全文获取类型
收费全文 | 5933篇 |
免费 | 788篇 |
国内免费 | 840篇 |
专业分类
化学 | 4351篇 |
晶体学 | 56篇 |
力学 | 491篇 |
综合类 | 61篇 |
数学 | 643篇 |
物理学 | 1959篇 |
出版年
2024年 | 13篇 |
2023年 | 94篇 |
2022年 | 181篇 |
2021年 | 237篇 |
2020年 | 267篇 |
2019年 | 232篇 |
2018年 | 191篇 |
2017年 | 206篇 |
2016年 | 246篇 |
2015年 | 243篇 |
2014年 | 294篇 |
2013年 | 397篇 |
2012年 | 488篇 |
2011年 | 518篇 |
2010年 | 360篇 |
2009年 | 318篇 |
2008年 | 368篇 |
2007年 | 301篇 |
2006年 | 318篇 |
2005年 | 292篇 |
2004年 | 213篇 |
2003年 | 200篇 |
2002年 | 195篇 |
2001年 | 155篇 |
2000年 | 138篇 |
1999年 | 165篇 |
1998年 | 117篇 |
1997年 | 107篇 |
1996年 | 116篇 |
1995年 | 83篇 |
1994年 | 59篇 |
1993年 | 72篇 |
1992年 | 57篇 |
1991年 | 57篇 |
1990年 | 43篇 |
1989年 | 39篇 |
1988年 | 25篇 |
1987年 | 18篇 |
1986年 | 18篇 |
1985年 | 18篇 |
1984年 | 12篇 |
1983年 | 14篇 |
1982年 | 12篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1973年 | 7篇 |
1972年 | 5篇 |
1970年 | 4篇 |
排序方式: 共有7561条查询结果,搜索用时 171 毫秒
101.
Qin Ren Hong Jin Zhang Xiao Kang Zhang Bao Tong Huang 《Journal of polymer science. Part A, Polymer chemistry》1993,31(4):847-851
To get hydrogenated polybutadiene-polymethyl methacrylate (HPB-b-PMMA) block copolymer to be used as a compatibilizer for blends of polyolefin/polar polymer, PB-b-PMMA was synthesized by anionic-free radical mechanism transformation polymerization. Selective extraction, gradient elution thin layer chromatography, and oil-oil emulsion separation techniques were tried to attempt to separate the copolymerization products. Hydrogenation of the PB sequence in PB-b-PMMA yielded HPB-b-PMMA. The compatibilizing function of PB-b-PMMA was shown in blending experiments. © 1993 John Wiley & Sons, Inc. 相似文献
102.
The interaction of water-soluble porphyrin TPPS(4) (tetraphenylporphyrin tetrasulfonate) with proteins in acidic solution was studied by spectrophotometry. The absorption spectra of TPPS(4)-protein complexes, the aggregation of TPPS(4) in acidic solution, and comparison of the absorption spectra of TPPS(4)-protein conjugate with that of the TPPS(4)-protein complex was investigated in detail. The effects of denaturants including urea and SDS were also examined. A mechanism was proposed that TPPS(4) would be distributed between microphase of protein and the aqueous solution and then aggregated in the microphase. 相似文献
103.
Jing Li Huayi Shi Runzhi Chen Xiaofeng Wu Jiayi Cheng Fenglin Dong Houyu Wang Yao He 《Chemical science》2021,12(3):896
Synthesis of programmable atom-like nanoparticles (PANs) with high valences and high yields remains a grand challenge. Here, a novel synthetic strategy of microfluidic galvanic displacement (μ-GD) coupled with microfluidic DNA nanoassembly is advanced for synthesis of single-stranded DNA encoder (SSE)-encoded PANs for reliable surface-enhanced Raman scattering (SERS) sensing. Notably, PANs with high valences (e.g., n-valence, n = 12) are synthesized with high yields (e.g., >80%) owing to the effective control of interfacial reactions sequentially occurring in the microfluidic system. On the basis of this, we present the first demonstration of a PAN-based automatic analytical platform, in which sensor construction, sample loading and on-line monitoring are carried out in the microfluidic system, thus guaranteeing reliable quantitative measurement. In the proof-of-concept demonstration, accurate determination of tetracycline (TET) in serum and milk samples with a high recovery close to 100% and a low relative standard deviation (RSD) less than 5.0% is achieved by using this integrated analytical platform.A novel synthetic strategy is presented for microfluidic preparation of programmable atom-like nanoparticles with high valences and high yields. 相似文献
104.
Proteins are continuously synthesized during cell growth and proliferation. At the same time, excessive and misfolded proteins have to be degraded, otherwise they are a burden to cells. Protein degradation is essential to maintain proteostasis in cells, and dysfunction of protein degradation systems results in numerous diseases such as cancer and neurodegenerative diseases. Despite the importance of protein degradation, the degradation pathways of many proteins remain to be explored. Here, we comprehensively investigated the degradation of newly synthesized proteins in human cells by integrating metabolic labeling, click chemistry, and multiplexed proteomics, and systematic and quantitative analysis of newly synthesized proteins first revealed the degradation pathways of many proteins. Bioinformatic analysis demonstrates that proteins degraded through two major pathways have distinct properties and functions. Proteins degraded through the ubiquitin-proteasome pathway contain more disordered structures, whereas those through the autophagy-lysosome pathway have significantly higher hydrophobicity. Systematic and quantitative investigation of the dynamics of newly synthesized proteins provides unprecedented and valuable information about protein degradation, which leads to a better understanding of protein properties and cellular activities.Systematic quantification of the dynamics of newly synthesized proteins first reveals the degradation pathways of many proteins in human cells, and proteins degraded through each of the two major pathways have distinct properties and functions. 相似文献
105.
Tong ZHAO 《数学年刊B辑(英文版)》2022,43(2):195-208
This paper characterizes the limits of a large system of interacting particles distributed on the real line. The interaction occurring among neighbors involves two kinds of independent actions with different rates. This system is a generalization of the voter process, of which each particle is of type A or a. Under suitable scaling, the local proportion functions of A particles converge to continuous functions which solve a class of stochastic partial differential equations driven by Fisher-Wrig... 相似文献
106.
Given a family of Riemann surfaces and a holomorphic vector bundle Beilinson and Schechtman construct a canonical connection on the associated determinant bundle. We prove the conjecture which states that their connection coincides with the Quillen connection. This is done by reducing to the case where
along fibers are invertible. Both connection forms become more accessible in this case.Supported in part by N.S.F. Grant No. DMS-9201022Supported in part by National Science Council of Republic of China Grant No. NSC 82-0208-M-002-125-T, and NSERC of Canada Grant No. OGP 0121883 相似文献
107.
108.
109.
110.