全文获取类型
收费全文 | 1382665篇 |
免费 | 34544篇 |
国内免费 | 10889篇 |
专业分类
化学 | 702015篇 |
晶体学 | 20326篇 |
力学 | 76376篇 |
综合类 | 243篇 |
数学 | 245184篇 |
物理学 | 383954篇 |
出版年
2021年 | 14579篇 |
2020年 | 16953篇 |
2019年 | 17228篇 |
2018年 | 12536篇 |
2016年 | 28825篇 |
2015年 | 21947篇 |
2014年 | 32075篇 |
2013年 | 76538篇 |
2012年 | 41804篇 |
2011年 | 38851篇 |
2010年 | 38376篇 |
2009年 | 40442篇 |
2008年 | 37229篇 |
2007年 | 32589篇 |
2006年 | 39964篇 |
2005年 | 30869篇 |
2004年 | 32118篇 |
2003年 | 30040篇 |
2002年 | 31286篇 |
2001年 | 30958篇 |
2000年 | 26432篇 |
1999年 | 23657篇 |
1998年 | 21823篇 |
1997年 | 21710篇 |
1996年 | 21661篇 |
1995年 | 19655篇 |
1994年 | 18999篇 |
1993年 | 18491篇 |
1992年 | 18634篇 |
1991年 | 18852篇 |
1990年 | 18019篇 |
1989年 | 17987篇 |
1988年 | 17528篇 |
1987年 | 17399篇 |
1986年 | 16429篇 |
1985年 | 22790篇 |
1984年 | 23924篇 |
1983年 | 20091篇 |
1982年 | 21785篇 |
1981年 | 20978篇 |
1980年 | 20286篇 |
1979年 | 20512篇 |
1978年 | 21796篇 |
1977年 | 21395篇 |
1976年 | 21146篇 |
1975年 | 19873篇 |
1974年 | 19576篇 |
1973年 | 20040篇 |
1972年 | 14512篇 |
1967年 | 12672篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
Theoretical and Mathematical Physics - We study a phenomenological model in which dark matter in the cosmological constant form is identified with the mean energy–momentum tensor of a... 相似文献
52.
Moroz Ya. A. Lozinskyy N. S. Lopanov A. N. Chebyshev K. A. 《Russian Journal of General Chemistry》2022,92(1):101-107
Russian Journal of General Chemistry - Tungstophosphatozincates with the Keggin anion structure Kt5[PW11O39Zn(H2O)]?nH2O, Kt = Rb+, Cs+, (CH3)4N+; (C2H5)4N+ were synthesized. Their... 相似文献
53.
Filatova S. M. Guseva M. K. Bodrova T. G. Parshina D. V. Budanova U. A. Sebyakin Yu. L. 《Russian Journal of General Chemistry》2022,91(1):S13-S23
Russian Journal of General Chemistry - The review article traces the main trends of the synthetic approach to the solution of the problem of overcoming the resistance of pathogenic bacterial... 相似文献
54.
55.
JETP Letters - Using the spectroscopic data on the 235UF6 and 238UF6 molecules and on the lasing frequencies of CF4 and para-H2 lasers and recent results, a method has been proposed to increase the... 相似文献
56.
Knyazev Yu. V. Kazak N. V. Gavrichkov V. A. Polukeev S. I. Ovchinnikov S. G. 《JETP Letters》2022,116(8):567-573
JETP Letters - Changes in the magnetic properties of FeBO3 single crystals in the course of spin crossover occurring with increasing pressure up to 63 GPa are studied both experimentally and... 相似文献
57.
Chemistry of Heterocyclic Compounds - 2-Imino-2,5-dihydrofurans are a highly valuable class of heterocyclic compounds that show versatile biological activity and are used in diverse fields of... 相似文献
58.
Low-flow chromatography has a rich history of innovation but has yet to reach widespread implementation in bioanalytical applications. Improvements in pump technology, microfluidic connections, and nano-electrospray sources for MS have laid the groundwork for broader application, and innovation in this space has accelerated in recent years. This article reviews the instrumentation used for nano-flow LC, the types of columns employed, and strategies for multidimensionality of separations, which are key to the future state of the technique to the high-throughput needs of modern bioanalysis. An update of the current applications where nano-LC is widely used, such as proteomics and metabolomics, is discussed. But the trend toward biopharmaceutical development of increasingly complex, targeted, and potent therapeutics for the safe treatment of disease drives the need for ultimate selectivity and sensitivity of our analytical platforms for targeted quantitation in a regulated space. The selectivity needs are best addressed by mass spectrometric detection, especially at high resolutions, and exquisite sensitivity is provided by nano-electrospray ionization as the technology continues to evolve into an accessible, robust, and easy-to-use platform. 相似文献
59.
Zhengcheng Wang Shangyan Zhou Wei Liao Qian Zhou Meida Chen Jin Long Prof. Qingmei Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(66):e202201987
The designs of efficient and inexpensive Pt-based catalysts for methanol oxidation reaction (MOR) are essential to boost the commercialization of direct methanol fuel cells. Here, the highly catalytic performance PtFe alloys supported on multiwalled carbon nanotubes (MWCNTs) decorating nitrogen-doped carbon (NC) have been successfully prepared via co-engineering of the surface composition and electronic structure. The Pt1Fe3@NC/MWCNTs catalyst with moderate Fe3+ feeding content (0.86 mA/mgPt) exhibits 2.26-fold enhancement in MOR mass activity compared to pristine Pt/C catalyst (0.38 mA/mgPt). Furthermore, the CO oxidation initial potential of Pt1Fe3@NC/MWCNTs catalyst is lower relative to Pt/C catalyst (0.71 V and 0.80 V). Benefited from the optimal surface compositions, the anti-corrosion ability of MWCNT, strong electron interaction between PtFe alloys and MWCNTs and the N-doped carbon (NC) layer, the Pt1Fe3@NC/MWCNTs catalyst presents an improved MOR performance and anti-CO poisoning ability. This study would open up new perspective for designing efficient electrocatalysts for the DMFCs field. 相似文献
60.
Journal of Analytical Chemistry - The present study reports the development of a magnetic polyethylene glycol nanocomposite based on graphite reinforcement carbon paste electrode for the sensitive... 相似文献