全文获取类型
收费全文 | 1584篇 |
免费 | 29篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 84篇 |
综合类 | 2篇 |
化学工业 | 444篇 |
金属工艺 | 46篇 |
机械仪表 | 39篇 |
建筑科学 | 21篇 |
能源动力 | 113篇 |
轻工业 | 133篇 |
水利工程 | 10篇 |
石油天然气 | 1篇 |
无线电 | 140篇 |
一般工业技术 | 284篇 |
冶金工业 | 93篇 |
原子能技术 | 48篇 |
自动化技术 | 158篇 |
出版年
2023年 | 7篇 |
2022年 | 17篇 |
2021年 | 21篇 |
2020年 | 13篇 |
2019年 | 25篇 |
2018年 | 17篇 |
2017年 | 15篇 |
2016年 | 29篇 |
2015年 | 18篇 |
2014年 | 51篇 |
2013年 | 108篇 |
2012年 | 87篇 |
2011年 | 87篇 |
2010年 | 74篇 |
2009年 | 96篇 |
2008年 | 87篇 |
2007年 | 70篇 |
2006年 | 55篇 |
2005年 | 55篇 |
2004年 | 41篇 |
2003年 | 51篇 |
2002年 | 50篇 |
2001年 | 26篇 |
2000年 | 34篇 |
1999年 | 42篇 |
1998年 | 52篇 |
1997年 | 31篇 |
1996年 | 36篇 |
1995年 | 23篇 |
1994年 | 19篇 |
1993年 | 31篇 |
1992年 | 25篇 |
1991年 | 16篇 |
1990年 | 16篇 |
1989年 | 17篇 |
1988年 | 15篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 15篇 |
1984年 | 13篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1981年 | 14篇 |
1980年 | 17篇 |
1979年 | 12篇 |
1978年 | 11篇 |
1977年 | 11篇 |
1976年 | 11篇 |
1968年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有1616条查询结果,搜索用时 15 毫秒
111.
Kazunori Kageyama Yasumasa Iwasaki Yutaka Watanuki Kanako Niioka Makoto Daimon 《International journal of molecular sciences》2021,22(11)
The hypothalamic-pituitary-adrenal axis is stimulated in response to stress. When activated, it is suppressed by the negative feedback effect of glucocorticoids. Glucocorticoids directly inhibit proopiomelanocortin (Pomc) gene expression in the pituitary. Glucocorticoid signaling is mediated via glucocorticoid receptors, 11β-hydroxysteroid dehydrogenases, and the FK506-binding immunophilins, Fkbp4 and Fkbp5. Fkbp4 and Fkbp5 differentially regulate dynein interaction and nuclear translocation of the glucocorticoid receptor, resulting in modulation of the glucocorticoid action. Here, we explored the regulation of Fkbp4 and Fkbp5 genes and their proteins with dexamethasone, a major synthetic glucocorticoid drug, in murine AtT-20 corticotroph cells. To elucidate further roles of Fkbp4 and Fkbp5, we examined their effects on Pomc mRNA levels in corticotroph cells. Dexamethasone decreased Pomc mRNA levels as well as Fkpb4 mRNA levels in mouse corticotroph cells. Dexamethasone tended to decrease Fkbp4 protein levels, while it increased Fkpb5 mRNA and its protein levels. The dexamethasone-induced decreases in Pomc mRNA levels were partially canceled by Fkbp4 knockdown. Alternatively, Pomc mRNA levels were further decreased by Fkbp5 knockdown. Thus, Fkbp4 contributes to the negative feedback of glucocorticoids, and Fkbp5 reduces the efficiency of the glucocorticoid effect on Pomc gene expression in pituitary corticotroph cells. 相似文献
112.
Kazuaki Sasaki Michiya Kishida Yutaka Ekida 《International journal for numerical methods in engineering》2002,54(5):671-683
In this paper, a finite element dislocation model is proposed, based on well‐known mathematical dislocation model. As application examples, the stress distributions around an edge dislocation in infinite homogeneous and inhomogeneous regions are calculated and compared with the analytical results. The FEM results coincide well with the exact solutions. The results show an applicability and a usefulness of finite element dislocation model, and further, a possibility of analysing a dislocation problem in finite region with complicated shapes and boundary conditions. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
113.
Jun-ichi Nishizawa Takenori Tanno Takahiro Oohashi Hiraku Watanabe Yutaka Oyama 《Synthetic Metals》2008
The solid-state synthesis of a tetrathiafulvalene–chloranil (TTF–CA) complex was demonstrated, and progress in the formation of the complex was monitored using a GaP Raman terahertz (THz) spectrometer. Clear transitions in the THz absorption spectra indicated that the mixture of TTF and CA became the black phase TTF–CA complex. The results of X-ray diffraction, Raman scattering, and FTIR spectra are presented as supporting evidence. 相似文献
114.
Shuqi Guo 《材料科学与工程学报》2000,18(z1):321-326
This study consists of following two sections: (i) interface microstructure observation and (ii) interface degradationevaluation during fatigue. The microstructure of the interfacial reaction layer in SiC(SCS-6) fiberreinforced Ti-15-3 alloy matrix composite has been studied using transmission electron microscopy. 相似文献
115.
