全文获取类型
收费全文 | 2468篇 |
免费 | 133篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 25篇 |
综合类 | 1篇 |
化学工业 | 627篇 |
金属工艺 | 41篇 |
机械仪表 | 56篇 |
建筑科学 | 73篇 |
矿业工程 | 2篇 |
能源动力 | 101篇 |
轻工业 | 169篇 |
水利工程 | 8篇 |
石油天然气 | 4篇 |
无线电 | 282篇 |
一般工业技术 | 487篇 |
冶金工业 | 123篇 |
原子能技术 | 11篇 |
自动化技术 | 592篇 |
出版年
2024年 | 2篇 |
2023年 | 30篇 |
2022年 | 43篇 |
2021年 | 66篇 |
2020年 | 62篇 |
2019年 | 53篇 |
2018年 | 73篇 |
2017年 | 62篇 |
2016年 | 90篇 |
2015年 | 63篇 |
2014年 | 103篇 |
2013年 | 178篇 |
2012年 | 184篇 |
2011年 | 228篇 |
2010年 | 174篇 |
2009年 | 147篇 |
2008年 | 146篇 |
2007年 | 151篇 |
2006年 | 103篇 |
2005年 | 88篇 |
2004年 | 67篇 |
2003年 | 50篇 |
2002年 | 53篇 |
2001年 | 49篇 |
2000年 | 34篇 |
1999年 | 40篇 |
1998年 | 55篇 |
1997年 | 39篇 |
1996年 | 21篇 |
1995年 | 16篇 |
1994年 | 17篇 |
1993年 | 17篇 |
1992年 | 21篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有2602条查询结果,搜索用时 15 毫秒
91.
Benoit Charlas Olivier Gillia Pierre Doremus Didier Imbault 《International Journal of Hydrogen Energy》2012
The storage of hydrogen in hydride materials is currently much researched as a mean of energy storage. This reversible storage is achieved by successive hydriding and dehydriding reactions. During these reactions, the material undergoes structural transformations which result in swelling of the hydride powder grains due to the absorption of hydrogen. This phenomenon can generate major mechanical stresses on the cell containing the hydride. The present experimental study examines the cyclic swelling of a granular bed consisting of hydride Ti–Cr–V + Zr–Ni. Two superimposed phenomena are identified: a cyclic rearrangement causing a reduction and then an increase in porosity coupled with gradual densification of the stack. 相似文献
92.
Minh Trung DangGuillaume Wantz Habiba BejboujiMathieu Urien Olivier J. DautelLaurence Vignau Lionel Hirsch 《Solar Energy Materials & Solar Cells》2011,95(12):3408-3418
Polymeric photovoltaic (PV) solar cells have been fabricated using six solvents: chloroform (CHCl3), toluene (T), chlorobenzene (CB), orthodichlorobenzene (ODCB), 1,2,3,4-tetrahydronaphthalene (THN) and 1,2,4-trichlorobenzene (TCB). The active layers were composed of poly(3-hexyl)thiophene (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM). Special care has been taken to keep all experimental parameters constant (thickness of the active layers, donor/acceptor weight ratio, area of active surface and electrodes) in order to avoid artefacts and truly study the effect of solvents. Studies using atomic force microscopy (AFM) and optical absorption (UV-vis) showed the relationship between the photovoltaic performance and the evaporation rate of solvents. The use of solvents with high boiling point results in a higher degree of organization in the structure of P3HT. A direct comparison with devices processed with thermal treatment has also been performed. As often reported thermal annealing increases photo-conversion efficiency of devices created from common solvents, due to better separation of phase between the two materials of the blend. In the case of solvents with high boiling point such as THN and TCB, neither phase separation nor modification of P3HT crystallization induced by thermal annealing has been observed. However thermal treatment appears to enhance performance, ensuing the evaporation of remaining solvent in the active layers. An overview of the effect of solvent on the electrical properties of films containing pure P3HT and P3HT:PCBM blend reported in the literature has been completed for the discussion. 相似文献
93.
94.
95.
