Author Keywords: Radiation detection; Long-lasting phosphor; Luminescence; Temperature dependence; Fade-out effect 相似文献
全文获取类型
收费全文 | 2885篇 |
免费 | 91篇 |
国内免费 | 12篇 |
专业分类
电工技术 | 195篇 |
综合类 | 5篇 |
化学工业 | 541篇 |
金属工艺 | 68篇 |
机械仪表 | 56篇 |
建筑科学 | 70篇 |
矿业工程 | 1篇 |
能源动力 | 83篇 |
轻工业 | 280篇 |
水利工程 | 16篇 |
石油天然气 | 3篇 |
无线电 | 320篇 |
一般工业技术 | 472篇 |
冶金工业 | 555篇 |
原子能技术 | 70篇 |
自动化技术 | 253篇 |
出版年
2023年 | 11篇 |
2022年 | 51篇 |
2021年 | 84篇 |
2020年 | 38篇 |
2019年 | 50篇 |
2018年 | 57篇 |
2017年 | 40篇 |
2016年 | 58篇 |
2015年 | 57篇 |
2014年 | 92篇 |
2013年 | 126篇 |
2012年 | 113篇 |
2011年 | 181篇 |
2010年 | 123篇 |
2009年 | 131篇 |
2008年 | 141篇 |
2007年 | 113篇 |
2006年 | 82篇 |
2005年 | 97篇 |
2004年 | 77篇 |
2003年 | 63篇 |
2002年 | 70篇 |
2001年 | 43篇 |
2000年 | 52篇 |
1999年 | 52篇 |
1998年 | 212篇 |
1997年 | 127篇 |
1996年 | 97篇 |
1995年 | 69篇 |
1994年 | 62篇 |
1993年 | 67篇 |
1992年 | 39篇 |
1991年 | 26篇 |
1990年 | 19篇 |
1989年 | 26篇 |
1988年 | 29篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 21篇 |
1984年 | 20篇 |
1983年 | 17篇 |
1982年 | 18篇 |
1981年 | 16篇 |
1980年 | 12篇 |
1979年 | 14篇 |
1978年 | 7篇 |
1977年 | 18篇 |
1976年 | 16篇 |
1975年 | 7篇 |
1967年 | 6篇 |
排序方式: 共有2988条查询结果,搜索用时 15 毫秒
1.
2.
The present paper includes experimental and analytical data on the fracture properties of a nickel-iron superalloy, a ferromagnetic austenite, at 4 K in magnetic fields of 0 and 6 T. The tensile, notch tensile and small punch tests are employed. A finite element analysis is also performed to convert the experimentally measured load-displacement data into useful engineering information. To interpret the results we review the available theory of the influence of magnetic field on the stress intensity factor for a crack in ferromagnetic materials. 相似文献
3.
OBJECTIVE: The aims were to validate the use of a direct reading NO electrode, to compare the effects of diverse acting drugs on altering coronary flow (CF) and NO release, and to examine the effects of altered perfusion pressure on flow-induced changes in NO concentration [NO] in the hemoglobin free effluent of guinea pig isolated hearts. METHODS: Hearts were isolated and perfused initially at a constant perfusion pressure (55 mmHg) with a modified Krebs-Ringer's solution equilibrated with 97% O2 and 3% CO2 at 37 degrees C. Heart rate, left ventricular pressure, CF, and effluent pH, pCO2, pO2, and NO generated current were monitored continuously on-line. Effluent was sampled for L-citrulline. Percent O2 extraction and O2 consumption were calculated. [NO] was quantitated with a sensitive amperometric sensor (sensitivity > or = 1 nmol/l approximately 3 pA) and a selective gas permeable membrane. RESULTS: The electrode was not sensitive to changes in solution pO2, flow, or pressure. The electrode was sensitive to pCO2 (-0.50 nmol/l/mmHg) and temperature (+24.5 nmol/l/degree C), so coronary effluent pCO2 was measured to compensate for a small decrease in pCO2 that occurred with an increase in coronary flow, and effluent temperature was rigidly controlled. Serotonin, bradykinin, and nitroprusside increased NO release along with CF, whereas nifedipine, butanedione monoxime, zaprinast, and bimakalim comparably increased CF but did not increase [NO] or NO release. Increases in CF (ml/g/min) and NO release (pmol/g/min), respectively, were 5.0 +/- 1 and 100 +/- 17 for 1 mumol/l serotonin, 7.5 +/- 1 and 148 +/- 18 for 100 nmol/l bradykinin, and 7.8 +/- 1 and 173 +/- 28 for 100 mumol/l nitroprusside. The increases in effluent NO by bradykinin were proportional to the increases in L-citrulline. Tetraethylammonium decreased CF, but did not change NO release, indomethacin changed neither CF nor NO release, and NG-nitro-L-arginine methyl ester (L-NAME) reduced CF by 2.6 +/- 1 ml/g/min and NO release by 25 +/- 8 pmol/g/min. An increase of CF of 8.0 +/- 0.3 ml/g/min, produced by increasing perfusion pressure from 25 to 90 mmHg, increased [NO] by 30 +/- 4 nmol/l; L-NAME but did not reduce the pressure-induced increase in CF, but reduced the increase in [NO] to 10 +/- 5 nmol/l. CONCLUSIONS: This study demonstrates in intact hearts real-time release of NO by several vasodilator drugs and by pressure-induced increases in flow (shear stress) and attenuation of these effects by L-NAME. 相似文献
4.
