全文获取类型
收费全文 | 1592篇 |
免费 | 37篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 69篇 |
综合类 | 1篇 |
化学工业 | 338篇 |
金属工艺 | 53篇 |
机械仪表 | 30篇 |
建筑科学 | 28篇 |
能源动力 | 62篇 |
轻工业 | 101篇 |
水利工程 | 3篇 |
石油天然气 | 2篇 |
无线电 | 129篇 |
一般工业技术 | 307篇 |
冶金工业 | 370篇 |
原子能技术 | 43篇 |
自动化技术 | 99篇 |
出版年
2023年 | 6篇 |
2022年 | 13篇 |
2021年 | 22篇 |
2020年 | 12篇 |
2019年 | 17篇 |
2018年 | 19篇 |
2017年 | 14篇 |
2016年 | 31篇 |
2015年 | 16篇 |
2014年 | 52篇 |
2013年 | 66篇 |
2012年 | 46篇 |
2011年 | 58篇 |
2010年 | 59篇 |
2009年 | 59篇 |
2008年 | 67篇 |
2007年 | 73篇 |
2006年 | 44篇 |
2005年 | 61篇 |
2004年 | 52篇 |
2003年 | 46篇 |
2002年 | 36篇 |
2001年 | 40篇 |
2000年 | 24篇 |
1999年 | 42篇 |
1998年 | 141篇 |
1997年 | 82篇 |
1996年 | 71篇 |
1995年 | 43篇 |
1994年 | 52篇 |
1993年 | 43篇 |
1992年 | 12篇 |
1991年 | 22篇 |
1990年 | 21篇 |
1989年 | 30篇 |
1988年 | 19篇 |
1987年 | 17篇 |
1986年 | 13篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1983年 | 11篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 11篇 |
1976年 | 14篇 |
1975年 | 5篇 |
1973年 | 3篇 |
排序方式: 共有1635条查询结果,搜索用时 15 毫秒
161.
A Ohshima I Miura K Hashimoto N Takahashi S Utsumi T Nimura M Saito T Miki S Hirosawa AB Miura 《Canadian Metallurgical Quarterly》1997,27(3-4):329-334
Chromosome aberrations affecting 3q27 are among the most frequent non-random abnormalities in non-Hodgkin's lymphomas (NHL), especially the diffuse, large cell type. Recently, an association between BCL6 rearrangement and frequent extranodal lesions, rare bone marrow infiltration and a favorable clinical outcome was reported. We performed molecular studies of the BCL6 gene in 54 patients with NHL. Twelve patients (22%) with rearranged BCL6 genes were selected for histological, clinical, molecular, and cytogenetic studies. Ten of these cases were diffuse, large cell type lymphoma, one a follicular lymphoma, and one a mantle cell lymphoma (MCL). All cases were of the B-cell type and this is the first time a rearranged BCL6 gene has been found in an MCL. Cytogenetic data for 10 cases were available and the partner sites of the 3q27 translocation were determined in 7 of 10 patients. These locations were variable, including 6p21.3, 9p22, and 14q11 in addition to the immunoglobulin loci 14q32 (IGH), 2p12 (IGK), and 22q11 (IGL). The heterogeneity in partner sites is distinct from other lymphoma subgroups and may suggest that the genetic events are not uniform among patients with BCL6 rearrangements. 相似文献
162.
Nawalage F. Cooray Katsumi Kushiya Atsushi Fujimaki Ichiro Sugiyama Tadayuki Miura Daisuke Okumura Masao Sato Mineo Ooshita Osamu Yamase 《Solar Energy Materials & Solar Cells》1997,49(1-4)
In this study, two deposition methods (i.e. MOCVD and sputtering methods) to prepare n-type ZnO window layers for CIGS-based thin-film solar cells are discussed. In order to make ZnO : Al transparent conductive oxide (TCO) films prepared by DC magnetron sputtering comparable to ZnO : B TCO prepared by MOCVD, a new ZnO sputtering process is proposed by introducing a multilayer structure. Using these films, CIGS thin-film solar cells with efficiencies of greater than 14% have been fabricated with an active area of 3.2 cm2. This structure was adapted to fabricate CIGS thin-film mini-modules with efficiencies around 11% having aperture area of 50 cm2. 相似文献
163.
164.
Mostafa M. Fouda Hiroki Nishiyama Ryu Miura Nei Kato 《Wireless Personal Communications》2014,74(4):1311-1327
In recent time, a great deal of research effort has been directed toward promptly facilitating post-disaster communication by using wireless mesh networks (WMNs). WMN technology has been considered to be effectively exploited for this purpose as it provides multi-hop communication through an access network comprising wireless mesh routers, which are connected to the Internet through gateways (GWs). One of the critical challenges in using WMNs for establishing disaster-recovery networks is the issue of distributing traffic among the users in a balanced manner in order to avoid congestion at the GWs. To overcome this issue, we envision a disaster zone WMN comprising a network management center. First, we thoroughly investigate the problem of traffic load balancing amongst the GWs in our considered disaster zone WMN. Then, we develop traffic load distribution techniques from two perspectives. Our proposal from the first perspective hinges upon a balanced distribution of the bandwidth to be allocated per user. On the other hand, our second perspective considers the dynamic (i.e., varying) bandwidth demands from the disaster zone users that requires a more practical and refined distribution of the available bandwidth by following an intelligent forecasting method. The effectiveness of our proposals is evaluated through computer-based simulations. 相似文献
165.
