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   433篇
  免费   31篇
  国内免费   4篇
化学   255篇
晶体学   8篇
力学   15篇
数学   82篇
物理学   108篇
  2024年   2篇
  2023年   8篇
  2022年   40篇
  2021年   29篇
  2020年   17篇
  2019年   13篇
  2018年   21篇
  2017年   27篇
  2016年   29篇
  2015年   19篇
  2014年   13篇
  2013年   31篇
  2012年   36篇
  2011年   31篇
  2010年   14篇
  2009年   19篇
  2008年   18篇
  2007年   9篇
  2006年   8篇
  2005年   5篇
  2004年   4篇
  2003年   6篇
  2002年   5篇
  2001年   8篇
  2000年   3篇
  1999年   1篇
  1998年   4篇
  1997年   4篇
  1996年   2篇
  1995年   4篇
  1994年   2篇
  1992年   3篇
  1991年   4篇
  1990年   2篇
  1989年   4篇
  1988年   2篇
  1987年   3篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1983年   3篇
  1980年   1篇
  1979年   1篇
  1977年   2篇
  1976年   1篇
  1972年   1篇
  1957年   1篇
  1956年   2篇
  1955年   1篇
排序方式: 共有468条查询结果,搜索用时 15 毫秒
91.
Bacterial infection poses life-threatening challenge to humanity and stimulates to the researchers for developing better diagnostic and therapeutic agents complying with existing theranostic techniques. Nuclear medicine technique helps to visualize hard-to-diagnose deep-seated bacterial infections using radionuclide-labeled tracer agents. Metronidazole is an antiprotozoal antibiotic that serves as a preeminent anaerobic chemotherapeutic agent. The aim of this study was to develop technetium-99m-labeled metronidazole radiotracer for the detection of deep-seated bacterial infections. Radiosynthesis of 99mTc-metronidazole was carried by reacting reduced technetium-99m and metronidazole at neutral pH for 30 min. The stannous chloride dihydrate was used as the reducing agent. At optimum radiolabeling conditions, ~ 94% radiochemical was obtained. Quality control analysis was carried out with a chromatographic paper and instant thin-layer chromatographic analysis. The biodistribution study of radiochemical was performed using Escherichia coli bacterial infection-induced rat model. The scintigraphic study was performed using E. coli bacterial infection-induced rabbit model. The results showed promising accumulation at the site of infection and its rapid clearance from the body. The tracer showed target-to-non-target ratio 5.57 ± 0.04 at 1 h post-injection. The results showed that 99mTc-MNZ has promising potential to accumulate at E. coli bacterial infection that can be used for E. coli infection imaging.  相似文献   
92.
The accurate calibration of powder diffraction data acquired from area detectors using calibration standards is a crucial step in the data reduction process to attain high‐quality one‐dimensional patterns. A novel algorithm has been developed for extracting Debye–Scherrer rings automatically using an approach based on computer vision and pattern recognition techniques. The presented technique requires no human intervention and, unlike previous approaches, makes no restrictive assumptions on the diffraction setup and/or rings. It can detect complete rings as well as portions of them, and works on several types of diffraction images with various degrees of ring graininess, textured diffraction patterns and detector tilt with respect to the incoming beam.  相似文献   
93.
Huang  Xinan  Jiang  Hong  Li  Yongxin  Sang  Lijia  Zhou  Huipeng  Shahzad  Sohail Anjum  Ibupoto  Zafar Hussain  Yu  Cong 《Mikrochimica acta》2017,184(7):2325-2331
Microchimica Acta - A sensitive and selective luminescent nanoprobe (referred to as DEPN) is designed for the determination of Cu(II) ions. DEPN shows two emission peaks, one at 602 nm and...  相似文献   
94.
Ion population fraction(IPF) calculations are very important to understand the radiative spectrum emitted from the hot dense matter. IPF calculations require detailed knowledge of all the ions and correlation interactions between the electrons of an ion which are present in a plasma environment. The average atom models, e.g., screened hydrogenic model with l-splitting(SHML), now have the capabilities for such calculations and are becoming more popular for in line plasma calculations. In our previous work [Ali A, Shabbir Naz G, Shahzad M S, Kouser R, Rehman A and Nasim M H 2018 High Energy Density Phys. 26 48], we have improved the continuum lowering model and included the exchange and correlation effects in SHML. This study presents the calculation of IPF using classical theory of fluctuation for our improved screened hydrogenic model with l-splitting(I-SHML) under local thermodynamic equilibrium conditions for iron and aluminum plasma over a wide range of densities and temperatures. We have compared our results with other models and have found a very good agreement among them.  相似文献   
95.
Journal of Thermal Analysis and Calorimetry - The phase equilibria in the ternary Tl–Se–I system have been investigated by means of differential thermal analysis, X-ray powder...  相似文献   
96.
Research on Chemical Intermediates - In this study, the complex combinations of Ru(II), Co(II) and Ni(II) with Schiff base obtained through the condensation of (E)-methyl...  相似文献   
97.
98.
99.
Gaussian quantum steering is a type of quantum correlation in which two entangled states exhibit asymmetry. An efficient theoretical proposal is presented for the control of quantum steering and enhancement of entanglement in a Laguerre–Gaussian (LG) cavity optomechanical system. The system contains two rotating mirrors and a coherently driven optical parametric amplifier (OPA). The numerical results show significantly improved mirror-mirror and mirror-cavity entanglements by controlling the system parameters such as parametric gain, parametric phase, and the frequency of the two rotating mirrors. In addition to bipartite entanglement, our system also exhibits mirror-cavity-mirror tripartite entanglement as well. Another intriguing finding is the control of quantum steering, for which several results were obtained by investigating it for various system parameters. It is shown that the steering directivity is primarily determined by the frequency of two rotating mirrors. Furthermore, for two rotating mirrors, quantum steering is found to be asymmetric both one-way and two-way. Therefore, it can be asserted that the current proposal may help in the understanding of non-local correlations and entanglement verification tasks.  相似文献   
100.
Kuhn-Tucker points play a fundamental role in the analysis and the numerical solution of monotone inclusion problems, providing in particular both primal and dual solutions. We propose a class of strongly convergent algorithms for constructing the best approximation to a reference point from the set of Kuhn-Tucker points of a general Hilbertian composite monotone inclusion problem. Applications to systems of coupled monotone inclusions are presented. Our framework does not impose additional assumptions on the operators present in the formulation, and it does not require knowledge of the norm of the linear operators involved in the compositions or the inversion of linear operators.  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