全文获取类型
收费全文 | 183940篇 |
免费 | 2675篇 |
国内免费 | 823篇 |
专业分类
化学 | 101046篇 |
晶体学 | 2237篇 |
力学 | 7887篇 |
综合类 | 7篇 |
数学 | 20471篇 |
物理学 | 55790篇 |
出版年
2021年 | 1103篇 |
2020年 | 1259篇 |
2019年 | 1282篇 |
2018年 | 1276篇 |
2017年 | 1282篇 |
2016年 | 2582篇 |
2015年 | 2184篇 |
2014年 | 2758篇 |
2013年 | 8332篇 |
2012年 | 6887篇 |
2011年 | 8759篇 |
2010年 | 5300篇 |
2009年 | 5397篇 |
2008年 | 8060篇 |
2007年 | 8062篇 |
2006年 | 7772篇 |
2005年 | 7369篇 |
2004年 | 6593篇 |
2003年 | 5653篇 |
2002年 | 5480篇 |
2001年 | 6211篇 |
2000年 | 4736篇 |
1999年 | 3635篇 |
1998年 | 2777篇 |
1997年 | 2748篇 |
1996年 | 2514篇 |
1995年 | 2353篇 |
1994年 | 2268篇 |
1993年 | 2102篇 |
1992年 | 2431篇 |
1991年 | 2386篇 |
1990年 | 2105篇 |
1989年 | 2064篇 |
1988年 | 2115篇 |
1987年 | 2049篇 |
1986年 | 1932篇 |
1985年 | 2982篇 |
1984年 | 2930篇 |
1983年 | 2340篇 |
1982年 | 2590篇 |
1981年 | 2432篇 |
1980年 | 2441篇 |
1979年 | 2359篇 |
1978年 | 2428篇 |
1977年 | 2397篇 |
1976年 | 2296篇 |
1975年 | 2256篇 |
1974年 | 2157篇 |
1973年 | 2233篇 |
1972年 | 1253篇 |
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
11.
Mathematical Programming - We seek tight bounds on the viable parallelism in asynchronous implementations of coordinate descent that achieves linear speedup. We focus on asynchronous coordinate... 相似文献
12.
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
13.
Paired single residue‐transposed Lys‐N and Lys‐C digestions for label‐free identification of N‐terminal and C‐terminal MS/MS peptide product ions: ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry and tandem mass spectrometry for peptide de novo sequencing 下载免费PDF全文
14.
15.
The European Physical Journal Special Topics - The removal of suspended particles from the interior of a thermocapillary liquid bridge via a finite-particle-size effect restricting the particle... 相似文献
16.
17.
18.
An approach of dynamic mesh adaptation for simulating 3‐dimensional unsteady moving‐immersed‐boundary flows 下载免费PDF全文
In this paper, we present an approach of dynamic mesh adaptation for simulating complex 3‐dimensional incompressible moving‐boundary flows by immersed boundary methods. Tetrahedral meshes are adapted by a hierarchical refining/coarsening algorithm. Regular refinement is accomplished by dividing 1 tetrahedron into 8 subcells, and irregular refinement is only for eliminating the hanging points. Merging the 8 subcells obtained by regular refinement, the mesh is coarsened. With hierarchical refining/coarsening, mesh adaptivity can be achieved by adjusting the mesh only 1 time for each adaptation period. The level difference between 2 neighboring cells never exceeds 1, and the geometrical quality of mesh does not degrade as the level of adaptive mesh increases. A predictor‐corrector scheme is introduced to eliminate the phase lag between adapted mesh and unsteady solution. The error caused by each solution transferring from the old mesh to the new adapted one is small because most of the nodes on the 2 meshes are coincident. An immersed boundary method named local domain‐free discretization is employed to solve the flow equations. Several numerical experiments have been conducted for 3‐dimensional incompressible moving‐boundary flows. By using the present approach, the number of mesh nodes is reduced greatly while the accuracy of solution can be preserved. 相似文献
19.
20.