166.
A number of redox systems composed of carbon and bivalent metal-ferrites, MFe2O4(M = bivalent metal ions), were studied to find the most reactive and selective working materials for a thermochemical water-decomposition cycle combined with CO production from a carbon compound. Magnetite and Mg(II)-, Mn(II)-, Co(II)-, Ni(II)-, and Zn(II)-ferrites mixed with carbon powder have been screened for reactivity and selectivity in the CO-production step (first step) and subsequent water-decomposition step (second step). The Ni(II)-ferrite showed the most reactivity and selectivity for CO formation from carbon in the first step at temperatures above 700°C. The Ni(II)-ferrite could be completely reduced with carbon to the metallic phase of the Ni---Fe alloy and Ni in the first step although only a small portion of magnetite was reduced to wustite under similar conditions. The ferrites reduced in the first step were oxidized with water vapor to generate H2 in the second step. The highest conversion of H2O to H2 was obtained using the Ni(II)-ferrite. The total amount of evolved H2 using Ni(II)-ferrite was 10 times larger than for the magnetite at 500°C. The processes could be repeated using the phase transition between Ni(II)-ferrite and Ni---Fe alloy in the temperature range 700–800°C, with the highly efficient net reaction H2O + C → H2 + CO. 相似文献
167.
Thick-film 20 mol% ZnO-doped RuO2 sensing electrodes (SEs) were fabricated by screen-printing technique on the platinised alumina substrate of the planar electrochemical dissolved oxygen (DO) sensor. The effect of ZnO doping on morphology, electrochemical properties and sensing characteristics of the sensor was investigated. It was found that ZnO doping has not only improved the SE structure, but has also enhanced selectivity of the DO sensor. Selectivity testing exhibited that the presence of Cl−, Li+, SO42−, NO3−, Ca2+, PO43−, Mg2+, Na+ and K+ with a concentration range of 10−7 to 10−1 mol/L in the solution had practically no effect on the sensor's emf. The reason in enhancement of the sensor characteristics could be related to the establishment of the better structured SE as more advanced crystallization is achieved for the doped RuO2-SE. 相似文献
168.
Mitsuru Uesaka Takuya NatsuiKiwoo Lee Katsuhiro DobashiTomohiko Yamamoto Takeshi FujiwaraHaito Zhu Kazuyuki DemachiEiji Tanabe Masashi YamamotoNaoki Nakamura Joichi KusanoToshiyasu Higo Shigeki FukudaMitsuhiro Yoshida Shuji Matsumoto 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2011,657(1):82-87
We are developing compact X-band linac X-ray sources for nondestructive evaluation and medicine. First, we develop a portable X-ray system by a 950 keV 9.4 GHz X-band linac to realize on-site inspection. We use a low power (250 kW) magnetron as an RF source for compactness of the whole system. Since the RF power source is quite small and the stored energy in the structure is also small, we faced the problem of beam loading and current/RF-power oscillation. We are analyzing the problem by the circuit model. We plan to use this system for erosion inspection of metal pipes of petrochemical complex. By adopting a side-coupling cavity design to avoid the oscillation, we have developed 6 MeV X-band (9.3 GHz) linac for pinpoint dynamic tracking cancer therapy. Furthermore, we are manufacturing 3.95 MeV X-band (9.3 GHz) linac X-ray source with flexible waveguides for on-site bridge inspection. Updated results and situations are presented. 相似文献
169.
Mashimo T Toyama S 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(4):844-848
Cubic design of a stator in a rotary-linear piezoelectric actuator is sophisticated and interesting, but the vibration theory of the cubic stator remains unclear when using the finite element method (FEM). In this paper, we analyze the vibration behavior of the cubic stator by applying the energy method, which distinguishes the component of mechanical energy. By changing the design of the stator (especially the length in the direction of the through-hole axis), we clarify how the vibration modes are in accordance at one equal frequency in cubic shape. The behavior of the vibration modes is discussed using conventional vibration theory of a beam and a plate. 相似文献
170.
Indre Jasineviciute Md Nazmul Hasan Juozas Grigas Arnoldas Pautienius Arunas Stankevicius Judita Zymantiene Naoki Miura 《International journal of molecular sciences》2023,24(1)
Various microRNAs (miRNAs) present in autologous blood products of canines have not been studied recently. We aimed to elucidate the existence of miRNAs in platelet-rich fibrin (PRF) and the stability of canine autologous blood products under various storage conditions. Total RNAs were isolated from PRF and other autologous blood products following newly adapted protocols used in commercial kits for plasma and tissue samples. Quantitative real-time polymerase chain reaction analysis (qPCR) was used to detect miRNAs in autologous blood products. The miR-16, miR-21, miR-155, and miR-146a were abundant in PRF and other autologous blood products of canines. Furthermore, we found they could maintain stability under protracted freezing temperatures of −30 °C for at least one month. Our findings revealed that PRF might be a stable resource for various canine miRNAs. 相似文献