首页 | 官方网站   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   440篇
  免费   20篇
  国内免费   1篇
工业技术   461篇
  2024年   1篇
  2023年   11篇
  2022年   20篇
  2021年   32篇
  2020年   24篇
  2019年   29篇
  2018年   37篇
  2017年   25篇
  2016年   25篇
  2015年   12篇
  2014年   18篇
  2013年   27篇
  2012年   28篇
  2011年   27篇
  2010年   17篇
  2009年   19篇
  2008年   12篇
  2007年   11篇
  2006年   10篇
  2005年   9篇
  2004年   1篇
  2002年   5篇
  2001年   1篇
  2000年   3篇
  1998年   8篇
  1997年   12篇
  1996年   1篇
  1995年   12篇
  1994年   4篇
  1993年   4篇
  1992年   3篇
  1990年   2篇
  1989年   6篇
  1986年   2篇
  1983年   1篇
  1979年   1篇
  1977年   1篇
排序方式: 共有461条查询结果,搜索用时 38 毫秒
91.
92.
Protection of Metals and Physical Chemistry of Surfaces - Collective oscillation of electrons in the conduction band of noble metal nanoparticles is known as localized surface plasmon resonance...  相似文献   
93.
Wireless Personal Communications - This work presents a novel frequency reconfigurable patch antenna design for Internet of Things (IoT) applications. The proposed antenna structure has hexagonal...  相似文献   
94.
Metallurgical and Materials Transactions B - EAF slag constitutes a major waste in the steel industry, which necessitates the development of processes to recover its valuable compounds and thermal...  相似文献   
95.
Exercise can improve health and well-being. With this in mind, immersive virtual reality (VR) games are being developed to promote physical activity, and are generally evaluated through user studies. However, building such applications is time consuming and expensive. This paper introduces VR-Rides, an object-oriented application framework focused on the development of experiment-oriented VR exergames. Following the modular programming pattern, this framework facilitates the integration of different hardware (such as VR devices, sensors, and physical activity devices) within immersive VR experiences that overlay game narratives on Google Street View panoramas. Combining software engineering and interaction patterns, modules of VR-Rides can be easily added and managed in the Unity game engine. We evaluate the code efficiency and development effort across our VR exergames developed using VR-Rides. The reliability, maintainability, and usability of our framework are also demonstrated via code metrics analysis and user studies. The results show that investing in a systematic approach to reusing code and design can be a worthwhile effort for researchers beyond software engineering.  相似文献   
96.
Wireless Personal Communications - In this work, we propose a new and efficient algorithm to mitigate the signal look direction error problem in adaptive beamforming without broadening the main...  相似文献   
97.
Wireless Networks - Cognitive radios and femtocell networks are gaining much popularity due to the formers ability to carry out unlicensed transmission in licensed bands and the latter’s...  相似文献   
98.
A good understanding of the factors involved in female urinary incontinence is essential for the therapeutic management of incontinent women. Urinary stress incontinence involves three variables which participate in the pressure equilibrium during effort: mobility of the urethrovesical junction, urethral resistance and the intensity of effort. The most appropriate treatment for each patient can only be selected by investigating all three of these factors and by determining their respective roles in incontinence. Urge incontinence is also multifactorial, but, very often, no cause can be found on the aetiological assessment, leading to the diagnosis of idiopathic instability. The factors of detrusor motor instability are discussed and their aetiological treatment is proposed.  相似文献   
99.
Pulsed photo-stimulated luminescence (PPSL) is a simple screening method that can be employed qualitatively at the spot for the detection of eggs treated with ionizing radiation.Due to the variations in the results during storage,the eggs of ostrich,duck,hen,and quail were irradiated to doses of 0,1,2,and 3 kGy.Most of the samples were incorrectly identified during storage after four months of irradiation.Thermoluminescence (TL) technique was also tried by using egg shells in order to confirm the irradiation treatment in eggs.TL glow curves were recorded between the temperatures 50℃to 400℃at the rate of 5°/s for all the control and irradiated samples.On the basis of integrated areas of first glow curves (TL1),the glow curve ratios (TL1/TL2) and the shapes of maxima of TL1, the irradiation treatment of all the eggs was confirmed.Furthermore,the presence of calcite and aragonite minerals that cause the TL signal in the egg shells were studied using X-ray diffraction spectrometry.  相似文献   
100.
We have studied the expression of gelatinase A, gelatinase B, interstitial collagenase, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in reactive lymphoid cells, as well as in a series of cell lines derived from neoplasms of B- and T-cell lineage. Using both Northern blot analysis and zymography, gelatinase B activity was detected by zymography in two Burkitt cell lines and in a tonsillar cell suspension, while gelatinase A and interstitial collagenase activities were not detected by either method. TIMP-1 expression was demonstrated by Northern blot analysis in the multipotential neoplastic K-562 cell line, the high grade Burkitt's B-cell lymphoma lines, isolated tonsillar B cells and at low levels in peripheral blood T cells, but was not expressed in any of the neoplastic T-cell lines or isolated peripheral blood B cells. In contrast, TIMP-2 expression was restricted to tissues containing cells of T-cell lineage with high levels being observed in the neoplastic T-cell lines and lower levels in normal peripheral blood T cells and hyperplastic tonsil. Expression of TIMP-1 and TIMP-2 was confirmed at the protein level by reverse zymography and immunofluorescence assays using antihuman TIMP polyclonal antibodies. Expression of gelatinase B by the high grade B-cell Burkitt's lymphoma cell lines is consistent with previous findings in large cell immunoblastic lymphomas and indicates that this enzyme may play an important role in high grade non-Hodgkin's lymphomas. TIMP expression correlated with cell lineage in that TIMP-1 was primarily observed in B cells and TIMP-2 was restricted to T cells.  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-23

京公网安备 11010802026262号