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981.
P. S. Lee D. Mangelinck K. L. Pey J. Ding D. Z. Chi J. Y. Dai A. See 《Journal of Electronic Materials》2001,30(12):1554-1559
The key feature of this study is to incorporate N2
+ implant prior to Ni sputtering on the poly-Si gate and source/drain regions. The results show that the incorporation of the
presilicide N2
+ implant is able to suppress agglomeration in the Ni silicide films up to 900°C and enhance the phase stability of NiSi on
Si(100) up to 750°C. Stable and low sheet resistance was achieved on the silicided undoped poly-Si up to 700°C due to reduced
layer inversion, which is driven by grain boundary energy and the surface energy of the poly-Si. 相似文献
982.
Ben Sbeh Z. Cohen L.D. Mimoun G. Coscas G. 《IEEE transactions on medical imaging》2001,20(12):1321-1333
Segmentation of bright blobs in an image is an important problem in computer vision and particularly in biomedical imaging. In retinal angiography, segmentation of drusen, a yellowish deposit located on the retina, is a serious challenge in proper diagnosis and prevention of further complications. Drusen extraction using classic segmentation methods does not lead to good results. We present a new segmentation method based on new transformations we introduced in mathematical morphology. It is based on the search for a new class of regional maxima components of the image. These maxima correspond to the regions inside the drusen. We present experimental results for drusen extraction using images containing examples having different types and shapes of drusen. We also apply our segmentation technique to two important cases of dynamic sequences of drusen images. The first case is for tracking the average gray level of a particular drusen in a sequence of angiographic images during a fluorescein exam. The second case is for registration and matching of two angiographic images from widely spaced exams in order to characterize the evolution of drusen. 相似文献
983.
The horizontal inhomogeneity of the atmosphere within a satellite microwave radiometer's field of view (FOV) has always been considered as a source of rainfall retrieval errors. The hydrometeor profile retrieval algorithm presented exploits it to obtain an approximation of a radiative transfer model, which allows relatively simple inversion. The atmosphere within the FOV is treated as a combination of horizontally homogeneous domains. Assuming that one of known “basic” hydrometeor profiles occurs in each domain, the inverse problem is reduced to a determination of “beamfilling coefficients.” The online procedure includes determination of beamfilling coefficients and a footprint-averaged hydrometeor profile as a linear combination of “basic” ones. Off-line procedures involve the selection of a minimum number of necessary “basic” brightness temperature vectors and correction of “basic” hydrometeor profiles to provide the best retrieval accuracy for a given cloud/radiative simulation. The performance of the algorithm is tested for both numerical simulations and TRMM/TMI data. Numerical simulation has allowed a comparison of the information content of radiometer measurements from SSM/I, TMI, and the future AMSR. The effectiveness of the algorithm is being tested for rain water integral and rain rate retrievals from TRMM TMI measurements 相似文献
984.
熔融石英的热及电场诱导机理 总被引:1,自引:0,他引:1
详细分析了熔融石英样品经热及电场诱导后 ,建立二阶极化率的机理。该机理表明 ,二阶极化率是由样品耗尽区中偶极子的定向和三阶极化率经强静电场作用共同形成的。在一般条件下诱导 ,前者是主要因素 ;在较高电压诱导时 ,后者是主要因素。推导了二阶极化率的表达式 ,并进行了数值计算。数值结果表明 ,在一般情况下 ,χ3 3 ( 2 ) 约 1pm/V ,χ3 3 ( 2 ) ∶χ3 1( 2 ) 约为 3。理论证明提高诱导的外加电压和选用Na和OH杂质浓度较大的石英材料能提高二阶极化率。 相似文献
985.
986.
Baoxin Li Chellappa R. Qinfen Zheng Der S.Z. 《IEEE transactions on image processing》2001,10(6):897-908
An approach to model-based dynamic object verification and identification using video is proposed. From image sequences containing the moving object, we compute its motion trajectory. Then we estimate its three-dimensional (3-D) pose at each time step. Pose estimation is formulated as a search problem, with the search space constrained by the motion trajectory information of the moving object and assumptions about the scene structure. A generalized Hausdorff (1962) metric, which is more robust to noise and allows a confidence interpretation, is suggested for the matching procedure used for pose estimation as well as the identification and verification problem. The pose evolution curves are used to assist in the acceptance or rejection of an object hypothesis. The models are acquired from real image sequences of the objects. Edge maps are extracted and used for matching. Results are presented for both infrared and optical sequences containing moving objects involved in complex motions 相似文献
987.
A novel variable optical attenuator (VOA) is introduced that can provide high dynamic range and high-resolution all at fast submicrosecond speeds. The VOA design exploits an in-line one-to-one imaging optical architecture operating with Bragg-mode acoustooptic Bragg cells. Optical attenuation is achieved via frequency and drive voltage control of the Bragg cells, leading to flexible and precise attenuation-level settings. VOA demonstrated a 45-dB dynamic range with a 175-ns switching time. Other measured parameters include 1.14-dB/MHz resolution, 1.56-dB polarization dependent loss, and an excess loss of 3.55 dB 相似文献
988.
An analysis of nine years of Nimbus/SMMR 6.6 GHz brightness temperatures over central Spain revealed a systematic discrepancy between daytime and nighttime H-polarization emissivities, calculated using independently derived surface temperatures. It was found that daytime emissivities were systematically lower than nighttime emissivities which is explained from the difference between the actual surface temperature (Ts) and the effective temperature of the microwave emitting surface layer (Teff). In order to estimate the long-term mean difference between Ts and Teff, average daytime and nighttime thermal correction factors were calculated. The criterion used for judging the magnitude of these thermal correction factors is the hypothesis that daytime emissivity, when averaged over a longer period, should not be lower than nighttime emissivity. From a combined analysis of all daytime and nighttime Nimbus/SMMR signatures over the nine-year period, and short-term field evidence of daytime and nighttime soil temperature profiles, the magnitude of the thermal correction factors could be estimated. Averaged over the nine-year period with 320 nighttime and 498 daytime observations the thermal correction factors amount to -12.5 K for the daytime and +5.0 K for the nighttime, with 90% of the cases satisfying the defined criterion 相似文献
989.
Song Y.W. Pan Z. Starodubov D. Grubsky V. Salik E. Havstad S.A. Xie Y. Willner A.E. Feinberg J. 《Photonics Technology Letters, IEEE》2001,13(10):1103-1105
We demonstrate an all-fiber wavelength-division-multiplexed optical crossconnect using ultrastrong fiber Bragg gratings (FBGs) with wide tunability. These FBGs have 0.2-nm bandwidths and can be tuned over ~52 nm due to a novel grating preparation technique to reduce mechanical strength degradation. There is negligible distortion in the transmission spectra while tuning the grating, and the crossconnect architecture uses cascades of these gratings for WDM operation. The ability to tune these >98% reflectivity gratings completely out of the entire WDM signal band minimizes the leakage of unwanted signal power and leads to the improvements of >10-dB crosstalk and >0.6-dB power penalty compared with conventional gratings 相似文献
990.