全文获取类型
收费全文 | 3329篇 |
免费 | 102篇 |
国内免费 | 10篇 |
专业分类
化学 | 2269篇 |
晶体学 | 40篇 |
力学 | 104篇 |
数学 | 211篇 |
物理学 | 817篇 |
出版年
2023年 | 35篇 |
2022年 | 41篇 |
2021年 | 72篇 |
2020年 | 65篇 |
2019年 | 90篇 |
2018年 | 66篇 |
2017年 | 74篇 |
2016年 | 110篇 |
2015年 | 66篇 |
2014年 | 95篇 |
2013年 | 299篇 |
2012年 | 184篇 |
2011年 | 254篇 |
2010年 | 146篇 |
2009年 | 123篇 |
2008年 | 158篇 |
2007年 | 133篇 |
2006年 | 107篇 |
2005年 | 98篇 |
2004年 | 98篇 |
2003年 | 70篇 |
2002年 | 80篇 |
2001年 | 51篇 |
2000年 | 49篇 |
1999年 | 35篇 |
1997年 | 27篇 |
1996年 | 34篇 |
1995年 | 30篇 |
1994年 | 27篇 |
1993年 | 37篇 |
1992年 | 23篇 |
1991年 | 17篇 |
1989年 | 19篇 |
1988年 | 32篇 |
1987年 | 23篇 |
1986年 | 21篇 |
1985年 | 34篇 |
1984年 | 29篇 |
1983年 | 29篇 |
1981年 | 24篇 |
1980年 | 35篇 |
1979年 | 28篇 |
1978年 | 30篇 |
1977年 | 31篇 |
1976年 | 16篇 |
1975年 | 18篇 |
1966年 | 25篇 |
1965年 | 18篇 |
1963年 | 17篇 |
1962年 | 43篇 |
排序方式: 共有3441条查询结果,搜索用时 31 毫秒
1.
Russian Journal of Organic Chemistry - A highly efficient green protocol has been proposed for the synthesis of symmetrical S-aryl arenesulfonothioates by irradiation of N-hydroxy arenesulfonamides... 相似文献
2.
Journal of Applied Spectroscopy - The elemental composition of one- and two-rupee coins issued in different years by the Reserve Bank of India (RBI) was investigated using laser-induced breakdown... 相似文献
3.
The serine protease, DegP exhibits proteolytic and chaperone activities, essential for cellular protein quality control and normal cell development in eukaryotes. The P. falciparum DegP is essential for the parasite survival and required to combat the oscillating thermal stress conditions during the infection, protein quality checks and protein homeostasis in the extra-cytoplasmic compartments, thereby establishing it as a potential target for drug development against malaria. Previous studies have shown that diisopropyl fluorophosphate (DFP) and the peptide SPMFKGV inhibit E. coli DegP protease activity. To identify novel potential inhibitors specific to PfDegP allosteric and the catalytic binding sites, we performed a high throughput in silico screening using Malaria Box, Pathogen Box, Maybridge library, ChEMBL library and the library of FDA approved compounds. The screening helped identify five best binders that showed high affinity to PfDegP allosteric (T0873, T2823, T2801, , CD00811) and the catalytic binding site (T0078L, T1524, T2328, BTB11534 and 552691). Further, molecular dynamics simulation analysis revealed RJC02337, BTB11534 as the best hits forming a stable complex. WaterMap and electrostatic complementarity were used to evaluate the novel bio-isosteric chemotypes of RJC02337, that led to the identification of 231 chemotypes that exhibited better binding affinity. Further analysis of the top 5 chemotypes, based on better binding affinity, revealed that the addition of electron donors like nitrogen and sulphur to the side chains of butanoate group are more favoured than the backbone of butanoate group. In a nutshell, the present study helps identify novel, potent and Plasmodium specific inhibitors, using high throughput in silico screening and bio-isosteric replacement, which may be experimentally validated. RJC02337相似文献
4.
