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   881篇
  免费   2篇
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
  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
841.
The existing concept of medical maintenance of flying personnel not takes into account the phase changes of functional condition and professional performance of a pilot. It causes the necessity of additional preventive rehabilitation, directed on restoration and preservation of important professional qualities of the pilots during the training and combat activity. The author offered reasonable system of rehabilitation measures, including indications, means and conditions of correction measures application. Is carried out practical introduction of preventive rehabilitation in system of medical maintenance of the Armed Forces of Ukraine. The data about its efficiency are given.  相似文献   
842.
843.
844.
845.
846.
The effects of daily intraperitoneal injections of alpha-tocopherol (30 mg/kg per day) and synthetic antioxidant IHFAN-30 (30 mg/day) in rats were compared during low-level ionizing radiation (10 days, dose rate 5 mGy/h, total dose 1.2 Gy). There were analysed: (1) amplitude of population spike of hippocampal slices; (2) endogenous phosphorylation in vitro of hippocampal synaptic proteins in the presence of cAMP; (3) formation, manifestation and reduction of food-procuring reflex. The findings showed that antioxidants made some correction of the functional state of hippocampal slices and cAMP-dependent phosphorylation system activity in brain cells from irradiated animals. No influence on training and memory functions was detected.  相似文献   
847.
Excitation spectra and light curves were studied in three species of marine algae at monochromatic light excitation of the second-range afterglow. It was shown that light curves were satisfactorily described by an equation similar to the equation of enzyme catalysis with low light intensity of half-saturation (about 0.5 W X m-2). Shapes of the excitation spectra and spectral curves of quantum yield of the second-range afterglow was analysed considering the early non-linearity of its light curves. It was found that the results obtained and the literature data on a relatively high quantum yield of the second-range afterglow in the region of absorption of long-wave pigment system (above 680 nm) can be explained by the non-linearity mentioned above, not suggesting a participation of PSI in the generation of this afterglow.  相似文献   
848.
Analysis of clinical and morphological findings in 306 patients making use of a complex of modern methods at tissue, cellular, and subcellular levels enabled the authors to define the early precancer changes in the bronchial epithelium. The diagnostic value of precancer changes in the lungs and lung cancer was assessed by successive statistical analysis and mathematical estimations. Medical mathematical decisive rules have been developed and are proposed for practical use, which permit the diagnosis of precancer and cancer of the lungs with a high degree of reliability (87 and 89%, respectively).  相似文献   
849.
850.
As there are no studies done on the prevalence of intestinal parasites in Lebanon since 1967, this study was undertaken to reveal the current patterns of intestinal parasitic infestations in Lebanese patients from two geographic regions: Beirut and Tripoli. Analysis was based on 33,253 stool specimens examined at the American University of Beirut Medical Center (AUH) and 11,611 specimens examined at the Islamic Hospital (IH) in Tripoli over five and three years, respectively. The prevalence of intestinal parasites at AUH and IH were 8.47% and 45.35%, respectively (overall 18%). The prevalence in males vs females was almost the same; being 8.23% vs 8.74%, and 44.67% vs 45.88%, at AUH and IH, respectively. Multiple infections were noted in 8.8% and 3.5% of stool specimens at AUH and IH, respectively. Although 18 different types of parasites were encountered, the most common pathogenic parasites found at AUH vs IH were: Giardia lamblia (20.7% vs 10.5% of parasites found), Entamoeba histolytica (19.41% vs 1.25%), Taenia spp. (6.03% vs 4.08%) and Ascaris lumbricoides (2.09% vs 46.97%). The overall yearly or monthly prevalence of parasites recovered from both hospitals did not show clear seasonal patterns. Compared to developed countries, Lebanon still suffers from a high prevalence and a wide spectrum of intestinal parasites.  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