全文获取类型
收费全文 | 1063篇 |
免费 | 33篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 8篇 |
综合类 | 3篇 |
化学工业 | 343篇 |
金属工艺 | 16篇 |
机械仪表 | 11篇 |
建筑科学 | 58篇 |
矿业工程 | 2篇 |
能源动力 | 31篇 |
轻工业 | 223篇 |
水利工程 | 10篇 |
石油天然气 | 7篇 |
无线电 | 37篇 |
一般工业技术 | 161篇 |
冶金工业 | 92篇 |
原子能技术 | 4篇 |
自动化技术 | 91篇 |
出版年
2024年 | 3篇 |
2023年 | 8篇 |
2022年 | 36篇 |
2021年 | 56篇 |
2020年 | 11篇 |
2019年 | 22篇 |
2018年 | 20篇 |
2017年 | 20篇 |
2016年 | 31篇 |
2015年 | 23篇 |
2014年 | 26篇 |
2013年 | 94篇 |
2012年 | 55篇 |
2011年 | 65篇 |
2010年 | 48篇 |
2009年 | 40篇 |
2008年 | 53篇 |
2007年 | 51篇 |
2006年 | 48篇 |
2005年 | 45篇 |
2004年 | 31篇 |
2003年 | 28篇 |
2002年 | 36篇 |
2001年 | 6篇 |
2000年 | 17篇 |
1999年 | 13篇 |
1998年 | 22篇 |
1997年 | 15篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 15篇 |
1993年 | 15篇 |
1992年 | 9篇 |
1991年 | 8篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1983年 | 3篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1955年 | 3篇 |
1942年 | 3篇 |
1917年 | 3篇 |
排序方式: 共有1097条查询结果,搜索用时 15 毫秒
31.
Mario Lhr Wolfgang Hrtig Almut Schulze Matthias Kroiß Silviu Sbiera Constantin Lapa Bianca Mages Sabrina Strobel Jennifer Elisabeth Hundt Simone Bohnert Stefan Kircher Sudha Janaki-Raman Camelia-Maria Monoranu 《International journal of molecular sciences》2022,23(7)
Targeting molecular alterations as an effective treatment for isocitrate dehydrogenase-wildtype glioblastoma (GBM) patients has not yet been established. Sterol-O-Acyl Transferase 1 (SOAT1), a key enzyme in the conversion of endoplasmic reticulum cholesterol to esters for storage in lipid droplets (LD), serves as a target for the orphan drug mitotane to treat adrenocortical carcinoma. Inhibition of SOAT1 also suppresses GBM growth. Here, we refined SOAT1-expression in GBM and IDH-mutant astrocytoma, CNS WHO grade 4 (HGA), and assessed the distribution of LD in these tumors. Twenty-seven GBM and three HGA specimens were evaluated by multiple GFAP, Iba1, IDH1 R132H, and SOAT1 immunofluorescence labeling as well as Oil Red O staining. To a small extent SOAT1 was expressed by tumor cells in both tumor entities. In contrast, strong expression was observed in glioma-associated macrophages. Triple immunofluorescence labeling revealed, for the first time, evidence for SOAT1 colocalization with Iba1 and IDH1 R132H, respectively. Furthermore, a notable difference in the amount of LD between GBM and HGA was observed. Therefore, SOAT1 suppression might be a therapeutic option to target GBM and HGA growth and invasiveness. In addition, the high expression in cells related to neuroinflammation could be beneficial for a concomitant suppression of protumoral microglia/macrophages. 相似文献
32.
Sylvain Lamoine Mlissa Cumenal David A. Barriere Vanessa Pereira Mathilde Fereyrolles Laëtitia Prival Julie Barbier Ludivine Boudieu Emilie Brasset Benjamin Bertin Yoan Renaud Elisabeth Miot-Noirault Marie-Ange Civiale David Balayssac Youssef Aissouni Alain Eschalier Jrme Busserolles 《International journal of molecular sciences》2022,23(1)
33.
Peter Zipper Andrs Jnosi Wolfgang Geymayer Elisabeth Ingolic Ernst Fleischmann 《Polymer Engineering and Science》1996,36(4):467-482
Rectangular plates were injection molded from two grades of commercial polypropylene (PP) differing in the molar mass distribution. The mold was mechanically sealed when a desired pressure pi,max (up to 1560 bar) was reached. Samples were taken from each plate at different distances from the gate and were investigated by applying various methods. In spatially resolved wide-angle X-ray studies, the cross section of the sample was scanned with a fine X-ray beam (collimated by a Kratky small-angle camera) and the intensity of scattering was registered by a linear detector as a function of position in the cross section. The evaluation of the scattering data delivered profiles of several parameters, describing the distribution of crystallite modification β-PP and γ-PP, the degree of orientation, the size of crystallites, and interplanar spacing, depending on the distance from surface. These results and those from measurements of birefringence and elongation at break, and from polarization microscopy and transmission electron microscopy, provided details of the layered structures in the plates, at different flow lengths, and allowed far-reaching statements about the influence of molecular properties and processing conditions on the development of texture in the plates. 相似文献
34.
