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71.
The multidirectional asymmetrical microlens-array light-control film (MAMA-LCF) is developed for enhancing the image brightness and contrast ratio of various reflective liquid-crystal displays. By use of index-matching material, the interface reflection is greatly reduced. Through optimized designs, the surface-scattering effect is also suppressed; thus the contrast ratio is much enhanced. From experimental results, the MAMA-LCF leads to a approximately 1.5 x gain in brightness over the MgO standard white and a 15:1 contrast ratio for the reflective color super-twist nematic liquid-crystal display, 2.8 x MgO and a 23:1 contrast ratio for the polymer-dispersed liquid-crystal, and 2.8 x MgO and a 13:1 contrast ratio for the cholesteric liquid-crystal display. Potential applications of this low-cost plastic thin film for reflective liquid-crystal displays are foreseeable. 相似文献
72.
A volumetric optical disk that has multiple transparent films with optical switching layers is used as a recording medium to increase the number of recording layers. In the disk the optical switching layer is adapted to reduce decay of laser energy and increase reading and recording sensitivity. Well-defined marks of approximately 100-nm depth can be placed precisely on the transparent films by a focused laser beam. Writing and reading of a four-layer recordable disk, fabricated by molding and spin bonding, have been demonstrated experimentally. The volumetric disk can achieve a high recording capacity with conventional optical pickups. 相似文献
73.
W. T. Shieh 《International Journal of Fracture》1978,14(6):633-638
The formation of fine short relaxation cracks frequently found along the cyclically propagating 45° compressive maximum shear crack were analyzed. Comparison was made of the results computed from two different fracture criteria, the minimum strain energy density (MSED) and the maximum tensile (tangential) stress (MTS). The measured directions θ0 of the relaxation cracks were in excellent accord with both the theoretical MSED directions and the MTS directions. The computed MSED crack directions were predicated on two conditions: 1) the strain energy density factor was minimum, S min, and 2) the volume change component S v of S min was greater than the distortion component S d. Such requirements correspond to crack directions with locally maximum tensile tangential stresses. 相似文献
74.
W. T. Shieh 《Metallurgical and Materials Transactions B》1974,5(5):1069-1085
A method is described for the transmission and scanning electron microscope study of the relationship between the microstructure
and the fracture properties of two quenched and tempered, electron beam melted, modified SAE 4620 steels consisting of tempered
low carbon martensite. Among all the microstructure constituents considered, the constituentR (randomly oriented, “tempered low carbon martensite, TLCM”) achieved the highest probability for dimple fracture. The thick
TLCM laths (designated as the microstructure constituent II) exhibited higher probability of dimple plus quasi-dimple mode
of fracture than the thin laths (I). It is concluded that the steel EB1035 derived the high toughness from a) the high concentration
of the “high toughness” microstructure constituentsR and II, b) “non-embrittled” prior austenite grain boundaries with 50 pct probability for smooth plus quasi-smooth mode and
50 pct dimple plus quasi-dimple mode of intergranular fracture. In contrast, besides having low content ofR and II, the steel EB1014 displayed “completely embrittled” prior austenite grain boundaries with 100 pct probability for
smooth plus quasi-smooth intergranular fracture. The conclusions derived from the microconstituentsR, II and I seemed to reflect the “embrittling” effect of decreased spacings between the pseudo twin related laths and between
the lath boundary cementite films, and the “toughening” effect of the randomly oriented laths. Auger spectra obtained from
the fracture surface before and after sputtering is analyzed to determine the presence of grain boundary sulfur segregation. 相似文献
75.
PMD-Supported Coherent Optical OFDM Systems 总被引:2,自引:0,他引:2
Although polarization-mode dispersion (PMD) greatly impairs conventional high-speed single-carrier systems, it is shown that for multicarrier systems such as coherent optical orthogonal frequency-division-multiplexed systems (CO-OFDM), not only does PMD not cause any impairment, but it also provides a benefit of polarization diversity against polarization-dependent-loss-induced fading and consequently improves the system margin. The PMD benefit to fiber nonlinearity reduction in CO-OFDM systems is also predicted 相似文献
76.
