全文获取类型
收费全文 | 3922篇 |
免费 | 100篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 54篇 |
综合类 | 11篇 |
化学工业 | 911篇 |
金属工艺 | 78篇 |
机械仪表 | 79篇 |
建筑科学 | 234篇 |
矿业工程 | 18篇 |
能源动力 | 78篇 |
轻工业 | 568篇 |
水利工程 | 20篇 |
石油天然气 | 3篇 |
无线电 | 397篇 |
一般工业技术 | 707篇 |
冶金工业 | 492篇 |
原子能技术 | 50篇 |
自动化技术 | 327篇 |
出版年
2022年 | 34篇 |
2021年 | 38篇 |
2020年 | 33篇 |
2019年 | 44篇 |
2018年 | 39篇 |
2017年 | 47篇 |
2016年 | 74篇 |
2015年 | 77篇 |
2014年 | 82篇 |
2013年 | 132篇 |
2012年 | 167篇 |
2011年 | 155篇 |
2010年 | 117篇 |
2009年 | 142篇 |
2008年 | 130篇 |
2007年 | 147篇 |
2006年 | 157篇 |
2005年 | 122篇 |
2004年 | 108篇 |
2003年 | 87篇 |
2002年 | 93篇 |
2001年 | 70篇 |
2000年 | 55篇 |
1999年 | 70篇 |
1998年 | 142篇 |
1997年 | 112篇 |
1996年 | 77篇 |
1995年 | 77篇 |
1994年 | 68篇 |
1993年 | 55篇 |
1992年 | 64篇 |
1991年 | 50篇 |
1990年 | 45篇 |
1989年 | 51篇 |
1988年 | 55篇 |
1987年 | 61篇 |
1986年 | 55篇 |
1985年 | 46篇 |
1984年 | 60篇 |
1983年 | 51篇 |
1982年 | 44篇 |
1981年 | 52篇 |
1980年 | 44篇 |
1979年 | 44篇 |
1978年 | 46篇 |
1977年 | 47篇 |
1976年 | 58篇 |
1975年 | 30篇 |
1973年 | 34篇 |
1971年 | 32篇 |
排序方式: 共有4027条查询结果,搜索用时 0 毫秒
1.
Dr. Yibin Zhang Dr. Shuai Xia Shulin Wan Tessa E. Steenwinkel Tara Vohs Prof. Rudy L. Luck Prof. Thomas Werner Prof. Haiying Liu 《Chembiochem : a European journal of chemical biology》2021,22(13):2282-2291
Abnormal levels of glutathione, a cellular antioxidant, can lead to a variety of diseases. We have constructed a near-infrared ratiometric fluorescent probe to detect glutathione concentrations in biological samples. The probe consists of a coumarin donor, which is connected through a disulfide-tethered linker to a rhodamine acceptor. Under the excitation of the coumarin donor at 405 nm, the probe shows weak visible fluorescence of the coumarin donor at 470 nm and strong near-infrared fluorescence of the rhodamine acceptor at 652 nm due to efficient Forster resonance energy transfer (FRET) from the donor to the acceptor. Glutathione breaks the disulfide bond through reduction, which results in a dramatic increase in coumarin fluorescence and a corresponding decrease in rhodamine fluorescence. The probe possesses excellent cell permeability, biocompatibility, and good ratiometric fluorescence responses to glutathione and cysteine with a self-calibration capability. The probe was utilized to ratiometrically visualize glutathione concentration alterations in HeLa cells and Drosophila melanogaster larvae. 相似文献
2.
3.
4.
Raffael Ott Xenia Pawlow Andreas Weiß Anna Hofelich Melanie Herbst Nadine Hummel Cornelia Prehn Jerzy Adamski Werner Rmisch-Margl Gabi Kastenmüller Anette-G. Ziegler Sandra Hummel 《International journal of molecular sciences》2020,21(24)
Shared metabolomic patterns at delivery have been suggested to underlie the mother-to-child transmission of adverse metabolic health. This study aimed to investigate whether mothers with gestational diabetes mellitus (GDM) and their offspring show similar metabolomic patterns several years postpartum. Targeted metabolomics (including 137 metabolites) was performed in plasma samples obtained during an oral glucose tolerance test from 48 mothers with GDM and their offspring at a cross-sectional study visit 8 years after delivery. Partial Pearson’s correlations between the area under the curve (AUC) of maternal and offspring metabolites were calculated, yielding so-called Gaussian graphical models. Spearman’s correlations were applied to investigate correlations of body mass index (BMI), Matsuda insulin sensitivity index (ISI-M), dietary intake, and physical activity between generations, and correlations of metabolite AUCs with lifestyle variables. This study revealed that BMI, ISI-M, and the AUC of six metabolites (carnitine, taurine, proline, SM(-OH) C14:1, creatinine, and PC ae C34:3) were significantly correlated between mothers and offspring several years postpartum. Intergenerational metabolite correlations were independent of shared BMI, ISI-M, age, sex, and all other metabolites. Furthermore, creatinine was correlated with physical activity in mothers. This study suggests that there is long-term metabolic programming in the offspring of mothers with GDM and informs us about targets that could be addressed by future intervention studies. 相似文献
5.
