全文获取类型
收费全文 | 208139篇 |
免费 | 2978篇 |
国内免费 | 862篇 |
专业分类
化学 | 115344篇 |
晶体学 | 3710篇 |
力学 | 8249篇 |
综合类 | 14篇 |
数学 | 19747篇 |
物理学 | 64915篇 |
出版年
2020年 | 1906篇 |
2019年 | 2098篇 |
2018年 | 2383篇 |
2017年 | 2498篇 |
2016年 | 3780篇 |
2015年 | 2447篇 |
2014年 | 3864篇 |
2013年 | 9533篇 |
2012年 | 7111篇 |
2011年 | 8601篇 |
2010年 | 6080篇 |
2009年 | 6036篇 |
2008年 | 7575篇 |
2007年 | 7464篇 |
2006年 | 7056篇 |
2005年 | 6338篇 |
2004年 | 5755篇 |
2003年 | 5287篇 |
2002年 | 5055篇 |
2001年 | 6244篇 |
2000年 | 4712篇 |
1999年 | 3612篇 |
1998年 | 2811篇 |
1997年 | 2761篇 |
1996年 | 2680篇 |
1995年 | 2481篇 |
1994年 | 2376篇 |
1993年 | 2209篇 |
1992年 | 2861篇 |
1991年 | 2760篇 |
1990年 | 2703篇 |
1989年 | 2718篇 |
1988年 | 2732篇 |
1987年 | 2749篇 |
1986年 | 2603篇 |
1985年 | 3317篇 |
1984年 | 3328篇 |
1983年 | 2611篇 |
1982年 | 2722篇 |
1981年 | 2773篇 |
1980年 | 2541篇 |
1979年 | 2880篇 |
1978年 | 2865篇 |
1977年 | 2987篇 |
1976年 | 2822篇 |
1975年 | 2556篇 |
1974年 | 2513篇 |
1973年 | 2467篇 |
1972年 | 1704篇 |
1968年 | 1704篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
Rajkumar P. Diwakar K. Subadevi R. Gnanamuthu R. M. Wang Fu-Ming Liu Wei-Ren Sivakumar M. 《Journal of Solid State Electrochemistry》2021,25(3):939-948
Journal of Solid State Electrochemistry - The “shuttle effect” of polysulfides is a serious issue, resulting in a decrease in the life-cycle of lithium-sulfur (Li-S) batteries. To... 相似文献
33.
Journal of Thermal Analysis and Calorimetry - Low productivity of single-slope solar still is the main barrier for its worldwide usability. An attempt has been conducted to enhance the distillate... 相似文献
34.
Ramesh G. K. Manjunatha S. Roopa G. S. Chamkha Ali J. 《Journal of Thermal Analysis and Calorimetry》2021,146(3):1347-1357
Journal of Thermal Analysis and Calorimetry - Modeling and computations are performed to study the ND-Co3O4/EG hybrid nanoliquid mixed convective flow past a vertical porous cylinder. The flow... 相似文献
35.
36.
37.
38.
A nanomaterials-based novel molecular beacon has attracted growing attentions in fluorescent assays as many nanomaterials possess excellent quenching efficiency. In this work, a gold-based nanobeacon probe was established to detect organophosphorus pesticides for the first time. The constructed gold-based nanobeacon acted as a signal indicator and could display the decreasing of the intensity in the presence of targets, which competitively bound to single strand DNA. To achieve a high sensitive probe, some parameters including solution pH, temperature and reaction time were investigated and optimized. The gold-based nanobeacon probe assay was proved to be rapid and sensitive to achieve a detection limit of 0.035 μM for isocarbophos, 0.134 μM for profenofos, 0.384 μM for phorate and 2.35 μM for omethoate, respectively. The prepared nanobeacon effectively reduced the background and improved the detection sensitivity and selectivity. The probe is stable, easy to operate and does not need sophisticated instruments. These features makes the probe feasible for screening trace organophosphorus pesticides in real samples. 相似文献
39.
S. Q. Hou W. Wang Z. Y. Wang Z. W. Hu K. Liu 《Journal of Applied Mechanics and Technical Physics》2018,59(1):153-162
In order to investigate the characteristics of force chains in a granular flow system, a parallel plate shear cell is constructed to simulate the shear movement of an infinite parallel plate and observe variations in relevant parameters. The shear dilatancy process is divided into three stages, namely, plastic strain, macroscopic failure, and granular recombination. The stickslip phenomenon is highly connected with the evolution of force chains during the shear dilatancy process. The load–distribution rate curves and patterns of the force chains are utilized to describe the load-carrying behaviors and morphologic changes of force chains separately. Force chains, namely, “diagonal gridding,” “tadpole-shaped,” and “pinnate” are defined according to the form of the force chains in the corresponding three stages. 相似文献
40.