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121.
The perils of using encryption without authentication or integrity protection are well known in the cryptographic research community. Yet its exactly the mandatory support for unauthenticated encryption that forms the basis of a serious security flaw in an IPsec implementation we recently discovered. In response, the UK's equivalent to CERT, the National Infrastructure Coordination Centre published a vulnerability advisory about the flaw. Vendors also issued updated recommendations to customers, and we saw a flurry of discussion on Slash-dot and the sci.crypt newsgroup. In the aftermath, we asked ourselves, how did this happen?. 相似文献
122.
How-Lung Eng Junxian Wang Alvin Harvey Kam Siew Wah Wei-Yun Yau 《IEEE transactions on image processing》2006,15(6):1583-1600
This paper presents a real-time foreground detection method for monitoring swimming activities at an outdoor swimming pool. Robust performance and high accuracy of detecting objects-of-interest are two central issues of concern. Therefore, in this paper, a considerable amount of attention has been placed on the following aspects: 1) to establish a better method of modeling aquatic background, which exhibitis dynamic characteristics with random spatial movements, and 2) to establish a method of enhancing the visibility of the foreground by removing specular reflection at nighttime. First, the development of a new background modeling method is reported. In the proposed approach, the background is modeled as a composition of homogeneous blob movements. With an implementation of a spatial searching process, the proposed method shows capability in associating and distinguishing movements caused by the background. Hence, this contributes to better performance in foreground detection. On the issue of enhancing the visibility of the foreground, a decision-based filtering scheme is proposed as a preprocessing step. A defined concept term, fluctuation measure, is defined for classifying each pixel to be one of the predefined types. This has allowed suitable spatial or spatiotemporal filters to be applied accordingly for color the compensation step. All of these developments are evaluated by testing live on a busy Olympic-size outdoor public swimming pool. Both qualitative and quantitative evaluations are reported. This provides a comprehensive study of the system. 相似文献
123.
J. P. Skelly M. K. Yau J. S. Elkins L. A. Yamamoto V. P. Shah W. H. Barr 《Drug development and industrial pharmacy》1986,12(8):1177-1201
The pH dissolution profiles and bioavailability data of six quinidine gluconate controlled release products were obtained, and attempts were made to identify a dissolution condition that is most indicative of in vivo bioavailability. This was achieved by graphically displaying the pH dissolution profiles of the six products in multi-dimensional graphs utilizing a topographical plotting technique. These graphs were found to be quite effective in illustrating: a) the effects of pH and buffer composition on the dissolution rate of the test products, and b) the in vitro condition that best correlates with in vivo data. It was found that for the quinidine gluconate controlled release dosage forms studied, dissolution carried out in pH 5.4 phosphate buffer was most meaningful in showing the differences among dosage forms and for predicting in vivo bioavailability 相似文献
124.
The Dynamic Flowgraph Methodology (DFM) is a new approach for embedded system safety analysis. This methodology integrates the modeling and analysis of the hardware and software components of an embedded system. The objective is to complement the traditional approaches which generally follow the philosophy of separating out the hardware and software portions of the assurance analysis. In this paper, the DFM approach is demonstrated using the Titan II Space Launch Vehicle Digital Flight Control System. The hardware and software portions of this embedded system are modeled in an integrated framework. In addition, the time dependent behavior and the switching logic can be captured by this DFM model. In the modeling process, the dimensionality of the decision tables for software subroutines creates a problem. A possible solution for solving the software portion of the DFM model is suggested. This approach makes use of a well-known numerical method, the Newton-Raphson method, to solve the equations implemented in the subroutines in reverse. Convergence can be achieved in a few steps. 相似文献
125.
A Texture Mapping Approach to 3-D Facial Image Synthesis 总被引:2,自引:0,他引:2
A method of synthesising and animating a realistic image of a person's face by means of computer graphics is described. The key feature contributing to realism in image synthesis lies in the use of texture mapping in the rendering of surface detail on the face. Full facial animation is made possible by manipulating a 3-D model of the face in conjunction with a relatively small data set of pre-stored sub-images. 相似文献
126.
A 31-year-old man with the acquired immunodeficiency syndrome presented with herpes zoster ophthalmicus on the right. Five days after he began treatment for the zoster pseudodendrites and skin lesions, he developed superficial punctate keratitis, uveitis, and crusting skin lesions in the left eye. After treatment, the ocular lesions resolved in both eyes without incident. The bilateral manifestation of herpes zoster ophthalmicus is a result of the increased severity associated with immunosuppression caused by the human immunodeficiency virus. 相似文献
127.
