全文获取类型
收费全文 | 645篇 |
免费 | 21篇 |
国内免费 | 1篇 |
专业分类
化学 | 518篇 |
晶体学 | 5篇 |
力学 | 7篇 |
数学 | 41篇 |
物理学 | 96篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 9篇 |
2020年 | 12篇 |
2019年 | 11篇 |
2018年 | 8篇 |
2017年 | 10篇 |
2016年 | 15篇 |
2015年 | 11篇 |
2014年 | 17篇 |
2013年 | 30篇 |
2012年 | 41篇 |
2011年 | 39篇 |
2010年 | 24篇 |
2009年 | 27篇 |
2008年 | 44篇 |
2007年 | 47篇 |
2006年 | 36篇 |
2005年 | 32篇 |
2004年 | 41篇 |
2003年 | 29篇 |
2002年 | 18篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1998年 | 9篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 13篇 |
1993年 | 5篇 |
1992年 | 10篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1967年 | 2篇 |
1964年 | 4篇 |
1956年 | 4篇 |
1955年 | 4篇 |
1954年 | 3篇 |
1909年 | 2篇 |
排序方式: 共有667条查询结果,搜索用时 922 毫秒
41.
42.
Yoshitaka Yoda Yasuhiko Imai Hisao Kobayashi Syunji Goto Kunikazu Takeshita Makoto Seto 《Hyperfine Interactions》2012,206(1-3):83-86
An Upgrade of the nuclear resonant scattering beamline, BL09XU in SPring-8 has been conducted. A liquid nitrogen cooled high-heat load monochromator was installed and a 2nd experimental hutch was constructed. The instruments installed in the hutch allow for a variety of sample conditions. Newly developed high-resolution monochromators with better stability including the back scattering geometry monochromator have opened up the easy access to more isotopes and more precise measurements. 相似文献
43.
Saeed Kamali Hongxin Wang Devrani Mitra Hideaki Ogata Wolfgang Lubitz Brian C. Manor Thomas B. Rauchfuss Deborah Byrne Violaine Bonnefoy Francis E. Jenney Michael W. W. Adams Yoshitaka Yoda Ercan Alp Jiyong Zhao Stephen P. Cramer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2013,125(2):752-756
44.
Naoya Hosoda Hideaki Kamito Miki Takano Yoshitaka Takebe Yoshitaka Yamaguchi Masatoshi Asami 《Tetrahedron》2013,69(6):1739-1746
Chiral diamines, 2-(anilinophenylmethyl)pyrrolidines and 2-(anilinodiphenylmethyl)pyrrolidine, were prepared from N-(tert-butoxycarbonyl)pyrrolidine or (S)-proline as a starting material, respectively. These chiral diamines were efficient for the catalytic enantioselective borane reduction of acetophenone. Using (S)-2-(anilinodiphenylmethyl)pyrrolidine, chiral secondary alcohols were obtained from prochiral ketones with good to excellent enantiomeric excesses (up to 98% ee). 相似文献
45.
Oleg Tkachenko Abdur Rahim Andrey Baraban Ruslan Sukhov Inna Khristenko Yoshitaka Gushikem Yuriy Kholin 《Journal of Sol-Gel Science and Technology》2013,66(1):145-154
A sol–gel based hybrid process was developed by manipulating different techniques in sol–gel process to synthesize γ-alumina and (CuO, CuO + ZnO) doped γ-alumina spherical particles. Catalysts having spherical geometry have an important advantage over powders or pellets which are impervious to fluids, when packed in a reactor. Boehmite sol was used as alumina precursor for synthesizing porous γ-alumina and doped materials. γ-alumina particles having 5 wt% CuO, 4 wt% CuO + 1 wt% ZnO, 3 wt% CuO + 2 wt% ZnO and 2 wt% CuO + 3 wt% ZnO were prepared by adding required amounts of Cu(NO3)2 and Zn(NO3)2 solutions prior to gelation of the sol. Methanol dehydration studies were carried out by employing these synthesized catalysts. Hundred percent conversion of methanol to dimethyl ether was observed with (4 wt% CuO + 1 wt% ZnO)-γ-alumina and (5 wt% CuO)-γ-alumina microspheres at 325 and 350 °C, respectively. 相似文献
46.
