首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   248篇
  免费   2篇
  国内免费   1篇
电工技术   12篇
化学工业   67篇
金属工艺   8篇
机械仪表   3篇
建筑科学   10篇
能源动力   6篇
轻工业   29篇
石油天然气   1篇
无线电   28篇
一般工业技术   25篇
冶金工业   29篇
原子能技术   1篇
自动化技术   32篇
  2023年   4篇
  2022年   3篇
  2021年   7篇
  2020年   1篇
  2019年   3篇
  2018年   5篇
  2017年   3篇
  2016年   3篇
  2015年   4篇
  2014年   4篇
  2013年   15篇
  2012年   6篇
  2011年   14篇
  2010年   7篇
  2009年   6篇
  2008年   16篇
  2007年   12篇
  2006年   8篇
  2005年   5篇
  2004年   4篇
  2003年   10篇
  2002年   4篇
  2001年   3篇
  2000年   6篇
  1999年   8篇
  1998年   14篇
  1997年   10篇
  1996年   3篇
  1995年   6篇
  1994年   7篇
  1993年   5篇
  1992年   8篇
  1991年   4篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1985年   3篇
  1984年   3篇
  1983年   3篇
  1982年   2篇
  1981年   1篇
  1980年   4篇
  1979年   4篇
  1978年   2篇
  1977年   1篇
  1976年   3篇
排序方式: 共有251条查询结果,搜索用时 15 毫秒
121.
When a cation exchange membrane having carboxyl groups, made of poly(isobutylene-alternative co-maleic anhydride) and poly(vinyl alcohol), was set in a diaphragm type cell, in which one side of the solution was adjusted to be acidic and the other side alkaline, metal ions were actively transported from the alkaline side to the acidic side across the membrane against the concentration gradient of metal ions between both sides. The driving force of the transport of metal ions was the difference in H+ ion concentration between both sides. It was presumed that the active transport was carried out chemically and physically. In the selective transport of metal ions, the selectivity was dependent on both the hydrated ionic radius for the metal ions and the affinity between the carrier fixed to the membrane, the carboxyl group, and the metal ions.  相似文献   
122.
123.
空间的力量     
编者按:原文最初以日、英双语形式刊登在日本《A+U》2011年第7期P6-11,现经作者本人同意、《A+U》  相似文献   
124.
An energy transport simulation method for graded AlGaAs/GaAs heterojunction bipolar transistors (HBTs) is presented in which Al composition-, doping density-, and energy-dependences of transport parameters are considered. For several representative Al composition and doping densities, parameters such as electron mobility, energy relaxation time, and upper-valley fraction are evaluated as a function of electron energy by a Monte Carlo method. For the other Al composition, these are determined by a linear interpolation method. Calculated cutoff frequency characteristics and electron velocity profiles are compared with those obtained by using more simplified approaches, demonstrating the importance of giving adequate transport parameters, particularly in analyzing graded band-gap base HBTs  相似文献   
125.
Template image matching is a method for seeking a target image area that is similar to a registered template image. However, template matching is a general‐purpose technique for various image applications, and the image under consideration must generally have the right position with respect to the template image. Therefore, the computational cost is large when both the location and inclination of the target image area are unknown. This paper proposes a method of searching for a target image area with arbitrary location and inclination by multiple matching using separated block template images. In the method, the template image is divided into small block areas with a size of 3 × 3 pixels. The image pattern in each block is rotated by 45° and matching is performed between the rotated blocks and the image under consideration. The experimental results show that the proposed method has higher matching reliability than the conventional methods. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(1): 66–73, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20107  相似文献   
126.
Mercuric-chloride (HgCl2) induces a lymphoproliferative disorder and autoimmune glomerulonephritis in Brown Norway rats. The effects of a new immunosuppressant FK 506 on this model of glomerulonephritis were studied. Brown Norway rats were treated with HgCl2 according to a standard protocol (HgCl2 1 mg/kg s.c. 3 times/ week). Rats developed proteinuria at day 7, which reached a plateau level at day 14. On day 14, renal histology showed prominent mesangial cellular proliferation and the expansion of mesangial matrix. Electron microscopic study showed the effacement of visceral epithelial foot processes and the microvillous transformation of the visceral epithelium. Immunofluorescence study showed a strong linear staining for IgG and the adhesion molecule ICAM-1 in all glomeruli. Coadministration of FK 506 (1 mg/kg s.c. daily) prevented the appearance of proteinuria at day 14 (621.4 +/- 30.5 vs. 2.2 +/- 2.7 mg/day) and the morphological lesions. These findings suggest that FK 506 could be useful for the therapy of certain types of human glomerulonephritis.  相似文献   
127.