Jason Sheng-Hong Tsai Zi-Yi Yang Shu-Mei Guo Leang-San Shieh Chia-Wei Chen 《国际通用系统杂志》2013,42(6):643-672
In this paper, a linear quadratic Nash game-based tracker for multiparameter singularly perturbed sample-data systems is developed. A generalized cross-coupled multiparameter algebraic Riccati equation (GCMARE) with two quadratic cost functions is solved by applying the LQR design methodology for the optimal tracker design. Firstly, the asymptotic expansions of the GCMARE are newly established, and the proposed algorithm is able to effectively solve the GCMARE with the quadratic convergence rate. Then, the low-gain digital controller with a high design performance is realized through the prediction-based digital redesign method. Finally, for further improving the tracking performance, the chaos-evolutionary-programming algorithm (CEPA) is utilized to optimally tune the parameters of the tracker. An example is presented to demonstrate the effectiveness of the proposed methodology. 相似文献
77.
Cheng-Chien Liu Chjeng-Lun Shieh Jia-Chin Lin An-Ming Wu 《International journal of remote sensing》2013,34(23):8519-8540
The occurrence of landslides in the catchment area is a potential threat to the water quality and the lifespan of a reservoir. Due to the limitations of spatial coverage in ground surveys and of temporal resolution in aerial photos, it is difficult to monitor such events in the entire catchment area at short intervals. Formosat-2 is the first commercial satellite dedicated to site surveillance with a high-spatial-resolution sensor placed in a daily revisit orbit (2 m in panchromatic and 8 m in multi-spectral). In this research, a new approach is proposed to identify the non-vegetated areas in the multi-temporal and multi-spectral images taken by Formosat-2 by integrating the Getis statistic, the spectral index and the unsupervised K-means classification. With this new approach, we analyse a total of 16 pairs of Formosat-2 images, taken in the catchment area of Tseng-Wen Reservoir from February to December 2006 at an interval of three to four weeks. The results show that newly developed non-vegetated areas are closely related to earthquakes and rainfall. Once the slump material is generated by an earthquake, a comparatively low amount of rainfall will trigger its flushing. However, once the slump material has gone, there are no significant changes in the non-vegetated areas, even with severe weather events such as typhoons or storms. This suggests that the most critical time for protecting the reservoir is right after an earthquake and before the next rain. If the slump material is not managed or removed during this crucial period of time, eventually it will fall into the reservoir. Since the catchment area of Tseng-Wen Reservoir is protected and restricted from access, most of the non-vegetated areas should be closely related to landslides caused by natural processes (such as rainfall or earthquake) rather than man-made processes (such as tree cutting or degradation of vegetation). This research demonstrates the potential of Formosat-2 imagery in monitoring the spatial and temporal variations of landslides in the catchment areas of reservoirs. 相似文献
78.
Terng-Yin Hsu Bai-Jue Shieh Chen-Yi Lee 《Solid-State Circuits, IEEE Journal of》1999,34(8):1063-1073
A new algorithm for all-digital phase-locked loops (ADPLL) with fast acquisition and large pulling range is presented in this paper. Based on the proposed algorithm, portable cell-based implementations for clock recovery with functions of a frequency synthesizer and on-chip clock generator are completed by standard cell. These modules have been designed and verified on a 0.6-μm CMOS process. Test results are summarized as follows: 1) the proposed ADPLL can satisfy full locked bandwidth and fast acquisition within one data transition; 2) the on-chip clock generator can generate any target clock rate fclock ; and 3) the function of nonreturn-to-zero clock recovery has a maximum fclock/4 recovering capability with a locking range of (τinput±τinput/2)) where τ input is the input period 相似文献
79.
Fang‐Cheng Lin Yi‐Pai Huang Ching‐Ming Wei Han‐Ping D. Shieh 《Journal of the Society for Information Display》2009,17(3):221-228
Abstract— Field‐sequential color (FSC) is a potential technique for low‐power liquid‐crystal displays (LCDs). However, it still experiences a serious visual artifact, color break‐up (CBU), which degrades image quality. Consequently, the “Stencil Field‐Sequential‐Color (Stencil‐FSC)” method, which applies local color‐backlight‐dimming technology at a 240‐Hz field rate to FSC‐LCDs, is proposed. Using the Stencil‐FSC method not only suppressed CBU efficiently but also enhanced the image contrast ratio by using low average power consumption. After backlight signal optimization, the Stencil‐FSC method was demonstrated on a 32‐in. FSC‐LCD and effectively suppressed the CBU, which resulted in more than a 27,000:1 dynamic contrast ratio and less than 40‐W average power consumption. 相似文献
80.