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   731381篇
  免费   7459篇
  国内免费   2869篇
化学   362612篇
晶体学   10101篇
力学   38237篇
综合类   78篇
数学   116424篇
物理学   214257篇
  2021年   5826篇
  2020年   6463篇
  2019年   7179篇
  2018年   19127篇
  2017年   19013篇
  2016年   19082篇
  2015年   8424篇
  2014年   12692篇
  2013年   29343篇
  2012年   26352篇
  2011年   36977篇
  2010年   25425篇
  2009年   25597篇
  2008年   31883篇
  2007年   33649篇
  2006年   23966篇
  2005年   22505篇
  2004年   20956篇
  2003年   19329篇
  2002年   18345篇
  2001年   18759篇
  2000年   14598篇
  1999年   11139篇
  1998年   9623篇
  1997年   9424篇
  1996年   9004篇
  1995年   8037篇
  1994年   8061篇
  1993年   7755篇
  1992年   8259篇
  1991年   8668篇
  1990年   8222篇
  1989年   8113篇
  1988年   7894篇
  1987年   7606篇
  1986年   7374篇
  1985年   9540篇
  1984年   9898篇
  1983年   8318篇
  1982年   8737篇
  1981年   8164篇
  1980年   7745篇
  1979年   8280篇
  1978年   8650篇
  1977年   8536篇
  1976年   8531篇
  1975年   8077篇
  1974年   7993篇
  1973年   8330篇
  1972年   6173篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
241.
Physics of Atomic Nuclei - The paper presents a comparison of three neutrons identifying methods in scintillators based on ZnS with 6Li and 10B: charge integration method, pulse gradient analysis,...  相似文献   
242.
Physics of Atomic Nuclei - A two-stage method is proposed for controlling the regulators in the fuel burnup process during a single operating period. At the first stage, the coefficient of the heat...  相似文献   
243.
Journal of Applied Spectroscopy - Aqueous solutions of human hemoglobin have been studied by the multi-angle static light scattering method. The tendency of sickle-shaped erythrocytes to aggregate...  相似文献   
244.
Kamashev  A. A.  Garifullin  I. A. 《JETP Letters》2021,113(3):194-206
JETP Letters - We have demonstrated that with increasing the exchange splitting of the conduction band of a ferromagnet and, respectively, of the degree of the spin polarization, the probability of...  相似文献   
245.
Russian Journal of Organic Chemistry - A procedure has been proposed for the synthesis of a series of substituted N-(1,3-thiazol-2-yl)-pyrimidin-2-amines and N-(pyrimidin-2-yl)thioureas by...  相似文献   
246.
Aliev  A. B.  Shafieva  G. H. 《Differential Equations》2022,58(8):1028-1042
Differential Equations - We study a mixed problem for systems of one-dimensional semilinear hyperbolic equations with variable nonlinearity growth rate and nonlinear boundary conditions. Theorems...  相似文献   
247.
Russian Journal of General Chemistry - Kinetics of the reaction of triphenylphosphine with methyl vinyl ketone has been studied using the stopped flow technique. The experimental data have...  相似文献   
248.
Optics and Spectroscopy - The optical absorption spectra of zinc oxide (ZnO) thin films formed by reactive cathode sputtering are studied. The observed absorption of light in the region of photon...  相似文献   
249.
Russian Journal of Organic Chemistry - Selenopheno[2,3-d]pyrimidine- and selenopheno[2,3-d][1,2,3]triazine-containing compounds were synthesized starting from...  相似文献   
250.
Monomeric sarcosine oxidase (mSOx) fusion with the silaffin peptide, R5, designed previously for easy protein production in low resource areas, was used in a biosilification process to form an enzyme layer electrode biosensor. mSOx is a low activity enzyme (10–20 U/mg) requiring high amounts of enzyme to obtain an amperometric biosensor signal, in the clinically useful range <1 mM sarcosine, especially since the Km is >10 mM. An amperometric biosensor model was fitted to experimental data to investigate dynamic range. mSOx constructs were designed with 6H (6×histidine) and R5 (silaffin) peptide tags and compared with native mSOx. Glutaraldehyde (GA) cross‐linked proteins retained ~5 % activity for mSOx and mSOx‐6H and only 0.5 % for mSOx‐R5. In contrast R5 catalysed biosilification on (3‐mercaptopropyl) trimethoxysilane (MPTMS) and tetramethyl orthosilicate (TMOS) particles created a ‘self‐immobilisation’ matrix retaining 40 % and 76 % activity respectively. The TMOS matrix produced a thick layer (>500 μm) on a glassy carbon electrode with a mediated current due to sarcosine in the clinical range for sarcosinemia (0–1 mM). The mSOx‐R5 fusion protein was also used to catalyse biosilification in the presence of creatinase and creatininase, entrapping all three enzymes. A mediated GC enzyme linked current was obtained with dynamic range available for creatinine determination of 0.1–2 mM for an enzyme layer ~800 nm.  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