全文获取类型
收费全文 | 1389篇 |
免费 | 2篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 266篇 |
金属工艺 | 47篇 |
机械仪表 | 50篇 |
建筑科学 | 9篇 |
矿业工程 | 24篇 |
能源动力 | 12篇 |
轻工业 | 15篇 |
水利工程 | 17篇 |
石油天然气 | 79篇 |
武器工业 | 1篇 |
无线电 | 117篇 |
一般工业技术 | 403篇 |
冶金工业 | 211篇 |
原子能技术 | 78篇 |
自动化技术 | 55篇 |
出版年
2022年 | 27篇 |
2021年 | 21篇 |
2020年 | 23篇 |
2019年 | 30篇 |
2018年 | 52篇 |
2017年 | 52篇 |
2016年 | 57篇 |
2015年 | 19篇 |
2014年 | 32篇 |
2013年 | 62篇 |
2012年 | 33篇 |
2011年 | 44篇 |
2010年 | 31篇 |
2009年 | 37篇 |
2008年 | 35篇 |
2007年 | 36篇 |
2006年 | 21篇 |
2005年 | 23篇 |
2004年 | 16篇 |
2003年 | 21篇 |
2002年 | 19篇 |
2001年 | 15篇 |
2000年 | 15篇 |
1999年 | 19篇 |
1998年 | 25篇 |
1997年 | 29篇 |
1994年 | 15篇 |
1993年 | 15篇 |
1992年 | 16篇 |
1991年 | 18篇 |
1990年 | 23篇 |
1988年 | 19篇 |
1987年 | 14篇 |
1986年 | 18篇 |
1985年 | 20篇 |
1984年 | 17篇 |
1983年 | 15篇 |
1982年 | 19篇 |
1981年 | 32篇 |
1980年 | 19篇 |
1978年 | 30篇 |
1977年 | 30篇 |
1976年 | 38篇 |
1975年 | 25篇 |
1974年 | 20篇 |
1973年 | 21篇 |
1972年 | 17篇 |
1971年 | 22篇 |
1970年 | 23篇 |
1968年 | 16篇 |
排序方式: 共有1393条查询结果,搜索用时 15 毫秒
11.
众多植物多糖中,阿拉伯半乳聚糖对嗜黏蛋白阿克曼菌(Akkermansia muciniphila,Akk)模式菌株(DSM 22959)的促生长效果最佳.为进一步探究阿拉伯半乳聚糖对Akk代谢物的影响,本研究将阿拉伯半乳聚糖作为部分碳源对Akk进行体外发酵培养,确定了阿拉伯半乳聚糖的补充量以便于Akk发酵液样本的后续分... 相似文献
12.
Dmitrii Iudin Marina Vasilieva Elena Knyazeva Viktor Korzhikov-Vlakh Elena Demyanova Antonina Lavrentieva Yury Skorik Evgenia Korzhikova-Vlakh 《International journal of molecular sciences》2022,23(5)
The growing number of drug-resistant pathogenic bacteria poses a global threat to human health. For this reason, the search for ways to enhance the antibacterial activity of existing antibiotics is now an urgent medical task. The aim of this study was to develop novel delivery systems for polymyxins to improve their antimicrobial properties against various infections. For this, hybrid core–shell nanoparticles, consisting of silver core and a poly(glutamic acid) shell capable of polymyxin binding, were developed and carefully investigated. Characterization of the hybrid nanoparticles revealed a hydrodynamic diameter of approximately 100 nm and a negative electrokinetic potential. The nanoparticles demonstrated a lack of cytotoxicity, a low uptake by macrophages, and their own antimicrobial activity. Drug loading and loading efficacy were determined for both polymyxin B and E, and the maximal loaded value with an appropriate size of the delivery systems was 450 µg/mg of nanoparticles. Composite materials based on agarose hydrogel were prepared, containing both the loaded hybrid systems and free antibiotics. The features of polymyxin release from the hybrid nanoparticles and the composite materials were studied, and the mechanisms of release were analyzed using different theoretical models. The antibacterial activity against Pseudomonas aeruginosa was evaluated for both the polymyxin hybrid and the composite delivery systems. All tested samples inhibited bacterial growth. The minimal inhibitory concentrations of the polymyxin B hybrid delivery system demonstrated a synergistic effect when compared with either the antibiotic or the silver nanoparticles alone. 相似文献
13.
