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   970篇
  免费   40篇
  国内免费   1篇
化学   542篇
晶体学   12篇
力学   21篇
数学   78篇
物理学   358篇
  2023年   11篇
  2022年   8篇
  2021年   24篇
  2020年   31篇
  2019年   32篇
  2018年   26篇
  2017年   22篇
  2016年   36篇
  2015年   22篇
  2014年   34篇
  2013年   49篇
  2012年   70篇
  2011年   64篇
  2010年   46篇
  2009年   34篇
  2008年   57篇
  2007年   52篇
  2006年   61篇
  2005年   49篇
  2004年   40篇
  2003年   37篇
  2002年   36篇
  2001年   15篇
  2000年   11篇
  1999年   3篇
  1998年   5篇
  1997年   4篇
  1996年   10篇
  1995年   2篇
  1994年   9篇
  1993年   11篇
  1992年   13篇
  1991年   5篇
  1990年   6篇
  1989年   9篇
  1988年   5篇
  1987年   2篇
  1985年   2篇
  1984年   7篇
  1982年   2篇
  1981年   7篇
  1980年   5篇
  1978年   2篇
  1977年   3篇
  1976年   7篇
  1975年   4篇
  1974年   4篇
  1973年   4篇
  1972年   5篇
  1958年   1篇
排序方式: 共有1011条查询结果,搜索用时 671 毫秒
1.
DK Choudhury  PK Sahariah 《Pramana》2002,58(4):599-610
We obtain a solution of the DGLAP equation for the gluon at low x first by expanding the gluon in a Taylor series and then using the method of characteristics. We test its validity by comparing it with that of Glück, Reya and Vogt. The convergence criteria of the approximation used are also discussed. We also calculate εF 2(x,Q)2/ε In Q 2 using its approximate relations with the gluon distribution at low x. The predictions are then compared with the HERA data.  相似文献   
2.
A new integrable long-range model is derived from a new asymmetric R-matrix recently discussed by Bibikov in relation to a XXZ spin chain in an external magnetic field. The algebraic Bethe Ansatz is used to derive the eigenvalues and equations for the eigen momenta both for the usual and long-range model.  相似文献   
3.
The title complex, 2CH4N2S·C4H6O4, is a host–guest system. The asymmetric unit consists of one complete thio­urea mol­ecule and one‐half of a dimethyl oxalate mol­ecule lying on an inversion centre. The host thio­urea mol­ecules are connected to form zigzag chains by N—H⋯S hydrogen bonds. The guest dimethyl oxalate mol­ecules provide O‐atom acceptors for N—H⋯O hydrogen bonds, thus inter­connecting the chains of thio­urea mol­ecules to form completely connected sheets. The reduction in temperature from 300 to 100 K leaves the structure unchanged and still isostructural with that previously determined for the analogous thio­urea–diethyl oxalate (2/1) complex. It does, however, induce closer packing of the mol­ecules, general shrinkage of the unit cell and shortening of the hydrogen bonds, these last two to the extent of 1–2%.  相似文献   
4.
This is summary of the activities of the working group on collider physics in the IXth Workshop on High Energy Physics Phenomenology (WHEPP-9) held at the Institute of Physics, Bhubaneswar, India in January 2006. Some of the work subsequently done on these problems by the subgroups formed during the workshop is included in this report.  相似文献   
5.
This paper examines the steady state behaviour of a batch arrival queue with two phases of heterogeneous service along and Bernoulli schedule vacation under multiple vacation policy, where after two successive phases service or first vacation the server may go for further vacations until it finds a new batch of customer in the system. We carry out an extensive stationary analysis of the system, including existence of stationary regime, queue size distribution of idle period process, embedded Markov chain steady state distribution of stationary queue size, busy period distribution along with some system characteristics.  相似文献   
6.
It is shown that in the case of a spherical nonstatic fluid distribution undergoing shear-free motion the field equations in higher dimensional space-time can be reduced to a single second-order differential equation involving an arbitrary function of the radial co-ordinate. This result extends to higher dimensions a similar one obtained by Wyman and Faulkes earlier for 4D space-time. Solving this differential equation a number of new solutions is found, and the dynamical behaviour of one of the models is briefly discussed. The ansatz is later generalised to include the electromagnetic field as well.  相似文献   
7.
In the present paper we introduce a random iteration scheme for three random operators defined on a closed and convex subset of a uniformly convex Banach space and prove its convergence to a common fixed point of three random operators. The result is also an extersion of a known theorem in the corresponding non-random case.  相似文献   
8.
Laser flash photolysis of phenazine (PZ) solution reveals the existence of a stable species with a long lifetime at 380 nm in addition to the usual triplet PZ at 440 nm. The former is suggested to be due to formation of triplet PZ excimer. The triplet excimer also undergoes photoinduced electron transfer with some aromatic amines. The formation of PZ dimer anion radical and amine cation radicals are confirmed by external magnetic field effect studies. Measurement of B1/2, which estimates hyperfine present in the system, also supports this assignment.  相似文献   
9.
D K Choudhury  J K Sarma 《Pramana》1992,39(3):273-277
We present further analysis of the structure functions at low-x using the approximate solutions of Altarelli-Parisi equations recently reported by us. We also compare our results with non-perturbative and non-linear evolutions.  相似文献   
10.
This is the report of flavor physics and model building working group at WHEPP-9. While activites in flavor physics have been mainly focused on B-physics, those in model building have been primarily devoted to neutrino physics. We present summary of working group discussions carried out during the workshop in the above fields, and also briefly review the progress made in some projects subsequently.  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