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951.
Andrea Nolte Susanne Hossfeld Marcell Post Jan Niederlaender Tobias Walker Christian Schlensak Hans Peter Wendel 《Journal of materials science. Materials in medicine》2014,25(9):2121-2130
Chitosan is used in several pharmaceutical and medical applications, owing to its good cytocompatibility and hemocompatibility. However, there are conflicting reports regarding the biological activities of chitosan with some studies reporting anti-inflammatory properties while others report pro-inflammatory properties. In this regards we analyzed the endotoxin content in five different chitosans and examined these chitosans with their different deacetylation degrees for their hemocompatibility and cytocompatibility. Therefore, we incubated primary human endothelial cells or whole blood with different chitosan concentrations and studied the protein and mRNA expression of different inflammatory markers or cytokines. Our data indicate a correlation of the endotoxin content and cytokine up-regulation in whole blood for Poly-Morpho-Nuclear (PMN)-Elastase, soluble terminal complement complex SC5b-9, complement component C5/C5a, granulocyte colony-stimulating factor, Interleukin-8 (IL), IL-10, IL-13, IL-17E, Il-32α and monocyte chemotactic protein-1. In contrast, the incubation of low endotoxin containing chitosans with primary endothelial cells resulted in increased expression of E-selectin, intercellular adhesion molecule-1, vascular cell adhesion protein-1, IL-1β, IL-6 and IL-8 in endothelial cells. We suggest that the endotoxin content in chitosan plays a major role in the biological activity of chitosan. Therefore, we strongly recommend analysis of the endotoxin concentration in chitosan, before further determining if it has pro- or anti-inflammatory properties or if it is applicable for pharmaceutical and medical fields. 相似文献
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954.
Matthias Böhm Marcus Einert Christian Suchomski Bernd M. Smarsly Stephen Mutisya Massimo F. Bertino 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(8):1566-1574
Macroporous TiO2 (anatase) thin films are fabricated by an all low‐temperature process in which substrates are dip‐coated in suspensions of mixed anatase nanoparticles and polystyrene beads, and the templating agents are removed by ultraviolet (UV) irradiation at a temperature below 50 °C. Scanning electron microscopy (SEM) and Raman spectroscopy show that the templating polymer beads are removed by UV irradiation combined with the photocatalytic activity of TiO2. X‐Ray diffraction reveals that nanoparticle growth is negligible in UV irradiated films, while nanoparticle size increases by almost 10 times in calcined films that are prepared for comparison. The macroporous films are prepared on FTO‐(fluorine‐doped tin oxide) coated glass and ITO (indium tin oxide) coated flexible plastics and thereby used as working electrodes. In both cases, the films are electrochemically addressable, and cyclic voltammetry is consistent with the response of bulk TiO2 for calcined films and of nanoscale‐TiO2 for UV‐irradiated films. 相似文献
955.
Jameson L. Toole Carlos Herrera-Yaqüe Christian M. Schneider Marta C. González 《Journal of the Royal Society Interface》2015,12(105)
Studies using massive, passively collected data from communication technologies have revealed many ubiquitous aspects of social networks, helping us understand and model social media, information diffusion and organizational dynamics. More recently, these data have come tagged with geographical information, enabling studies of human mobility patterns and the science of cities. We combine these two pursuits and uncover reproducible mobility patterns among social contacts. First, we introduce measures of mobility similarity and predictability and measure them for populations of users in three large urban areas. We find individuals'' visitations patterns are far more similar to and predictable by social contacts than strangers and that these measures are positively correlated with tie strength. Unsupervised clustering of hourly variations in mobility similarity identifies three categories of social ties and suggests geography is an important feature to contextualize social relationships. We find that the composition of a user''s ego network in terms of the type of contacts they keep is correlated with mobility behaviour. Finally, we extend a popular mobility model to include movement choices based on social contacts and compare its ability to reproduce empirical measurements with two additional models of mobility. 相似文献
956.
