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941.
Additive‐Morphology Interplay and Loss Channels in “All‐Small‐Molecule” Bulk‐heterojunction (BHJ) Solar Cells with the Nonfullerene Acceptor IDTTBM 下载免费PDF全文
Ru‐Ze Liang Maxime Babics Akmaral Seitkhan Kai Wang Paul Bythell Geraghty Sergei Lopatin Federico Cruciani Yuliar Firdaus Marco Caporuscio David J. Jones Pierre M. Beaujuge 《Advanced functional materials》2018,28(7)
Achieving efficient bulk‐heterojunction (BHJ) solar cells from blends of solution‐processable small‐molecule (SM) donors and acceptors is proved particularly challenging due to the complexity in obtaining a favorable donor–acceptor morphology. In this report, the BHJ device performance pattern of a set of analogous, well‐defined SM donors— DR3TBDTT ( DR3 ), SMPV1 , and BTR —used in conjunction with the SM acceptor IDTTBM is examined. Examinations show that the nonfullerene “All‐SM” BHJ solar cells made with DR3 and IDTTBM can achieve power conversion efficiencies (PCEs) of up to ≈4.5% (avg. 4.0%) when the solution‐processing additive 1,8‐diiodooctane (DIO, 0.8% v/v) is used in the blend solutions. The figures of merit of optimized DR3:IDTTBM solar cells contrast with those of “as‐cast” BHJ devices from which only modest PCEs <1% can be achieved. Combining electron energy loss spectrum analyses in scanning transmission electron microscopy mode, carrier transport measurements via “metal‐insulator‐semiconductor carrier extraction” methods, and systematic recombination examinations by light‐dependence and transient photocurrent analyses, it is shown that DIO plays a determining role—establishing a favorable lengthscale for the phase‐separated SM donor–acceptor network and, in turn, improving the balance in hole/electron mobilities and the carrier collection efficiencies overall. 相似文献
942.
Federico Ferreres Paula Andrade Francisco A. Tomás-Barberán 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1994,199(1):32-37
The flavonoids present in twenty samples of Portuguese heather honey were analysed by reversed-phase HPLC. The flavonoid fraction was purified by a combination of chromatography on Amberlite XAD-2 and Sephadex LH-20 columns. The total amount of flavonoids ranged between 60 and 500 g/100g honey, values which are much smaller than those previously found for Spanish rosemary honey samples (500-2000 g/100 g honey). The main flavonoids present in Portuguese heather honey were the flavanones pinocembrin and pinobanksin and the flavones chrysin and galangin. These analyses showed that all the samples contained a similar flavonoid pattern composed of at least 22 compounds. The most characteristic substances were myricetin, myricetin 3-methyl ether, myricetin 3'-methyl ether and tricetin. These four flavonoids have in common the structural feature of having a trioxygenated ring B (3',4',5'-trioxygenation), this being an attribute not found in the flavonoids detected in any other honey sample of different plant origin analysed so far, suggesting that these substances could probably be used as markers for the botanical origin of heather honey.
Flavonoide aus portugiesischem Heidehonig
Zusammenfassung Die Flavonoide aus portugiesischem Heidehonig wurden mit der HPLC in reversed-phase-Technik analysiert. Die Fraktionen wurden durch Adsorptionsund Gelchromatographie gereinigt, ihre Gesamtausbeute betrug 60 bis 500 g/100 g Honig. Als Hauptkomponenten wurden Pinocembrin und Pinobanksin (Flavanone) sowie Chrysin und Galangin (Flavone) identifiziert. Alle Proben erhielten ein ähnliches Muster aus mindestens 22 Flavonoiden. Charakteristisch waren Myricitin sowie dessen 3- und 3'-Methylether sowie Tricetin. Derartige Verbindungen wurden bisher in keinem anderen Honig gefunden und eignen sich möglicherweise als Herkunftsnachweis für Heidehonig.相似文献
943.
Leopoldina Fortunati Mark Deuze Federico de Luca 《Journal of Computer-Mediated Communication》2014,19(2):121-140
This paper presents cross‐national research on news readership diversification. We compare written news (print and free newspapers, online and mobile news services) audiences in the 5 most populous and industrialized European countries (Italy, France, Spain, the UK and Germany). Outlining a sociodemographic portrait of these different news users is important in order to understand the changes undergone inside the world of written news. We draw on a telephone survey carried out in 2009, using a representative population sample (N=7,255). The survey considers sociodemographic variables, including a range of social activities and attitudinal variables, television, computer, and mobile phone ownership, and Internet access and use. Findings show a rich, but volatile relationship between written news, audience behaviors, and community participation. 相似文献
944.
Carlos L. Céspedes José S. Calderón Federico Gomez-Garibay Rosabel Segura Beatriz King-Diaz Blas Lotina-Hennsen 《Journal of chemical ecology》1999,25(12):2665-2676
An epimeric mixture of the limonoid photogedunin, isolated from the heartwood of C. ciliolata, as well as its R- and S-acetate derivative were evaluated for phytotoxicity in mono- and dicotyledoneous plants. A mixture of epimeric photogedunin 1 and 2, a mixture of epimeric photogedunin acetate, (R)-photogedunin acetate 3, and (S)-photogedunin acetate 4 inhibited seed germination, seedling growth, and root and hypocotyl/coleoptyle growth in all species assayed. The concentration of phytochemicals required for 50% inhibition ranged from 4.5 to 300 M. Inhibitory plant responses appeared to require that the OH-group at C-23 be acetylated in photogedunin, since the nonacetylated compound showed less phytotoxic activity. 相似文献
945.