Savita Verma Deepak M. Maher Samadhan S. Nagane Bhausaheb V. Tawade Prakash P. Wadgaonkar 《Journal of polymer science. Part A, Polymer chemistry》2019,57(5):588-597
New aromatic (co)polyesters containing pendant propargyloxy groups were synthesized by phase transfer‐catalyzed interfacial polycondensation of 5‐(propargyloxy)isophthaloyl chloride (P‐IPC) and various compositions of P‐IPC and isophthaloyl chloride with bisphenol A. FTIR and NMR spectroscopic data, respectively, revealed successful incorporation of pendant propargyloxy groups into (co)polyesters and formation of (co)polyesters with desired compositions. (Co)polyesters exhibited good solubility in common organic solvents such as chloroform, dichloromethane, and tetrahydrofuran and could be cast into transparent, flexible, and tough films from chloroform solution. Inherent viscosities and number average molecular weights of (co)polyesters were in the range 0.77–1.33 dL/g and 43,600–118,000 g/mol, respectively, indicating the achievement of reasonably high‐molecular weights. The 10% weight loss temperatures of (co)polyesters were in the range 390–420 °C, demonstrating their good thermal stability. (Co)polyesters exhibited Tg in the range 146–170 °C and Tg values decreased with increase in mol % incorporation of P‐IPC. The study of non‐isothermal curing by DSC indicated thermal crosslinking of (co)polyesters via propargyloxy groups. The utility of pendant propargyloxy group was demonstrated by post‐modification of the selected copolyester with 1‐(4‐azidobutyl)pyrene, 9‐(azidomethyl)anthracene, and azido‐terminated poly(ethyleneglycol) monomethyl ether via copper(I)‐catalyzed Huisgen 1,3‐dipolar cycloaddition reaction. FTIR and 1H NMR spectra confirmed that click reaction was quantitative. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 588–597 相似文献
5.
6.
7.
Properties of nonparametric estimators of autocovariance for stationary random fields 总被引:1,自引:0,他引:1
Summary We introduce nonparametric estimators of the autocovariance of a stationary random field. One of our estimators has the property that it is itself an autocovatiance. This feature enables the estimator to be used as the basis of simulation studies such as those which are necessary when constructing bootstrap confidence intervals for unknown parameters. Unlike estimators proposed recently by other authors, our own do not require assumptions such as isotropy or monotonicity. Indeed, like nonparametric function estimators considered more widely in the context of curve estimation, our approach demands only smoothness and tail conditions on the underlying curve or surface (here, the autocovariance), and moment and mixing conditions on the random field. We show that by imposing the condition that the estimator be a covariance function we actually reduce the numerical value of integrated squared error. 相似文献
8.
V Ravindran Pankaj Agrawal Rahul Basu Satyaki Bhattacharya J Blümlein V Del Duca R Harlander D Kosower Prakash Mathews Anurag Tripathi 《Pramana》2006,67(5):983-992
This is the report of the subgroup QCD of Working Group-4 at WHEPP-9. We present the activities that had taken place in the
subgroup and report some of the partial results arrived at following the discussion at the working group meetings. 相似文献
9.
Satya Prakash 《Pramana》1989,33(1):109-131
This article summarizes the recent radiochemical investigations on mass, charge kinetic energy and fragment angular distributions
in low energy fission of actinides. 相似文献
10.
Over the last two decades many strategies have been planned to design specific drugs for rare diseases to target their action
at the DNA level. Advancements in our understanding of the interactions of small nonpeptide molecules with DNA have opened
the doors for “rational” drug design. Special methods have now been developed to give accurate account of the precise location
of ligand-DNA adducts on target DNA. We are now in a position to think of designing ligands that recognize particular sequences
of base pairs. This work will allow us to enter into a new era of gene therapy for diseases like Cystic fibrosis, Alzheimer’s
disease and many related disorders at genetic level. These ligands can also be employed in the treatment of various types
of cancers. They may also be useful as highly specific probes to locate particular sequences in the genomic DNA. 相似文献