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   743篇
  免费   38篇
  国内免费   2篇
电工技术   20篇
综合类   20篇
化学工业   125篇
金属工艺   19篇
机械仪表   9篇
建筑科学   7篇
矿业工程   91篇
能源动力   13篇
轻工业   98篇
水利工程   3篇
石油天然气   3篇
无线电   35篇
一般工业技术   63篇
冶金工业   234篇
原子能技术   2篇
自动化技术   41篇
  2024年   1篇
  2023年   3篇
  2022年   12篇
  2021年   19篇
  2020年   18篇
  2019年   14篇
  2018年   17篇
  2017年   17篇
  2016年   23篇
  2015年   11篇
  2014年   15篇
  2013年   36篇
  2012年   21篇
  2011年   53篇
  2010年   32篇
  2009年   27篇
  2008年   16篇
  2007年   24篇
  2006年   20篇
  2005年   12篇
  2004年   50篇
  2003年   38篇
  2002年   53篇
  2001年   48篇
  2000年   23篇
  1999年   44篇
  1998年   42篇
  1997年   26篇
  1996年   9篇
  1995年   6篇
  1994年   10篇
  1993年   9篇
  1992年   2篇
  1991年   3篇
  1990年   6篇
  1988年   5篇
  1987年   3篇
  1986年   1篇
  1984年   3篇
  1982年   1篇
  1979年   2篇
  1977年   2篇
  1975年   1篇
  1974年   3篇
  1969年   1篇
  1968年   1篇
排序方式: 共有783条查询结果,搜索用时 15 毫秒
1.
Alkyd resins are generally used in the production of printing inks. All industries look for alternative raw materials in the production of ink with the growing inclination toward using natural products. Resins forming the vehicle of the ink to be obtained from natural resources will provide benefits for the environment, nature, and living creatures. The aim of the study was to promote the use of natural resin in the ink system. Natural Pinus pinaster resin was added into vegetable and mineral oil-based solvents in pure form with alkyd resin in different amounts and ink varnishes of different combinations were prepared. Then, printing inks were produced from these varnishes in pure and hybrid form. Following the assessment of the rheological properties of the inks prepared, printing tests were conducted to assess the printing quality parameters. Ideal mixing ratios of the natural resins in the ink were determined for printability. The environmental importance and advantages of the use of natural resins were discussed. Recommendations were given in line with the results to encourage widespread use of natural resins in near future.  相似文献   
2.
This short paper discusses the method of effectively canceling equal status normal mode noise not only on a sensor line but also on a transmission line of an optical instrument using a sensor with a sensordummy resistance  相似文献   
3.
黄药合成工艺的生产实践   总被引:1,自引:0,他引:1  
熊薪 《铜业工程》2003,(2):29-31
本文介绍了永平铜矿强力公司黄药合成的工艺概况 ,并论述了在生产实践中对提高产品质量所采取的主要措施  相似文献   
4.
虚假的会计信息,将严重扭曲股票的价值,扰乱资本市场秩序,侵害投资者的利益。笔者就会计信息失真的原因进行了分析,并就如何防范进行了探讨。  相似文献   
5.
曾炯  王军利 《铜业工程》2002,(2):42-43,32
钢丝绳芯胶带是一种优质高效的运输带 ,影响它使用寿命的因素很多。本文重点介绍了张紧力对钢丝绳芯胶带的影响 ,阐述了实际工作中如何及时调节张紧力 ,并提供了几种调整张紧力的方法。  相似文献   
6.
The aim of this study is to examine the effects of various loading conditions on the stress of a pin-loaded woven-glass fiber reinforced epoxy laminate conveying chain component. A numerical and experimental study was carried out to determine the stress distribution of composite conveying chain components used to convey loads. For the experimental study, an apparatus was developed to simulate chain components in real motion. Two different working conditions of the chain component were investigated. The first condition represents the movement of the chain components without loading. In the second condition, the chain component touches and moves the load. The commercial finite element package ANSYS was used to perform the numerical analysis using a three dimensional eight-noded layered structural solid elements. Chain tensile forces were loaded through pins and chosen as 250, 500, 750, 1000 and 1250 N for the two conditions of chain components. Experimental and numerical studies were compared and discussed for two conditions and five different tensile forces. A good agreement between experimental results and numerical predictions is obtained.  相似文献   
7.
黎益昌  罗友海 《铜业工程》2004,(3):61-62,18
本文利用回归分析导出材料耗用的回归方程 ,并对方程进行拟合优度检测和显著性检验 ,以及对材料耗用情况进行综合评价。  相似文献   
8.
通过总结大关山矿硐室爆破的主要特点,并就硐室爆破实施过程中采取的新措施、新办法进行了分析。  相似文献   
9.
The aim of this study was exploration of the genetic background of conjunctival melanoma (CM) and correlation with recurrent and metastatic disease. Twenty-eight CM from the Rotterdam Ocular Melanoma Study group were collected and DNA was isolated from the formalin-fixed paraffin embedded tissue. Targeted next-generation sequencing was performed using a panel covering GNAQ, GNA11, EIF1AX, BAP1, BRAF, NRAS, c-KIT, PTEN, SF3B1, and TERT genes. Recurrences and metastasis were present in eight (29%) and nine (32%) CM cases, respectively. TERT promoter mutations were most common (54%), but BRAF (46%), NRAS (21%), BAP1 (18%), PTEN (14%), c-KIT (7%), and SF3B1 (4%) mutations were also observed. No mutations in GNAQ, GNA11, and EIF1AX were found. None of the mutations was significantly associated with recurrent disease. Presence of a TERT promoter mutation was associated with metastatic disease (p-value = 0.008). Based on our molecular findings, CM comprises a separate entity within melanoma, although there are overlapping molecular features with uveal melanoma, such as the presence of BAP1 and SF3B1 mutations. This warrants careful interpretation of molecular data, in the light of clinical findings. About three quarter of CM contain drug-targetable mutations, and TERT promoter mutations are correlated to metastatic disease in CM.  相似文献   
10.
Catalytic ring hydrogenations of naphthalene and 1-naphthol were studied over several supported metal catalysts in supercritical carbon dioxide solvent at low temperature. Higher concentration of hydrogen in supercritical carbon dioxide and lower reaction temperature were responsible for higher catalyst activity and selectivities to the desired partial ring hydrogenated products as compared with those observed in organic solvent for the same catalyst.  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