Christine Vignon Christelle Debeissat Jrme Bourgeais Nathalie Gallay Farah Kouzi Adrienne Anginot Frdric Picou Philippe Guardiola Elfi Ducrocq Amlie Foucault Nomie Ravalet Louis-Rome Le Nail Jorge Domenech Marie-Christine Bn Marie-Caroline Le Bousse-Kerdils Emmanuel Gyan Olivier Herault 《International journal of molecular sciences》2020,21(22)
The bone marrow (BM) microenvironment plays a crucial role in the development and progression of leukemia (AML). Intracellular reactive oxygen species (ROS) are involved in the regulation of the biology of leukemia-initiating cells, where the antioxidant enzyme GPx-3 could be involved as a determinant of cellular self-renewal. Little is known however about the role of the microenvironment in the control of the oxidative metabolism of AML cells. In the present study, a coculture model of BM mesenchymal stromal cells (MSCs) and AML cells (KG1a cell-line and primary BM blasts) was used to explore this metabolic pathway. MSC-contact, rather than culture with MSC-conditioned medium, decreases ROS levels and inhibits the Nrf-2 pathway through overexpression of GPx3 in AML cells. The decrease of ROS levels also inactivates p38MAPK and reduces the proliferation of AML cells. Conversely, contact with AML cells modifies MSCs in that they display an increased oxidative stress and Nrf-2 activation, together with a concomitant lowered expression of GPx-3. Altogether, these experiments suggest that a reciprocal control of oxidative metabolism is initiated by direct cell–cell contact between MSCs and AML cells. GPx-3 expression appears to play a crucial role in this cross-talk and could be involved in the regulation of leukemogenesis. 相似文献
96.
Sven de Mey Ins Dufait Heng Jiang Cyril Corbet Hui Wang Melissa Van De Gucht Lisa Kerkhove Ka Lun Law Hugo Vandenplas Thierry Gevaert Olivier Feron Mark De Ridder 《International journal of molecular sciences》2020,21(24)
Mitochondrial metabolism is an attractive target for cancer therapy. Reprogramming metabolic pathways can potentially sensitize tumors with limited treatment options, such as triple-negative breast cancer (TNBC), to chemo- and/or radiotherapy. Dichloroacetate (DCA) is a specific inhibitor of the pyruvate dehydrogenase kinase (PDK), which leads to enhanced reactive oxygen species (ROS) production. ROS are the primary effector molecules of radiation and an increase hereof will enhance the radioresponse. In this study, we evaluated the effects of DCA and radiotherapy on two TNBC cell lines, namely EMT6 and 4T1, under aerobic and hypoxic conditions. As expected, DCA treatment decreased phosphorylated pyruvate dehydrogenase (PDH) and lowered both extracellular acidification rate (ECAR) and lactate production. Remarkably, DCA treatment led to a significant increase in ROS production (up to 15-fold) in hypoxic cancer cells but not in aerobic cells. Consistently, DCA radiosensitized hypoxic tumor cells and 3D spheroids while leaving the intrinsic radiosensitivity of the tumor cells unchanged. Our results suggest that although described as an oxidative phosphorylation (OXPHOS)-promoting drug, DCA can also increase hypoxic radioresponses. This study therefore paves the way for the targeting of mitochondrial metabolism of hypoxic cancer cells, in particular to combat radioresistance. 相似文献
97.
Dr. Mimouna Madaoui Dr. Olivier Vidal Albert Meyer Mathieu Noël Prof. Dr. Jean-Marie Lacroix Dr. Jean-Jacques Vasseur Prof. Dr. Alberto Marra Dr. François Morvan 《Chembiochem : a European journal of chemical biology》2020,21(23):3433-3448
Galacto- and fuco-clusters conjugated with one to three catechol or hydroxamate motifs were synthesised to target LecA and LecB lectins of Pseudomonas aeruginosa (PA) localised in the outer membrane and inside the bacterium. The resulting glycocluster–pseudosiderophore conjugates were evaluated as Trojan horses to cross the outer membrane of PA by iron transport. The data suggest that glycoclusters with catechol moieties are able to hijack the iron transport, whereas those with hydroxamates showed strong nonspecific interactions. Mono- and tricatechol galactoclusters ( G1C and G3C ) were evaluated as inhibitors of infection by PA in comparison with the free galactocluster ( G0 ). All of them exhibited an inhibitory effect between 46 to 75 % at 100 μM, with a higher potency than G0 . This result shows that LecA localised in the outer membrane of PA is involved in the infection mechanism. 相似文献
98.
