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   1350篇
  免费   88篇
电工技术   9篇
化学工业   505篇
金属工艺   7篇
机械仪表   28篇
建筑科学   38篇
矿业工程   1篇
能源动力   43篇
轻工业   379篇
水利工程   3篇
石油天然气   4篇
无线电   72篇
一般工业技术   197篇
冶金工业   36篇
原子能技术   4篇
自动化技术   112篇
  2024年   3篇
  2023年   14篇
  2022年   101篇
  2021年   103篇
  2020年   48篇
  2019年   50篇
  2018年   51篇
  2017年   56篇
  2016年   50篇
  2015年   41篇
  2014年   58篇
  2013年   87篇
  2012年   81篇
  2011年   90篇
  2010年   89篇
  2009年   72篇
  2008年   68篇
  2007年   47篇
  2006年   44篇
  2005年   29篇
  2004年   30篇
  2003年   26篇
  2002年   28篇
  2001年   13篇
  2000年   7篇
  1999年   11篇
  1998年   29篇
  1997年   15篇
  1996年   15篇
  1995年   11篇
  1994年   5篇
  1993年   9篇
  1992年   7篇
  1990年   1篇
  1989年   4篇
  1988年   1篇
  1987年   4篇
  1986年   1篇
  1985年   3篇
  1984年   9篇
  1983年   4篇
  1982年   5篇
  1981年   2篇
  1980年   4篇
  1979年   2篇
  1978年   4篇
  1977年   2篇
  1973年   1篇
  1962年   1篇
  1961年   1篇
排序方式: 共有1438条查询结果,搜索用时 15 毫秒
991.
Incomplete removal of micropollutants in wastewater treatment leads to contamination of the aquatic environment. Mixed-matrix membranes with different shares of embedded adsorbents are considered promising for the elimination of commonly found pharmaceuticals. However, their ideal geometry and reusability after a loading cycle remain uncertain. In this study, the life cycle of loaded membranes could be extended through chemical regeneration with ethanol at different temperatures. Moreover, membrane stability and adsorbent-to-membrane-area ratio could be enhanced through a seven-bore geometry.  相似文献   
992.
Graphene coating on the cobalt-chromium alloy was optimized and successfully carried out by a cold-wall chemical vapor deposition (CW-CVD) method. A uniform layer of graphene for a large area of the Co-Cr alloy (discs of 10 mm diameter) was confirmed by Raman mapping coated area and analyzing specific G and 2D bands; in particular, the intensity ratio and the number of layers were calculated. The effect of the CW-CVD process on the microstructure and the morphology of the Co-Cr surface was investigated by scanning X-ray photoelectron microscope (SPEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Nanoindentation and scratch tests were performed to determine mechanical properties of Co-Cr disks. The results of microbiological tests indicate that the studied Co-Cr alloys covered with a graphene layer did not show a pro-coagulant effect. The obtained results confirm the possibility of using the developed coating method in medical applications, in particular in the field of cardiovascular diseases.  相似文献   
993.
994.
995.
996.
Ataxia in children is a common clinical sign of numerous neurological disorders consisting of impaired coordination of voluntary muscle movement. Its most common form, cerebellar ataxia, describes a heterogeneous array of neurologic conditions with uncountable causes broadly divided as acquired or genetic. Numerous genetic disorders are associated with chronic progressive ataxia, which complicates clinical management, particularly on the diagnostic stage. Advances in omics technologies enable improvements in clinical practice and research, so we proposed a multi-omics approach to aid in the genetic diagnosis and molecular elucidation of an undiagnosed infantile condition of chronic progressive cerebellar ataxia. Using whole-exome sequencing, RNA-seq, and untargeted metabolomics, we identified three clinically relevant mutations (rs141471029, rs191582628 and rs398124292) and an altered metabolic profile in our patient. Two POLR1C diagnostic variants already classified as pathogenic were found, and a diagnosis of hypomyelinating leukodystrophy was achieved. A mutation on the MMACHC gene, known to be associated with methylmalonic aciduria and homocystinuria cblC type, was also found. Additionally, preliminary metabolome analysis revealed alterations in our patient’s amino acid, fatty acid and carbohydrate metabolism. Our findings provided a definitive genetic diagnosis reinforcing the association between POLR1C mutations and hypomyelinating leukodystrophy and highlighted the relevance of multi-omics approaches to the disease.  相似文献   
997.
998.
999.
Background: Diabetic retinopathy (DR) is a neurovascular disease, characterized by a deficiency of brain-derived neurotrophic factor (BDNF), a regulator of autophagy. Beta-hydroxybutyrate (BHB), previously reported as a protective agent in DR, has been associated with BDNF promotion. Here, we investigated whether systemic BHB affects the retinal levels of BDNF and local autophagy in diabetic mice with retinopathy; Methods: C57BL/6J mice were administered with intraperitoneal (i.p.) streptozotocin (STZ) (75 mg/kg) injection to develop diabetes. After 2 weeks, they received i.p. injections of BHB (25–50–100 mg/kg) twice a week for 10 weeks. Retinal samples were collected in order to perform immunofluorescence, Western blotting, and ELISA analysis; Results: BHB 50 mg/kg and 100 mg/kg significantly improved retinal BDNF levels (p < 0.01) in diabetic mice. This improvement was negatively associated with autophagosome–lysosome formations (marked by LC3B and ATG14) and to higher levels of connexin 43 (p < 0.01), a marker of cell integrity. Moreover, BHB administration significantly reduced M1 microglial activation and autophagy (p < 0.01); Conclusions: The systemic administration of BHB in mice with DR improves the retinal levels of BDNF, with the consequent reduction of the abnormal microglial autophagy. This leads to retinal cell safety through connexin 43 restoration.  相似文献   
1000.
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