The dynamics of magnetic reversal process plays an important role in the design of the magnetic recording devices in the long time scale limit. In addition to long time scale, microscopic effects such as the entropic effect become important in magnetic nano-scale systems. Many advanced simulation methods have been developed, but few have the ability to simulate the long time scale limit and to accurately model the microscopic effects of nano-scale systems at the same time. We develop a new Monte Carlo method for calculating the dynamics of magnetic reversal at arbitrary long time. For example, actual calculations were performed up to 1050 Monte Carlo steps. This method is based on microscopic interactions of many constituents and the master equation for magnetic probability distribution function is solved symbolically. 相似文献
116.
Hiroshi Kihira Takehide Senuma Kiyoshi Nishioka Yutaka Sakata 《Corrosion Science》2005,47(10):2377-2390
Japanese Specification for Highway Bridges [Japan Road Association: Specification for Highway Bridges—I & II, 2002.3] has been revised in 2002, which clearly states that degradation of bridge members, including those of weathering steels, to occur in prolonged period of time must be taken into account at the design stage to realize long term structural durability. To cope with the revised paradigm, SABI chemistry committee in Japan Society of Corrosion Engineers has proposed durable state concept [SABI Chemistry Committee of Japan Society of Corrosion Engineers, in: Proc. 132nd Symposium for Corrosion and Protection, 2001.6.25, p. 3], which is defined as a condition in which corrosion rate of steel is slow enough not to form thick rust [H. Kihira, K. Shiotani, H. Miyuki, T. Nakayama, M. Takemura, Y. Watanabe, Doboku Gakkai Ronbun-shu (J. Japan Soc. Civil Engineers) No. 745/I-65, 2003.10, pp.77-87]. Since corrosiveness of atmosphere differs by location, a corrosion prediction method for both conventional and advanced weathering steels [H. Kihira, A. Usami, K. Tanabe, M. Ito, G. Shigesato, Y. Tomita, T. Kusunoki, T. Tsuzuki, S. Ito, T. Murata, in: Electrochemical Society Proceedings, vol. 99-26, 2000, pp. 127-136] is needed to ensure structural durability for future. Thus, versatile computational scheme for it has been derived through mathematical modeling based upon the durable state concept. 相似文献
117.
Yutaka Tokuda Youichi Nagae Hitoshi Sakane Jyoji Ito 《Journal of Electronic Materials》2010,39(6):719-722
Defect production behavior in hydrogen-implanted n-type silicon has been studied by varying the implantation temperature from 88 K to 303 K. Deep-level transient spectroscopy
has been used to reveal electron trap spectra for Schottky diodes fabricated at room temperature after implantation. Metastable
defects are observed in addition to vacancy- and hydrogen-related defects. It is found that the production rates of these
defects are greatly enhanced by hydrogen implantation near 270 K. It is suggested that hydrogen plays an important role in
enhancement of defect production rates, since such defect production behavior is not observed in He-implanted samples. 相似文献
118.
119.
Numata M Nakamura N Koshikawa H Terashima Y 《Environmental science & technology》2002,36(20):4389-4394
Chlorine isotope fractionation during reductive dechlorination of trichloroethene (TCE) and tetrachloroethene (PCE) to cis-1,2-dichloroethene (cDCE) by anaerobic bacteria was investigated. The changes in the 37Cl/35Cl ratio observed during the one-step reaction (TCE to cDCE) can be explained by the regioselective elimination of chlorine accompanied by the Rayleigh fractionation. The fractionation factors (alpha) of the TCE dechlorination by three kinds of anaerobic cultures were approximately 0.994-0.995 at 30 degrees C. The enrichment of 37Cl in the organic chlorine during the two-step reaction (PCE to cDCE) can be explained by the random elimination of one chlorine atom in the PCE molecule followed by the regioselective elimination of one chlorine atom in the TCE molecule. The fractionation factors for the first step of the PCE dechlorination with three kinds of anaerobic cultures were estimated to be 0.987-0.991 at 30 degrees C using a mathematical model. Isotope fractionation during the first step would be the primary factor for the chlorine isotope fractionation during the PCE dechorination to cDCE. The developed models can be utilized to evaluate the fractionation factors of regioselective and multistep reactions. 相似文献
120.
Takeda K Ishiguro Y Tanaka R Maruyama J Kasamatsu T Okawa S Hori S 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2002,43(5):280-288
Ion-trap GC/MS/MS was evaluated for the multi-residue determination of pesticides in agricultural products. Matrices were extracted from samples (spinach, carrot, onion and brown rice) with acetone and submitted to gel permeation chromatography, followed by a clean-up step through a graphite carbon cartridge. Thirty-five pesticides were added to either matrix, and analyzed by GC/MS/MS. Detection limits of pesticides by GC/MS/MS was almost the same as those by GC/MS (SIM). Coefficients of variation of peak area in 5 measurements of each pesticide at 0.1 microgram/mL or 0.05 microgram/mL with or without matrices were mostly acceptable, though those of 20 pesticides out of 35 were higher than 10% at a concentration of 0.02 microgram/mL. It was indicated that matrix artifacts, which interfere with GC/MS-Scan analysis, could be eliminated in some cases by using GC/MS/MS. 相似文献