Eugen Seel Elisabeth Zeeb und Karl Reihling 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1919,37(1-2):1-17
Zusammenfassung Die Ergebnisse der chemischen Untersuchung von Fleisch- und Wurstwaren sind als ausschließliche Grundlage für ihre Beurteilung durchaus ungenügend; denn wir können noch nicht annähernd sämtliche chemischen Einzelbestandteile des Fleisches und der Wurstwaren mittels der im praktischen Laboratorium anwend aren Methoden nachweisen und noch viel weniger diese Einzelbestandteile quantitativ ermitteln. Es läßt sich aber auch im allgemeinen durch die chemische Untersuchung allein nicht feststellen, ob eine unter bestimmten Namen in den Handel gebrachte Ware die in diesem Namen zum Ausdruck gebrachten Fleischbestandteile tatsächlich enthält, wie z. B., ob Leberwurst Leber enthält, ferner ob minderwertige oder verbotene Organund Gewebeteile beigemischt sind oder nicht.Daher ist die mikroskopische Untersuchung, besonders in gerichtlichen Fällen, unerläßlich.Die nur auf mikroskopischem Wege erreichbare Kenntnis der in Fleisch und Wurstwaren enthaltenen Gewebe und Organe erleichtert bezw. ermöglicht die Beurteilung von Fleisch- und Wurstwaren nicht nur in vorgenannter Richtung, sondern sie erleichtert auch sehr wesentlich die Beurteilung ihres Gesamtwertes. Dieser ist verschieden je nach dem Vorhandensein der mikroskopisch nachzuweisenden Gewebe bezw. Organe und nach deren Wassergehalt. Letzterer wiederum ist z. B. bei Muskelfleisch konstanter und liegt in engeren Grenzen als bei den drüsigen Organen; im elastischen Bindegewebe ist er bedeutend niedriger als im kollagenen Bindegewebe oder im Muskelfleisch.In der vorliegenden Arbeit ist der Versuch gemacht, die mikroskopischen Schnitte der wichtigsten in Betracht kommenden Gewebe und Organe in gekochtem Zustande so zu charakterisieren, daß sie in Gemischen einwandfrei identifiziert werden können.Die Technik der mikroskopischen Untersuchung von Fleisch- und Wurstwaren ist unter Angabe bewährter Verfahren eingehend dargestellt. 相似文献
35.
36.
Advanced sludge treatment affects extracellular polymeric substances to improve activated sludge dewatering 总被引:41,自引:0,他引:41
The management of wastewater sludge, now often referred to as biosolids, accounts for a major portion of the cost of the wastewater treatment process and represents significant technical challenges. In many wastewater treatment facilities, the bottleneck of the sludge handling system is the dewatering operation. Advanced sludge treatment (AST) processes have been developed in order to improve sludge dewatering and to facilitate handling and ultimate disposal. The authors have extensively reported lab-scale, semi-pilot and pilot investigations on either thermal and thermochemical processes, or chemical oxidation using hydrogen peroxide. To understand the action of these advanced sludge technologies, the essential role played by extracellular polymeric substances (EPS) needs to be understood. EPS form a highly hydrated biofilm matrix, in which the micro-organisms are embedded. Hence they are of considerable importance in the removal of pollutants from wastewater, in bioflocculation, in settling and in dewatering of activated sludge. The present paper reviews the characteristics of EPS and the influence of thermochemical and oxidation mechanisms on degradation and flocculation of EPS. Experimental investigations on waste activated sludge are conducted by the authors to evaluate the various literature findings. From the experiments, it is concluded that AST methods enhance cake dewaterability in two ways: (i) they degrade EPS proteins and polysaccharides reducing the EPS water retention properties; and (ii) they promote flocculation which reduces the amount of fine flocs. 相似文献
37.
