全文获取类型
收费全文 | 647篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 7篇 |
金属工艺 | 1篇 |
轻工业 | 5篇 |
水利工程 | 2篇 |
一般工业技术 | 4篇 |
冶金工业 | 633篇 |
出版年
2022年 | 1篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2012年 | 2篇 |
2010年 | 1篇 |
2008年 | 1篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2004年 | 4篇 |
2003年 | 1篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 18篇 |
1998年 | 186篇 |
1997年 | 112篇 |
1996年 | 72篇 |
1995年 | 42篇 |
1994年 | 35篇 |
1993年 | 29篇 |
1992年 | 4篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 10篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 21篇 |
1976年 | 46篇 |
1975年 | 1篇 |
1964年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有652条查询结果,搜索用时 31 毫秒
651.
Epidemiologic data revealed that a low sodium intake might have a favorable influence on blood pressure throughout an individual's lifetime. Sodium restriction was reported to lead to a modest fall in blood pressure in some studies, although a few groups of hypertensive patients experienced a rise in blood pressure. Left ventricular hypertrophy has been demonstrated to be related to cardiovascular morbidity and mortality independent of other risk factors. Dietary salt intake participates in the hypertrophic process independent of other determinants. Thus, 24-hour urinary sodium excretion has been reported to correlate with left ventricular mass independent of levels of arterial pressure. Three different mechanisms may link dietary salt intake to myocardial hypertrophy: the renin-angiotensin-aldosterone system, the sympathetic nervous system, and fluid volume homeostasis. Whether salt restriction reduces cardiovascular structural damage independent of arterial pressure has not been determined. 相似文献
652.
Adult rat hippocampus-derived neural progenitor cells (AHPC) show considerable adaptability following grafting to several brain regions. To evaluate the plasticity of AHPCs within the optic retina, retrovirally engineered AHPCs were grafted into the vitreous cavity of the adult and newborn rat eye. Within the adult eye, AHPCs formed a uniform nondisruptive lamina in intimate contact with the inner limiting membrane. Within 4 weeks of grafting to the developing eye, the AHPCs were well integrated into the retina and adopted the morphologies and positions of Müller, amacrine, bipolar, horizontal, photoreceptor, and astroglial cells. Although the cells expressed neuronal or glial markers, none acquired end-stage markers unique to retinal neurons. This suggests that the adult-derived stem cells can adapt to a wide variety of heterologous environments and express some but not all features of retinal cells when exposed to the cues present late in retinal development. 相似文献