全文获取类型
收费全文 | 4115篇 |
免费 | 132篇 |
国内免费 | 10篇 |
专业分类
化学 | 2216篇 |
晶体学 | 27篇 |
力学 | 127篇 |
数学 | 456篇 |
物理学 | 1431篇 |
出版年
2022年 | 37篇 |
2021年 | 63篇 |
2020年 | 75篇 |
2019年 | 75篇 |
2018年 | 86篇 |
2017年 | 59篇 |
2016年 | 109篇 |
2015年 | 80篇 |
2014年 | 104篇 |
2013年 | 253篇 |
2012年 | 226篇 |
2011年 | 263篇 |
2010年 | 161篇 |
2009年 | 148篇 |
2008年 | 210篇 |
2007年 | 206篇 |
2006年 | 217篇 |
2005年 | 183篇 |
2004年 | 127篇 |
2003年 | 115篇 |
2002年 | 101篇 |
2001年 | 76篇 |
2000年 | 75篇 |
1999年 | 43篇 |
1998年 | 39篇 |
1997年 | 38篇 |
1996年 | 42篇 |
1995年 | 48篇 |
1994年 | 43篇 |
1993年 | 54篇 |
1992年 | 43篇 |
1991年 | 33篇 |
1990年 | 49篇 |
1989年 | 40篇 |
1988年 | 37篇 |
1987年 | 38篇 |
1986年 | 29篇 |
1985年 | 44篇 |
1984年 | 38篇 |
1983年 | 39篇 |
1982年 | 35篇 |
1981年 | 33篇 |
1980年 | 38篇 |
1979年 | 32篇 |
1978年 | 37篇 |
1977年 | 33篇 |
1976年 | 37篇 |
1975年 | 30篇 |
1974年 | 34篇 |
1973年 | 36篇 |
排序方式: 共有4257条查询结果,搜索用时 15 毫秒
1.
Archiv der Mathematik - Let G be a simple simply-connected connected linear algebraic group over $${\mathbb {C}}$$ . We prove a 2-birational Torelli theorem for the moduli space of semistable... 相似文献
2.
Molecular Diversity - Tuberculosis (TB) is an infectious disease and the leading cause of death globally. The rapidly emerging cases of drug resistance among pathogenic mycobacteria have been a... 相似文献
3.
Surbhi Grewal Pravesh Kumar Dr. Saonli Roy Dr. Indu Bala Dr. Chitranjan Sah Dr. Santanu Kumar Pal Dr. Sugumar Venkataramani 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(19):e202104602
Two tripodal C3-symmetric photoswitchable molecular systems T1 and T2 are reported that have extended conjugation at external and internal positions using an acryl group. The influence of the extended π-bonds in their absorption properties, thermal relaxation of the photoisomers and their propensities in forming supramolecular self-assemblies have been explored through spectroscopy, and microscopic studies. In particular, the investigations on the self-assembly have been carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), polarized optical microscopy (POM), X-ray diffraction studies (XRD) and atomic force microscopy (AFM). Remarkably, the position of the acryl group influences the behaviour of the two target molecules in supramolecular assembly, and also in the formation of photoresponsive organic hydrogels or microcrystals. 相似文献
4.
Seema Yadav Sriparna Ray Ajeet Singh Shaikh M. Mobin Tapta Kanchan Roy Chandrakanta Dash 《应用有机金属化学》2020,34(11):e5942
Dinuclear gold(I)-N-heterocyclic carbene complexes were developed for the hydrohydrazidation of terminal alkynes. The gold(I)-N-heterocyclic carbene complexes 2a-2b were synthesized in good yields from silver complexes synthesized in situ, which in turn were obtained from the corresponding imidazolium salts with Ag2O in dichloromethane as a solvent. The new air-stable gold(I)-NHC complexes, 2a - 2b, were characterized using NMR spectroscopy, elemental analysis, infrared, and mass spectroscopy studies. The gold(I) complex 2a was characterized using X-ray crystallography. Bis-N-heterocyclic carbene–based gold(I) complexes 2a - 2b exhibited excellent catalytic activities for hydrohydrazidation of terminal alkynes yielding acylhydrazone derivatives. The working catalytic system can be used in gram-scale synthesis. In addition, the catalytic reaction mechanism of the hydrohydrazidation of terminal alkynes by gold(I)-NHC complex was studied in detail using density functional theory. 相似文献
5.
Sing Lai Cong Roy Anitha Hui Lok Yong Mun Chan Sook Rajak Harish Karunakaran Rohini Ravichandran Veerasamy 《Structural chemistry》2022,33(3):649-669
Structural Chemistry - Quinoline- and acridine-based drugs are widely used as anti-breast cancer agents. These drugs act through various mechanisms of action; for example, neratinib acts on... 相似文献
6.
7.
Back Cover: Activation of Elemental Sulfur at a Two‐Coordinate Platinum(0) Center (Chem. Eur. J. 36/2016) 下载免费PDF全文
8.
9.
Multidrug‐Containing,Salt‐Based,Injectable Supramolecular Gels for Self‐Delivery,Cell Imaging and Other Materials Applications 下载免费PDF全文
Rajdip Roy Prof. Parthasarathi Dastidar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(42):14929-14939
Both molecular and crystal‐engineering approaches were exploited to synthesize a new class of multidrug‐containing supramolecular gelators. A well‐known nonsteroidal anti‐inflammatory drug, namely, indomethacin, was conjugated with six different l ‐amino acids to generate the corresponding peptides having free carboxylic acid functionality, which reacted further with an antiviral drug, namely, amantadine, a primary amine, in 1:1 ratio to yield six primary ammonium monocarboxylate salts. Half of the synthesized salts showed gelation ability that included hydrogelation, organogelation and ambidextrous gelation. The gels were characterized by table‐top and dynamic rheology and different microscopic techniques. Further insights into the gelation mechanism were obtained by temperature‐dependent 1H NMR spectroscopy, FTIR spectroscopy, photoluminescence and dynamic light scattering. Single‐crystal X‐ray diffraction studies on two gelator salts revealed the presence of 2D hydrogen‐bonded networks. One such ambidextrous gelator (capable of gelling both pure water and methyl salicylate, which are important solvents for biological applications) was promising in both mechanical (rheoreversible and injectable) and biological (self‐delivery) applications for future multidrug‐containing injectable delivery vehicles. 相似文献
10.
Investigation of N‐Heterocyclic Carbene‐Supported Group 12 Triflates as Pre‐catalysts for Hydrosilylation/Borylation 下载免费PDF全文
Matthew M. D. Roy Dr. Michael J. Ferguson Dr. Robert McDonald Prof. Dr. Eric Rivard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(50):18236-18246
N‐Heterocyclic carbene (NHC) complexes of Cd and Hg triflates (OTf) were prepared and their attempted conversion into rare cadmium and mercury hydrides was explored. In contrast to zinc, which forms stable [ZnH]+ complexes with NHCs, the heavier Cd and Hg congeners could not be formed; the increased instability of Cd‐H and Hg‐H units was rationalized with the aid of computations. It was also discovered that the dimeric adduct [IPr?Cd(μ‐OTf)2]2 (IPr=[(HCNDipp)2C:]; Dipp=2,6‐iPr2C6H3) is an active precatalyst for the hydrosilylation and hydroborylation of hindered aldehydes and ketones. The related zinc congener was inactive as a catalyst highlighting a distinct advantage of using heavy Group 12 metals to promote catalytic hydrosilylation/borylation. 相似文献