virtue of its elevated receptor numbers and activity. Two synthetic steroid analogues were administered to obese animals; RU28362, a specific type II receptor agonist, and the type II antagonist RU486. RU28362 promoted a strong catabolic effect, which was associated with reduced food intake and the abolition of growth in the rats. The agonist, RU28362, attenuated developmental increases in antioxidant enzyme activities, and altered the growth of the tissue. At the age studied, development of the lung phosphatidylcholine (PC) system was almost complete, but RU28362 increased disaturated PC 16:0/16:0 concentrations by almost 2-fold, and altered the molecular composition of total pulmonary PC. RU486 attenuated the growth of the rats and reduced their food intake. Treatment with the type II antagonist attenuated lung growth and increased the activities of pulmonary copper zinc (Cu/Zn) and manganese (Mn) superoxide dismutases. RU486 had no effect on lung PC concentrations and molecular composition. The data suggest a role for type I glucocorticoid receptors in the regulation of the antioxidant enzyme system in the lung, as type II antagonism will channel endogenous glucocorticoid binding to the type I site. Type II receptor binding would appear to play a role in regulating the lung PC content. 相似文献
110.