Toshihiko Hoshide Junpei Fujita 《Journal of Materials Engineering and Performance》2008,17(5):627-632
Strength of ground ceramics may be affected by residual stress as well as surface flaws induced by grinding. Strength prediction
for ground ceramics is convenient for mechanical design of ceramic components. In this article, a numerical procedure based
on fracture mechanics was proposed to estimate strength distribution of ground ceramics by considering grinding-induced residual
stress. Bending strength and residual stress of ground ceramics were measured for three grinding-conditions. By comparison
of simulated results with experimental ones, it was revealed that strength characteristics in experiments were well simulated
by using the proposed procedure. 相似文献
5.
J.H. Kaneko T. Tanaka S. Kawamura Y. Oshiki K. Tsuji M. Katagiri K. Ochiai T. Nishitani F. Fujita A. Homma T. Sawamura T. Iida M. Furusaka 《Diamond and Related Materials》2005,14(11-12):2027
Radiation detector was made of a high-quality CVD polycrystalline diamond composed of frost column like structure diamond grains, and induced charge distribution spectra and drift velocities were measured by using alpha particles. As a result, the CVD polycrystalline achieved maximum induced charge of 83% of HP/HT type IIa diamond. Moreover, the CVD crystal had lower charge loss on electrons compared with the HP/HT type IIa diamond. Drift velocities of electrons and holes were ve = 7.7 × 104 and vh = 7.3 × 104cm/s at an electric field of 20 kV/cm, respectively. In addition, response function measurement for 14 MeV neutrons was carried out. 相似文献
6.
7.
Koji Kamei Kunihiko Fujita Eva Jettmar Sen Yoshida Kazuhiro Kuwabara 《Interacting with computers》2002,14(6):438-759
In this paper, we present and discuss Community Organizer, a system designed to support network communities. The main characteristic of Community Organizer is the use of spatial representations for the relationships among community members including the communications exchanged among these members. These spatial representations reflect the degree of closeness of interests and concerns among the members, and are intended to provide users with clues on how to form network communities. In order to investigate the effectiveness of the proposed spatial representations, we conducted experiments with two different versions of the software. One version offered meaningful spatial representations while the other version did not. The subjects who used the former software version felt a greater sense of ‘community’, enjoyed using the software more, and actively used it longer than the subjects using the latter software version (control condition). These results indicated that the proposed spatial representations are effective in supporting network community formation. 相似文献
8.
9.
A floating-gate analog memory device for neural networks 总被引:1,自引:0,他引:1
A floating-gate MOSFET device that can be used as a precision analog memory for neural network LSIs is described. This device has two floating gates. One is a charge-injection gate with a Fowler-Nordheim tunnel junction, and the other is a charge-storage gate that operates as a MOSFET floating gate. The gates are connected by high resistance, and the charge-injection gate is small so that its capacitance is much less than that of the charge-storage gate. By applying control pulses to the charge-injection gate, it is possible to charge and discharge the MOSFET floating gate in order to modify the MOSFET current with high resolution over 10 b. The charge injection can be carried out without disturbing the MOSFET output current with high voltage control pulses. This device is useful for on-chip learning in analog neural network LSIs 相似文献
10.
Munehiko Kowatari Daisuke Koyama Yoshiyuki Satoh Kouichi Iinuma Shunsuke Uchida 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2002,480(2-3):431-439
The temperature dependence of luminescence from a long-lasting phosphor (LLP), SrAl2O4 : Eu2+,Dy3+, exposed to ionizing radiation has been measured to understand the LLP luminescence mechanism. Evaluation of the decay constants of the LLP exposed to -, β- or γ-rays at temperatures from 200 to 390 K showed that the decay constant is divided into four components ranging from 10−4 to 10−1 s−1 with activation energies of 0.02–0.35 eV.
Total luminous intensity from the LLP with changing irradiation temperature has its maximum value around the room temperature. Irradiation at elevated temperature (390 K) has the total luminescence pattern with monotonous decrease as temperature rises. As a result of evaluating the temperature dependence of luminescence, the luminescence mechanism is considered as follows: