全文获取类型
收费全文 | 233117篇 |
免费 | 7802篇 |
国内免费 | 4066篇 |
专业分类
化学 | 132641篇 |
晶体学 | 2865篇 |
力学 | 10058篇 |
综合类 | 252篇 |
数学 | 23319篇 |
物理学 | 75850篇 |
出版年
2021年 | 2500篇 |
2020年 | 3125篇 |
2019年 | 3191篇 |
2018年 | 3344篇 |
2017年 | 3373篇 |
2016年 | 5063篇 |
2015年 | 3735篇 |
2014年 | 5466篇 |
2013年 | 11540篇 |
2012年 | 9649篇 |
2011年 | 11158篇 |
2010年 | 7834篇 |
2009年 | 7659篇 |
2008年 | 9304篇 |
2007年 | 8981篇 |
2006年 | 8479篇 |
2005年 | 7540篇 |
2004年 | 6785篇 |
2003年 | 6055篇 |
2002年 | 5400篇 |
2001年 | 6589篇 |
2000年 | 4978篇 |
1999年 | 3993篇 |
1998年 | 3159篇 |
1997年 | 3104篇 |
1996年 | 3061篇 |
1995年 | 2949篇 |
1994年 | 2800篇 |
1993年 | 2568篇 |
1992年 | 3175篇 |
1991年 | 3001篇 |
1990年 | 2920篇 |
1989年 | 2830篇 |
1988年 | 2853篇 |
1987年 | 2842篇 |
1986年 | 2634篇 |
1985年 | 3383篇 |
1984年 | 3365篇 |
1983年 | 2630篇 |
1982年 | 2710篇 |
1981年 | 2756篇 |
1980年 | 2521篇 |
1979年 | 2847篇 |
1978年 | 2841篇 |
1977年 | 2962篇 |
1976年 | 2807篇 |
1975年 | 2560篇 |
1974年 | 2495篇 |
1973年 | 2454篇 |
1968年 | 1702篇 |
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
51.
JETP Letters - A new mechanism of thinning of smectic nanofilms is discovered, differing from that previously described in experimental and theoretical works. The size and shape of a meniscus... 相似文献
52.
Journal of Analytical Chemistry - We review the main techniques, procedures, and information products used in non-target analysis (NTA) to reveal the composition of substances. Sampling and sample... 相似文献
53.
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
54.
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
55.
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
56.
57.
Lin Yu Wu Yeyu Tan Xuecai Wu Jiawen Huang Kejing Mi Yan Ou Panpan Wei Fucun 《Journal of Solid State Electrochemistry》2022,26(4):959-971
Journal of Solid State Electrochemistry - An ultrasensitive “signal-off–on” electrochemiluminescence (ECL) biosensor is constructed based on f1-TiO2/g-C3N4/PDA for thrombin... 相似文献
58.
Structural Chemistry - In order to evaluate the electrical response of boron nitride nanocones (BNNCs) to phenol gas, density functional theory (DFT) calculations are employed. The sensitivity and... 相似文献
59.
Ibotov Sh. Kh. Yuldasheva N. K. Mukarramov N. I. Zakirova R. P. Gusakova S. D. 《Chemistry of Natural Compounds》2022,58(4):728-731
Chemistry of Natural Compounds - 相似文献
60.
Dr. Swati Deswal Rishukumar Panday Dr. Dipti R. Naphade Prashant Dixit Dr. Balu Praveenkumar Dr. Jan K. Zaręba Prof. Dr. Thomas D. Anthopoulos Prof. Dr. Satishchandra Ogale Prof. Dr. Ramamoorthy Boomishankar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(33):e202200751
Bismuth containing hybrid molecular ferroelectrics are receiving tremendous attention in recent years owing to their stable and non-toxic composition. However, these perovskite-like structures are primarily limited to ammonium cations. Herein, we report a new phosphonium based discrete perovskite-like hybrid ferroelectric with a formula [Me(Ph)3P]3[Bi2Br9] ( MTPBB ) and its mechanical energy harvesting capability. The Polarization-Electric field (P-E) measurements resulted in a well-defined ferroelectric hysteresis loop with a remnant polarization value of 2.1 μC cm−2. Piezoresponse force microscopy experiments enabled visualization of the ferroelectric domain structure and evaluation of the piezoelectric strain coefficient (d33) for an MTPBB single crystal and thin film sample. Furthermore, flexible devices incorporating MTPBB in polydimethylsiloxane (PDMS) matrix at various concentrations were fabricated and explored for their mechanical energy harvesting properties. The champion device with 20 wt % of MTPBB in PDMS rendered a maximum peak-to-peak open-circuit voltage of 22.9 V and a maximum power density of 7 μW cm−2 at an optimal load of 4 MΩ. Moreover, the potential of MTPBB -based devices in low power electronics was demonstrated by storing the harvested energy in various electrolytic capacitors. 相似文献