全文获取类型
收费全文 | 1036篇 |
免费 | 29篇 |
国内免费 | 8篇 |
专业分类
化学 | 489篇 |
晶体学 | 17篇 |
力学 | 30篇 |
数学 | 137篇 |
物理学 | 400篇 |
出版年
2020年 | 8篇 |
2019年 | 15篇 |
2018年 | 10篇 |
2017年 | 12篇 |
2016年 | 13篇 |
2015年 | 16篇 |
2014年 | 24篇 |
2013年 | 61篇 |
2012年 | 32篇 |
2011年 | 50篇 |
2010年 | 17篇 |
2009年 | 23篇 |
2008年 | 39篇 |
2007年 | 41篇 |
2006年 | 43篇 |
2005年 | 51篇 |
2004年 | 29篇 |
2003年 | 31篇 |
2002年 | 28篇 |
2001年 | 26篇 |
2000年 | 16篇 |
1999年 | 13篇 |
1998年 | 9篇 |
1997年 | 12篇 |
1996年 | 24篇 |
1995年 | 13篇 |
1994年 | 11篇 |
1993年 | 19篇 |
1992年 | 13篇 |
1991年 | 13篇 |
1990年 | 21篇 |
1989年 | 32篇 |
1988年 | 24篇 |
1987年 | 24篇 |
1986年 | 10篇 |
1985年 | 29篇 |
1984年 | 18篇 |
1983年 | 8篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 19篇 |
1978年 | 18篇 |
1977年 | 15篇 |
1976年 | 14篇 |
1975年 | 12篇 |
1974年 | 10篇 |
1973年 | 7篇 |
1972年 | 8篇 |
1971年 | 8篇 |
1969年 | 8篇 |
排序方式: 共有1073条查询结果,搜索用时 31 毫秒
61.
Carolina Resmini Melo Elidio Angioletto Humberto Gracher Riella Michael Peterson Márcio Roberto Rocha Aline Resmini Melo Luciano Silva Susane Strugale 《Journal of Thermal Analysis and Calorimetry》2012,109(3):1341-1345
Research focused on the transformation and utilization of industrial wastes into products of commercial interest plays an increasingly important role. Residual pulp can become useful in the manufacture of different materials, providing high value to this waste and reducing its environmental impact when disposed of improperly in the environment. The main constituents of this waste are kaolin and calcium carbonate (CaCO3). Starting from kaolin, metakaolin can be produced by calcination of the residue at 630?°C for 2?h in a rotary reactor with air flow, followed by solubilization with hydrochloric acid to remove the CaCO3. The development of technological alternatives aimed at the reuse of certain wastes can result in applications of real economic interest to the chemical industry and ceramics and glass, which is the case in this study. The raw material and metakaolin obtained were analyzed by thermogravimetric analysis and derivative thermogravimetric analysis, X-ray diffraction, and X-ray fluorescence spectroscopy with promising results. This is because metakaolin was obtained free of contamination by other materials. 相似文献
62.
63.
Detoxification of Chemical Warfare Agents Using a Zr6‐Based Metal–Organic Framework/Polymer Mixture
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)
Dr. Su‐Young Moon Emmanuel Proussaloglou Gregory W. Peterson Dr. Jared B. DeCoste Morgan G. Hall Dr. Ashlee J. Howarth Prof. Joseph T. Hupp Prof. Omar K. Farha 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(42):14864-14868
Owing to their high surface area, periodic distribution of metal sites, and water stability, zirconium‐based metal–organic frameworks (Zr6‐MOFs) have shown promising activity for the hydrolysis of nerve agents GD and VX, as well as the simulant, dimethyl 4‐nitrophenylphosphate (DMNP), in buffered solutions. A hurdle to using MOFs for this application is the current need for a buffer solution. Here the destruction of the simulant DMNP, as well as the chemical warfare agents (GD and VX) through hydrolysis using a MOF catalyst mixed with a non‐volatile, water‐insoluble, heterogeneous buffer is reported. The hydrolysis of the simulant and nerve agents in the presence of the heterogeneous buffer was fast and effective. 相似文献
64.
65.
Chemical inhibitors, whether natural products or synthetic, have had an enormous impact on the study of the eukaryotic cytoskeleton. Here we review the history of some of the most widely used cytoskeletal poisons and their influence on our understanding of cytoskeletal functions. We then highlight several new inhibitors and the targeted screens used to identify them and discuss why this approach has been successful. 相似文献
66.
67.
Bornheim A Lipeles E Pappas SP Shapiro A Sun WM Weinstein AJ Masek G Paar HP Mahapatra R Morrison RJ Briere RA Chen GP Ferguson T Tatishvili G Vogel H Adam NE Alexander JP Bebek C Berkelman K Blanc F Boisvert V Cassel DG Drell PS Duboscq JE Ecklund KM Ehrlich R Gibbons L Gittelman B Gray SW Hartill DL Heltsley BK Hsu L Jones CD Kandaswamy J Kreinick DL Magerkurth A Mahlke-Krüger H Meyer TO Mistry NB Nordberg E Palmer M Patterson JR Peterson D Pivarski J Riley D Sadoff AJ Schwarthoff H 《Physical review letters》2002,88(23):231803
We report a new measurement of the Cabibbo-Kobayashi-Maskawa parameter Vub made with a sample of 9.7 x 10(6) BB- events collected with the CLEO II detector. Using heavy quark theory, we combine the observed yield of leptons from semileptonic B decay in the end-point momentum interval 2.2-2.6 GeV/c with recent CLEO II data on B-->X(s)gamma to find Vub = (4.08+/-0.34+/-0.44+/-0.16+/-0.24)x10(-3), where the first two uncertainties are experimental and the last two are from theory. 相似文献
68.
Addition of sodium/potassium alloy to THF solutions containing dodecamethylcyclohexasilane and a diene or a silane, affords silacyclopentenes and disilanes, respectively. 相似文献
69.
Host sensitized energy transfer in CaWO4 doped with Eu3+ and Sm3+ is investigated using pulsed laser time-resolved spectroscopy techniques. The excitation is into the long wavelength tail of the absorption edge and the results indicate that this selectively excites tungstate ions which are located next to activator impurity ions. The subsequent energy transfer is found to be consistent with a single step, nearest neighbor process. Both electric dipole-dipole and exchange interactions can predict strong enough transfer to account for the observed rates. These results are compared to those obtained previously for broad band excitation into the highest energy absorption bands of CaWO4 crystals. 相似文献
70.
S. F. Peterson F. Tera G. H. Morrison 《Journal of Radioanalytical and Nuclear Chemistry》1969,2(1-2):115-125
Isotopic ion exchange for the rapid separation of radioactive mixtures has been further extended through the use of an acetone-water-hydrochloric
acid system. Distribution data were obtained for 27 elements in the range of 15–90% acetone, 0.3N HCl indicating a number of new separations. The approach was used for the separation of several radioisotopes from short
half-life magnesium matrix for activation analysis. The separations were completed in less than 5 minutes.
Research supported by the Advanced Research Projects Agency. 相似文献