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   797篇
  免费   9篇
  国内免费   1篇
电工技术   2篇
化学工业   23篇
金属工艺   1篇
机械仪表   4篇
建筑科学   4篇
矿业工程   1篇
能源动力   6篇
轻工业   15篇
石油天然气   1篇
无线电   19篇
一般工业技术   29篇
冶金工业   668篇
原子能技术   3篇
自动化技术   31篇
  2023年   3篇
  2022年   3篇
  2021年   4篇
  2020年   6篇
  2019年   6篇
  2018年   8篇
  2017年   5篇
  2016年   7篇
  2015年   7篇
  2014年   15篇
  2013年   8篇
  2012年   7篇
  2011年   8篇
  2010年   10篇
  2009年   4篇
  2008年   4篇
  2007年   3篇
  2005年   8篇
  2004年   2篇
  2003年   3篇
  2001年   3篇
  2000年   1篇
  1999年   15篇
  1998年   192篇
  1997年   112篇
  1996年   83篇
  1995年   42篇
  1994年   44篇
  1993年   42篇
  1992年   7篇
  1991年   11篇
  1990年   7篇
  1989年   6篇
  1988年   7篇
  1987年   14篇
  1986年   8篇
  1985年   3篇
  1982年   3篇
  1981年   3篇
  1980年   3篇
  1978年   1篇
  1977年   23篇
  1976年   52篇
  1975年   1篇
  1955年   2篇
  1954年   1篇
排序方式: 共有807条查询结果,搜索用时 14 毫秒
11.
Pehnotypings of serum proteins and erythrocyte enzyme polymorphisms were used in addition to classic erythrocyte antigens in a study of 281 paternity cases. This group was compared with 877 cases in which only the erythrocyte antigens were tested. In the study group 80 exclusions were found for 52 alleged fathers. The expanded test battery increased the exclusion rate by 62%. In addition to 30 direct exclusions, serum proteins and erythrocyte enzymes corroborated indirect exclusions obtained with erythrocyte antigen tests in eight instances.  相似文献   
12.
13.
The first results of the movable electrode biasing experiments performed on the IR-T1 tokamak are presented. For this purpose, a movable electrode biasing system was designed, constructed, and installed on the IR-T1 tokamak, and then the positive voltage applied to an electrode inserted inside the tokamak limiter and the plasma current, poloidal and radial components of the magnetic fields, loop voltage, and diamagnetic flux in the absence and presence of the biased electrode were measured. Results compared and discussed.  相似文献   
14.
15.
In many industrial applications, the quality of mixing between different materials is fundamental to guarantee the desired properties of products. However, properly modeling and understanding polymer mixing presents noticeable difficulties, because of the variety and complexity of the phenomena involved. This is also the case with the Cavity Transfer Mixer (CTM), an add‐on to be mounted downstream of existing extruders, to improve distributive mixing. The present work proposes a fully three‐dimensional model of the CTM: a finite element solver provides the transient velocity field, which is used in the mapping method implementation to compute the concentration field evolution and quantify mixing. Several simulations are run assessing the impact on mixing of geometrical and functioning parameters. In general, the number of cavities per row should be limited and the cavity size rather big to guarantee good mixing quality. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1034–1048, 2018  相似文献   
16.
An electrochemical approach to nanoporous film-based gold catalyst design using the underpotential deposition and redox replacement technique is presented. The procedure consisted of the underpotential deposition (UPD) of copper on the gold nanoporous film, with subsequent replacement of the copper by palladium at open circuit in a palladium containing solution. The resulting electrode was studied using cyclic voltammetry and scanning electron microscopy. The electrocatalytic activity of as-prepared palladium nanoporous gold film electrodes toward the oxygen reduction reaction is presented.  相似文献   
17.
Liquid-phase adsorption has hardly been established in micro-flow, although this constitutes an industrially vital method for product separation. A micro-flow UV-photo isomerization process converts cis-cyclooctene partly into trans-cyclooctene, leaving an isomeric mixture. Trans-cyclooctene adsorption and thus separation was achieved in a fixed-bed micro-flow reactor, packed with AgNO3/SiO2 powder, while the cis-isomer stays in the flow. The closed-loop recycling-flow has been presented as systemic approach to enrich the trans-cyclooctene from its cis-isomer. In-flow adsorption in recycling-mode has hardly been reported so that a full theoretical study has been conducted. This insight is used to evaluate three process design options to reach an optimum yield of trans-cyclooctene. These differ firstly in the variation of the individual residence times in the reactor and separator, the additional process option of refreshing the adsorption column under use, and the periodicity of the recycle flow.  相似文献   
18.
The edible red seaweed Eucheuma cottonii is abundantly cultivated for carrageenan production. This study investigated the effects of dietary E. cottonii polyphenol-rich extract (ECME) on breast cancer. In vitro assays showed that ECME was antiproliferative against oestrogen-dependent MCF-7 and oestrogen-independent MB-MDA-231 human breast-cancer cells (IC50 values of 20 and 42 μg/ml, respectively) but was non-toxic to normal cell lines. The ECME (150 and 300 mg/kg BW) was fed to female rats and, after 4 weeks, rat mammary tumour was induced using LA7 cells (inoculated subcutaneously). The ECME inhibited tumour development and erythrocyte lipid peroxidation in the cancer-induced rats, dose-dependently. It showed anti-oestrogenic effects on the rat estrous cycle and serum hormone levels. Electron microscopy and histopathology observations confirmed apoptosis in the rat mammary tumours. The polyphenol-rich ECME was tumour-suppressive via apoptosis induction, downregulating the endogenous oestrogen biosynthesis, and improving antioxidative status in the rats.  相似文献   
19.
20.
Although myelin basic protein (MBP)-recognizing T cells are not readily obtained after immunization of BALB/c mice with MBP (reflecting the BALB/c resistance to actively induced experimental autoimmune encephalomyelitis (EAE)), they can be expanded and cloned after several rounds of in vitro culture. The majority of BALB/c-derived clones recognize an epitope defined by MBP peptide 59-76. When transferred to naive BALB/c recipients, these clones cause classical EAE, with characteristic inflammation and demyelination of the central nervous system (CNS). We previously showed that two related clones recognizing a minor epitope, defined by MBP peptide 151-168, cause inflammation and demyelination preferentially of the peripheral nervous system (PNS). Because MBP has alternatively spliced isoforms, residues 151-168 are not present contiguously in all MBP isoforms. In order to determine whether induction of PNS disease is idiosyncratic to these sister clones, or related to their properties of epitope recognition, an independent T-cell line with similar recognition properties was studied. Clone 116F, derived from a BALB/c shiverer mouse, expresses a different T-cell receptor (TCR), with distinct TCR contact residues, but like the previously described T cells, this clone requires residues from both exons 6 and 7 for optimal stimulation. When adoptively transferred to BALB/c recipients, this clone preferentially induces disease of the PNS. A control BALB/c shiverer-derived MBP 59-76-recognizing clone, in contrast, induces CNS disease. These data strongly suggest that the site of disease initiation may correlate with epitope recognition, particularly when alternative isoforms are involved.  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