全文获取类型
收费全文 | 6401篇 |
免费 | 91篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 266篇 |
综合类 | 10篇 |
化学工业 | 867篇 |
金属工艺 | 117篇 |
机械仪表 | 95篇 |
建筑科学 | 73篇 |
能源动力 | 135篇 |
轻工业 | 354篇 |
水利工程 | 16篇 |
石油天然气 | 3篇 |
无线电 | 529篇 |
一般工业技术 | 790篇 |
冶金工业 | 2839篇 |
原子能技术 | 130篇 |
自动化技术 | 277篇 |
出版年
2023年 | 22篇 |
2022年 | 48篇 |
2021年 | 72篇 |
2020年 | 26篇 |
2019年 | 55篇 |
2018年 | 52篇 |
2017年 | 32篇 |
2016年 | 54篇 |
2015年 | 59篇 |
2014年 | 67篇 |
2013年 | 174篇 |
2012年 | 135篇 |
2011年 | 194篇 |
2010年 | 153篇 |
2009年 | 145篇 |
2008年 | 165篇 |
2007年 | 150篇 |
2006年 | 157篇 |
2005年 | 111篇 |
2004年 | 115篇 |
2003年 | 143篇 |
2002年 | 100篇 |
2001年 | 121篇 |
2000年 | 97篇 |
1999年 | 195篇 |
1998年 | 976篇 |
1997年 | 600篇 |
1996年 | 423篇 |
1995年 | 243篇 |
1994年 | 205篇 |
1993年 | 215篇 |
1992年 | 89篇 |
1991年 | 87篇 |
1990年 | 92篇 |
1989年 | 86篇 |
1988年 | 79篇 |
1987年 | 62篇 |
1986年 | 65篇 |
1985年 | 58篇 |
1984年 | 48篇 |
1983年 | 34篇 |
1982年 | 47篇 |
1981年 | 37篇 |
1980年 | 52篇 |
1979年 | 29篇 |
1978年 | 27篇 |
1977年 | 60篇 |
1976年 | 150篇 |
1975年 | 19篇 |
1973年 | 22篇 |
排序方式: 共有6501条查询结果,搜索用时 0 毫秒
131.
TransCAIP: A Live 3D TV System Using a Camera Array and an Integral Photography Display with Interactive Control of Viewing Parameters 总被引:1,自引:0,他引:1
Taguchi Y. Koike T. Takahashi K. Naemura T. 《IEEE transactions on visualization and computer graphics》2009,15(5):841-852
The system described in this paper provides a real-time 3D visual experience by using an array of 64 video cameras and an integral photography display with 60 viewing directions. The live 3D scene in front of the camera array is reproduced by the full-color, full-parallax autostereoscopic display with interactive control of viewing parameters. The main technical challenge is fast and flexible conversion of the data from the 64 multicamera images to the integral photography format. Based on image-based rendering techniques, our conversion method first renders 60 novel images corresponding to the viewing directions of the display, and then arranges the rendered pixels to produce an integral photography image. For real-time processing on a single PC, all the conversion processes are implemented on a GPU with GPGPU techniques. The conversion method also allows a user to interactively control viewing parameters of the displayed image for reproducing the dynamic 3D scene with desirable parameters. This control is performed as a software process, without reconfiguring the hardware system, by changing the rendering parameters such as the convergence point of the rendering cameras and the interval between the viewpoints of the rendering cameras. 相似文献
132.
Robust control method for the inverted pendulum system with structured uncertainty caused by measurement error 总被引:1,自引:1,他引:0
In this article, we propose a design method for an inverted pendulum system with a structured uncertainty. We consider that
such an uncertainty is caused by a measurement error in the rotation angle of the pendulum and effects on the system structure
that cannot be included in the nominal elements. For the uncertain system obtained, we apply an integral tracking control
and the guaranteed cost control to design a robust, stable, tracking control system. Finally, we show the effectiveness of
our method through a numerical example. 相似文献
133.
