全文获取类型
收费全文 | 1723篇 |
免费 | 56篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 35篇 |
综合类 | 1篇 |
化学工业 | 293篇 |
金属工艺 | 72篇 |
机械仪表 | 17篇 |
建筑科学 | 53篇 |
矿业工程 | 2篇 |
能源动力 | 42篇 |
轻工业 | 114篇 |
水利工程 | 17篇 |
石油天然气 | 2篇 |
无线电 | 185篇 |
一般工业技术 | 246篇 |
冶金工业 | 475篇 |
原子能技术 | 12篇 |
自动化技术 | 217篇 |
出版年
2023年 | 14篇 |
2022年 | 24篇 |
2021年 | 47篇 |
2020年 | 34篇 |
2019年 | 35篇 |
2018年 | 36篇 |
2017年 | 43篇 |
2016年 | 34篇 |
2015年 | 25篇 |
2014年 | 36篇 |
2013年 | 76篇 |
2012年 | 63篇 |
2011年 | 67篇 |
2010年 | 56篇 |
2009年 | 58篇 |
2008年 | 80篇 |
2007年 | 54篇 |
2006年 | 39篇 |
2005年 | 44篇 |
2004年 | 40篇 |
2003年 | 34篇 |
2002年 | 30篇 |
2001年 | 27篇 |
2000年 | 24篇 |
1999年 | 34篇 |
1998年 | 127篇 |
1997年 | 85篇 |
1996年 | 42篇 |
1995年 | 44篇 |
1994年 | 27篇 |
1993年 | 35篇 |
1992年 | 12篇 |
1991年 | 21篇 |
1990年 | 18篇 |
1989年 | 11篇 |
1987年 | 17篇 |
1986年 | 14篇 |
1985年 | 11篇 |
1984年 | 14篇 |
1983年 | 15篇 |
1982年 | 10篇 |
1981年 | 14篇 |
1980年 | 12篇 |
1979年 | 11篇 |
1978年 | 12篇 |
1977年 | 20篇 |
1976年 | 38篇 |
1975年 | 9篇 |
1974年 | 15篇 |
1973年 | 10篇 |
排序方式: 共有1783条查询结果,搜索用时 31 毫秒
61.
Jordan Schilbach 《国外电子测量技术》2014,(7)
正1引言移动数据流量的很大部分发生在室内。确保室内高密度用户的最佳网络质量显得特别重要。为了规划、实施和优化室内无线网络,首选必须对所有广泛使用的网络的无线信道质量进行可靠和全面评估。极其轻便和紧凑的路测扫描仪非常适合这一目标。甚至采用背包系统就能并行测量所有相关标准,因此极大缩短了测量时间。因为宽带市场上涌现出智能手机和平板电脑,移动宽带数据业务应用急速增加。仅2012年,全球移动数据 相似文献
62.
Eduardo Di Mauro Matteo Camaggi Nils Vandooren Caleb Bayard Jordan De Angelis Alessandro Pezzella Bill Baloukas Richard Silverwood Abdellah Ajji Christian Pellerin Clara Santato 《Polymer International》2019,68(5):984-991
In the human body, the black‐brown biopigment eumelanin blocks harmful ultraviolet (UV) radiation. In the plastics industry, additives are often added to polymers to increase their UV‐absorption properties. We herein report an assessment of the biopigment eumelanin as a nature‐inspired additive for plastics to enhance their UV absorption. Since eumelanin is produced by natural sources and is nontoxic, it is an interesting candidate in the field of sustainable plastic additives. In this work, the eumelanin‐containing films of commercial ethylene–vinyl acetate copolymer, a plastic used for packaging applications, were obtained by melt compounding and compression molding. The biopigment dispersion in the films was improved by means of the melanin free acid treatment. It was observed that eumelanin amounts as low as 0.8 wt% caused an increase of the UV absorption, up to one order of magnitude in the UVA range. We also evaluated the effect of eumelanin on the thermal stability and photostability of the films: the biopigment proved to be double‐edged, working both as UV‐absorption enhancer and photo‐prooxidant, as thermogravimetric analysis and infrared spectroscopy revealed. © 2019 Society of Chemical Industry 相似文献
63.
Tiana D. Warren Krishna Patel Jordan L. Rivera James R. Eshleman Marc Ostermeier 《American Institute of Chemical Engineers》2020,66(3):e16688
Improved prodrug-activating enzymes have the potential to increase the therapeutic efficacy of gene-directed enzyme prodrug therapy (GDEPT). Yeast cytosine deaminase (yCD) is commonly used to convert the prodrug 5-fluorocytosine (5-FC) to the chemotherapeutic 5-fluorouracil for GDEPT. Mutagenesis studies on yCD aimed at improving its application in GDEPT have been limited to subsets of residues or have sought to improve a single property of the enzyme. We performed comprehensive site-saturation mutagenesis (CSM) on yCD designed to create all 2,983 possible unique protein mutants with a single amino acid substitution. We identified active variants through Escherichia coli genetic complementation and screened these mutants, and combinations thereof, for increased ability to sensitize E. coli and HT1080 fibrosarcoma cells to 5-FC. Several mutants identified in this study showed increased sensitization ability for both E. coli and HT1080 cells indicating that CSM is an effective directed evolution tool for identifying unexpectedly beneficial mutations. 相似文献
64.
