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991.
992.
993.
Health Outcomes and Socio-economic Status Among the Elderly in China: Evidence from the CHARLS Pilot
John Strauss Xiaoyan Lei Albert Park Yan Shen James P. Smith Zhe Yang Yaohui Zhao 《Journal of population ageing》2010,3(3-4):111-142
We are concerned in this paper with measuring health outcomes among the elderly in Zhejiang and Gansu provinces, China, and examining the relationships between different dimensions of health status and measures of socio-economic status (SES). We are CHARLS pilot data to document health conditions, using a very rich set of health indicators that include both self-reported measures and biomarkers. We also examine correlations between these health outcomes and two important indicators of socio-economic status (SES): education and log of per capita expenditure (log pce), our preferred measure of household resources. In general education tends to be positively correlated with better health outcomes, as it is in other countries. However, unmeasured community influences turn out to be highly important, much more so than one usually finds in other countries. While it is not yet clear which aspects of communities matter and why they matter, we set up an agenda for future research on this topic. We also find a large degree of under-diagnosis of hypertension, a major health problems that afflicts the aged. This implies that the current health system is not well prepared to address the rapid aging of the Chinese population, at least not in Gansu and Zhejiang. 相似文献
994.
Lei Guo Liping Yin Hong Wang Tianyou Chai 《Automatic Control, IEEE Transactions on》2009,54(4):804-810
In this paper, the fault isolation (FI) problem is investigated for nonlinear non-Gaussian systems with multiple faults(or abrupt changes of system parameters) in the presence of noises. By constructing a filter to estimate the states, the FI problem can be reduced to an entropy optimization problem subjected to the non-Gaussian estimation error systems. The design objective for the FI purpose is that the entropy of the estimation error is maximized in the presence of diagnosed fault and is minimized in the presence of the nuisance faults or noises. It is shown that the error dynamics is represented by a nonlinear non-Gaussian stochastic system, for which new relationships are applied to formulate the probability density functions (PDFs) of the stochastic error in terms of the PDFs of the noises and the faults. The Renyi's entropy has been used to simplify the computations in the filtering for the recursive design algorithms. It is noted that the output can be supposed to be immeasurable (but with known stochastic distributions), which is different from the existing results where the output is always measurable for feedback. Finally, simulations are given to demonstrate the effectiveness of the proposed data-driven FI filtering algorithms. 相似文献
995.
Huawen Liu Author Vitae Lei Liu Author Vitae Huijie Zhang Author Vitae 《Pattern recognition》2009,42(7):1330-2058
Feature selection plays an important role in data mining and pattern recognition, especially for large scale data. During past years, various metrics have been proposed to measure the relevance between different features. Since mutual information is nonlinear and can effectively represent the dependencies of features, it is one of widely used measurements in feature selection. Just owing to these, many promising feature selection algorithms based on mutual information with different parameters have been developed. In this paper, at first a general criterion function about mutual information in feature selector is introduced, which can bring most information measurements in previous algorithms together. In traditional selectors, mutual information is estimated on the whole sampling space. This, however, cannot exactly represent the relevance among features. To cope with this problem, the second purpose of this paper is to propose a new feature selection algorithm based on dynamic mutual information, which is only estimated on unlabeled instances. To verify the effectiveness of our method, several experiments are carried out on sixteen UCI datasets using four typical classifiers. The experimental results indicate that our algorithm achieved better results than other methods in most cases. 相似文献
996.