A. F. Aleksandrov K. V. Vavilin E. A. Kral’kina P. A. Neklyudova A. M. Nikonov V. B. Pavlov A. A. Airapetov V. V. Odinokov G. Ya. Pavlov V. A. Sologub 《Journal of Communications Technology and Electronics》2018,63(4):374-380
A plasma reactor that contains vacuum–arc and magnetron sputtering sources and radio-frequency discharge that generates high-density plasma in the presence of external magnetic field is developed, constructed, and optimized. The reactor can be used for deposition of various functional coatings with ion stimulation. The parameters of the inductive radio-frequency discharge generated in the presence of external magnetic field that serves as a source of assisting ions are optimized. It is shown that the working interval of the induction of external magnetic field corresponds to the resonant excitation of the coupled helicon and Trivelpiece–Gold waves. The effect of magnitude and configuration of magnetic field on the parameters of gas-discharge plasma and ion current in the substrate region is studied in the presence of separately and simultaneously initiated magnetron and inductive discharges. The effect of ion flux that is incident on the films in the course of growth on the structure of functional coatings is analyzed. 相似文献
14.
15.
A. Pavlov G. D. García de Fernando O. Díaz M. Fernández D. López J. A. Ordóñez L. de la Hoz 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1994,198(6):465-468
Changes in the -hydroxyacyl-CoA-dehydrogenase (HADH) activity of squid (Loligo vulgaris), mackerel (Scomber scombrus), tuna (Thunnus alalunga), sea bream (Pagellus centrodontus), sole (Solea solea), hake and small hake (Merluccius merluccius) meat due to freezing treatment at –10° C, –18° C, –35° C, –80° C or –196° C were investigated. With the exception of the small hake, the HADH activity of aqueous extracts from meat was significantly higher (p<0.0001) in all frozen/thawed fish species studied than in unfrozen animals because during freezing there was a release of HADH. HADH activity values of frozen/thawed squid, unfrozen mackerel, frozen/thawed and unfrozen sea bream and unfrozen hake were affected by the storage time in crushed ice.
Effekt des Gefrierens auf die-Hydroxyacyl-CoA-dehydrogenase (HADH)-Aktivität von Fischfleisch
Zusammenfassung Änderungen in der Aktivität der -Hydroxyacyl-CoA-dehydrogenase (HADH) im Fleisch von Tintenfisch, Makrele, Thunfisch, Seebrassen, Seezunge und Seehecht als Folge des Gefrierens bei –10 °C, –18 °C, –35 °C, –80 °C und –196 °C wurden untersucht. Mit Ausnahme kleiner Seehechte war die HADH-Aktivität wäßriger Extrakte des Fleisches bei allen gefrorenen und dann aufgetauten Fischen signifikant höher (p<0,0001) als bei ungefroren gelagerten Tieren. Dies ist Folge des Austrittes von HADH aus den Zellen während des Gefrierens. Die HADH-Aktivitäten von gefrorenem/aufgetautem Tintenfisch und Seebrassen sowie ungefrorenen Makrelen, Seebrassen und Seehechten wurden auch durch Lagern auf gestoßenem Eis beeinflußt.相似文献
16.
N. P. Dubankova K. I. Kobrakov N. N. Pavlov T. E. Platova G. S. Stankevich V. A. Terent'eva E. M. Khitrova 《Fibre Chemistry》2003,35(1):12-16
The possibility of deliberately altering the biocidal and capillary properties of a fabric by combined treatment with solutions of metal salts and low-molecular-weight organic substances with special properties — dyeing, biocidal, etc., is demonstrated. 相似文献
17.
Authors Index
Author Index 相似文献18.
