全文获取类型
收费全文 | 21165篇 |
免费 | 166篇 |
国内免费 | 90篇 |
专业分类
化学 | 10664篇 |
晶体学 | 444篇 |
力学 | 621篇 |
综合类 | 7篇 |
数学 | 1781篇 |
物理学 | 7904篇 |
出版年
2017年 | 164篇 |
2016年 | 256篇 |
2015年 | 181篇 |
2014年 | 289篇 |
2013年 | 878篇 |
2012年 | 611篇 |
2011年 | 670篇 |
2010年 | 493篇 |
2009年 | 494篇 |
2008年 | 653篇 |
2007年 | 715篇 |
2006年 | 667篇 |
2005年 | 605篇 |
2004年 | 519篇 |
2003年 | 497篇 |
2002年 | 482篇 |
2001年 | 707篇 |
2000年 | 525篇 |
1999年 | 440篇 |
1998年 | 361篇 |
1997年 | 344篇 |
1996年 | 321篇 |
1995年 | 387篇 |
1994年 | 356篇 |
1993年 | 332篇 |
1992年 | 355篇 |
1991年 | 395篇 |
1990年 | 370篇 |
1989年 | 376篇 |
1988年 | 341篇 |
1987年 | 343篇 |
1986年 | 336篇 |
1985年 | 415篇 |
1984年 | 432篇 |
1983年 | 323篇 |
1982年 | 329篇 |
1981年 | 350篇 |
1980年 | 326篇 |
1979年 | 342篇 |
1978年 | 338篇 |
1977年 | 314篇 |
1976年 | 336篇 |
1975年 | 297篇 |
1974年 | 285篇 |
1973年 | 299篇 |
1972年 | 184篇 |
1969年 | 160篇 |
1968年 | 189篇 |
1967年 | 335篇 |
1966年 | 285篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
991.
992.
993.
Mechanics of Composite Materials - The shapes of force–displacement curves recorded in single-fiber pullout and microbond tests are analyzed within the framework of a stress-based model of... 相似文献
994.
Dr. Anna Notaro Marta Jakubaszek Severin Koch Dr. Riccardo Rubbiani Dr. Orsolya Dömötör Dr. Éva A. Enyedy Mazzarine Dotou Dr. Fethi Bedioui Mickaël Tharaud Dr. Bruno Goud PD Dr. Stefano Ferrari Prof. Dr. Enzo Alessio Dr. Gilles Gasser 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(22):4997-5009
Cancer is one of the main causes of death worldwide. Chemotherapy, despite its severe side effects, is to date one of the leading strategies against cancer. Metal-based drugs present several potential advantages when compared to organic compounds and they have gained trust from the scientific community after the approval on the market of the drug cisplatin. Recently, we reported the ruthenium complex ([Ru(DIP)2(sq)](PF6) (where DIP is 4,7-diphenyl-1,10-phenantroline and sq is semiquinonate) with a remarkable potential as chemotherapeutic agent against cancer, both in vitro and in vivo. In this work, we analyse a structurally similar compound, namely [Ru(DIP)2(mal)](PF6), carrying the flavour-enhancing agent approved by the FDA, maltol (mal). To possess an FDA approved ligand is crucial for a complex, whose mechanism of action might include ligand exchange. Herein, we describe the synthesis and characterisation of [Ru(DIP)2(mal)](PF6), its stability in solutions and under conditions that resemble the physiological ones, and its in-depth biological investigation. Cytotoxicity tests on different cell lines in 2D model and on HeLa MultiCellular Tumour Spheroids (MCTS) demonstrated that our compound has higher activity than cisplatin, inspiring further tests. [Ru(DIP)2(mal)](PF6) was efficiently internalised by HeLa cells through a passive transport mechanism and severely affected the mitochondrial metabolism. 相似文献
995.
Eric C. Chi Liuyi Hu Arvind K. Saibaba Arvind U. K. Rao 《Journal of computational and graphical statistics》2019,28(1):36-47
We consider the problem of performing matrix completion with side information on row-by-row and column-by-column similarities. We build upon recent proposals for matrix estimation with smoothness constraints with respect to row and column graphs. We present a novel iterative procedure for directly minimizing an information criterion to select an appropriate amount of row and column smoothing, namely, to perform model selection. We also discuss how to exploit the special structure of the problem to scale up the estimation and model selection procedure via the Hutchinson estimator, combined with a stochastic Quasi-Newton approach. Supplementary material for this article is available online. 相似文献
996.
Birgit U. Jaki Anton Bzhelyansky Guido F. Pauli 《Magnetic resonance in chemistry : MRC》2021,59(1):7-15
In the last two decades, quantitative NMR (qNMR) has become increasingly important for the analysis of pharmaceuticals, chemicals, and natural products including dietary supplements. For the purpose of quality control and chemical standardization of a large variety of pharmaceutical, chemical, and medicinal products, qNMR has proven to be a valuable orthogonal quantification method and a compelling alternative to chromatographic techniques. This work reviews a fundamental component of the early development of qNMR, reflected in the pioneering work of the late George M. Hanna during the years between 1984 and 2006 at the US Food and Drug Administration (FDA). Because Hanna performed the majority of his groundbreaking work on a 90‐MHz instrument, his legacy output connects with recent progress in low‐field benchtop NMR instrumentation. Hanna gradually established the utility of qNMR for the routine quality control analyses practiced in pharmaceutical and related operations well ahead of his peers. His work has the potential to inspire new developments in qNMR applied to small molecules of biomedical importance. 相似文献
997.
JPC – Journal of Planar Chromatography – Modern TLC - Commiphora mukul of the family Burseraceae, commonly known as guggul, is commonly used worldwide. The major phytoconstituents... 相似文献
998.
999.
1000.
V. L. Y. Loke G. M. Huda E. U. Donev V. Schmidt J. T. Hastings M. Pinar Mengüç T. Wriedt 《Applied physics. B, Lasers and optics》2014,115(2):237-246
We investigate the plasmonic response of gold nanospheres calculated using discrete dipole approximation validated against the results from other discretization methods, namely the finite-difference time-domain method and the finite-element methods. Comparisons are also made with calculations from analytical methods such as the Mie solution and the null-field method with discrete sources. We consider the nanoparticle interacting with the incident field both in free space and sitting on a planar substrate. In the latter case, discrete dipole approximation with surface interaction is used; this includes the interaction with the ‘image dipoles’ using Sommerfeld integration. 相似文献