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   572篇
  免费   15篇
电工技术   11篇
综合类   2篇
化学工业   160篇
金属工艺   34篇
机械仪表   5篇
建筑科学   11篇
矿业工程   1篇
能源动力   9篇
轻工业   18篇
水利工程   8篇
石油天然气   1篇
无线电   41篇
一般工业技术   121篇
冶金工业   108篇
原子能技术   6篇
自动化技术   51篇
  2023年   4篇
  2022年   20篇
  2021年   35篇
  2020年   9篇
  2019年   11篇
  2018年   14篇
  2017年   19篇
  2016年   20篇
  2015年   12篇
  2014年   22篇
  2013年   28篇
  2012年   25篇
  2011年   41篇
  2010年   20篇
  2009年   21篇
  2008年   14篇
  2007年   29篇
  2006年   18篇
  2005年   15篇
  2004年   6篇
  2003年   9篇
  2002年   14篇
  2001年   6篇
  1999年   3篇
  1998年   13篇
  1997年   4篇
  1996年   6篇
  1995年   10篇
  1994年   9篇
  1993年   7篇
  1991年   4篇
  1990年   9篇
  1989年   8篇
  1988年   6篇
  1987年   6篇
  1986年   7篇
  1985年   9篇
  1984年   9篇
  1983年   5篇
  1982年   5篇
  1981年   4篇
  1980年   3篇
  1979年   4篇
  1977年   6篇
  1976年   9篇
  1975年   3篇
  1972年   4篇
  1971年   4篇
  1966年   2篇
  1965年   2篇
排序方式: 共有587条查询结果,搜索用时 15 毫秒
91.
Targeting the programmed cell death protein 1/programmed cell death 1 ligand 1 (PD-1/PD-L1) interaction has become an established strategy for cancer immunotherapy. Although hundreds of small-molecule, peptide, and peptidomimetic inhibitors have been proposed in recent years, only a limited number of drug candidates show good PD-1/PD-L1 blocking activity in cell-based assays. In this article, we compare representative molecules from different classes in terms of their PD-1/PD-L1 dissociation capacity measured by HTRF and in vitro bioactivity determined by the immune checkpoint blockade (ICB) co-culture assay. We point to recent discoveries that underscore important differences in the mechanisms of action of these molecules and also indicate one principal feature that needs to be considered, which is the eventual human PD-L1 specificity.  相似文献   
92.
93.
94.
Latex, a sticky emulsion produced by specialized cells called laticifers, is a crucial part of a plant’s defense system against herbivory and pathogens. It consists of a broad spectrum of active compounds, which are beneficial not only for plants, but for human health as well, enough to mention the use of morphine or codeine from poppy latex. Here, we reviewed latex’s general role in plant physiology and the significance of particular compounds (alkaloids and proteins) to its defense system with the example of Chelidonium majus L. from the poppy family. We further attempt to present latex chemicals used so far in medicine and then focus on functional studies of proteins and other compounds with potential pharmacological activities using modern techniques such as CRISPR/Cas9 gene editing. Despite the centuries-old tradition of using latex-bearing plants in therapies, there are still a lot of promising molecules waiting to be explored.  相似文献   
95.
Strain engineering as one of the most powerful techniques for tuning optical and electronic properties of Ⅲ-nitrides requires reliable methods for strain invest...  相似文献   
96.
Polish architecture tutors and critics Roman Rutkowski and Lukasz Wojciechowski identify a new kind of architecture in [ecosistema urbano]'s ingenious temporary tower pavilions for a sterile new housing estate in Madrid. Contributing power to the local electricity grid, these towers are explicitly designed to provide shelter from the unmediated heat of the harsh external environment through their cooling effect and in so doing to stimulate communal activities and events. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
97.
A processing technique using femtosecond laser pulses to microstructure the surface of a silicon avalanche photodiode (APD) has been used to enhance its near-infrared (near-IR) response. Experiments were performed on a series of APDs and APD arrays using various structuring parameters and poststructuring annealing sequences. Following thermal annealing, we were able to fabricate APD arrays with quantum efficiencies as high as 58% at 1064 nm without degradation of their noise or gain performance. Experimental results provided evidence to suggest that the improvement in charge collection is a result of increased absorption in the near-IR.  相似文献   
98.
We report the synthesis of polycrystalline La x MnO3 + δ (x = 0.815, 0.90, 0.94, 0.97, 1.0) samples and their crystal structure at 300 K. All of the samples are single-phase and have an orthorhombically distorted (Pnma) perovskite structure. Also possible is that some of the samples have a rhombohedrally distorted structure. The unit-cell parameters of La0.90MnO3 differ most significantly from those of the x = 1.0 material. We have assessed the structural imperfection of the samples (cation vacancy concentration) and proposed overall chemical formulas of the manganites that take into account structural defects. Comparison of the X-ray and measured (hydrostatic weighing) densities of the samples demonstrates that their relative density increases with decreasing lanthanum content.  相似文献   
99.
Gamma irradiated synthetic hydroxyapatite, bone substituting materials NanoBone(?) and HA Biocer were examined using EPR spectroscopy and compared with powdered human compact bone. In every case, radiation-induced carbon centered radicals were recorded, but their molecular structures and concentrations differed. In compact bone and synthetic hydroxyapatite the main signal assigned to the CO(2) (-) anion radical was stable, whereas the signal due to the CO(3) (3-) radical dominated in NanoBone(?) and HA Biocer just after irradiation. However, after a few days of storage of these samples, also a CO(2) (-) signal was recorded. The EPR study of irradiated compact bone and the synthetic graft materials suggest that their microscopic structures are different. In FT-IR spectra of NanoBone(?), HA Biocer and synthetic hydroxyapatite the HPO(4) (2-) and CO(3) (2-) in B-site groups are detected, whereas in compact bone signals due to collagen dominate.  相似文献   
100.
The complete elastic modulus matrix of Li2Zn2(MoO4)3 single crystals has been measured for the first time. The sound velocity has been measured in different directions of the crystals by a pulse-phase method. The measurement results have been used to calculate elastic moduli. The sound velocity has been calculated in the three main crystallographic planes of the crystals.  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