In order to improve the mass efficiency of an automotive soundproof package, it is important to predict the middle to high frequency range of noise and vibration during vehicle operation. A hybrid method of experimental and analytical SEA (statistical energy analysis) has been applied for the prediction of air-borne noise. However, for predicting structure-borne noise, there are no definitive simulation methods that can address the soundproof specifications in an actual vehicle. Thus, in this paper, a FEM (finite element method)'SEA hybrid method is used. The FEM'SEA hybrid method predicts structure-borne noise in the middle to high frequency range. First, we explain the basic concept of the FEM'SEA hybrid method; Second, we describe our experiment to verify the analytical results of the FEM'SEA hybrid method; Third, we provide the details of the FEM model versus the FEM'SEA hybrid model; Finally, we verify the validity and availability of the FEM'SEA hybrid method through comparisons of the FEM analysis results, FEM-SEA analysis results and measured results.  相似文献   
128.
We previously designed a Carbopol gel formulation (N-IND/MEN) based on a combination of indomethacin solid nanoparticles (IND-NPs) and l-menthol, and we reported that the N-IND/MEN showed high transdermal penetration. However, the detailed mechanism for transdermal penetration of IND-NPs was not clearly defined. In this study, we investigated whether endocytosis in the skin tissue of rat and Göttingen minipig is related to the transdermal penetration of IND-NPs using pharmacological inhibitors of endocytosis. The pharmacological inhibitors used in this study are as follows: 54 µM nystatin, a caveolae-mediated endocytosis (CavME) inhibitor; 40 µM dynasore, a clathrin-mediated endocytosis (CME) inhibitor; and 2 µM rottlerin, a micropinocytosis (MP) inhibitor. The N-IND/MEN was prepared by a bead mill method, and the particle size of solid indomethacin was 79–216 nm. In both rat and Göttingen minipig skin, skin penetration of approximately 80% IND-NPs was limited by the stratum corneum (SC), although the penetration of SC was improved by the combination of l-menthol. On the other hand, the treatment of nystatin and dynasore decreased the transdermal penetration of indomethacin in rats and Göttingen minipigs treated with N-IND/MEN. Moreover, in addition to nystatin and dynasore, rottlerin attenuated the transdermal penetration of IND-NPs in the Göttingen minipigs’ skin. In conclusion, we found that l-menthol enhanced the SC penetration of IND-NPs. In addition, this study suggests that the SC-passed IND-NPs are absorbed into the skin tissue by energy-dependent endocytosis (CavME, CME, and/or MP pathways) on the epidermis under the SC, resulting in an enhancement in transdermal penetration of IND-NPs. These findings provide significant information for the design of nanomedicines in transdermal formulations.  相似文献   
129.
高温合金叶片定向凝固过程中辐射换热的计算   总被引:2,自引:0,他引:2  
提出改进型Monte Carlo射线追踪法进行辐射换热计算,通过子空间的划分,并结合定向凝固的特点回避了传统辐射换热计算中角系数的直接计算,节省了计算时间.把该方法嵌入自行开发的三维模拟软件对柱状晶和单晶叶片的定向凝固过程进行了温度场模拟,并对实际叶片凝固过程进行温度场测试,模拟结果与实测结果较好吻合.  相似文献   
130.
In 5 cases, an infectious giant bulla was opened with the use of video-assisted thoracoscopic surgery (VATS). Because all bullae adhered to the thoracic wall and were noncommunicating with the airway, they were opened without complete resection, leaving their inside walls at the lung and lateral walls on the thoracic wall. The expansion of remnant lung was excellent, and postoperative air leakage did not occur in any case. The postoperative vital capacity and FEV1 improved significantly over the preoperative condition (p<0.01). Because the bronchial communication of bulla is frequently obliterated after infection within the bulla, opening of a bulla is curative and simpler, more effective, and less invasive than complete resection.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号