Preparation of transparent,electrically conducting ZnO film from zinc acetate and alkoxide 总被引:1,自引:0,他引:1
Very uniform and transparent zinc oxide thin films doped with aluminium and indium were fabricated by the dip-coating technique using solutions prepared by the ethanolamine method. As starting materials, zinc acetate and zinc n-propoxide were used. Zinc acetate and propoxide are soluble in PriOH in the presence of diethanolamine, although they are hardly soluble without the amine. The prepared solutions were very stable and suitable for dip-coating. Zinc oxide was crystallized by heating above 500 °C, and doping of aluminium and indium retarded the crystallization. The electrical resistivity of the film was decreased by doping with aluminium and indium. The lowest resistivity of 2 × 10–2 cm was obtained by post-coating treatment in a nitrogen atmosphere. 相似文献
134.
Watabe H Hatazawa J Ishiwata K Ido T Itoh M Iwata R Takahashi T Hatano K Nakamura T 《IEEE transactions on medical imaging》1995,14(4):688-696
We proposed a new method (;linearized method') to analyze neuroleptic ligand-receptor specific binding in a human brain using positron emission tomography (PET). We derived the linear equation to solve four rate constants, k(3), k(4), k(5), k(6) from PET data. This method does not demand a radioactivity curve in plasma as an input function to the brain, and can perform fast calculations in order to determine rate constants. We also tested the nonlinearized method including nonlinear equations which is a conventional analysis using plasma radioactivity corrected for ligand metabolites as an input function. We applied these methods to evaluate dopamine D(2) receptor specific binding of [(11)C] YM-09151-2. The value of B(max)/K(d)=k(3)/k (4) obtained by the linearized method was 5.72+/-3.1 which was consistent with the value of 5.78+/-3.4 obtained by the nonlinearized method. 相似文献
135.
Taiju Takahashi Yukihiro Kudoh Yuichi Saito Yoshihiro Aoyagi 《Journal of the Society for Information Display》2023,31(3):101-111
Recently, there has been considerable research on optical devices, such as liquid crystal (LC) lenses and special optical plates, using LCs. In such devices, relatively small LC cells are frequently used, or unique LC orientations are required. As an LC orientation process, we focused on the LC director's orientation induced by the magnetic force line distribution of a small neodymium magnet. We propose a simple method for obtaining radial orientation, which is rather difficult to obtain using the ordinary rubbing method. The initial orientation in the LC cell is a vertical orientation cell with almost zero azimuth anchoring. With the proposed method, the reorientation process is performed with an assisting electric field and a small permanent magnet, unlike the conventional magnetic field orientation process that requires a large electromagnet. Furthermore, a polymer stabilization treatment is used to fix the obtained radial orientation pattern in the LC cell. After the treatment, the applying voltage can control the tilt angle of the director in weak polymer treatment, and a completely fixed orientation pattern can be obtained that in strong. 相似文献
136.
The present study investigated a numerical simulation of molding-defect formation during resin transfer molding using boundary element method and line dynamics. The proposed method enables to simulate small molding defects by increasing the node for required position during time evolution; thereby, the method computes high-resolution flow front without being affected by the initial mesh geometry. The method was applied to the radial injection RTM with single inlet, and it was confirmed by comparison with theoretical value based on Darcy’s law that the flow advancement was computed with high accuracy. In addition, the method was also applied to the flow advancement for inclusion problem with cylinder, and four-point injection problem. The simulated flow behavior, void formation, and shrinkage agreed with the results in references. Finally, the method was compared with experiments using two-point injection problem. The computed configuration of the flow front and weld line agreed well with the experimental results. 相似文献
137.
