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991.
The method of moments (MoM) solution on the magnetic field integral equation (MFIE) for electromagnetic scattering problems of conducting objects with Rao–Wilton–Glisson (RWG) basis functions requires the evaluation of almost singular double surface integrals over triangular subdomains. Calculating these integrals accurately is essential for the successful solution of the MFIE by MoM especially for small sharp-edged conducting objects. This paper studies the singularity of the MFIE and uses an accurate singularity extraction technique to avoid logarithmic singularity of the integration on the testing triangles for the MFIE. Based on the numerical examples of several small sharp-edged conducting objects, it is demonstrated that the accuracy of the MFIE is improved greatly with the use of the new singularity extraction technique. 相似文献
992.
Three competing schemes have been proposed for multimedia transport over broadband wireless channels: (a) traditional UDP
(Postel, The User Datagram Protocol, 1980 [1]), (b) semi-cross-layer UDP-Lite (The Lightweight User Datagram Protocol, 2004
[2]), and (c) cross-layer header estimation (Khayam et al., IEEE Transactions on Multimedia 9(2):377–385, 2007 [3]; Khayam
and Radha, IEEE Transactions on Wireless Communications 6(11):3946–3954, 2007 [4]). In all these schemes, corrupted and lost
packets are recovered using FEC at the application layer. In this paper, we analytically and experimentally compare the performances
of these broadband wireless multimedia schemes. First, we derive lower bounds on the excepted FEC redundancy required by ideal
cross-layer header estimation, UDP and UDP-Lite over an arbitrary-order Markov wireless channel. We show that under realistic
wireless channel conditions, the cross-layer header estimation scheme always requires lesser redundancy than UDP and UDP-Lite.
We then propose a practical minimum distance decoding (MDD) header estimation scheme, which is receiver-based, low complexity
and highly accurate. Trace-driven multimedia experiments over wireless LANs demonstrate that MDD header estimation requires
significantly lesser FEC redundancy and renders better video quality than existing schemes. 相似文献
993.
994.
Analysis of DC and AC properties of a humidity sensor based on polyaniline–chromium oxide composites
K. C. Sajjan Aashis S. Roy Ameena Parveen Syed Khasim 《Journal of Materials Science: Materials in Electronics》2014,25(3):1237-1243
Polyaniline–Chromia (PANI–Cr2O3) composites were synthesized by in situ polymerization. The prepared composites were characterized by scanning electron microscopy, X-ray diffraction and Fourier transforms infrared spectroscopy. The structural studies confirm the polymerization of aniline over Cr2O3 particles which results into strong interaction between PANI and Cr2O3 particles. Direct current conductivity of composites increases with increase in temperature. Among all composites, 30 wt% shows high conductivity. The humidity sensing mechanism of the PANI–Cr2O3 composites is studied and change in its resistance with respect to percentage relative humidity ranging from 20 to 95 % is recorded. The humidity sensing studies shows that the change in the resistance is due to the uncurling of polymer chains by the absorption of water vapor which leads to increase in conduction paths. The results indicate better humidity sensing response by the addition of Cr2O3 particles to PANI, among all the composites, 30 wt% composite shows higher sensitivity. 相似文献
995.
Ali A. Obeed Al-Azawi 《国际水资源开发杂志》2017,33(4):628-648
An important challenge facing the design of sustainable aquifer management plans is weak primary data on aquifer recharge and use patterns. Weak data limit the ability of policy makers to design efficient aquifer protection plans. The objectives of this article are (1) to estimate groundwater use patterns for an important food-producing region of southern Iraq, the Bahr Al-Najaf Basin; (2) to compare groundwater use patterns with the renewable groundwater supply; and (3) to describe a sustainable groundwater policy alternative to current use patterns. For this study, original data on groundwater pumping were secured for 2006–2011. The data show a pattern of unsustainable groundwater withdrawals. A policy intervention is described in which pumping permits could be assigned to groundwater users to promote sustainable use. Allowing or encouraging the permits to be transferable through trading to higher-valued uses could reduce the economic costs of protecting the aquifer while promoting its sustainable use. 相似文献
996.
