全文获取类型
收费全文 | 328篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 55篇 |
综合类 | 2篇 |
化学工业 | 65篇 |
金属工艺 | 8篇 |
机械仪表 | 9篇 |
建筑科学 | 2篇 |
矿业工程 | 2篇 |
能源动力 | 11篇 |
轻工业 | 21篇 |
水利工程 | 2篇 |
石油天然气 | 7篇 |
武器工业 | 1篇 |
无线电 | 45篇 |
一般工业技术 | 29篇 |
冶金工业 | 39篇 |
原子能技术 | 3篇 |
自动化技术 | 33篇 |
出版年
2024年 | 2篇 |
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 10篇 |
2013年 | 18篇 |
2012年 | 15篇 |
2011年 | 17篇 |
2010年 | 15篇 |
2009年 | 12篇 |
2008年 | 12篇 |
2007年 | 10篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 3篇 |
2002年 | 6篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 8篇 |
1998年 | 25篇 |
1997年 | 22篇 |
1996年 | 9篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 9篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有334条查询结果,搜索用时 15 毫秒
21.
Sasao T Itoh N Takano H Watanabe S Wei G Tsukamoto T Kuzumaki N Takimoto M 《Reproduction (Cambridge, England)》2004,128(6):709-716
We have previously identified and cloned a human gene, D40, that is preferentially expressed in testis among normal organs, while it is widely expressed in various human tumor cell lines and primary tumors derived from different organs. In this report, we have examined the expression and localization of this protein in human testis with an antibody specific to D40 protein. In Western analyses, the anti-D40 antibody recognized a major band with a molecular mass of 300 kDa and a minor band of 250 kDa. These bands were not observed in the testis lysates from patients with Sertoli-cell-only syndrome and with Kleinfelter syndrome, who lack germ cells of the testis, indicating that D40 protein is expressed in the germ cells of normal testis. Immunohistochemical studies have revealed that D40 protein is highly expressed in spermatocytes and in the pre-acrosome of round spermatids. In the acrosome, D40 protein expression is observed not inside but outside the acrosome membrane. This is consistent with the finding that the amino-acid sequence at the amino terminal of the D40 protein lacks a hydrophobic signal peptide that is required for proteins to translocate to the membrane. Expression of D40 protein is observed in the acrosome of ejaculated spermatozoa as well, although the level is low compared with that in the pre-acrosome of spermatids. These results suggest that D40 protein plays important roles in spermatogenesis, especially in the formation and maintenance of the acrosome. 相似文献
22.
Time‐resolved fluorescence properties of 9‐methylanthracene (9MAn) dispersed in film of polyvinylchloride (PVC) containing carbon black were studied under tensile loadings. The fluorescence lifetime of 9MAn decreased from 5.70 to 5.55 ns, whereas the stresses acting on the films increased from 0 to 3 MPa. The change in fluorescence lifetimes of 9MAn during the stress relaxation process showed that the fluorescence lifetimes were correlated with the stresses, not with the strains. The results suggest that 9MAn is a useful probe for monitoring stresses acting on the matrix. With the use of the fluorescence properties of 9MAn, the residual tensile stresses on the skin‐layer of PVC injection‐molded test pieces were estimated. The estimated residual stresses were about ~ 1 MPa. The residual stresses were relaxed to 0 MPa with annealing at 100°C. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2600–2603, 2002 相似文献
23.
Nano-sized gold particles were prepared in a solution containing polyethylenimine (PEI) utilizing a batch reactor. PEI acts as a reducing agent as well as a stabilizing agent of nanoparticles. The effects of initial concentration of PEI on the mean particle diameter, coefficient of variation (C.V.), growth rate, nucleation rate and the number of nuclei were studied. The particle diameter of gold decreased markedly with increasing initial concentration of PEI, from 3.3 μm to a minimum value of about 5 nm. The observed decrease of particle diameter was considered to be caused by the growth-inhibiting effect of PEI, which affects the conclusive number of nuclei. 相似文献
24.
Shigenao Maruyama Yuhei Takeuchi Shigeki Hirasawa 《Numerical Heat Transfer, Part A: Applications》2013,63(8):761-776
The radiation element method by ray emission model (REM2) has been improved by using the law of reciprocity for the specular view factor and the incomplete Cholesky conjugate gradient (ICCG) method to reduce computational time. This improved method was applied to analyze the radiative heat transfer between arbitrary three-dimensional bodies composed of specular and diffuse surfaces. The accuracy of the improved method was evaluated by comparing analytical solutions. And the method was used to calculate radiative heat transfer between machine elements and heater panels. CPU time to calculate the radiative exchange for a model composed of 3193 elements was reduced to 1/430 of that by the previous numerical method using a decomposition method. 相似文献
25.
