全文获取类型
收费全文 | 17602篇 |
免费 | 5164篇 |
国内免费 | 2790篇 |
专业分类
化学 | 2090篇 |
晶体学 | 176篇 |
力学 | 2490篇 |
综合类 | 871篇 |
数学 | 7884篇 |
物理学 | 12045篇 |
出版年
2024年 | 171篇 |
2023年 | 449篇 |
2022年 | 573篇 |
2021年 | 663篇 |
2020年 | 456篇 |
2019年 | 560篇 |
2018年 | 406篇 |
2017年 | 616篇 |
2016年 | 714篇 |
2015年 | 759篇 |
2014年 | 1399篇 |
2013年 | 912篇 |
2012年 | 989篇 |
2011年 | 1101篇 |
2010年 | 1102篇 |
2009年 | 1171篇 |
2008年 | 1427篇 |
2007年 | 1211篇 |
2006年 | 1147篇 |
2005年 | 1132篇 |
2004年 | 1044篇 |
2003年 | 904篇 |
2002年 | 785篇 |
2001年 | 759篇 |
2000年 | 626篇 |
1999年 | 602篇 |
1998年 | 498篇 |
1997年 | 449篇 |
1996年 | 436篇 |
1995年 | 406篇 |
1994年 | 408篇 |
1993年 | 328篇 |
1992年 | 332篇 |
1991年 | 300篇 |
1990年 | 282篇 |
1989年 | 238篇 |
1988年 | 83篇 |
1987年 | 53篇 |
1986年 | 18篇 |
1985年 | 16篇 |
1984年 | 2篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1980年 | 1篇 |
1959年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 2 毫秒
41.
A functional equation of nonlinear iterates is discussed on the circle S1 for its continuous solutions and differentiable solutions. By lifting to R, the existence, uniqueness and stability of those solutions are obtained. Techniques of continuation are used to guarantee the preservation of continuity and differentiability in lifting. 相似文献
42.
Laboratory Studies of the Stratified Rotating Flow Passing over an Isolated Obstacle 总被引:6,自引:0,他引:6 下载免费PDF全文
We study the flow of a density-stratified fluid passing over an isolated obstacle,using towing-tank experiments.Our special concern is the response of the flow with different Froude numbers passing over a three-dimensional obstacle.A series of experiments of the stratified rotating flow passing over an isolated obstacle was carried out with the towering -tank controlled by the similarity laws and dynamic non-dimension parameters.These experiments show that the Froude number is a very important parameter,and the lee wave and the eddy structure experiments show that the Froude number is a very important parameter,and the lee wave and the eddy structure appear simultaneously under an appropriate conditions.The effect of rotation on the lee wave is mainly to change wave amplitude,particularly to restrain the development of the lee wave and to promote the formation of an eddy. 相似文献
43.
用微分脉冲溶出伏安法研究了镍(11)与酸性铬兰K(ACBK)所生成的络合物在悬汞电极上的电化学特性及电化学反应机理,发现电极反应为镍与酸性铬兰K所生成的络合物吸附在电极表面后发生的不可逆还原。在HCl-硼砂介质中(pH8.67),络合物在-316mV处有一吸附还原峰,其峰电流与镍浓度在0.001~0.010μ/mL范围内呈现良好的线性关系,其最低检出浓度为0.0005μg/mL。 相似文献
44.
46.
Banach空间二阶周期边值问题解的存在性 总被引:2,自引:0,他引:2
利用一些比较结果,讨论了Banach空间中二阶周期边值问题解的存在性,获得了若干解的存在性与唯一性结果。 相似文献
47.
48.
KANG Zihua WANG Mingwei QIAN Jiamei RAO Jun LI Xiujuan ZHENG Tieliu WANG Xuehua 《核工业西南物理研究院年报(英文版)》2004,(1):73-76
Lower hybrid wave (LHW), electro cyclotron (EC) and neutral beam injection (NBI) etc. are the important methods of auxiliary heating. They would be devoted to the HL-2A tokamak step by step. In order to satisfy the debug of each system and the need of the experiment, the system should be equipped with high voltage pulse power (HVPP) according to the requirement. 相似文献
49.
WANGFeng ZHAOJunwei LIHongsheng 《声学学报:英文版》2003,22(3):268-273
A kind of Combined Constant Modulus Algorithm (CCMA) is presented to compensate the defects of the Constant Modulus Algorithm (CMA) and the Sign Error CMA (SECMA). And CCMA is applied to the equalization of the underwater acoustic channel (UWAC). Based on the decision of the equalizer‘s output, its iteration process switches between CMA and SECMA automatically. It is more robust than SECMA, and more computationally efficient than CMA. Therefore, it is very suitable for the recovery of the underwater data transmission. The performance of CCMA is proven by computer simulation for the equalization of the UWAC. 相似文献
50.
We study the energy density in quark-gluon plasma. At the very high temperature, the quark matter is a hot and dense matter in the colour deconfinement condition, and quarks can coalescent diquarks. Energy density of this system is worked out and compared with the energy density in the other two kinds of situations. Possible energy density is about ε0≈2.4 GeV/fm^3 according to our estimation for quark matter including diquarks. 相似文献