全文获取类型
收费全文 | 293722篇 |
免费 | 4751篇 |
国内免费 | 795篇 |
专业分类
化学 | 168678篇 |
晶体学 | 3693篇 |
力学 | 10457篇 |
综合类 | 10篇 |
数学 | 36552篇 |
物理学 | 79878篇 |
出版年
2021年 | 2773篇 |
2020年 | 3157篇 |
2019年 | 3457篇 |
2018年 | 4801篇 |
2017年 | 4481篇 |
2016年 | 6905篇 |
2015年 | 4657篇 |
2014年 | 6202篇 |
2013年 | 14105篇 |
2012年 | 12222篇 |
2011年 | 14031篇 |
2010年 | 9506篇 |
2009年 | 8851篇 |
2008年 | 12947篇 |
2007年 | 12972篇 |
2006年 | 11865篇 |
2005年 | 10913篇 |
2004年 | 9514篇 |
2003年 | 8326篇 |
2002年 | 7838篇 |
2001年 | 7370篇 |
2000年 | 5941篇 |
1999年 | 4421篇 |
1998年 | 3753篇 |
1997年 | 3705篇 |
1996年 | 3701篇 |
1995年 | 2909篇 |
1994年 | 3061篇 |
1993年 | 3123篇 |
1992年 | 3260篇 |
1991年 | 3180篇 |
1990年 | 3033篇 |
1989年 | 2980篇 |
1988年 | 2870篇 |
1987年 | 2846篇 |
1986年 | 2723篇 |
1985年 | 3608篇 |
1984年 | 3723篇 |
1983年 | 2934篇 |
1982年 | 3292篇 |
1981年 | 3130篇 |
1980年 | 2887篇 |
1979年 | 3078篇 |
1978年 | 3169篇 |
1977年 | 3146篇 |
1976年 | 3167篇 |
1975年 | 2985篇 |
1974年 | 2948篇 |
1973年 | 3131篇 |
1972年 | 2018篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Isaeva A. I. Maikov E. Gibizova V. V. Petrova G. P. 《Journal of Applied Spectroscopy》2021,88(4):789-793
Journal of Applied Spectroscopy - Aqueous solutions of human hemoglobin have been studied by the multi-angle static light scattering method. The tendency of sickle-shaped erythrocytes to aggregate... 相似文献
102.
Stolpovskaya N. V. Kruzhilin A. A. Zorina A. V. Shikhaliev Kh. S. Ledeneva I. V. Kosheleva E. A. Vandyshev D. Yu. 《Russian Journal of Organic Chemistry》2019,55(9):1322-1328
Russian Journal of Organic Chemistry - A procedure has been proposed for the synthesis of a series of substituted N-(1,3-thiazol-2-yl)-pyrimidin-2-amines and N-(pyrimidin-2-yl)thioureas by... 相似文献
103.
Tagouegni Senghor Fotsa-Ngaffo Fernande Kenfack-Jiotsa Aurélien 《Optical and Quantum Electronics》2022,54(3):1-57
Optical and Quantum Electronics - In the past few decades, the academic research and industrial synergy is dramatically accelerating to conceptualize high data rate services. The congestion in the... 相似文献
104.
Adly M. E. Gedawy E. M. El-Malah A. A. El-Telbany F. A. 《Russian Journal of Organic Chemistry》2019,55(8):1189-1196
Russian Journal of Organic Chemistry - Selenopheno[2,3-d]pyrimidine- and selenopheno[2,3-d][1,2,3]triazine-containing compounds were synthesized starting from... 相似文献
105.
It is known that under resonance conditions, a group of strongly interacting bosonic atoms, trapped in a double-well potential, mimics a single particle, performing Rabi oscillations between the wells. By implication, all atoms need to tunnel at roughly the same time, even though the Bose–Hubbard Hamiltonian accounts only for one-atom-at-a-time transfers. The mechanism of this collective behavior is analyzed, the Rabi frequencies in the process are evaluated, and the limitation of this simple picture is discussed. In particular, it is shown that the small rapid oscillations superimposed on the slow Rabi cycle result from splitting the transferred cluster at the sudden onset of tunnelling, and disappear if tunnelling is turned on gradually. 相似文献
106.
Nováková Kateřina Hrdlička Vojtěch Navrátil Tomáš Vyskočil Vlastimil Barek Jiří 《Monatshefte für Chemie / Chemical Monthly》2015,146(5):761-769
Monatshefte für Chemie - Chemical Monthly - The voltammetric behavior of 5-nitroindazole was investigated at polished (p-AgSAE) and at mercury meniscus-modified (m-AgSAE) silver solid amalgam... 相似文献
107.
Synthesis of partially fluorinated poly(arylene ether sulfone) multiblock copolymers bearing perfluorosulfonic functions 下载免费PDF全文
Luca Assumma Cristina Iojoiu Régis Mercier Sandrine Lyonnard Huu Dat Nguyen Emilie Planes 《Journal of polymer science. Part A, Polymer chemistry》2015,53(16):1941-1956
Partially fluorinated poly(arylene ether sulfone) multiblock copolymers bearing perfluorosulfonic functions (ps‐PES‐FPES), with ionic exchange capacity (IEC) ranging between 0.9 and 1.5 meq H+/g, are synthesized by regioselective bromination of partially fluorinated poly(arylene ether sulfone) multiblock copolymers (PES‐FPES), followed by Ullman coupling reaction with lithium 1,1,2,2‐tetrafluoro‐2‐(1,1,2,2‐tetrafluoro‐2‐iodoethoxy)ethanesulfonate. The PES‐FPES are prepared by aromatic nucleophilic substitution reaction by an original approach, that is, “one pot two reactions synthesis.” The chemical structures of polymers are analyzed by 1H and 19F NMR spectroscopy. The resulted ionomers present two distinct glass transitions and α relaxations revealing phase separation between the hydrophilic and the hydrophobic domains. The phase separation is observed at much lower block lengths of ps‐PES‐FPES as compared with the literature. AFM and SANS observations supported the phase separation, the hydrophilic domains are well dispersed but the connectivity to each other depends on the ps‐PES block lengths. The thermomechanical behavior, the water up‐take, and the conductivity of the ps‐PES‐FPES membranes are compared with those of Nafion 117® and randomly functionalized polysulfone (ps‐PES). Conductivities close or higher to those of Nafion 117® are obtained. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1941–1956 相似文献
108.
Saleh Z. M. Nasser H. Özkol E. Günöven M. Abak K. Canli S. Bek A. Turan R. 《Journal of nanoparticle research》2015,17(10):1-12
Journal of Nanoparticle Research - Plasmonic interfaces consisting of silver nanoparticles of different sizes (50–100&;nbsp;nm) have been processed by the self-assembled dewetting... 相似文献
109.
E. V. Shadrina O. N. Malinkina T. G. Khonina A. B. Shipovskaya V. I. Fomina E. Yu. Larchenko N. A. Popova I. G. Zyryanova L. P. Larionov 《Russian Chemical Bulletin》2015,64(7):1633-1639
The biomimetic sol—gel synthesis of silicon—chitosan-containing glycerohydrogels was carried out using silicon tetraglycerolate as a precursor. It was found that chitosan accelerates gel formation in weakly acidic media. In more acidic media, the kinetics of the process changes according to the curve with a maximum, which can be attributed to different mechanisms of silanol condensation before and after the isoelectric point. The investigated silicon—chitosan-containing glycerohydrogels exhibit antibacterial, anti-inflammatory, and wound healing activity. The synthesized hybrid glycerohydrogels are promising materials for biomedical applications. 相似文献
110.