全文获取类型
收费全文 | 282954篇 |
免费 | 9109篇 |
国内免费 | 5426篇 |
专业分类
化学 | 136209篇 |
晶体学 | 3783篇 |
力学 | 10651篇 |
综合类 | 247篇 |
数学 | 23642篇 |
物理学 | 76634篇 |
无线电 | 46323篇 |
出版年
2021年 | 2849篇 |
2020年 | 2949篇 |
2019年 | 2827篇 |
2018年 | 2838篇 |
2017年 | 2687篇 |
2016年 | 4487篇 |
2015年 | 3878篇 |
2014年 | 5222篇 |
2013年 | 11826篇 |
2012年 | 9869篇 |
2011年 | 11355篇 |
2010年 | 8178篇 |
2009年 | 8419篇 |
2008年 | 10508篇 |
2007年 | 10722篇 |
2006年 | 10454篇 |
2005年 | 9457篇 |
2004年 | 8334篇 |
2003年 | 7316篇 |
2002年 | 7070篇 |
2001年 | 8663篇 |
2000年 | 7032篇 |
1999年 | 6078篇 |
1998年 | 5064篇 |
1997年 | 5007篇 |
1996年 | 4892篇 |
1995年 | 4480篇 |
1994年 | 4253篇 |
1993年 | 4036篇 |
1992年 | 4476篇 |
1991年 | 4229篇 |
1990年 | 3928篇 |
1989年 | 3818篇 |
1988年 | 3630篇 |
1987年 | 3234篇 |
1986年 | 2973篇 |
1985年 | 3883篇 |
1984年 | 3842篇 |
1983年 | 3226篇 |
1982年 | 3318篇 |
1981年 | 3229篇 |
1980年 | 3079篇 |
1979年 | 3154篇 |
1978年 | 3392篇 |
1977年 | 3179篇 |
1976年 | 3156篇 |
1975年 | 2978篇 |
1974年 | 2907篇 |
1973年 | 2927篇 |
1967年 | 2217篇 |
排序方式: 共有10000条查询结果,搜索用时 531 毫秒
21.
Li Y. Shi W. H. Dong L. M. Xu S. X. Huang H. J. Yin J. R. 《Journal of Applied Spectroscopy》2022,89(3):534-541
Journal of Applied Spectroscopy - Sr3B2O6:Dy3+, Eu3+ single-matrix white-light-emitting materials are prepared using the high-temperature solid-state method. The microstructure, emission spectrum,... 相似文献
22.
Liu Jingze Fei Qingguo Wu Shaoqing Tang Zhenhuan Zhang Dahai 《Nonlinear dynamics》2021,106(3):1869-1890
Nonlinear Dynamics - Rolling bearing and squeeze film damper will introduce structural nonlinearity into the dynamic model of aeroengine. Rubbing will occur due to the clearance reduction design of... 相似文献
23.
Vasile M. Loots H. Vercammen L. Bruggeman M. Verrezen F. 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(8):3349-3357
Journal of Radioanalytical and Nuclear Chemistry - In this paper a study for the selection of an NPE (nonylphenol ethoxylates)—free cocktail is discussed in order to be used for our routine... 相似文献
24.
Lili Hao Jiaxiang Li Peng Wang Zongliang Wang Zhenxu Wu Yu Wang Zixue Jiao Min Guo Tongfei Shi Qigang Wang Yoshihiro Ito Yen Wei Peibiao Zhang 《Advanced functional materials》2021,31(15):2009661
The degradation behavior of implants is significantly important for bone repair. However, it is still unprocurable to spatiotemporally regulate the degradation of the implants to match bone ingrowth. In this paper, a magneto-controlled biodegradation model is established to explore the degradation behavior of magnetic scaffolds in a magnetothermal microenvironment generated by an alternating magnetic field (AMF). The results demonstrate that the scaffolds can be heated by magnetic nanoparticles (NPs) under AMF, which dramatically accelerated scaffold degradation. Especially, magnetic NPs modified by oleic acid with a better interface compatibility exhibit a greater heating efficiency to further facilitate the degradation. Furthermore, the molecular dynamics simulations reveal that the enhanced motion correlation between magnetic NPs and polymer matrix can accelerate the energy transfer. As a proof-of-concept, the feasibility of magneto-controlled degradation for implants is demonstrated, and an optimizing strategy for better heating efficiency of nanomaterials is provided, which may have great instructive significance for clinical medicine. 相似文献
25.
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
26.
Wireless Networks - In such mobile platforms as ships and aircraft, the detection and reconnaissance devices are near to the communication facilities. When working at the same time, they will... 相似文献
27.
28.
Nonlinear Dynamics - Epilepsy is the second largest neurological disease which seriously threatens human life and health. The one important reason of inducing epileptic seizures is ischemic stroke... 相似文献
29.
30.
Rongrong Li Hongjie Peng Qingping Wu Xuejun Zhou Jiang He Hangjia Shen Minghui Yang Chilin Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(29):12227-12236
Herein, we propose the construction of a sandwich-structured host filled with continuous 2D catalysis–conduction interfaces. This MoN-C-MoN trilayer architecture causes the strong conformal adsorption of S/Li2Sx and its high-efficiency conversion on the two-sided nitride polar surfaces, which are supplied with high-flux electron transfer from the buried carbon interlayer. The 3D self-assembly of these 2D sandwich structures further reinforces the interconnection of conductive and catalytic networks. The maximized exposure of adsorptive/catalytic planes endows the MoN-C@S electrode with excellent cycling stability and high rate performance even under high S loading and low host surface area. The high conductivity of this trilayer texture does not compromise the capacity retention after the S content is increased. Such a job-synergistic mode between catalytic and conductive functions guarantees the homogeneous deposition of S/Li2Sx, and avoids thick and devitalized accumulation (electrode passivation) even after high-rate and long-term cycling. 相似文献