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   749873篇
  免费   8087篇
  国内免费   2200篇
化学   390003篇
晶体学   9157篇
力学   35914篇
综合类   23篇
数学   98372篇
物理学   226691篇
  2021年   6253篇
  2020年   6927篇
  2019年   7662篇
  2018年   9862篇
  2017年   9901篇
  2016年   14451篇
  2015年   8622篇
  2014年   13717篇
  2013年   33812篇
  2012年   25910篇
  2011年   31319篇
  2010年   22361篇
  2009年   22204篇
  2008年   29281篇
  2007年   29285篇
  2006年   27175篇
  2005年   24313篇
  2004年   22428篇
  2003年   20065篇
  2002年   19915篇
  2001年   21337篇
  2000年   16496篇
  1999年   12952篇
  1998年   10983篇
  1997年   10740篇
  1996年   10357篇
  1995年   9374篇
  1994年   9168篇
  1993年   8869篇
  1992年   9581篇
  1991年   9940篇
  1990年   9225篇
  1989年   9024篇
  1988年   9076篇
  1987年   8696篇
  1986年   8320篇
  1985年   11114篇
  1984年   11534篇
  1983年   9613篇
  1982年   10223篇
  1981年   9799篇
  1980年   9299篇
  1979年   9949篇
  1978年   10207篇
  1977年   10140篇
  1976年   10055篇
  1975年   9608篇
  1974年   9374篇
  1973年   9819篇
  1972年   6671篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Nonlinear Dynamics - In this paper, we analyze the effect which the choice of a friction model has on tippe top inversion in the case where the resulting action of all dissipative forces is...  相似文献   
82.
Optical and Quantum Electronics - Classification of hyperspectral image (HSI) is widely used for the study of remotely sensed images. Convolutional Neural Networks (CNNs) are one of the most...  相似文献   
83.
Journal of Applied Mechanics and Technical Physics - Turbulent mixing at interfaces of three-layer gas systems after shock-wave passage has been studied. The influence of the initial roughness of...  相似文献   
84.
Radiophysics and Quantum Electronics - We find self-consistent stationary distributions of the electric field and plasma density in the process of ionization self-channeling of quasielectrostatic...  相似文献   
85.
Chen  R. J.  Chen  W.  Kong  F. L. 《Analysis Mathematica》2022,48(1):19-28

Restricted testing conditions were considered recently. For the maximal operator, Hytönen, Li and Sawyer [8] first obtained parental testing condition. Later, they [9] showed that it suffices to restrict testing to doubling cubes. Chen and Lacey [3] gave a similar restricted testing condition. In our paper, we discuss a version of the latter in the multilinear setting.

  相似文献   
86.
Melnikov  A.  Aksentyev  A.  Senichev  Y. 《Physics of Atomic Nuclei》2021,84(11):1871-1873
Physics of Atomic Nuclei - We have investigated the robustness of the spin-navigator based method for manipulating the beam polarization to bend magnet installation errors. Toward that end,...  相似文献   
87.
Atopic dermatitis is characterized by leukocyte migration into the skin dermis and typically driven by excessive chemokine production at the site of inflammation. Conventional topical formulations such as gels, creams, and ointments are insufficient for this treatment because of low penetration of drug molecules into the targeted skin tissues. Herein, using a simple, green, sustainable strategy, we have developed novel primary zein nanoparticles embedded in curcumin (Cur) and coated with silk sericin (ZHSCs) for the topical delivery of Cur to penetrate into the dermis and exercise anti-dermatitis effects on the lesion with minimal side-effects. Transdermal delivery experiments and porcine skin fluorescence imaging indicated that ZHSCs facilitate the penetration of Cur across the epidermis layer of skin to reach deep-seated sites. Notably, ZHSCs = 1:0.25 (zein-to-silk sericin mass ratios of 1:0.25) markedly elevated the skin permeability and cumulative turnover of Cur transferred, which were provided a greater than a 3.8-fold increase relative to free Cur. The special nanoparticles of ZHS = 1:0.25 possessed the deepest localization depth and experience a transition of the particle structure and core-shell separation after penetrating into the dermis of skin. In a cell model of dermatitis induced by tumor necrosis factor α/interferon γ co-stimulation, compared with free Cur, Cur-loaded ZHS nanoparticles down-regulated the generation of inflammatory cytokines and chemokines in keratinocytes through suppression of the nuclear translocation of NF-κBp65 and hence exerted an anti-dermatitis effect. This strategy may provide new avenues and direction for the demanding issues of valid topical delivery systems.  相似文献   
88.
Crystallography Reports - The orientation of grains and the special boundaries formed by them in multicrystalline silicon has been studied by electron backscattered diffraction. It is found that...  相似文献   
89.
Crystallography Reports - Some questions related to the establishment, development, and prospects of physical studies using inelastic thermal-neutron scattering are briefly reviewed. The directions...  相似文献   
90.
Theoretical and Mathematical Physics - The fractional derivative method is used to take wave dispersion into account in the wave equation when describing the propagation of gravitational soliton...  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