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   72篇
  免费   2篇
化学   17篇
晶体学   4篇
力学   24篇
数学   11篇
物理学   18篇
  2022年   1篇
  2020年   1篇
  2019年   1篇
  2018年   1篇
  2016年   1篇
  2015年   2篇
  2014年   2篇
  2012年   1篇
  2011年   1篇
  2009年   3篇
  2008年   7篇
  2007年   3篇
  2006年   4篇
  2005年   4篇
  2004年   3篇
  2003年   2篇
  2002年   5篇
  2001年   2篇
  2000年   3篇
  1999年   2篇
  1998年   1篇
  1996年   2篇
  1995年   2篇
  1994年   2篇
  1993年   1篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1986年   2篇
  1985年   2篇
  1984年   1篇
  1983年   2篇
  1982年   1篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1972年   1篇
  1967年   1篇
排序方式: 共有74条查询结果,搜索用时 15 毫秒
41.
We show that strong light with the frequency slightly less then the ‘gap’ in electron spectrum of fused quartz cuts off macroscopic balls with fixed diameter 2 ± 0.2 μm and throws them out of the ablation crater. The reason for the phenomenon is the light driven electron bunching and generation of strong static electric field on the bunch boundaries resulting in effective photon absorption and bonds breaking in these regions while the main part of a sample is almost transparent for the photons.  相似文献   
42.
The behavior of clusters formed by magnetic particles of magnetic liquid placed into a cylindrical capillary tube in magnetic field is described. Spicular clusters are formed from the sediment at the application of a magnetic field. They arrange themselves along the capillary repeating the direction of external magnetic field. Clusters distribute uniformly in the region of a magnetic field maximum. Such a state remains steady with respect to changes of the magnetic field gradient profile in definite limits. The structure of the uniformly ordered clusters is obtained experimentally. The capability of control of the structure period is shown. It is observed that increasing of magnetic field gradient up to the magnitude higher than a certain threshold value results in rearrangement of the clusters row into a multi-row hexagonal structure.  相似文献   
43.
The choice of the coefficients of sliding friction in the static equilibrium problem for a system of three solids with friction at two points is discussed. This system simulates the mechanism of gravitational seismic isolation of a solid. It is shown that the coefficients of friction must be identical at both points of frictional contact irrespective of the type of the material and surface finish. A formula for the balanced coefficient of friction is derived based on experimental data  相似文献   
44.
Solid state nuclear track detectors (SSNTD) find wide application in registration of different types of ionization irradiation due to excellent features: low cost, compactness, passivity and possibility of long term exposure for low activity measurements. One of the most shortcomings is in complex processing of the detector surface and following image analysis. However, present methods which allow reconstruction of track ranges and particle energies are intensively being developed. A developing trend in SSNTD alpha-spectrometry uses automated scanning microscope systems and specially designed mathematical software. Several parameters obtained from the analysis of etched tracks indi information about alpha-particle ranges in detector. The possibility to use some parameters (minor axis m and track end diameter d) for the spectrometry has been reported earlier. Intercomparison of SSNTD with semiconductor detectors (SCD) for 238,239Pu content in bioassay within the interval 10-3 to 1 Bq has been carried out. This comparison has demonstrated a good coincidence between these independent radiometric methods. A perspective of SSNTD use for spectrometric determination of low level activity is discussed. The background level playing a main role in low level detection has been also estimated. Influence of radon and thoron has been found as insignificant.  相似文献   
45.
A mathematical model of a diesel with swashplates is proposed. The results of studying its design, kinematics, and dynamics are presented. The kinematic chain of the statically determinate mechanism of the engine is schematized. The kinematic relations are obtained taking into account the presence of Hooke’s joints and swashplates. A mathematical model of the dynamic system of the engine is described. A numerical example is given. The kinematics and dynamic processes of the engine are studied  相似文献   
46.
47.
Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Prikladnaya Mekhanika, Vol. 25, No. 6, pp. 81–88, June, 1989.  相似文献   
48.
Methanol decomposition in a water–methanol equimolar mixture is studied in the presence of a nickel-promoted copper–zinc–cement catalyst. Methanol decomposition at 200–300°C on the oxide and reduced forms of the catalyst yields a gas with an H2/CO ratio close to two. The use of an equimolar CH3OH–H2O mixture under analogous conditions enables obtaining gaseous products with a hydrogen concentration up to 75 vol %.  相似文献   
49.
Sialation of cell surface is known to be tightly connected with tumorigenicity, invasiveness, metastatic potential and clearance of aged cells, while sialation of immunoglobulin G (IgG) molecules determines their anti‐inflammatory properties. Recently, we have found for the first time IgG‐antibodies possessing sialidase‐like activity (sialylic abzyme) in blood serum of multiple myeloma and systemic lupus erythematosis patients. This abzyme was detected in a pool of IgGs purified by a typical procedure including immunoglobulin's precipitation with ammonium sulfate and following chromatography on protein G–Sepharose column. Here we describe a novel matrix for affinity purification of sialylic abzyme that is based on using bovine submandibular gland mucin conjugated to Sepharose matrix (mucin–Sepharose). This matrix preferentially binds sialidase‐like IgGs from a pool of sialidase‐active fraction of proteins precipitated with 50% ammonium sulfate from blood serum of the systemic lupus erythematosis patients. That allowed us to develop a new scheme of double‐step chromatography purification of sialidase‐like IgGs from human blood serum. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
50.
The paper outlines a mathematical model describing the vibrations of buildings and engineering structures with general-type passive shock-absorbers, rigid bodies, and ideal constraints. Two modifications of systems with passive shock absorbers are considered assuming constancy of their structure. These systems are studied numerically; the dynamic processes excited in them are compared __________ Translated from Prikladnaya Mekhanika, Vol. 43, No. 12, pp. 127–137, December 2007.  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