Research in humanoid robotics aims to develop autonomous systems that are able to assist humans in the performance of everyday tasks. Part of the robotics community claims that the best solution to guarantee the maximum adaptability of robots to the majority of human tasks is mimicry. Based on this premise both the structure of the human body and human behavior have been the focus of studies, with the aim of imitating and reproducing on robotic systems the results of millennia of human evolution. The research presented in this paper aims (i) at transferring the features of human locomotion to the COmpliant huMANoid (COMAN) robot, by means of kinematic motion primitives (kMPs) extracted from human subjects, and (ii) at improving the energetic performance of the walk of COMAN by exploiting its intrinsic compliance: it will be shown that, when the robot is walking at a gait frequency that is close to one of the main resonance frequencies of the mechanism, the springs contribute to tracking the human-like kMPs-based trajectories imposed, providing at the right time about 15 % of the energy required for locomotion, and that was previously stored. 相似文献
946.
947.
We propose a novel approach to extract quantitative chemical maps of surfaces with nanoscale resolution, from the analysis of data from x-ray photoemission electron microscopy, which is a minimally invasive technique. Our formulation allows us to extract chemical maps from the raw data even in cases when not all experimental parameters are well known or controlled. We illustrate our concept by the analysis of a ternary alloy with a nanoscale pattern, to achieve chemical maps of unprecedented quality. 相似文献
948.
Polysaccharides and other cationic polymers have recently been used in pharmaceutical research and industry for their properties to control the release of antibiotics, DNA, proteins, peptide drugs or vaccines, and they have also been extensively studied as non-viral DNA carriers for gene delivery and therapy. Among them, chitosan is the most used since it can promote long-term release of incorporated drugs. This work is focused on the preparation of chitosan and chitosan/DNA nanospheres by using a novel and simple osmosis-based method, recently patented. The morphology of chitosan/DNA particles is spherical (as observed by scanning electron microscopy, SEM) and the nanospheres' average diameter is 38 ± 4?nm (obtained by dynamic light scattering, DLS). With this method, DNA is incorporated with high yield (up to 30%) and the release process is gradual and prolonged in time. The novelty of the reported method resides in the general applicability to various synthetic or natural biopolymers. Solvent, temperature and membrane cut-off are the physicochemical parameters that one is able to use to control the overall osmotic process, leading to several nanostructured systems with different size and shape that may be used in several biotechnological applications. 相似文献
949.
Tigani D Zolezzi C Trentani F Ragaini A Iafisco M Manara S Palazzo B Roveri N 《Journal of materials science. Materials in medicine》2008,19(3):1325-1334
This paper explores the possibility of using biodegradable cross-linked gelatines as antibiotic devices for a long-term elution
(80 days). Capillary electrophoresis (CE) has been utilized to evaluate the mass percentage of vancomycin and gelatine contemporary
released from differently cross-linked vancomycin loaded gelatine samples in an elution time ranging from 24 to 1920 h. While
the solubilization kinetic of gelatine samples differently cross-linked can be very close described by the simplified Higuchi
model, the vancomycin release kinetic is contemporary governed by both the Fickian diffusion process trough the gelatine matrix
network and the dissolution process of the matrix due to its degradation. Comparing the antibiotic eluting kinetics from gelatine
at diverse cross-linking degree we observed that the degradation of the proteic matrix appears to have a minor influence in
the drug release control. Vancomycin released from all the gelatine partially cross-linked samples results active against
Staphylococcus aureus and Streptococcus faecalis which represent the most pathogens commonly isolated in orthopaedic infections. Vancomycin overcomes the minimum inhibitory
concentration for both the bacteria in the whole range of elution time. Cross-linked gelatine devices appear to represent
a useful biodegradable delivery system for local anti-infective therapy in arthoplasty. 相似文献
950.
Mazzei F Favero G Frasconi M Tata A Tuccitto N Licciardello A Pepi F 《Analytical chemistry》2008,80(15):5937-5944
Microperoxidase-11 (MP-11) was first soft landed onto the gold surface of a screen-printed electrode. Intact protein deposition was verified by time-of-flight secondary ion mass spectrometry. The coupling of soft landing with electrochemical techniques allowed unique information to be obtained about the deposition features. A full characterization of the direct electron-transfer properties was performed by modeling data obtained from cyclic voltammetry experiments; calculated values of kinetic electron-transfer constant, formal redox potential, and reorganization energy allow us to hypothesize the mechanism involved in soft landing immobilization and demonstrate the different conformation of the enzyme deposited from two different charged species. The strong interaction between MP-11 and the gold surface and long-term stability of the functionalized electrode characterizes the peculiar features of this procedure, which enhance its power with respect to the existing immobilization procedure and ensure its suitability for those practical applications that could benefit from an unmediated bridgeless bioeletrochemical electron transfer (e.g., biosensor transducers or electrode elements in biofuel cells). 相似文献