6.
Werner Hüning 《化学,工程师,技术》1985,57(10):850-857
Safety measures in thermal waste air purification units . Safety problems may arise in thermal waste air purification units from the occasional explosive nature of the exhaust gases, which may cause a flashback into the production plant. This must be avoided by the installation of safety devices that arrest a flashback. The number of such safety devices is determined by the probability of formation of explosive waste air, according to the zone classification of the explosion-protection guide. The principal explosion arrestor devices installed between combustion chamber and production plant are liquid submersion systems, detonation barriers, and dynamic flashback-free inlets into the combustion chamber, all of which must be operated under instrumental surveillance. This report presents a state-of-the-art summary of all suitable procedures and safety devices permitting safe design of systems for thermal air cleaning problems encountered in practice. 相似文献
7.
Werner Baltes Gloria Bochmann 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1987,184(3):179-186
Summary From model roastings of mixtures containing serine, threonine and sucrose about 350 volatile compounds were separated and identified by GC/MS. Among them there were more than 100 monocyclic furans, 13 furanones and 8 bicyclic furans, the mass spectra and retention indices of which are recorded. The most important mass spectrometric fragmentation pathways are described. Spectra obtained from roasting coffee under identical conditions are compared with the spectra from model roastings.
Dissertation Gloria Bochmann, TU Berlin 1984 相似文献
Modell-Reaktionen zur Röstaroma-BildungII. Die massenspektrometrische Identifizierung von Furanen und Furanonen aus der Reaktion von Serin und Threonin mit Saccharose unter den Bedingungen der Kaffeeröstung
Zusammenfassung Aus Modellröstungen von Gemischen aus Serin, Threonin und Saccharose unter den Bedingungen der Kaffeeröstung wurden etwa 350 flüchtige Verbindungen mittels GC/MS getrennt und identifiziert. Unter ihnen befanden sich über 100 monocyclische Furane und 13 Furanone sowie 8 bicyclische Furane, deren Massenspektren und Retentions-indices angegeben werden. Die wichtigsten massenspektrometrischen Fragmentierungswege werden beschrieben. -Die aus einer gleich behandelten Röstung von Rohkaffee erhaltenen Spektren werden mit denen der Modellröstungen verglichen.
Dissertation Gloria Bochmann, TU Berlin 1984 相似文献
8.
E. M. Telles J. C. S. Moraes A. Scalabrin D. Pereira G. Carelli C. A. Massa A. Moretti F. Strumia 《Journal of Infrared, Millimeter and Terahertz Waves》1995,16(12):2233-2248
We used a Stark-Optoacoustic cell and hybrid waveguide resonators to perform an Infrared and Far Infrared Stark Spectroscopy study on some transitions of13CD3OH. Different behaviours of the transitions in the presence of a d.c. electric field were observed. The Stark splittings of six FIR laser lines ranging from 34 to 136 MHz/kVcm?1 were determined. The analysis of the behaviour of the IR and FIR transitions in the presence of the external electric fields gives important and exclusive information on the levels involved in the transitions. 相似文献
9.
Growth of one spherulite within a thin foil of polypropylene around one circular obstacle or around combinations of circular obstacles is investigated. For each obstacle there exists a region of shadow, seen from the nucleus of the spherulite, which influences the growth of the spherulite. Within any region of shadow the growth fronts are evolvents of the obstacle's boundary, because the spherulite grows isotropically. When two growth fronts belonging to one spherulite meet each other inside the shadow, an intrinsic grain boundary is formed for each obstacle. Additionally, growth of one spherulite around a rectangular obstacle and a spherical obstacle is investigated. 相似文献
10.