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41.
42.
This paper presents a general method to formulate monotonically convergent algorithms for identifying optimal control fields to manipulate quantum dynamics phenomena beyond the linear dipole interaction. The method, facilitated by a field-dependent dipole moment operator, is based on an integral equation of the first kind arising from the Heisenberg equation of motion for tracking a time-dependent, dynamical invariant observable associated with a reference control field. 相似文献
43.
By exploiting the unattended nature of the wireless sensor networks, an attacker can physically capture and compromise sensor nodes and then launch a variety of attacks. He can additionally create many replicas of a few compromised nodes and spread these replicas over the network, thus launching further attacks with their help. In order to minimize the damage incurred by compromised and replicated nodes, it is very important to detect such malicious nodes as quickly as possible. In this review article, we synthesize our previous works on node compromise detection in sensor networks while providing the extended analysis in terms of performance comparison to the related work. More specifically, we use the methodology of the sequential analysis to detect static and mobile compromised nodes, as well as mobile replicated nodes in sensor networks. With the help of analytical and simulation results, we also demonstrate that our schemes provide robust and efficient node compromise detection capability. 相似文献
44.
45.
Photolithography to produce TiO2 patterns from amorphous films of (5-C5H5)2Ti(N3)2 has been demonstrated. The efficiency of the reaction has been measured yielding a quantum yield of 0.025. The mechanism of the photoreactions of (5-C5H5)2Ti(N3)2 has been studied using Fourier transform-infrared spectroscopy in both a low-temperature 1,2-epoxyethylbenzene glass and as surface films. In each case the primary photochemical process was found to be loss of a single azido group. The result of subsequent photolysis was found to be dependent upon medium and temperature. In the low-temperature glass no further photochemistry was observed. The exhaustive photolysis of films at 20 K, or room temperature, under a vacuum or in air led to loss of all ligands and the formation of TiO2. 相似文献
46.
The H∞ almost disturbance decoupling problem is considered. In this paper, a nonlinear design is proposed to find a state feedback controller for bilinear systems. The closed‐loop system is internally stable and achieves disturbance attenuation in nonlinear H∞ sense. We defined a special form of Lyapunov function, which is constructed in terms of one or a set of positive definite constant matrices. If, except of the origin of system, the corresponding polynomial of the positive definite matrix (or several polynomials relevant to the positive definite constant matrices) has (have) no zero on a given subset of state space, then we can construct a controller to solve our problem. It is found that the controller structure could be complicated, but is feasible in computation and may require optimization technique to search the solution. We consider both SIMO and MIMO cases with illustrated examples. 相似文献
47.
48.
In this study, a simple method for the fabrication of high aspect ratio silicon nanoporous arrays is developed. A N-type silicon wafer is used as the substrate material. A micro-scale pattern of the desired porous array is transferred to the front surface of the silicon wafer by photolithography after which the wafer is placed in a home-made fixture to efficiently expel the etching generated air and promptly hold the back-side illumination light. A halogen lamp is used as the light source for backside illumination to enhance the electron–hole pair generation. An anodization process is then carried out using a new etchant consisting of hydrofluoric acid and mixed EtOH and EMSO surfactant to effectively polish the pore surfaces and sharpen the tips of the etched pores. A nanochannel array with a nano-tip of 61.4?nm is obtained. 相似文献
49.
SungHoo Choi Jong Pil Yun Keunhwi Koo Sang Woo Kim 《Expert systems with applications》2012,39(9):7621-7636
This paper deals with algorithms for text localization and character segmentation in images for process automation in the steel-making industry. Each character which comprises slab identification numbers may be corrupted severely before it is captured by network cameras. Therefore, proper processing is required to localize the target texts successfully. In this paper, we propose (1) a method to evaluate the closeness of an edge patch to the form of a closed contour, (2) an edge inspection method to determine character colors and estimate font thickness, and (3) three reasonable binarization methods to increase the performance of the algorithm for the detection of the left and right boundaries of the text rectangle. The experimental results show that the proposed algorithms are reliable. 相似文献
50.
Operation, system architectures, and physical Layer design considerations of distributed MAC protocols for UWB 总被引:2,自引:0,他引:2
Impulse-based ultra wideband (I-UWB) is an attractive radio technology for large ad hoc and sensor networks due to its robustness to harmful multipath effects, sub-centimeter ranging ability, simple hardware, and low radiated power. To scale to large sizes, networks often implement distributed medium access control (MAC) protocols. However, most MAC protocols for I-UWB are centralized, and they target small wireless personal area networks and cellular networks. We propose three distributed MAC protocols suitable for I-UWB. Two multichannel protocols, called multichannel pulse sense multiple access (M-PSMA) and multichannel ALOHA achieve high aggregate throughput. A busy-signal protocol, called busy-signal multiple access (BSMA), reduces the energy wasted from re-transmitted packets. This paper describes the three protocols in terms of the protocol's operation, the supporting system architecture, and the I-UWB physical layer. Physical layer simulations confirm the feasibility of implementing the proposed systems and also provide parameters for network simulations. Network simulations show that the throughput of M-PSMA exceeds that of a centralized time-division multiple-access protocol and that the energy efficiency of BSMA far surpasses that of other distributed protocols. 相似文献