全文获取类型
收费全文 | 313501篇 |
免费 | 4614篇 |
国内免费 | 1158篇 |
专业分类
化学 | 169303篇 |
晶体学 | 3520篇 |
力学 | 13118篇 |
综合类 | 11篇 |
数学 | 37057篇 |
物理学 | 96264篇 |
出版年
2020年 | 2072篇 |
2019年 | 2094篇 |
2018年 | 2062篇 |
2017年 | 1979篇 |
2016年 | 4002篇 |
2015年 | 3355篇 |
2014年 | 4612篇 |
2013年 | 14512篇 |
2012年 | 11035篇 |
2011年 | 13709篇 |
2010年 | 8498篇 |
2009年 | 8457篇 |
2008年 | 12573篇 |
2007年 | 12808篇 |
2006年 | 12427篇 |
2005年 | 11319篇 |
2004年 | 10130篇 |
2003年 | 8862篇 |
2002年 | 8082篇 |
2001年 | 9735篇 |
2000年 | 7197篇 |
1999年 | 5581篇 |
1998年 | 4338篇 |
1997年 | 4363篇 |
1996年 | 4360篇 |
1995年 | 4303篇 |
1994年 | 4068篇 |
1993年 | 3893篇 |
1992年 | 4379篇 |
1991年 | 4243篇 |
1990年 | 3947篇 |
1989年 | 3805篇 |
1988年 | 4090篇 |
1987年 | 3734篇 |
1986年 | 3651篇 |
1985年 | 5352篇 |
1984年 | 5415篇 |
1983年 | 4370篇 |
1982年 | 4763篇 |
1981年 | 4810篇 |
1980年 | 4545篇 |
1979年 | 4702篇 |
1978年 | 4683篇 |
1977年 | 4684篇 |
1976年 | 4639篇 |
1975年 | 4529篇 |
1974年 | 4393篇 |
1973年 | 4573篇 |
1972年 | 2580篇 |
1971年 | 1874篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Pomogaev V. A. Lee H. J. Goh E. Tchaikovskaya O. N. Kononov A. I. Avramov P. V. 《Russian Physics Journal》2022,64(11):2076-2081
Russian Physics Journal - Theoretical calculations of excited states in the complexes of gold and silver three-atom nanoclusters with carbon quantum nanodots are performed using the M062X... 相似文献
2.
Ramos Fernando Flores Henoc Camarillo E. Adriana Ledo J. Manuel 《Structural chemistry》2022,33(2):379-388
Structural Chemistry - In the present work, the energy contribution of the sulfur atom in a heterocycle and in a disulfide bond in solid and gas phases was calculated. To achieve this goal,... 相似文献
3.
Heßberger F. P. Antalic S. Giacoppo F. Andel B. Ackermann D. Block M. Heinz S. Khuyagbaatar J. Kojouharov I. Venhart M. 《The European Physical Journal A - Hadrons and Nuclei》2022,58(1):1-18
The European Physical Journal A - The goal of the present paper is twofold. First, a novel expansion many-body method applicable to superfluid open-shell nuclei, the so-called Bogoliubov in-medium... 相似文献
4.
通过改装多旋翼无人机(UAV)和搭载各类载荷以及联合地基观测设备对大柴旦地区大气、环境以及气溶胶参数进行测量。利用获得的数据资料,对该地区近地层气溶胶粒子数浓度(即单位体积空气中气溶胶粒子的数目)、消光系数以及气象要素等特征进行了分析。结果表明,在大柴旦地区,近地层气溶胶粒子数浓度日变化显著,呈现双峰形态,气溶胶粒子数浓度的变化范围为75~220 cm-3,消光系数的变化范围为0.004~0.038 km-1;当风速小于6 m/s时,气溶胶粒子数浓度与风速呈负相关关系;当风速大于6 m/s时,二者呈正相关关系;相对湿度对气溶胶粒子的影响较小,这可能是由于该地区以沙尘型气溶胶为主,吸湿性较弱。本研究基于多旋翼无人机探测平台,可以有效地获得近地层精细化大气、环境结构,有助于研究人员了解该地区气溶胶的结构、变化特征以及建立气溶胶模式,同时也为气溶胶及大气环境参数探测方法提供了技术支撑及思路拓展。 相似文献
5.
Transport in Porous Media - Membrane filtration of feed containing multiple species of particles is a common process in the industrial setting. In this work, we propose a model for filtration of a... 相似文献
6.
Numerical Algorithms - An inverse central ordering of the nodes is proposed for the Newton interpolation formula. This ordering may improve the stability for certain distributions of nodes. For... 相似文献
7.
Nayak Debasis Dora J. K. Ghosh Sudipto Adyam Venimadhav 《Journal of Solid State Electrochemistry》2022,26(5):1231-1239
Journal of Solid State Electrochemistry - Sodium-ion batteries have emerged as an exciting alternative to commercially dominant lithium-ion batteries for electric vehicles and other applications.... 相似文献
8.
In this paper, the authors consider the asymptotic synchronization of a linear dissipative system with multiple feedback dampings. They ?rst show that under the observability of a scalar equation, Kalman’s rank condition is su?cient for the uniqueness of solution to a complex system of elliptic equations with mixedobservations. The authors then establish a general theory on the asymptotic stability and the asymptotic synchronization for the corresponding evolutional system subjected to mixed dampings of various natures. Some classic models are presented to illustrate the ?eld of applications of the abstract theory. 相似文献
9.
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
10.
JETP Letters - The magnetic properties of Co-doped CdS has been investigated by ab initio calculations using the GGA + U approximation. The study reveals the ferromagnetic ordering of Co-doped CdS... 相似文献