Gold was evaporated onto a fused silica substrate, and the normalized Stokes parameters S1, S2 and S3, which represent the state of polarization of the light reflected from the sample, were determined in situ for films of average thickness less than a few monolayers with an automatic ellipsometer; the film mass m per unit substrate area was measured simultaneously with a torsion microbalance. It was found that changes linearly with m for light of wavelength λ well outside the absorption band of the film. For λ = 440 nm the sensitivity is comparable with that of a good torsion microbalance. Thus an automatic ellipsometer can conveniently be employed in the microgravimetry of submonolayer films. 相似文献
26.
Zhi Ning Chen Hirasawa K. Kwok-Wa Leung Kwai-Man Luk 《Vehicular Technology, IEEE Transactions on》1999,48(4):1029-1032
A new antenna combining the use of a ring dielectric resonator (DR) and an inverted F antenna (IFA) is proposed and investigated experimentally. In this application, the DR not only fills the role of a dielectric coating, but also serves the function of a radiator. The measurements of input impedance, return loss, and radiation pattern for both the IFA with the DR (IFA-DR) and the wire IFA (WIFA) are conducted at the S band. The measured data demonstrate that the IFA-DR operates in multiple resonance modes unlike a WIFA. Compared with the WIFA, the one proposed here incorporating a ring DR and an IFA is more attractive in having a smaller size and a larger impedance bandwidth 相似文献
27.
According to Hebb's cell assembly theory, the brain has the capability of function localization. On the other hand, it is suggested that in the brain there are three different learning paradigms: supervised, unsupervised, and reinforcement learning, which are related deeply to the three parts of brain: cerebellum, cerebral cortex, and basal ganglia, respectively. Inspired by the above knowledge of the brain in this paper we present a brainlike learning system consisting of three parts: supervised learning (SL) part, unsupervised learning (UL) part, and reinforcement learning (RL) part. The SL part is a main part learning input–output mapping; the UL part is a competitive network dividing input space into subspaces and realizes the capability of function localization by controlling firing strength of neurons in the SL part based on input patterns; the RL part is a reinforcement learning scheme, which optimizes system performance by adjusting the parameters in the UL part. Numerical simulations have been carried out and the simulation results confirm the effectiveness of the proposed brainlike learning system. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(1): 32–39, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20600 相似文献
28.
H Kataoka A Tsuda Y Tsuda A Baba H Yoshida R Hirasawa Y Tobimatsu M Nishiguchi M Semma Y Ito 《Canadian Metallurgical Quarterly》1997,20(6):714-716
We found that an antigen-specific anaphylaxis was induced by antigen challenge to the abdominal wall, ear auricle, or subcutaneous tissue in mice sensitized 9 days previously with antigen and adjuvant. The anaphylactic reaction was detected by vascular permeability at the injected site 7 minutes after challenge, which was the best time for estimation. A novel method (AW method) for induction and detection of the anaphylactic reaction in mice was established using the abdominal wall as the challenge site. This method could detect the anaphylactic response in mice 1 to 3 weeks after sensitization. The increase in vascular permeability was completely inhibited by administration of diphenhydramine. 相似文献
29.
Rong Zhang Kaoru Shimada Shingo Mabu Kotaro Hirasawa 《IEEJ Transactions on Electrical and Electronic Engineering》2014,9(4):398-406
Attribute selection is a technique to prune less relevant information and discover high‐quality knowledge. It is especially useful for the classification of a large database, because the preprocessing of data increases the possibility that predictor attributes given to the mining algorithm become more relevant to the class attribute. In this paper, a method to acquire the optimal attribute subset for the genetic network programming (GNP) based class association rule mining has been proposed, and this attribute selection process using genetic algorithm (GA) leads to a higher accuracy for classification. Class association rule mining through GNP is conducted with a small subset of data rather than the original large number of attributes; thus simple but important rules are obtained for classification while the local optimal problem is avoided. Simulation results with educational data show that the classification accuracy is largely improved from 52.73 to 74.54%, when classification is made using the optimal attribute subset. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
30.
Mikio Fukuhara Yoshiyuki Kuwano Kiyoshi Saito Taiji Hirasawa Ichiro Komura 《NDT & E International》1998,31(3):211-216
The degree of fatigue in ferritic wrought steel during cyclic bending was determined by analysis of diffracted SH ultrasonic waves with the aid of multiple regression analysis. As the degree of fatigue increases, accompanied by residual stress, the incident waves curve to the interior region with positive stress field owing to the acoustoelastic effect. As a result, the propagation time of the launched waves lengthens, leading to a modulation of the received waveform. Multiple regression analysis for the waveform modulation produces a reliable estimation, with correlation coefficient of 0.948, for the degree of fatigue. 相似文献