全文获取类型
收费全文 | 106373篇 |
免费 | 6058篇 |
国内免费 | 6417篇 |
专业分类
化学 | 60835篇 |
晶体学 | 1336篇 |
力学 | 6142篇 |
综合类 | 378篇 |
数学 | 13082篇 |
物理学 | 37075篇 |
出版年
2023年 | 754篇 |
2022年 | 1715篇 |
2021年 | 2057篇 |
2020年 | 2323篇 |
2019年 | 2514篇 |
2018年 | 2902篇 |
2017年 | 2825篇 |
2016年 | 3507篇 |
2015年 | 2456篇 |
2014年 | 3497篇 |
2013年 | 5007篇 |
2012年 | 5154篇 |
2011年 | 6621篇 |
2010年 | 4899篇 |
2009年 | 4884篇 |
2008年 | 4562篇 |
2007年 | 4292篇 |
2006年 | 3980篇 |
2005年 | 3756篇 |
2004年 | 4233篇 |
2003年 | 3428篇 |
2002年 | 3429篇 |
2001年 | 3030篇 |
2000年 | 2187篇 |
1999年 | 1807篇 |
1998年 | 1770篇 |
1997年 | 1500篇 |
1996年 | 1403篇 |
1995年 | 1200篇 |
1994年 | 1253篇 |
1993年 | 1519篇 |
1992年 | 1540篇 |
1991年 | 1415篇 |
1990年 | 1414篇 |
1989年 | 1341篇 |
1988年 | 988篇 |
1987年 | 926篇 |
1986年 | 906篇 |
1985年 | 942篇 |
1984年 | 933篇 |
1983年 | 833篇 |
1982年 | 809篇 |
1979年 | 803篇 |
1978年 | 814篇 |
1977年 | 809篇 |
1976年 | 921篇 |
1975年 | 813篇 |
1974年 | 844篇 |
1973年 | 848篇 |
1972年 | 752篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Gurenkova Yu. S. Kornyakov I. V. Ostrovsky V. A. Skrylnikova M. A. Khramchikhin A. V. 《Russian Journal of General Chemistry》2020,90(7):1202-1206
Russian Journal of General Chemistry - 8-Phenyltetrazolo[5,1-b][1,3,4]thiadiazepine was obtained as a result of intermolecular cyclization of 1-amino-1H-tetrazole-5-thiol and 3-phenyl-2-propynal.... 相似文献
32.
Lijuan Shen Li Li Sheng Lu Xiaohan Zhang Jie Liu Junlin An Guojun Zhang Bo Wu Fei Wang 《中国颗粒学报》2015,(3):10-15
We conducted measurements of black carbon(BC) aerosol in Jiaxing,China during autumn from September 26 to November 30,2013.We investigated temporal and diurnal variations of BC,and its correlations with meteorological parameters and other major pollutants.Results showed that hourly mass concentrations of BC ranged from 0.2 to 22.0 μg/m3,with an average of 5.1 μg/m3.The diurnai variation of BC exhibited a bimodal distribution,with peaks at 07:00 and 18:00.The morning peak was larger than the evening peak.The mass percentages of BC in PM2.5 and PM10 were 7.1%and 4.8%,respectively.The absorption coefficient of BC was calculated to be 44.4 Mm-1,which accounted for 11.1%of the total aerosol extinction.BC was mainly emitted from local sources in southwestern Jiaxing where BC concentrations were generally greater than 11 μg/m3 during the measurement period.Correlation analysis indicated that the main sources of BC were motor vehicle exhaust,and domestic and industrial combustion. 相似文献
33.
V. A. Bespalov V. M. Glazov E. A. Il’ichev Yu. A. Klimov S. V. Kuklev A. E. Kuleshov R. M. Nabiev G. N. Petrukhin B. G. Potapov G. S. Rychkov D. S. Sokolov V. V. Fandeev E. A. Fetisov S. S. Yakushov 《Technical Physics》2015,60(4):553-560
The results of investigation of optical image detectors designed for the largest problem, near-VUV, range of the spectrum are presented. The possibility of using a dual-stage image detection system to appreciably lower the sensitivity threshold and make computer data processing feasible is considered. The integration of a UV module into a wideband image detector is studied. 相似文献
34.
35.
Applied Magnetic Resonance - The suggested approach allowed us to derive analytical expressions for modeling the shape of solid-echo signal and its time evolution for a system of three-spin groups... 相似文献
36.
37.
Inside Cover: Photoinduced Formation of an Azobenzene‐Based CD‐Active Supramolecular Cyclic Dimer (Chem. Eur. J. 18/2015)
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
38.
39.
Polypyrrole Shell@3D‐Ni Metal Core Structured Electrodes for High‐Performance Supercapacitors
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Gao‐Feng Chen Yu‐Zhi Su Pan‐Yong Kuang Zhao‐Qing Liu Dao‐Yi Chen Xu Wu Nan Li Prof. Shi‐Zhang Qiao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(12):4614-4621
Three‐dimensional (3D) nanometal films serving as current collectors have attracted much interest recently owing to their promising application in high‐performance supercapacitors. In the process of the electrochemical reaction, the 3D structure can provide a short diffusion path for fast ion transport, and the highly conductive nanometal may serve as a backbone for facile electron transfer. In this work, a novel polypyrrole (PPy) shell@3D‐Ni‐core composite is developed to enhance the electrochemical performance of conventional PPy. With the introduction of a Ni metal core, the as‐prepared material exhibits a high specific capacitance (726 F g?1 at a charge/discharge rate of 1 A g?1), good rate capability (a decay of 33 % in Csp with charge/discharge rates increasing from 1 to 20 A g?1), and high cycle stability (only a small decrease of 4.2 % in Csp after 1000 cycles at a scan rate of 100 mV s?1). Furthermore, an aqueous symmetric supercapacitor device is fabricated by using the as‐prepared composite as electrodes; the device demonstrates a high energy density (≈21.2 Wh kg?1) and superior long‐term cycle ability (only 4.4 % and 18.6 % loss in Csp after 2000 and 5000 cycles, respectively). 相似文献
40.