全文获取类型
收费全文 | 66004篇 |
免费 | 10874篇 |
国内免费 | 7311篇 |
专业分类
化学 | 46966篇 |
晶体学 | 793篇 |
力学 | 4058篇 |
综合类 | 460篇 |
数学 | 7871篇 |
物理学 | 24041篇 |
出版年
2024年 | 64篇 |
2023年 | 1314篇 |
2022年 | 1553篇 |
2021年 | 2298篇 |
2020年 | 2727篇 |
2019年 | 2622篇 |
2018年 | 2187篇 |
2017年 | 2180篇 |
2016年 | 3152篇 |
2015年 | 3139篇 |
2014年 | 3782篇 |
2013年 | 4814篇 |
2012年 | 6057篇 |
2011年 | 6148篇 |
2010年 | 4260篇 |
2009年 | 3933篇 |
2008年 | 4281篇 |
2007年 | 3830篇 |
2006年 | 3539篇 |
2005年 | 3001篇 |
2004年 | 2291篇 |
2003年 | 1871篇 |
2002年 | 1773篇 |
2001年 | 1448篇 |
2000年 | 1213篇 |
1999年 | 1381篇 |
1998年 | 1119篇 |
1997年 | 1043篇 |
1996年 | 1018篇 |
1995年 | 932篇 |
1994年 | 797篇 |
1993年 | 664篇 |
1992年 | 583篇 |
1991年 | 547篇 |
1990年 | 447篇 |
1989年 | 349篇 |
1988年 | 256篇 |
1987年 | 226篇 |
1986年 | 234篇 |
1985年 | 192篇 |
1984年 | 139篇 |
1983年 | 136篇 |
1982年 | 84篇 |
1981年 | 70篇 |
1980年 | 56篇 |
1979年 | 36篇 |
1977年 | 43篇 |
1976年 | 43篇 |
1975年 | 39篇 |
1973年 | 42篇 |
排序方式: 共有10000条查询结果,搜索用时 390 毫秒
11.
Li Quanxin Li Zheng He Cheng Sun Huilin Tan Shengheng Zhang Hua 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2105-2115
Journal of Radioanalytical and Nuclear Chemistry - The simplified 8-oxide system (SiO2-B2O3-Na2O-Al2O3-CaO-TiO2-MoO3-La2O3) has been prepared under two types of cooling methods, and analyzed with... 相似文献
12.
In this paper,we first construct compact embeddedλ-hypersurfaces with the topology of torus which are calledλ-torus in Euclidean spaces?n^+1.Then,we give many compact immersedλ-hypersurfaces in Euclidean spaces?n^+1. 相似文献
13.
Nonlinear Dynamics - This paper proposes an optimal parameter design of control scheme for mechanical systems by adopting the Stackelberg game theory. The goal of the control is to drive the... 相似文献
14.
Xu Mengtao Li Changyou Sun Yang Yang Tianzhi Zhang Hongzhuang Liu Zhendong Liu Haiyang Li Zhenyuan Zhang Yimin 《Nonlinear dynamics》2021,105(4):3061-3092
Nonlinear Dynamics - Investigation of the dynamic characteristics of linear guideway is essential for enhancing structural performance of machine tools. However, few mechanical models are... 相似文献
15.
Journal of Visualization - The increasing availability of spatiotemporal data provides unprecedented opportunities for understanding the structure of an urban area in terms of people’s... 相似文献
16.
Mathematical Programming - In the general equilibrium with incomplete asset markets (GEI) model, the excess demand functions are typically not continuous at the prices for which the assets have... 相似文献
17.
International Journal of Theoretical Physics - The Majorana representation, which provides an intuitive way to represent the quantum state by stars on the Bloch sphere, has drawn considerable... 相似文献
18.
Donglei Wei Huili Li Chuanqing Yang Jianmin Fu Hou Chen Liangjiu Bai Wenxiang Wang Huawei Yang Lixia Yang Ying Liang 《Journal of polymer science. Part A, Polymer chemistry》2022,60(10):1588-1594
Acridone as a new kind of visible light photocatalyst has been developed to catalyze metal free atom transfer radical polymerization (ATRP). The photocatalyst possess low excited state potential as can undergo an oxidative quenching pathway to initiate ATRP of vinyl monomers. Kinetic study and light on/off reaction demonstrate the “living”/controlled nature of the polymerization by light. Block copolymers can be achieved by using PMMA as macroinitiator to reinitiate polymerization of other vinyl monomers, which shows highly preserved Br chain-end functionality in the synthesized polymers. Moreover, the polymerization can be conducted under air atmosphere as most photocatalysts need anaerobic condition, which may give inspiration of further application of this kind of photocatalyst. 相似文献
19.
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
20.