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排序方式: 共有662条查询结果,搜索用时 859 毫秒
31.
Piao He Jian‐Guo Zhang Li‐Na Feng Kun Wang Tong‐Lai Zhang Shao‐Wen Zhang 《Journal of Physical Organic Chemistry》2015,28(6):423-427
1,5‐Daminotetrazole (DAT) is of much interest because of the practical significance and the diversity of characteristics. The study on the decomposition pathway and the kinetics of DAT has been performed based on the quantum chemistry theory. The minimum energy path (MEP) calculation has shown that NH2N3 and NH2CN are the initially detected products of DAT. And the structures of reactant, products and transition state were optimized with MP2 methods using 6‐311G** basis sets, and the energies were refined using CCSD(T)/6‐311G** levels of theory. The calculated rate constants were obtained using the conventional transition‐state theory (TST) and the canonical variational transition‐state theory (CVT) methods. The calculation results indicated that the energy barrier of decomposition reaction is 47.98 kcal mol?1 and the variational effect is small. In addition, the rate constants and the Arrhenius experience formula of DAT decomposition have been obtained between 200 and 2500 K temperature regions. The fitted three‐parameter expressions calculated using the TST and CVT methods are (TST) and (CVT). This work may provide the theoretical support for further experimental synthesis and testing. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
32.
Dr. Long Jiao Dr. Weijie Yang Dr. Gang Wan Rui Zhang Dr. Xusheng Zheng Dr. Hua Zhou Prof. Dr. Shu-Hong Yu Prof. Dr. Hai-Long Jiang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(46):20770-20776
Single-atom catalysts (SACs) are of great interest because of their ultrahigh activity and selectivity. However, it is difficult to construct model SACs according to a general synthetic method, and therefore, discerning differences in activity of diverse single-atom catalysts is not straightforward. Herein, a general strategy for synthesis of single-atom metals implanted in N-doped carbon (M1-N-C; M=Fe, Co, Ni and Cu) has been developed starting from multivariate metal–organic frameworks (MOFs). The M1-N-C catalysts, featuring identical chemical environments and supports, provided an ideal platform for differentiating the activity of single-atom metal species. When employed in electrocatalytic CO2 reduction, Ni1-N-C exhibited a very high CO Faradaic efficiency (FE) up to 96.8 % that far surpassed Fe1-, Co1- and Cu1-N-C. Remarkably, the best-performer, Ni1-N-C, even demonstrated excellent CO FE at low CO2 pressures, thereby representing a promising opportunity for the direct use of dilute CO2 feedstock. 相似文献
33.
Chao Wang Jiafang Piao Yujie Li Xiancheng Tian Yuanchen Dong Dongsheng Liu 《Angewandte Chemie (International ed. in English)》2020,59(35):15176-15180
The shape of eukaryotic cells is determined by the cytoskeleton associated with membrane proteins; however, the detailed mechanism of how the integral morphologies with structural stability is generated and maintained is still not fully understood. Here, based on the Frame‐Guided Assembly (FGA) strategy, we successfully prepared hetero‐liposomes with structural composition similar to that of eukaryotic cells by screening a series of transmembrane peptides as the leading hydrophobic groups (LHGs). It was demonstrated that the conformation and transmembrane mode of the LHGs played dominant roles during the FGA process. The FGA liposomes were formed with excellent stability, which may further provide evidence for the cytoskeleton–membrane protein–lipid bilayer model. Taking advantage of the biocompatibility and stability, the FGA liposomes were also applied to prepare novel drug delivery vehicles, which is promising in diagnostic imaging and cancer therapy applications. 相似文献
34.
组合生成算法与多元线性回归相结合用于近红外光谱波长的优选 总被引:6,自引:0,他引:6
分立波长型近红外光谱分析仪是光谱分析仪器中较为普及的一种快速成份定量分析仪。如滤光片型、发光二极管型等。该类分析仪器研发的一个主要问题是如何针对于待测物质主要成份进行近红外光谱解析。找到最优定标波长组合用于建立稳健的定标模型。常用的波长选择方法为相关光谱结合逐步多元线性回归方法,该方法依据各参与定标波长所对应的t检验值进行最优定标波长的判别,但在实际应用中定标模型的定标精度和预测精度相差较大,具有很大的不准确性。为了实现定标波长的优选引入了组合数学中的组合生成算法。可以在较短的时间内完成最优波长组合的选取,结果是令人满意的。 相似文献
35.
36.
Ping-Zhu Zhang Hai-Long Yang Cui-Cui Li Zhi-Chao Xia Xiao-Man Wang Hua Wei Rui-Xue Rong Zhi-Ran Cao Ke-Rang Wang Hua Chen Xiao-Liu Li 《中国化学快报》2014,25(7):1057-1059
A series of novel, azasugar-modified 2-monosubstituted, 2,6- and 2,7-bissubstituted anthraquinone derivatives have been synthesized by the nucleophilic substitution of N-alkylamino azasugar with mono-, bis(2-chloroacetamido)anthraquinones. Their cytotoxic activities against HeLa and MCF-7 ceils were preliminarily evaluated and compound 9a with mono-azasugar pendant at 2-position showed similar activity to the control drug (Cisplatin). 相似文献
37.
蛋白酪氨酸磷酸酶1B(PTP1B)作为胰岛素和瘦素信号转导通路的负调节因子,已成为治疗糖尿病和肥胖症的潜在靶标.为了寻找非磷酸酯类PTP1B抑制剂,设计、合成了一系列含3,4-二氢-2(1H)-喹啉酮结构的新型查尔酮衍生物,并对化合物进行了PTP1B抑制活性测定.结果显示,所有化合物对PTP1B均显示出较强的抑制活性,其中化合物(E)-6-{4-[3-(4-氯苯基)-3-氧代-1-丙烯基]苄氧基}-3,4-二氢-2(1H)-喹啉酮(4e)和(E)-6-{4-[3-(3-溴苯基)-3-氧代-1-丙烯基]苄氧基}-3,4-二氢-2(1H)-喹啉酮(4i)活性最佳,IC50分别为(4.64±0.38)和(4.36±0.41)μmol/L. 相似文献
38.
摘 要:基于第一性原理的计算方法,建立了本征石墨烯、空位石墨烯及钇( Y)掺杂空位石墨烯模型,并计算了CO、NO在三类石墨烯表面的吸附过程. 从表面能、吸附结构、吸附能和态密度四个方面进行分析讨论,研究掺杂Y对CO、NO气体吸附性能的影响. 结果表明:CO、NO与本征石墨烯之间的吸附为弱的物理吸附,掺杂Y后增强了材料表面对CO、NO的吸附效果,最大吸附能分别为7.414eV、6.702eV,属于化学吸附;掺杂Y使空位石墨烯费米能级附近有了更多的活跃电子,其吸附NO后体系由半金属转变为金属特性,该特性能为开发更加优良的石墨烯气敏材料提供理论支持. 相似文献
39.
40.
Wen Piao Satoru Tsuda Dr. Yuji Tanaka Dr. Satoshi Maeda Dr. Fengyi Liu Shodai Takahashi Yu Kushida Dr. Toru Komatsu Dr. Tasuku Ueno Dr. Takuya Terai Prof. Toru Nakazawa Prof. Masanobu Uchiyama Prof. Keiji Morokuma Prof. Tetsuo Nagano Dr. Kenjiro Hanaoka 《Angewandte Chemie (International ed. in English)》2013,52(49):13028-13032