Lei Ye Zhijun Wang Hao Che Henry B.C. Chan Constantino M. Lagoa 《Computer Communications》2009,32(5):800-805
Understanding the TCP congestion control mechanism from a global optimization point of view is not only important in its own right, but also crucial to the design of other transport layer traffic control protocols with provable properties. In this paper, we derive a global utility function and the corresponding optimal control law, known as TCP control law, which maximizes the global utility. The TCP control law captures the essential behaviors of TCP, including slow start, congestion avoidance, and the binary nature of congestion feedback in TCP. We find that the utility function of TCP is linear in the slow start phase and is proportional to the additive increase rate and approaches the well-known logarithm function as the data rate becomes large in the congestion avoidance phase. We also find that understanding the slow start phase with a fixed threshold is critical to the design of new transport layer control protocols to enable quality of service features. Finally, as an application, we design a Minimum Rate Guaranteed (MRG) traffic control law that shares the same utility function as the TCP control law. Our simulation study of the MRG control law indicates that it is indeed TCP friendly and can provide minimum rate guarantee as long as the percentage of network resource consumed by the MRG flows is moderately small. 相似文献
997.
Xingwei Wang Lei Guo Xuekui Wang Yu Zhang Xiaobing Zheng Weigang Hou Hongming Li Hongpeng Wang 《Computer Communications》2009,32(4):777-781
This paper proposes a new survivable algorithm named sub-path protection based on auxiliary virtual topology (SPAVT) to tolerate the single-link failure in WDM optical networks. First, according to the protection-switching time constraint, SPAVT searches multiple pairs of primary and backup paths for each node pair in the network by the off-line manner, and then map these paths to the virtual topology. When a connection request arrives, SPAVT only needs to run one time of the Dijkstra’s algorithm to search a virtual route in virtual topology, where the route may consist of multiple pairs of sub-paths, to meet the protection-switching time constraint. Then, according to the shared resources policy, SPAVT chooses an optimal pair of sub-paths. Simulation results show that SPAVT has smaller blocking probability and lower time complexity than conventional algorithms. 相似文献
998.
Aggregate signatures are useful in special areas where the signatures on many different messages generated by many different users need to be compressed. In this paper, we study aggregate signatures in certificateless public key settings. We first present the notion and security model of certificateless aggregate signature schemes. Then we give an efficient certificateless aggregate signature scheme. Our scheme is existentially unforgeable under adaptive chosen-message attacks assuming the computational Diffie–Hellman problem is hard. 相似文献
999.
Pei-Lan Lei Gloria Yi-Ming Kao Sunny S.J. Lin Chuen-Tsai Sun 《Computers in human behavior》2009,25(6):1270-1279
Google Earth search function was used to study the impacts of small-scale spatial ability, large-scale environmental cognition, and geographical knowledge on new technology usage. The participants were 153 junior high students from central Taiwan. Geography grades served as indicators of prior knowledge, mental rotation and abstract reasoning skills as indicators of spatial ability, and sketch maps of school neighborhoods as indicators of environmental cognition (including landmark representation, intersection representation, and frame of reference). Lastly, the authors announced the landmarks searching worksheet and asked the participants to accomplish 16 familiar and unfamiliar landmark searching tasks using Google Earth with keyword search function disabled. The result showed the strongest predictor of landmark searching performance is ‘frame of reference’ in environmental cognition, followed by ‘mental rotation’ of spatial ability, ‘landmark representation’ of environmental cognition, and geographical knowledge. Google Earth landmark searches require complex cognitive processing; therefore, our conclusion is that GIS-supported image search activities give students good practice of active knowledge construction. 相似文献
1000.
The traditional sphere-structured support vector machines algorithm is one of the learning methods. It can partition the training
samples space by means of constructing the spheres with the minimum volume covering all training samples of each pattern class
in high-dimensional feature space. However, the decision rule of the traditional sphere-structured support vector machines
cannot assign ambiguous sample points such as some encircled by more than two spheres to valid class labels. Therefore, the
traditional sphere-structured support vector machines is insufficient for obtaining the better classification performance.
In this article, we propose a novel decision rule applied to the traditional sphere-structured support vector machines. This
new decision rule significantly improves the performance of labeling ambiguous points. Experimental results of seven real
datasets show the traditional sphere-structured support vector machines based on this new decision rule can not only acquire
the better classification accuracies than the traditional sphere-structured support vector machines but also achieve the comparable
performance to the classical support vector machines.
An erratum to this article can be found at 相似文献