Tatyana Strekalova Dmitrii Pavlov Alexander Trofimov Daniel C. Anthony Andrei Svistunov Andrey Proshin Aleksei Umriukhin Alexei Lyundup Klaus-Peter Lesch Raymond Cespuglio 《International journal of molecular sciences》2022,23(4)
The phenomenon of individual variability in susceptibility/resilience to stress and depression, in which the hippocampus plays a pivotal role, is attracting increasing attention. We investigated the potential role of hippocampal cyclooxygenase-2 (COX-2), which regulates plasticity, neuroimmune function, and stress responses that are all linked to this risk dichotomy. We used a four-week-long chronic mild stress (CMS) paradigm, in which mice could be stratified according to their susceptibility/resilience to anhedonia, a key feature of depression, to investigate hippocampal expression of COX-2, a marker of microglial activation Iba-1, and the proliferation marker Ki67. Rat exposure, social defeat, restraints, and tail suspension were used as stressors. We compared the effects of treatment with either the selective COX-2 inhibitor celecoxib (30 mg/kg/day) or citalopram (15 mg/kg/day). For the celecoxib and vehicle-treated mice, the Porsolt test was used. Anhedonic (susceptible) but not non-anhedonic (resilient) animals exhibited elevated COX-2 mRNA levels, increased numbers of COX-2 and Iba-1-positive cells in the dentate gyrus and the CA1 area, and decreased numbers of Ki67-positive cells in the subgranular zone of the hippocampus. Drug treatment decreased the percentage of anhedonic mice, normalized swimming activity, reduced behavioral despair, and improved conditioned fear memory. Hippocampal over-expression of COX-2 is associated with susceptibility to stress-induced anhedonia, and its pharmacological inhibition with celecoxib has antidepressant effects that are similar in size to those of citalopram. 相似文献
19.
Radostin Stefanov Pavlov Juan B. Carda Castelló Vicente Blasco Marzá J. M. Hohembergerger 《Journal of the American Ceramic Society》2002,85(5):1197-1202
New high-stability red-shade ceramic pigments based on pyrochlore solid solutions Y2 Sn2− x Cr x O7−δ ( x = 0–1, 0 < δ= 0–1/2 x ) were developed employing conventional solid-state reaction synthesis. The relationship between their optical properties and microstructure was analyzed by X-ray diffractometry and ultraviolet–visible-light spectroscopy. Decomposition of the structure with formation of the perovskite YCrO3 observed for chromium substitutions x ≥ 5 was attributed mainly to high concentration of defects. The structural and optical parameters of the materials were found to correlate with the concentration of a species with higher oxidation state than Cr(III), such as Cr(IV) or Cr(V). 相似文献
20.
Marina A. Marchenko Victoria V. Nefedova Daria S. Yampolskaya Galina V. Kopylova Daniil V. Shchepkin Sergey Y. Bershitsky Natalia A. Koubassova Andrey K. Tsaturyan Dmitrii I. Levitsky Alexander M. Matyushenko 《International journal of molecular sciences》2020,21(22)
Tropomyosin (Tpm) is one of the major actin-binding proteins that play a crucial role in the regulation of muscle contraction. The flexibility of the Tpm molecule is believed to be vital for its functioning, although its role and significance are under discussion. We choose two sites of the Tpm molecule that presumably have high flexibility and stabilized them with the A134L or E218L substitutions. Applying differential scanning calorimetry (DSC), molecular dynamics (MD), co-sedimentation, trypsin digestion, and in vitro motility assay, we characterized the properties of Tpm molecules with these substitutions. The A134L mutation prevented proteolysis of Tpm molecule by trypsin, and both substitutions increased the thermal stability of Tpm and its bending stiffness estimated from MD simulation. None of these mutations affected the primary binding of Tpm to F-actin; still, both of them increased the thermal stability of the actin-Tpm complex and maximal sliding velocity of regulated thin filaments in vitro at a saturating Ca2+ concentration. However, the mutations differently affected the Ca2+ sensitivity of the sliding velocity and pulling force produced by myosin heads. The data suggest that both regions of instability are essential for correct regulation and fine-tuning of Ca2+-dependent interaction of myosin heads with F-actin. 相似文献