In the present article, we analyze a d36-effect piezoelectric torsion transducer following the Saint-Venant torsion theory taking the electrical field into account. A representation of the stress function, the electric potential, and the warping function are derived and solved with finite differences. Then, the one-dimensional governing equations at the structural beam level, including the constitutive relations as well as the balance equations for the dynamics of the transducer, are presented. The axial moment and the total charge are computed as functions of the rate of twist and the applied potential difference. As an example, a cantilevered transducer is studied. 相似文献
957.
Liquid–Liquid Diffusion‐Assisted Crystallization: A Fast and Versatile Approach Toward High Quality Mixed Quantum Dot‐Salt Crystals 下载免费PDF全文
Marcus Adam Zhiyu Wang Aliaksei Dubavik Gordon M. Stachowski Christian Meerbach Zeliha Soran‐Erdem Christin Rengers Hilmi Volkan Demir Nikolai Gaponik Alexander Eychmüller 《Advanced functional materials》2015,25(18):2638-2645
Here, a new, fast, and versatile method for the incorporation of colloidal quantum dots (QDs) into ionic matrices enabled by liquid–liquid diffusion is demonstrated. QDs bear a huge potential for numerous applications thanks to their unique chemical and physical properties. However, stability and processability are essential for their successful use in these applications. Incorporating QDs into a tight and chemically robust ionic matrix is one possible approach to increase both their stability and processability. With the proposed liquid–liquid diffusion‐assisted crystallization (LLDC), substantially accelerated ionic crystallization of the QDs is shown, reducing the crystallization time needed by one order of magnitude. This fast process allows to incorporate even the less stable colloids including initially oil‐based ligand‐exchanged QDs into salt matrices. Furthermore, in a modified two‐step approach, the seed‐mediated LLDC provides the ability to incorporate oil‐based QDs directly into ionic matrices without a prior phase transfer. Finally, making use of their processability, a proof‐of‐concept white light emitting diode with LLDC‐based mixed QD‐salt films as an excellent color‐conversion layer is demonstrated. These findings suggest that the LLDC offers a robust, adaptable, and rapid technique for obtaining high quality QD‐salts. 相似文献
958.
Semiconductor Nanocrystals: Liquid–Liquid Diffusion‐Assisted Crystallization: A Fast and Versatile Approach Toward High Quality Mixed Quantum Dot‐Salt Crystals (Adv. Funct. Mater. 18/2015) 下载免费PDF全文
959.
A physically based hourly radiation model for inclined planes is presented. The sky diffuse component is derived from typical radiance patterns for clear and overcast conditions, taking anisotropic effects into account. New developments are also proposed for the ground reflected component, in order to supplement the usual isotropic assumption. The proposed radiation model, called CDRS, may be used with different input data combinations, the relative advantages of which are discussed. CDRS outputs are in good agreement with four clear sky sophisticated spectral data sets when wideband as well as spectral irradiances are input. When compared to measured data, CDRS also appears to perform well during clear and overcast sky conditions. Good results from only two cloudy days are also obtained, but more systematic tests should be conducted in this case. All the five other selected engineering models exhibit some degree of inaccuracy for certain slope/azimuth/cloudiness combinations. Particularly, the ASHRAE and DOE-2 models give catastrophic results for southward vertical surfaces during overcast conditions. This unexpected result may lead to important bias in building energy consumption simulations. Finally, some experimental and computational problems are pointed out. These could interfere with models accuracy comparison in validation studies. 相似文献
960.
Vincent Larivière Etienne Vignola-Gagné Christian Villeneuve Pascal Gélinas Yves Gingras 《Scientometrics》2011,87(3):483-498
Using the entire population of professors at universities in the province of Quebec (Canada), this article analyzes the relationship
between sex and research funding, publication rates, and scientific impact. Since age is an important factor in research and
the population pyramids of men and women are different, the role of age is also analyzed. The article shows that, after they
have passed the age of about 38, women receive, on average, less funding for research than men, are generally less productive
in terms of publications, and are at a slight disadvantage in terms of the scientific impact (measured by citations) of their
publications. Various explanations for these differences are suggested, such as the more restricted collaboration networks
of women, motherhood and the accompanying division of labour, women’s rank within the hierarchy of the scientific community
and access to resources as well as their choice of research topics and level of specialization. 相似文献