Hassan Al Sabea Lucie Norel Olivier Galangau Thierry Roisnel Olivier Maury Franois Riob Stphane Rigaut 《Advanced functional materials》2020,30(30)
This work describes a class of complex combining three dithienylethene units and a lanthanide ion used as an optical system displaying a double encryption method: i) a colorful code, drawn and erased under UV and visible irradiations respectively, due to coloration and discoloration of the photochromic entities, and ii) a concomitant gradual disappearance and progressive restoration of the associated lanthanide ion luminescence triggered with the same stimuli. The innovation of the system stems from the emission color tunability, i.e., with either a lanthanide ion emitting only in the visible range (Eu3+) or with another lanthanide ion emitting only in the near infrared (NIR) range (Yb3+), therefore observable, or not, to the naked eye. This system is the very first one to achieve efficient repeatable modulation of pure NIR luminescence on photochemical command. Furthermore, it is proven to be highly efficient when embedded in a PDMS polymer opening real opportunities for practical applications as anti‐counterfeiting. 相似文献
99.
Luca Pezzato Leonardo Bertolucci Coelho Rachele Bertolini Alessio Giorgio Settimi Katya Brunelli Marjorie Olivier Manuele Dabal 《工业材料与腐蚀》2019,70(11):2103-2112
Plasma electrolytic oxidation (PEO) coatings were produced on AZ80 magnesium alloy in a solution containing silicates and phosphates and working at high current densities with short treatment times. The effect of a sealing treatment in boiling water on corrosion and mechanical properties of the coatings were investigated. Moreover, the corrosion mechanism of the samples with and without the sealing treatment was evaluated. The microstructure of the coatings was characterized with scanning electron microscope observation and X‐ray diffraction analysis. The mechanical properties were evaluated with nanoindentation tests and the corrosion resistance was studied by potentiodynamic polarization, electrochemical impedance spectroscopy, and scanning vibrating electrode technique. The results showed that the sealing did not influence the microstructure and the mechanical properties of the samples and instead produced a remarkable increase in the corrosion resistance. The crevice corrosion, present in the sample without the sealing, was avoided with the treatment in boiling water. 相似文献
100.
Iron-catalyzed oxidation of arsenic(III) by oxygen and by hydrogen peroxide: pH-dependent formation of oxidants in the Fenton reaction 总被引:1,自引:0,他引:1
The oxidation kinetics of As(III) with natural and technical oxidants is still notwell understood, despite its importance in understanding the behavior of arsenic in the environment and in arsenic removal procedures. We have studied the oxidation of 6.6 microM As(II) by dissolved oxygen and hydrogen peroxide in the presence of Fe(II,III) at pH 3.5-7.5, on a time scale of hours. As(III) was not measurably oxidized by O2, 20-100 microM H2O2, dissolved Fe(III), or iron(III) (hydr)-oxides as single oxidants, respectively. In contrast, As(III) was partially or completely oxidized in parallel to the oxidation of 20-90 microM Fe(II) by oxygen and by 20 microM H2O2 in aerated solutions. Addition of 2-propanol as an *OH-radical scavenger quenched the As(III) oxidation at low pH but had little effect at neutral pH. High bicarbonate concentrations (100 mM) lead to increased oxidation of As-(III). On the basis of these results, a reaction scheme is proposed in which H2O2 and Fe(II) form *OH radicals at low pH but a different oxidant, possibly an Fe(IV) species, at higher pH. With bicarbonate present, carbonate radicals might also be produced. The oxidant formed at neutral pH oxidizes As(III) and Fe(II) but does not react competitively with 2-propanol. Kinetic modeling of all data simultaneously explains the results quantitatively and provides estimates for reaction rate constants. The observation that As(III) is oxidized in parallel to the oxidation of Fe(II) by O2 and by H2O2 and that the As(III) oxidation is not inhibited by *OH-radical scavengers at neutral pH is significant for the understanding of arsenic redox reactions in the environment and in arsenic removal processes as well as for the understanding of Fenton reactions in general. 相似文献