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991.
Hourly thermal performance (both in laboratory and field conditions) of three designs of built-in-storage solar water heating systems of 100 litres capacity each has been reported. A different storage tank design is used in each of the three cases. Design I consists of three tanks connected in series; in Design II, a parallelepipedic tank is divided into five zones with baffles; Design III is a simple parallelepipedic tank. The first two designs help in inducing thermal stratification in the tank. It is seen from the results that the performance of Design II is the best of the three. © 1997 by John Wiley & Sons, Ltd. 相似文献
992.
Samta Gajbhiye Sanjeev Karmakar Monisha Sharma Sanjay Sharma 《Information Security Journal: A Global Perspective》2018,27(1):42-56
Secure Simple Pairing, a Bluetooth-pairing protocol, suffers from passive off-line and active online-guessing attack. These assaults are a direct result of the shortcomings in Bluetooth specification. Bluetooth technology uses the principles of device inquiry and inquiry scan. Scanning devices listen in on known frequencies for devices that are actively inquiring. If two Bluetooth devices know absolutely nothing about each other, one must run an inquiry to try to discover the other. One device sends out the inquiry request, and any device listening for such a request will respond with its address, and possibly its name, Input/Output capability and other information. Before connection, each device knows the address, their name, their capability, Quality-of-Service, etc. During pairing, Man-In-The-Middle attacker may capture all the information of connecting devices and impersonate them. This paper introduces the security augmentation in Bluetooth pairing by postponing exchange of Input-Output capability and other information like Quality-of-Service until it is essentially required and by casing the link key with a pair of Elliptic Curve Diffie-Hellman keys. Consequently, this leads to increased pairing time. Yet, we overlooked the increased pairing time, as the proposed Bluetooth-pairing protocol improves security by strengthening the link key. 相似文献
993.
Lois J. Gschwender Carl E. Snyder Shashi K. Sharma Stephanie R. Flanagan 《Lubrication Science》1999,16(1):35-50
The US Air Force Wright Laboratory's Materials Directorate has been involved with the development and transition of advanced fluids and lubricants since the 1950s. The driving force for the development of new hydraulic fluids has primarily been and still is, improved fire resistance, although biodegradability and low toxicity have become increasingly important. This paper briefly traces the use of military aircraft hydraulic fluids from the beginning to the current state-of-the-art. 相似文献
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997.
Chemical‐looping combustion — an overview and application of the recirculating fluidized bed reactor for improvement 下载免费PDF全文
This paper propose recirculating fluidized bed (RCFB) reactor for chemical‐looping combustion (CLC) to overcome some of the issues associated with the existing interconnected reactors arrangements like low residence time of bed material in the air reactor, high attrition of bed material in the cyclone separator, cluster formation in the air reactor, complex operation involving loop seals and high heat losses. RCFB has high solid circulation rate, long residence time, efficient fuel–oxygen carrier contact, low heat losses and low gas leak in between the reactors, as compared to the existing reactor configurations. A cold model study was performed on a Perspex made, semicircular, transparent RCFB reactor. A single RCFB reactor was operated in the alternate oxidation and fuel burning cycles to simulate the interconnected reactors arrangement for CLC. The generated experimental data has been used to predict the optimal RCFB reactor configuration for a RCFB‐based CLC power plant. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
998.
Dharmendra Pratap Singh Swadesh Kumar Gupta Satya Prakash Yadav P K Sharma A C Pandey Rajiv Manohar 《Bulletin of Materials Science》2014,37(3):511-518
The present paper deals with the characterization of a ferroelectric liquid crystal–nanoparticle (FLC–NP) composite system. The dielectric, electrical and polarization property of the FLC–NP composite system have been studied as a function of temperature and frequency. Ferroelectric Cu-doped ZnO (Cu–ZnO) nanoparticles have been added to the pure ferroelectric liquid crystal (FLC) Felix 17/100. The nanoparticles are bigger in size as compared to FLC molecules; therefore, they distort the existing geometry of FLC matrix and set up an antiparallel correlation with the dipole moments of the host FLC molecules. This antiparallel correlation of guest–host geometry reduces the net ferroelectricity of the composite system and modifies all the physical properties of the pure FLC. The change in properties has been analysed and explained in the light of guest–host interaction. 相似文献
999.
Potential of Sr4Al14O25: Eu2+,Dy3+ inorganic oxide-based nanophosphor in Latent fingermark detection
Vishal Sharma Amrita Das Vinay Kumar O. M. Ntwaeaborwa H. C. Swart 《Journal of Materials Science》2014,49(5):2225-2234
In this paper, the potential of the Sr4Al14O25: Eu2+,Dy3+ fluorescent nanophosphor is explored to visualize the latent fingermarks. The nanophosphor has been synthesized using self-propagating high temperature synthesis and shows intense luminescence and strong long after glow properties. These nano particles have been characterized for their particle size, crystalline phase, and photoluminescent properties. The calculated PL CIE co-ordinates (0.138, 0.359) correspond to the blue–green shade. Different porous, non-porous, as well as slightly non-smooth surfaces are taken and successfully tested for latent fingerprints development with the prepared Sr4Al14O25: Eu2+,Dy3+ fluorescent nanophosphor powder. Present nano powder is advantageous to use on luminescent or multicolored surfaces as it gives greater contrast and also eliminates the problem of background interferences with the friction ridges due to its strong long after glow property. The results are very good when latent fingerprints were developed on the currency notes with optical variable ink and highly fluorescent pattern areas. 相似文献
1000.
Normally Oriented Adhesion versus Friction Forces in Bacterial Adhesion to Polymer‐Brush Functionalized Surfaces Under Fluid Flow 下载免费PDF全文
Jan J. T. M. Swartjes Deepak H. Veeregowda Henny C. van der Mei Henk J. Busscher Prashant K. Sharma 《Advanced functional materials》2014,24(28):4435-4441
Bacterial adhesion is problematic in many diverse applications. Coatings of hydrophilic polymer chains in a brush configuration reduce bacterial adhesion by orders of magnitude, but not to zero. Here, the mechanism by which polymer‐brush functionalized surfaces reduce bacterial adhesion from a flowing carrier fluid by relating bacterial adhesion with normally oriented adhesion and friction forces on polymer (PEG)‐brush coatings of different softness is studied. Softer brush coatings deform more than rigid ones, which yields extensive bond‐maturation and strong, normally oriented adhesion forces, accompanied by irreversible adhesion of bacteria. On rigid brushes, normally oriented adhesion forces remain small, allowing desorption and accordingly lower numbers of adhering bacteria result. Friction forces, generated by fluid flow and normally oriented adhesion forces, are required to oppose fluid shear forces and cause immobile adhesion. Summarizing, inclusion of friction forces and substratum softness provides a more complete mechanism of bacterial adhesion from flowing carrier fluids than available hitherto. 相似文献