首页 | 官方网站   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   11253篇
  免费   603篇
  国内免费   273篇
工业技术   12129篇
  2023年   111篇
  2022年   192篇
  2021年   280篇
  2020年   248篇
  2019年   193篇
  2018年   289篇
  2017年   245篇
  2016年   256篇
  2015年   271篇
  2014年   358篇
  2013年   683篇
  2012年   497篇
  2011年   573篇
  2010年   490篇
  2009年   496篇
  2008年   506篇
  2007年   462篇
  2006年   444篇
  2005年   379篇
  2004年   297篇
  2003年   270篇
  2002年   281篇
  2001年   235篇
  2000年   275篇
  1999年   267篇
  1998年   325篇
  1997年   274篇
  1996年   257篇
  1995年   211篇
  1994年   184篇
  1993年   174篇
  1992年   152篇
  1991年   148篇
  1990年   104篇
  1989年   113篇
  1988年   113篇
  1987年   105篇
  1986年   91篇
  1985年   127篇
  1984年   121篇
  1983年   134篇
  1982年   97篇
  1981年   95篇
  1980年   84篇
  1979年   87篇
  1978年   74篇
  1977年   65篇
  1976年   72篇
  1975年   57篇
  1974年   53篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Ganapati  Reddi  Samoju  Visweswara Rao  Jammu  Bhaskara Rao 《SILICON》2021,13(9):2869-2880
Silicon - This paper presents, analytical modeling of surface potential,threshold voltage and DIBL for a Dual-Metal Double-Gate Gate-All-Around (DM-DG-GAA) MOSFET considering the parabolic...  相似文献   
3.
Neoantigen vaccines and adoptive dendritic cell (DC) transfer are major clinical approaches to initiate personalized immunity in cancer patients. However, the immunization efficacy is largely limited by the in vivo trajectory including neoantigens’ access to resident DCs and DCs’ access to lymph nodes (LNs). Herein, an innovative strategy is proposed to improve personalized immunization through neoantigen-loaded nanovaccines synergized with adoptive DC transfer. It is found that it enables selective delivery of neoantigens to resident DCs and macrophages by coating cancer cell membranes onto neoantigen-loaded nanoparticles. In addition, the nanovaccines promote the secretion of chemokine C-C motif ligand 2 (CCL2), CCL3, and C-X-C motif ligand 10 from macrophages, thus potentiating the access of transferred DCs to LNs. This immunization strategy enables coordinated delivery of identified neoantigens and autologous tumor lysate-derived undefined antigens, leading to initiation of antitumor T cell immunity in a personalized manner. It significantly inhibits tumor growth in prophylactic and established mouse tumor models. The findings provide a new vision for potentiating adoptive cell transfer by nanovaccines, which may open the door to a transformative possibility for improving personalized immunization.  相似文献   
4.
小型堆非能动安全系统初步设计   总被引:1,自引:0,他引:1  
  相似文献   
5.
6.
利用模糊控制和比例积分微分(PID)控制相结合的手段对注塑机料筒温度进行了控制,同时以Matlab 6.0软件为仿真平台,对料筒温度控制进行了模拟仿真研究。实验发现,在注塑机料筒升温过程中利用CHR整定的PID控制手段和模糊控制手段,恒温过程中利用人工整定的PID控制手段,可保证快速的料筒升温响应速率和稳定的保温过程。通过实际注塑实验对该仿真结果进行了验证,在十组实验中,料筒温度误差不超过2%,产品翘曲变形量不超过0.059 mm。  相似文献   
7.
The fracture behaviour and morphologies of high-strength boron steel were investigated at different temperatures at a constant strain rate of 0.1 s-1 based on isothermal tensile tests. Fracture mechanisms were also analyzed based on the relationship between microstructure transformation and continuous cooling transformation(CCT) curves. It is found that 1) fractures of the investigated steel at high temperatures are dimple fractures; 2) the deformation of high-strength boron steel at high temperatures accelerates diffusion transformations; thus, to obtain full martensite, a higher cooling rate is needed; and 3) the investigated steel has the best plasticity when the deformation temperature is 750 °C.  相似文献   
8.
为探究层叠顺序对双硬度UHMWPE-铝合金板抗冲击性能影响,以高分子聚乙烯(UHMWPE)板、7075高强铝合金板为对象,利用一级轻气炮开展一系列平头和卵形弹打靶试验,对靶板弹道极限速度、能量吸收率、破坏模式等进行分析.揭示板材层叠顺序对接触式高分子聚乙烯-铝合金靶板防护性能的影响规律.结果表明:平头弹撞击下,UHMWPE板在前铝合金板在后的叠放顺序("软+硬")防护性能更高;卵形弹撞击下,两种叠放顺序靶板防护性能相近;两种叠放顺序靶板在平头弹撞击下均发生"冲塞破坏",在卵形弹冲击下均发生"延性扩孔"破坏.  相似文献   
9.
The performance of low-to-intermediate temperature (400–800?°C) solid oxide fuel cells (SOFCs) depends on the properties of electrolyte used. SOFC performance can be enhanced by replacing electrolyte materials from conventional oxide ion (O2-) conductors with proton (H+) conductors because H+ conductors have higher ionic conductivity and theoretical electrical efficiency than O2- conductors within the target temperature range. Electrolytes based on cerate and/or zirconate have been proposed as potential H+ conductors. Cerate-based electrolytes have the highest H+ conductivity, but they are chemically and thermally unstable during redox cycles, whereas zirconate-based electrolytes exhibit the opposite properties. Thus, tailoring the properties of cerate and/or zirconate electrolytes by doping with rare-earth metals has become a main concern for many researchers to further improve the ionic conductivity and stability of electrolytes. This article provides an overview on the properties of four types of cerate and/or zirconate electrolytes including cerate-based, zirconate-based, single-doped ceratezirconate and hybrid-doped ceratezirconate. The properties of the proton electrolytes such as ionic conductivity, chemical stability and sinterability are also systematically discussed. This review further provides a summary of the performance of SOFCs operated with cerate and/or zirconate proton conductors and the actual potential of these materials as alternative electrolytes for proton-conducting SOFC application.  相似文献   
10.
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-23

京公网安备 11010802026262号