Ali Rashidinejad E. John Birch Dongxiao Sun-Waterhouse David W. Everett 《Critical reviews in food science and nutrition》2017,57(15):3188-3196
Tea consumption is practised as a tradition, and has shown potential to improve human health. Maximal uptake of tea antioxidants and milk proteins without a negative impact on tea flavor is highly desired by consumers. There is a conflicting evidence of the effect of milk addition to tea on antioxidant activity. Differences in the type of tea, the composition, type and amount of milk, preparation method of tea–milk infusions, the assays used to measure antioxidant activity, and sampling size likely account for different findings. Interactions between tea polyphenols and milk proteins, especially between catechins and caseins, could account for a decrease in antioxidant activity, although other mechanisms are also possible, given the similar effects between soy and bovine milk. The role of milk fat globules and the milk fat globule membrane surface is also important when considering interactions and loss of polyphenolic antioxidant activity, which has not been addressed in the literature. 相似文献
997.
We investigate the inaccuracy of the traditional magnetic field integral equation (MFIE) in the analysis of scattering of small conducting objects, with the use of Rao–Wilton–Glisson (RWG) basis functions. As a remedy to such problems, we propose to use a novel impedance matrix elements (IME) formulation of the MFIE, which is suitable to use RWG basis functions. Techniques to calculate the IME of the new formulation are outlined. It is shown that similar technique to compute the IME of the MFIE resulted from the use of curl-conforming basis functions can also be used here. Based on the examples of several relatively small conducting objects, it is demonstrated that significant improvement in the accuracy of the MFIE can be obtained for this new IME formulation with the use of RWG basis functions. 相似文献
998.
Ali Aberoumand 《Food Analytical Methods》2009,2(3):208-211
Human beings evolved on a diet that was balanced in the omega-6 and omega-3 polyunsaturated fatty acids (PUFA), and was high
in antioxidants. Edible wild plants provide alpha-linolenic acid and PUFA. Today, we know that omega-3 fatty acids are essential
for normal growth and development and may play an important role in the prevention and treatment of coronary artery disease,
hypertension, diabetes, arthritis, other inflammatory and autoimmune disorders, and cancer. Comparison of obtained results
from analysis of fatty acids of edible plant oils showed that Solanum oil has the highest nutritional value because it contains high contents of linoleic acid (62.29%) and oleic acid (8.6%) and
Asparagus oil has high nutritional value because it contains 66.12% oleic acid and 9.6% linoleic acid. Comparison of results of this
study with reported results by Artemis (2004) showed that palmetic acid (34.48%) and estearic acid (21.71%) contents of portulaca in this study were greater than the results reported by Artemis. Therefore, we can conclude that Solanum and Asparagus oil are edible and have good nutritive values. 相似文献
999.
1000.
Amy M. Bilton Richard Wiesman A.F.M. Arif Syed M. Zubair Steven Dubowsky 《Renewable Energy》2011,36(12):3246-3256
This paper presents a generalized methodology to evaluate the feasibility of photovoltaic-powered reverse osmosis (PVRO) systems for small, remote communities in challenging environments. The economic feasibility is determined by comparing the cost of water from a photovoltaic reverse osmosis system with the cost of water obtained using conventional diesel-powered reverse osmosis. For PVRO systems, the feasibility is a function of location due to variation in solar resource, water type, system demand and local governmental policies. A series of sample cases were analyzed to demonstrate the method. Analysis for community-scale seawater reverse osmosis systems was carried out for various locations using Geographic Information System (GIS) data. A site-specific analysis has been completed for seawater and brackish water reverse osmosis systems. It was found that photovoltaic-powered reverse osmosis is feasible for the majority of remote locations with a large solar resource. 相似文献