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   839篇
  免费   33篇
  国内免费   3篇
化学   499篇
晶体学   19篇
力学   28篇
数学   193篇
物理学   136篇
  2024年   2篇
  2023年   4篇
  2022年   10篇
  2021年   7篇
  2020年   26篇
  2019年   29篇
  2018年   31篇
  2017年   37篇
  2016年   55篇
  2015年   33篇
  2014年   71篇
  2013年   146篇
  2012年   49篇
  2011年   53篇
  2010年   55篇
  2009年   35篇
  2008年   46篇
  2007年   39篇
  2006年   22篇
  2005年   6篇
  2004年   5篇
  2003年   11篇
  2002年   14篇
  2001年   11篇
  2000年   4篇
  1999年   4篇
  1998年   5篇
  1997年   6篇
  1996年   7篇
  1995年   3篇
  1994年   8篇
  1993年   2篇
  1990年   3篇
  1987年   2篇
  1985年   2篇
  1984年   3篇
  1983年   3篇
  1982年   2篇
  1981年   5篇
  1980年   3篇
  1979年   2篇
  1978年   1篇
  1976年   4篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1968年   1篇
  1967年   1篇
  1965年   2篇
  1936年   1篇
排序方式: 共有875条查询结果,搜索用时 46 毫秒
121.
122.
Using the p-wave part of the charge asymmetric three-nucleon potential we calculate the charge asymmetric binding energy in 3He3H nuclei. The total contribution which arise from the electromagnetic corrections to the three-nucleon potential turns out to be negligble.  相似文献   
123.
124.
In this paper we introduce and study the notion of a graded (strongly) nil clean ring which is group graded. We also deal with extensions of graded (strongly) nil clean rings to graded matrix rings and to graded group rings. The question of when nil cleanness of the component, which corresponds to the neutral element of a group, implies graded nil cleanness of the whole graded ring is examined. Similar question is discussed in the case of groupoid graded rings as well.  相似文献   
125.
In the present paper, the numerical damage assessment of the masonry bell tower called “Haghia Sophia” in Trabzon, Turkey is performed by nonlinear 3D finite element modeling. The behavior of bell tower is determined under several different conditions: nonlinear static analysis containing dead and wind loads and nonlinear seismic analysis. In addition to, an assessment of the tower’s stability with respect to the tilt of the tower is carried out by means of a nonlinear analysis. In the nonlinear dynamic analysis, the east–west component of 1992 Erzincan earthquake is used. Cracking and crushing of the masonry have been taken into account, as well as the influence of material nonlinearity. The numerical analysis has given a valuable picture of possible damage evolution, providing useful hints for the prosecution of structural monitoring. The displacement and stress fields, as well as the distribution of cracking have been calculated and compared to the actual distribution of fractures in the tower. It is seen from the numerical results that there is a good agreement with present damages of the bell tower.  相似文献   
126.
127.
128.
The biosensor was constructed for determination of glucose by using glucose oxidase enzyme immobilized on poly(thiophene-3-boronic acid) (PTBA). Boronic acid functionalized polythiophene layer was obtained by electrochemical polymerization of Thiophene (Th) and thiophene-3-boronic acid (TBA) with different monomer rations. The reconstitution of the apo-glucose oxidase (apo-GOx) on a complexed flavin adenine dinucleotide (FAD) linked to polythiophene boronic acid (PTBA) monolayer yields an electrically contacted enzyme monolayer. The GOx-reconstituted enzyme electrode exhibited excellent electrocatalytic activities toward the reduction and oxidation of hydrogen peroxide as well. The PTBA/FAD/GOx biosensor shows an excellent performance for glucose at +0.4 V with a high sensitivity (2.14 μA/mM) and lower response time (~5 s) in a wide concentration range of 0.5–18 mM (correlation coefficient of 0.9952). Furthermore, the effects of applied potential, pH, temperature, electroactive interference, stability and reusability of the biosensors were discussed.  相似文献   
129.
HARUN REŞIT YAZAR 《Pramana》2013,81(4):579-585
The sd-interacting boson approximation (sd-IBA) and the df-interacting boson approximation (df-IBA) can be related to each other and the states of the interacting boson approximation model can be identified with the fully symmetric states in the sdf interacting boson approximation model. A systematic study of the sdf-IBA model showed that the constructed Hamiltonian can successfully describe the strong octupole correlations in the deformed nuclei. We showed that the interacting boson approximation may account for many of these K π ?=?0+ states. It was found that the calculated energy spectra of the gadolinium isotopes agree quite well with the experimental data. The observed B(E2) values were also calculated and compared with the experimental data.  相似文献   
130.
In this study, a film formation process from surfactant-free polystyrene (PS) latex particles is reported. Steady state fluorescence (SSF) and photon transmission (UVV) techniques were used to study the evolution of film formation. The latex films were prepared from pyrene (P)-labeled PS particles at room temperature and annealed at time intervals of 2.5?min above the glass transition temperature (T g) of PS. During the annealing processes, the transparency of the film changed considerably. Fluorescence intensity (I 0P) from P was measured after each annealing step to monitor the stages of film formation. Evolution of transparency of latex films were monitored by using photon transmission intensity, I tr. A drastic increase in I tr and I 0P above the critical annealing times, t r and t c were attributed, respectively to percolation behavior of PS material from one side to the other side of the latex film. Critical exponents, β of percolation clusters were measured and found to be around 0.35 and 0.25 for I tr and I 0P measurements, respectively.  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