65.
Jordan P. Hooker Florian Feist Laura Delafresnaye Leonie Barner Christopher Barner‐Kowollik 《Advanced functional materials》2020,30(26)
A new strategy for particle synthesis is enabled by utilizing modern synthetic, polymer, and photochemical techniques to facilitate the synthesis of highly narrow–disperse multifunctional microspheres from visible‐light induced crosslinking of prepolymers in both a single and dual polymer system. The approach requires no stabilizers, bases, or initiators, and proceeds at ambient temperature to yield microspheres with a tunable size range (0.25–5 µm) in less than 4 h, depending largely on solvent composition, but also polymer concentration (2–10 mg mL?1), ratio, and irradiation intensity (3–20 W). Critically, the visible‐light induced dimerization reaction exploited herein enables simple functional particle syntheses via a single polymer system. Underpinned by an in‐depth kinetic analysis of the particle formation as well as a detailed small molecule study, the mechanism for particle formation is also elucidated. Importantly, inherent advantages of the system are exploited for surface functionalization of residual acrylate and hydroxyl groups (generating inherently fluorescent particles). 相似文献
66.
Treatment of complex gaseous emissions emitted by a rendering facility using a semi‐industrial biofilter
下载免费PDF全文
![点击此处可从《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
67.
Chigozie K. Muoto Eric H. Jordan Maurice Gell Mark Aindow 《Journal of Thermal Spray Technology》2011,20(4):802-816
In solution precursor plasma spray chemical precursor solutions are injected into a standard plasma torch and the final material
is formed and deposited in a single step. This process has several attractive features, including the ability to rapidly explore
new compositions and to form amorphous and metastable phases from molecularly mixed precursors. Challenges include: (a) moderate
deposition rates due to the need to evaporate the precursor solvent, (b) dealing on a case by case basis with precursor characteristics
that influence the spray process (viscosity, endothermic and exothermic reactions, the sequence of physical states through
which the precursor passes before attaining the final state, etc.). Desirable precursor properties were identified by comparing
an effective precursor for yttria-stabilized zirconia with four less effective candidate precursors for MgO:Y2O3. The critical parameters identified were a lack of major endothermic events during precursor decomposition and highly dense
resultant particles. 相似文献
68.
David Geiger 《Building Research & Information》2013,41(2):81-87
Depuis la réalisation du Pavillon des Etats-Unis à I'Expo 70 d'Osaka, Japon, la recherche américaine a été centrée sur les tissus incombustibles « permanents », afin de permettre le classement des structures gonflables de faible hauteur et des structures tendues en tant que constructions permanentes, dans l'esprit de la législation en vigueur. Le Dr Geiger, de la Geiger Berger Associates, New York, traite en détail des cinq structures gonflables basses construites ou en cours de construction. 相似文献
69.
Nana Achile Alomayri Thamer Salman Venyite Paul Kaze Rodrigue C. Assaedi Hasan Suliman Nobouassia Christelle Bewa Sontia Jordan Valdès Metekong Ngouné Jean Kamseu Elie Leonelli Cristina 《SILICON》2022,14(1):263-274
Silicon - The synthesis, mechanical behaviour, and microstructure of metakaolin-based geopolymer mortar reinforced with quartz sand are presented in this investigation. Fine sand (quartz sand)... 相似文献
70.
Sharon Hausman-Cohen William LaValley Heather Way Emily Gutierrez Jordan Reeder 《International journal of molecular sciences》2022,23(4)
Molecular biology combined with genomics can be a powerful tool for developing potential intervention strategies for improving outcomes in children with autism spectrum disorders (ASD). Monogenic etiologies rarely cause autism. Instead, ASD is more frequently due to many polygenic contributing factors interacting with each other, combined with the epigenetic effects of diet, lifestyle, and environment. One limitation of genomics has been identifying ways of responding to each identified gene variant to translate the information to something clinically useful. This paper will illustrate how understanding the function of a gene and the effects of a reported variant on a molecular level can be used to develop actionable and targeted potential interventions for a gene variant or combinations of variants. For illustrative purposes, this communication highlights a specific genomic variant, SHANK3. The steps involved in developing molecularly genomically targeted actionable interventions will be demonstrated. Cases will be shared to support the efficacy of this strategy and to show how clinicians utilized these targeted interventions to improve ASD-related symptoms significantly. The presented approach demonstrates the utility of genomics as a part of clinical decision-making. 相似文献