全文获取类型
收费全文 | 16399篇 |
免费 | 1369篇 |
国内免费 | 703篇 |
专业分类
化学 | 8515篇 |
晶体学 | 253篇 |
力学 | 1179篇 |
综合类 | 69篇 |
数学 | 1739篇 |
物理学 | 6716篇 |
出版年
2023年 | 211篇 |
2022年 | 261篇 |
2021年 | 328篇 |
2020年 | 445篇 |
2019年 | 444篇 |
2018年 | 415篇 |
2017年 | 334篇 |
2016年 | 544篇 |
2015年 | 494篇 |
2014年 | 723篇 |
2013年 | 965篇 |
2012年 | 1195篇 |
2011年 | 1344篇 |
2010年 | 976篇 |
2009年 | 884篇 |
2008年 | 1015篇 |
2007年 | 873篇 |
2006年 | 868篇 |
2005年 | 663篇 |
2004年 | 549篇 |
2003年 | 470篇 |
2002年 | 368篇 |
2001年 | 540篇 |
2000年 | 468篇 |
1999年 | 360篇 |
1998年 | 283篇 |
1997年 | 273篇 |
1996年 | 284篇 |
1995年 | 222篇 |
1994年 | 210篇 |
1993年 | 159篇 |
1992年 | 160篇 |
1991年 | 160篇 |
1990年 | 149篇 |
1989年 | 109篇 |
1988年 | 91篇 |
1987年 | 55篇 |
1986年 | 59篇 |
1985年 | 58篇 |
1984年 | 52篇 |
1983年 | 33篇 |
1982年 | 45篇 |
1981年 | 42篇 |
1980年 | 34篇 |
1979年 | 27篇 |
1978年 | 27篇 |
1977年 | 21篇 |
1976年 | 20篇 |
1975年 | 24篇 |
1974年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
We experimentally analyze the heat capacity and thermal expansion of reference solids in a wide temperature range from several Kelvin to melting temperature,and establish a universal double-linear relation between the experimental heat capacity Cp and thermal expansion β,which is different from the previous models.The universal behavior between heat capacity and thermal expansion is important to predict the thermodynamic parameters at constant pressure,and is helpful for understanding the nature of thermal properties in solids. 相似文献
2.
3.
4.
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
5.
Russian Physics Journal - The improvement of chip integration leads to the increase of power density of system chips, which leads to the overheating of system chips. When dispatching the power... 相似文献
6.
Yang Gang Wang Yanhui Yang Xueying Pan Yuelong Liu Yu Cheng Jianfeng Jiang Qiao Tuo Xianguo 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2135-2145
Journal of Radioanalytical and Nuclear Chemistry - The preparation of C30 concrete for a cavernous waste repository under construction in China and its Cs(I) adsorption performance were... 相似文献
7.
8.
Crystallography Reports - A di-nuclear uranyl complex with the formula of [(UO2)2(L)4(H2O)2]?4H2O (1) (HL = quinoline-6-carboxylic acid) was synthesized hydrothermally and characterized by... 相似文献
9.
Non-noble bifunctional electrocatalysts with robust activity and stability toward oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are greatly significant but challenging for Zn-air batteries. Here, in situ confinement of FeNx active sites in high porosity carbon framework (FeNx/CMCC) derived from chelate of carboxymethylcellulose (CMC) and iron ions were synthesized. Particularly, construction of FeNx within porous carbon framework accelerates the electron transfer and the sufficient utilization of active centers, and then expedites the reaction kinetics of ORR and OER. As expected, the optimized FeNx/CMCC exhibits superior ORR activity with a larger half-wave potential of 0.869 V. The rechargeable Zn-air battery delivers a higher power density of 99.6 mW/cm2 and a special capacity of 781.9 mA h/gZn at 10 mA/cm2, together with excellent durability of over 335 h. Remarkably, the as-assembled solid-state battery exhibits a higher open circuit voltage (OCV) of 1.5 V, a special capacity of 709.7 mA h/gZn, as well as prolonged cycling stability (90 h). Moreover, the flexible solid-state battery displays negligible loss of electrochemical performance under various bending angles, illustrating its potential application in flexible electronic devices. 相似文献
10.
Liying Zhang Chuanrui Zhao Yujiao Bai Qian Wang Pan Ma Xiaojie Ma Peihua Zhu 《Electroanalysis》2022,34(2):302-309
The design and exploration of efficient, stable and environmentally compatible organic emitters for an electrochemiluminescence (ECL) sensor is a promising topic. Herein, a novel environmentally-friendly luminophore, ZnBCBTP@MWCNTs, were fabricated via self-assembly of porphyrin molecules (ZnBCBTP) onto multi-walled carbon nanotubes (MWCNTs). The resulting luminophore ZnBCBTP@MWCNTs displayed not only the highly ECL property and but also the good accelerated electron mobility. Then, a label-free ECL biosensor based ZnBCBTP@MWCNTs was constructed for the ultrasensitive detection of uric acid. Excitingly, this proposed ECL biosensor performed a good linear relationship in the range of 0–300 μM with a low detection limit of 1.4 μM, thus offering another reliable and feasible sensing platform for clinical bioanalysis with good selectivity, stability, and repeatability. 相似文献