A new method of analysis is presented for studying the mixed-mode interface crack between dissimilar isotropic materials. The method of approach is formulated on the basis of recently developed conservation laws in elasticity for nonhomogeneous solids and fundamental relationships in fracture mechanics of interface cracks. A solution procedure for the analysis is established and shown to be computationally efficient and operationally simple, involving only known auxiliary solutions and evaluation of conservation integrals along a path removed from the crack tip. An important feature of the present approach is that the crack-tip stress intensity factor solution for each individual fracture mode can be determined accurately and -conveniently by information extracted in the far field. Numerical examples, whose solutions are available in the literature, are presented to demonstrate the accuracy, convergence, and related characteristics of the current approach. 相似文献
128.
New rate-1/3 linear trellis (convolutional) codes with 8-PSK modulation for bandlimited additive white Gaussian noise (AWGN) channels are reported. The simulated bit error probability performance of the trellis-coded modulation schemes with unquantised Viterbi decoding shows useful coding gains over the uncoded coherent BPSK having the same bandwidth efficiency of 1 bit/s/Hz and the schemes are suitable for use in many practical bandlimited channels.<> 相似文献
129.
DJ Stewart R Goel MC Cripps S Huan J Yau S Verma 《Canadian Metallurgical Quarterly》1997,15(4):267-277
BACKGROUND: Chemotherapy resistance is probably multifactorial; hence, we assessed the feasibility of adding to carboplatin 6 concurrent resistance modulators in 53 patients with resistant cancers. METHODS: Pentoxifylline and dipyridamole were added to carboplatin 400 mg/m2 in cohort 1, and metronidazole was also given in cohort 2. Mannitol and saline were administered in each cohort with the theoretical objective of improving carboplatin delivery to tumors by reducing blood viscosity. Because of excessive toxicity in cohort 2, cohort 3 received the same modulators as in cohort 2 but with a reduced dose of carboplatin (200 mg/m2). Subsequent patients had the following drugs added to those in the previous cohort: novobiocin (cohort 4), tamoxifen (cohort 5), ketoconazole (cohort 6). Cohort 7 patients received the 6 cohort 6 modulators along with carboplatin 300 mg/m2. RESULTS: Thrombocytopenia was excessive in early cohorts with a carboplatin dose of 400 mg/m2, but was minimal at lower doses. Other toxicity was generally tolerable and reversible, particularly at carboplatin doses < or = 300 mg/m2, although gastrointestinal and neurological toxicity tended to worsen as additional modulators were added. No major responses (but 4 minor responses) were seen in this patient population with heavily pretreated or primarily resistant cancers. CONCLUSIONS: Acceptable doses for phase II studies are carboplatin 300 mg/m2, 20% mannitol 250 ml plus normal saline 500 ml over 1 hr prior to carboplatin, pentoxifylline 700 mg/m2/day p.o. from 3 days before carboplatin to cessation of therapy, dipyridamole 100 mg/m2 p.o. q6h x 6 days starting 24 hr before carboplatin, metronidazole (750 mg/m2 p.o. 12 hr and immediately before, and 24 hr after carboplatin; 250 mg/m2 suppository p.r. 12 hr and immediately before, and 6 and 24 hr after carboplatin; and 500 mg/m2 i.v. right after carboplatin), novobiocin 600 mg/m2 p.o. q12h x 6 days starting 24 hr before carboplatin, and tamoxifen 100 mg/m2/day plus ketoconazole 700 mg/m2/day x 3 days starting the day before carboplatin, with oral dexamethasone and ondansetron as antimetics. 相似文献
130.
The overall effectiveness of a wet six-row wickless heat pipe-heat exchanger (HPHX) for tropical building HVAC systems was simulated using a computer simulation program. This computer program, utilizing Fortran source code, was developed based on the effectiveness-NTU method together with the ridge model for predicting the film condensation and uses the concept of iteration to predict the temperature distribution across the HPHX and its overall effectiveness. The effects of inclination angle and inlet evaporator relative humidity on heat transfer coefficient for the HPHX were determined using TRNSYS Type98 component. The wet HPHX effectiveness and relative humidity were also studied in this research experimentally. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献