Hansson J Båth M Håkansson M Grundin H Bjurklint E Orvestad P Kjellström A Boström H Jönsson M Jonsson K Månsson LG 《Radiation protection dosimetry》2005,114(1-3):278-285
The aim of this study was to find the optimum tube voltage for neonatal chest imaging in computed radiography. The study was designed to take full advantage of the benefits of digital imaging, for example, by comparing the tube voltages at constant effective dose. A phantom study using a living rabbit was first conducted. Images were collected at tube voltages ranging from 40 to 90 kV(p). The reproduction of four structures (central vessels, peripheral vessels, carina and thoracic vertebrae) was rated by 10 radiologists. The reproduction of both central and peripheral vessels was relatively independent of tube voltage. The carina was better reproduced at higher tube voltages whereas the opposite was true for the thoracic vertebrae. Based on the higher importance of the reproduction of the carina it was decided that 90 kV(p) was the optimal tube voltage. To validate the result from the phantom study, a follow-up study was conducted in which images of neonates collected at the tube voltage regularly used at Sahlgrenska University Hospital (70 kV(p)) were compared with images collected at the tube voltage proposed by the phantom study. The follow-up study confirmed the results from the phantom study that the reproduction of the carina was better at 90 than at 70 kV(p). In conclusion, for neonatal chest imaging-given the same effective dose-90 kVp gives better reproduction of important structures than the regularly used 70 kV(p). 相似文献
38.
A. V. Kadomtseva A. M. Ob”edkov N. M. Semenov B. S. Kaverin K. V. Kremlev S. A. Gusev P. A. Yunin 《Inorganic Materials》2018,54(10):971-976
We have synthesized catalysts for the hydrogen reduction of germanium tetrachloride: a catalyst based on multiwalled carbon nanotubes and a hybrid catalyst based on multiwalled carbon nanotubes whose surface was decorated with copper-containing nanoparticles. The hybrid catalyst has been characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results demonstrate that it consists of multiwalled carbon nanotubes whose surface is decorated with copper nanoparticles in a cuprous oxide shell (Cu2O/Cu/MWCNTs). The catalytic activity of the hybrid catalyst exceeds that of the as-prepared MWCNTs. The use of the Cu2O/Cu/MWCNT hybrid catalyst as a catalyst for the hydrogen reduction of germanium tetrachloride allows the reaction temperature to be lowered and ensures 95.7% germanium tetrachloride conversion at 873 K. 相似文献
39.
V. Hynek M. Obšil J. Quint J. -P. E. Grolier 《International Journal of Thermophysics》1997,18(3):719-732
A new version of a vibrating tube flow densitometer has been designed permitting measurements of density differences between
two fluids in the temperature range from 298 to 723 K and at pressures up to 40 MPa. The instrument is equipped with a Pt/Rh20
vibrating tube (1.6-mm o.d.) and a Pt/Rh10 transporting tube (1.2-mm o.d.) permitting measurements with highly corrosive liquids.
The period of oscillation of the tube is about 7.5 ms, with a typical stability better than 10−4% over about a 1-h period over the entire temperature interval. The calibration constantK at room temperature is about 530 kg·m−3·ms−2, with a temperature coefficient of approximately −0.13kg·m−3·ms−2·K−1, and is practically pressure independent. It can be determined by calibration with a reproducibility generally better than
0.1%. The instrument was tested with NaCl(aq) solutions in the temperature range from 373 to 690 K for density differences
between sample and reference liquid ranging from 200 to 2 kg·m−3; the corresponding errors are believed to be below 0.3 and 5%, respectively. A highly automated temperature control maintains
the temperature of the tube stable to within ±0.02 K. 相似文献
40.
Elisabeth A. A. O'Flaherty Paraskevi Tsermoula Eileen E. O'Neill Nora M. O'Brien 《International Journal of Food Science & Technology》2019,54(4):1256-1264
Beef processing produces high volumes of protein rich, low value, ‘waste’ co-products such as offal. Beef improves uptake of low bioavailable non-haem iron (found in vegetables, fortificants, supplements) and this effect is dubbed the ‘meat-factor’, although the underlying mechanism is not fully understood. Here, we investigate whether bovine co-products (kidney, lung, heart) not previously studied share this enhancing potential. This was determined by coupled in vitro digestion of co-products and subsequent caco-2 cell ferritin formation (an intracellular iron storage protein). In this study we show that bovine co-products significantly increase caco-2 cells’ response to non-haem iron from infant rice cereal. The presence of these co-products, (kidney, lung and heart), increased relative uptake (by 207.13%, 171.21%, 265.28%, respectively), to a greater extent than beef (30.23%). Our findings present a novel function for co-products of beef processing that may have potential as food ingredients to improve non-haem iron bioavailability, thus adding value. 相似文献