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   2386篇
  免费   90篇
  国内免费   7篇
电工技术   25篇
综合类   10篇
化学工业   505篇
金属工艺   91篇
机械仪表   83篇
建筑科学   51篇
矿业工程   9篇
能源动力   164篇
轻工业   262篇
水利工程   17篇
石油天然气   9篇
无线电   168篇
一般工业技术   523篇
冶金工业   231篇
原子能技术   13篇
自动化技术   322篇
  2024年   9篇
  2023年   33篇
  2022年   94篇
  2021年   97篇
  2020年   79篇
  2019年   96篇
  2018年   101篇
  2017年   104篇
  2016年   95篇
  2015年   43篇
  2014年   102篇
  2013年   190篇
  2012年   111篇
  2011年   150篇
  2010年   115篇
  2009年   94篇
  2008年   93篇
  2007年   89篇
  2006年   54篇
  2005年   59篇
  2004年   39篇
  2003年   45篇
  2002年   49篇
  2001年   26篇
  2000年   28篇
  1999年   29篇
  1998年   44篇
  1997年   42篇
  1996年   34篇
  1995年   24篇
  1994年   22篇
  1993年   20篇
  1992年   20篇
  1991年   18篇
  1990年   20篇
  1989年   19篇
  1988年   24篇
  1987年   22篇
  1986年   16篇
  1985年   14篇
  1984年   8篇
  1983年   9篇
  1982年   7篇
  1981年   12篇
  1980年   9篇
  1979年   9篇
  1977年   6篇
  1976年   20篇
  1974年   8篇
  1973年   9篇
排序方式: 共有2483条查询结果,搜索用时 750 毫秒
91.
This paper summarizes the inhibitor activity of various reported thiourea derivatives in acid media used against the deterioration of mild steel. Acid solutions have been extensively employed in manufacturing and many industrial processes for pickling and removal of undesirable scale. Mild steel is highly susceptible to corrosion in such aggressive acid media. The additives such as inhibitors are widely employed in those cases to reduce the extent of corrosion as much as possible. The survey of literature on organic inhibitors clearly indicates the potential usage of thiourea derivatives as inhibitors of mild steel corrosion. The influence of physical-chemical properties on the inhibition activity of thiourea derivatives has been discussed. This information is highly useful for different industrial applications where good performing inhibitors are being required for protecting mild steel from aggressive acid media.  相似文献   
92.
The modern manufacturing organizations are adopting lean manufacturing principles so as to eliminate wastes and streamline their processes. The evaluation of leanness gains vital importance. Multiple tools/techniques are available for ensuring leanness. Due to the impreciseness and vagueness associated with decision-making problems, fuzzy logic need to be used. Relational databases enable decision-making process. This article presents a study in which fuzzy association rules mining approach has been used for leanness evaluation of an Indian modular switches manufacturing organization. The experiences gained as a result of the conduct of the study indicated that leanness evaluation could be performed by the decision makers without any constraints.  相似文献   
93.
Polycrystalline BiFeO3 (BFO) and Bi0.90Gd0.10Fe1?xZrxO3 (x = 0.0–0.10; BGFZx) ceramics were synthesized by solid‐state reaction method. Rietveld analysis of X‐ray diffraction patterns showed that BFO and BGFZx = 0.0 samples are stabilized in rhombohedral structure (space group R3c), whereas a small fraction of orthorhombic phase (space group Pn21a) is observed for BGFZx = 0.03–0.10 samples. Suppression and disappearance of some Raman modes indicated a structural phase transition with addition of Zr dopant at Fe site. Magnetic measurements exhibited weak ferromagnetic behavior of BGFZx samples with increasing Zr+4 concentrations. The insertion of Gd+3 ions at Bi+3 sites and nonmagnetic Zr+4 ions at Fe+3 sites in Fe–O–Fe network suppressed the spin cycloid structure of BFO which in turn enhanced the magnetization of these ceramics. Electron spin resonance spectra revealed the breaking of spin cycloid of BFO due to the development of free spins with addition of Zr+4 dopants at Fe sites. UV–Visible diffuse reflectance spectra showed one dd crystal field transition and two charge‐transfer (C–T) transitions along with a sharp absorption of light in visible region for all samples. Almost frequency‐independent dielectric constant and dielectric loss along with very low values of dielectric loss indicated greatly improved dielectric properties for BGFZx = 0.03–0.10 samples.  相似文献   
94.
95.
96.
Waste tyres have become a grave concern as their accumulation is aggregating every year. Not only the size of waste tyre has to be reduced, but also some useful energy has to be recovered out of it as the world badly requires energy from alternate sources. Pyrolysis is one such method to extract energy potential products from waste tyres. It is extensively used to generate carbon black (solid product), tyre-oil (liquid product) and syngas (gas product) from waste tyres. In that connection, this article discusses the effect of various parameters on the product composition of pyrolysis of waste tyres. The current usage of pyrolysis products and their typical characteristics are also discussed in this critique. Of late, extraction of high value added products, such as activated carbon from carbon black, and limonene from tyre-oil is gaining attention. The article also throws some light on the application and generation routes of activated carbon and limonene from waste tyres.  相似文献   
97.
98.
Nitroarenes are less preferred in drug discovery due to their potential to be mutagenic. However, several nitroarenes were shown to be promising antitubercular agents with specific modes of action, namely, nitroimidazoles and benzothiazinones. The nitro group in these compounds is activated through different mechanisms, both enzymatic and non‐enzymatic, in mycobacteria prior to binding to the target of interest. From a whole‐cell screening program, we identified a novel lead nitrobenzothiazole (BT) series that acts by inhibition of decaprenylphosphoryl‐β‐d ‐ribose 2′‐epimerase (DprE1) of Mycobacterium tuberculosis (Mtb). The lead was found to be mutagenic to start with. Our efforts to mitigate mutagenicity resulted in the identification of 6‐methyl‐7‐nitro‐5‐(trifluoromethyl)‐1,3‐benzothiazoles (cBTs), a novel class of antitubercular agents that are non‐mutagenic and exhibit an improved safety profile. The methyl group ortho to the nitro group decreases the electron affinity of the series, and is hence responsible for the non‐mutagenic nature of these compounds. Additionally, the co‐crystal structure of cBT in complex with Mtb DprE1 established the mode of binding. This investigation led to a new non‐mutagenic antitubercular agent and demonstrates that the mutagenic nature of nitroarenes can be solved by modulation of stereoelectronic properties.  相似文献   
99.
Bulletin of Engineering Geology and the Environment - Landslide susceptibility assessment was performed using the novel hybrid model Bagging-based Naïve Bayes Trees (BAGNBT) at Mu Cang Chai...  相似文献   
100.
Pal  Shaili  Kumar  Ajay  Kumar  Sunil  De  Arup Kumar  Prakash  Rajiv  Sinha  Indrajit 《Catalysis Letters》2022,152(11):3259-3271
Catalysis Letters - Magnetically recyclable visible light photocatalysts for the degradation of critical organic pollutants are an urgent industrial requirement. Nonetheless, one component...  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