S Lindstrom A Endo S Sugita M Pecoraro Y Hiromoto M Kamada T Takahashi K Nerome 《Canadian Metallurgical Quarterly》1998,143(8):1585-1598
Matrix (M) and nonstructural (NS) genes of thirteen equine H3N8 and H7N7 influenza viruses were sequenced and analyzed from an evolutionary point of view. The M and NS genes of H3N8 viruses isolated between 1989 and 1993 evolved into two minor branch clusters, including isolates from Europe and the American continent, respectively. It was noteworthy to reveal that the nucleotide sequences of the M and NS genes of an earlier American strain showed highest homology to those of recent European viruses. "Frozen evolution" was observed in the M and NS genes of A/eq/LaPlata/1/88. It was also evident that the NS gene of an H7N7 virus from 1977 was very similar to that of a 1979-H3N8 virus, while the M gene was closest phylogenetically to that of the earliest H7N7 virus isolated in 1956. Furthermore, the M2 protein of A/eq/Newmarket/1/77 virus contained a carboxyl terminal deletion of three amino acids. The evolutionary rates of the M and NS genes of H3N8 equine influenza viruses were estimated to be 5.4 x 10(-4) and 5.1 x 10(-4) substitutions per site per year, respectively, which were slower than those of human viruses. 相似文献
138.
S Ewig A Glasmacher B Ulrich K Wilhelm H Sch?fer KH Nachtsheim 《Canadian Metallurgical Quarterly》1998,114(2):444-451
STUDY OBJECTIVE: To determine predictors of mortality from pulmonary infiltrates in neutropenic patients with acute leukemia during chemotherapy, and the significance of those factors related to the underlying malignancy and its therapy as well as of those related to the severity of the illness associated with pulmonary infiltrates. DESIGN: A historical cohort study. SETTING: A university teaching hospital and tertiary referral center. PATIENTS AND METHODS: Overall, 53 patients with neutropenia during chemotherapy and with first episodes of pulmonary infiltrates during a 4-year period were studied. Prognostic analysis included 38 variables. Multivariate analyses were performed by logistic regression. RESULTS: The survival rate from pneumonia was 57% (30/53). The following eight parameters were significantly associated with death in univariate analysis: comorbidity present; development of "late" pulmonary infiltrates (> or = 14 days after hospital admission); heart rate > or = 100 beats/min; a ratio heart rate/systolic blood pressure (HR/SBP) > or = 1.2; urea nitrogen > 7 mmol/L; radiographic score > or = 3; neutropenia < 1.0x10(9)/L at the treatment end point; and failed complete remission. In a multivariate model including only parameters available at diagnosis of pulmonary infiltrates, the presence of a ratio HR/SBP > or = 1.2 and of a radiographic score > or = 3 remained independently associated with death. In a second model also including the evolutionary parameter neutropenia < or = 1.0x10(9)/L at the treatment end point, both parameters remained significant together with neutropenia <1.0x 10(9)/L at the treatment end point. The presence of a ratio HR/SBP > or = 1.2 was a strong marker of early death. CONCLUSION: Both therapy- and malignancy-associated neutropenia as well as the severity of illness associated with pulmonary infiltrates are independent prognostic factors. Patients with a ratio HR/SBP > or = 1.2 at diagnosis of pulmonary infiltrates suffer from potentially reversible acute illness, are at risk for early death and, therefore, may be appropriate candidates for treatment in an ICU. 相似文献
139.
G Litscher G Schwarz E Eger I Hadolt E Mahla KH Tscheliessnigg 《Canadian Metallurgical Quarterly》1998,43(6):158-163
There is a steady progress in the development of artificial heart and circulatory assist devices. There is also no doubt that further advances in energy systems, materials, and electronics will provide for smaller and more reliable electrically driven blood pumps, but the present engineering design appears to be adequate to provide devices satisfactory for initial clinical use. Due to problems in the availability of suitable donor hearts, the concept of replacing the natural heart with an artificial heart as a "bridge to transplantation" has gained attention in recent years. The present paper shows technical and clinical aspects of multivariable electrophysiologic neuromonitoring in a patient with an artificial heart assist device in the intensive care unit. The data (EEG, 40 Hz brain oscillations, brainstem auditory- and somatosensory evoked potentials) are discussed with respect to the influence of the artificial heart on their quality and reliability. Reasons for artifacts and problems of interpretation are shown. 相似文献
140.