Prof. Dr. Hiromitsu Maeda Wataru Hane Dr. Yuya Bando Dr. Yoshitaka Terashima Dr. Yohei Haketa Hiroshi Shibaguchi Prof. Dr. Tsuyoshi Kawai Prof. Dr. Masanobu Naito Dr. Kazuto Takaishi Prof. Dr. Masanobu Uchiyama Dr. Atsuya Muranaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(48):16263-16271
Anion‐responsive π‐conjugated compounds having chiral alkyl chains were synthesized. Circular dichroism (CD) and circularly polarized luminescence (CPL) were observed in the solution‐state assemblies of the chiral anion receptors and those of their anion complexes as salts of a planar triazatriangulenium cation. The CD and CPL spectral patterns of the ion‐pair‐based assemblies were completely opposite to those of the anion‐free assemblies, and this suggests that anion binding and subsequent ion pairing change the chirality of the assembly modes. 相似文献
47.
Dual Catalysis with Copper and Rhenium for Trifluoromethylation of Propargylic Alcohols: Efficient Synthesis of α‐Trifluoromethylated Enones
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. Hiromichi Egami Takafumi Ide Masashi Fujita Toshifumi Tojo Prof.Dr. Yoshitaka Hamashima Prof.Dr. Mikiko Sodeoka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(38):12061-12065
Trifluoromethylation of propargylic alcohols to provide (Z)‐α‐trifluoromethylated enones and β‐unsubstituted α‐trifluoromethylated enones proceeded with high yield and selectivity in the presence of CuI/Re2O7. The Z isomer was formed under kinetic control, though it is less stable than the E isomer in terms of steric repulsion. 相似文献
48.
Dr. Henry S. La Pierre Dr. Hajime Kameo MSc. Dominik P. Halter Dr. Frank W. Heinemann Prof. Dr. Karsten Meyer 《Angewandte Chemie (International ed. in English)》2014,53(28):7154-7157
Synthetic studies on the redox chemistry of trivalent uranium monoarene complexes were undertaken with a complex derived from the chelating tris(aryloxide)arene ligand (Ad,MeArO)3mes3?. Cyclic voltammetry of [{(Ad,MeArO)3mes}UIII] ( 1 ) revealed a nearly reversible and chemically accessible reduction at ?2.495 V vs. Fc/Fc+—the first electrochemical evidence for a formally divalent uranium complex. Chemical reduction of 1 indicates that reduction induces coordination and redox isomerization to form a uranium(IV) hydride, and addition of a crown ether results in hydride insertion into the coordinated arene to afford uranium(IV) complexes. This stoichiometric reaction sequence provides structural insight into the mechanism of arene functionalization at diuranium inverted sandwich complexes. 相似文献
49.
Yukiko Yasuoka Yuichiro Izumi Takashi Fukuyama Haruki Omiya Truyen D. Pham Hideki Inoue Tomomi Oshima Taiga Yamazaki Takayuki Uematsu Noritada Kobayashi Yoshitaka Shimada Yasushi Nagaba Tetsuro Yamashita Masashi Mukoyama Yuichi Sato Susan M. Wall Jeff M. Sands Noriko Takahashi Katsumasa Kawahara Hiroshi Nonoguchi 《Molecules (Basel, Switzerland)》2022,27(3)
Anemia is a major complication of chronic renal failure. To treat this anemia, prolylhydroxylase domain enzyme (PHD) inhibitors as well as erythropoiesis-stimulating agents (ESAs) have been used. Although PHD inhibitors rapidly stimulate erythropoietin (Epo) production, the precise sites of Epo production following the administration of these drugs have not been identified. We developed a novel method for the detection of the Epo protein that employs deglycosylation-coupled Western blotting. With protein deglycosylation, tissue Epo contents can be quantified over an extremely wide range. Using this method, we examined the effects of the PHD inhibitor, Roxadustat (ROX), and severe hypoxia on Epo production in various tissues in rats. We observed that ROX increased Epo mRNA expression in both the kidneys and liver. However, Epo protein was detected in the kidneys but not in the liver. Epo protein was also detected in the salivary glands, spleen, epididymis and ovaries. However, both PHD inhibitors (ROX) and severe hypoxia increased the Epo protein abundance only in the kidneys. These data show that, while Epo is produced in many tissues, PHD inhibitors as well as severe hypoxia regulate Epo production only in the kidneys. 相似文献
50.
In the presence of a catalytic amount of ammonium chiral borate salt, asymmetric Friedel-Crafts alkylation of indoles with α,β-disubstituted enals proceeded to give the corresponding 1,4-addition products with moderate enantioselectivities. 相似文献