全文获取类型
收费全文 | 102860篇 |
免费 | 17945篇 |
国内免费 | 10117篇 |
专业分类
化学 | 69900篇 |
晶体学 | 1217篇 |
力学 | 6855篇 |
综合类 | 545篇 |
数学 | 11985篇 |
物理学 | 40420篇 |
出版年
2024年 | 101篇 |
2023年 | 2119篇 |
2022年 | 2260篇 |
2021年 | 3425篇 |
2020年 | 4303篇 |
2019年 | 4138篇 |
2018年 | 3518篇 |
2017年 | 3250篇 |
2016年 | 5098篇 |
2015年 | 4821篇 |
2014年 | 5908篇 |
2013年 | 7669篇 |
2012年 | 9359篇 |
2011年 | 9886篇 |
2010年 | 6500篇 |
2009年 | 6228篇 |
2008年 | 6604篇 |
2007年 | 6046篇 |
2006年 | 5531篇 |
2005年 | 4624篇 |
2004年 | 3415篇 |
2003年 | 2675篇 |
2002年 | 2423篇 |
2001年 | 1981篇 |
2000年 | 1654篇 |
1999年 | 1967篇 |
1998年 | 1779篇 |
1997年 | 1659篇 |
1996年 | 1812篇 |
1995年 | 1488篇 |
1994年 | 1449篇 |
1993年 | 1156篇 |
1992年 | 1061篇 |
1991年 | 983篇 |
1990年 | 790篇 |
1989年 | 563篇 |
1988年 | 461篇 |
1987年 | 380篇 |
1986年 | 371篇 |
1985年 | 319篇 |
1984年 | 240篇 |
1983年 | 153篇 |
1982年 | 139篇 |
1981年 | 106篇 |
1980年 | 76篇 |
1979年 | 43篇 |
1978年 | 34篇 |
1976年 | 36篇 |
1975年 | 33篇 |
1974年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This article uses the shrinking projection method introduced by Takahashi, Kubota and Takeuchi to propose an iteration algorithm for a countable family of Bregman multi-valued quasi-nonexpansive mappings in order to have the strong convergence under a limit condition in the framework of reflexive Banach spaces. We apply our results to a zero point problem of maximal monotone mappings and equilibrium problems in reflexive Banach spaces. The results presented in the article improve and extend the corresponding results of that found in the literature. 相似文献
992.
Lin Feng Wang Ze Yu Zhang Liang Zhao Yu Jie Zhou 《Mathematical Methods in the Applied Sciences》2017,40(4):992-1002
We prove that on a smooth metric measure space with m ?Bakry–Émery curvature bounded from below by ?(m ? 1)K for some constant K ≥0 (i.e., Ricf ,m ≥?(m ? 1)K ), the following degenerate elliptic equation (0.1) has no nonconstant positive solution when p > 1 and constant λ f ,p satisfies Our approach is based on the local Sobolev inequality and the Moser's iterative technique and is different from Cheng‐Yau's method, which was used by Wang‐Zhu in 2012 to derive a same Liouville theorem when 1 < p ≤2, Ricf ,m ≥?(m ? 1)K and the sectional curvature is bounded from below. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
993.
In this paper, we are interested in exploring the dynamic causal relationships among two sets of three variables in different quarters. One set is futures sugar closing price in Zhengzhou futures exchange market (ZC), spot sugar price in Zhengzhou (ZS) and futures sugar closing price in New York futures exchange market(NC) and the other includes futures sugar opening price in Zhengzhou (ZO), ZS and NC. For each quarter, we first use Bayesian model selection to obtain the optimal causal graph with the highest BD scores and then use Bayesian model averaging approach to explore the causal relationship between every two variables. From the real data analysis, the two conclusions almost coincide, which shows that the two methods are practical. 相似文献
994.
Guangwu Wang Boling Guo Shaomei Fang 《Mathematical Methods in the Applied Sciences》2017,40(14):5262-5272
In this paper, we will firstly extend the results about Jiu, Wang, and Xin (JDE, 2015, 259, 2981–3003). We prove that any smooth solution of compressible fluid will blow up without any restriction about the specific heat ratio γ. Then we prove the blow‐up of smooth solution of compressible Navier–Stokes equations in half space with Navier‐slip boundary. The main ideal is constructing the differential inequality. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
995.
Threshold dynamics of a nonlinear multi‐group epidemic model with two infinite distributed delays 下载免费PDF全文
Xiaomei Feng Kai Wang Fengqin Zhang Zhidong Teng 《Mathematical Methods in the Applied Sciences》2017,40(7):2762-2771
The global stability of equilibria is investigated for a nonlinear multi‐group epidemic model with latency and relapses described by two distributed delays. The results show that the global dynamics are completely determined by the basic reproduction number under certain reasonable conditions on the nonlinear incidence rate. Moreover, compared with the results in Michael Y. Li and Zhisheng Shuai, Journal Differential Equations 248 (2010) 1–20, it is found that the two distributed delays have no impact on the global behaviour of the model. Our study improves and extends some known results in recent literature. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
996.
Composite generalized Laguerre spectral method for nonlinear Fokker–Planck equations on the whole line 下载免费PDF全文
Tian‐jun Wang 《Mathematical Methods in the Applied Sciences》2017,40(5):1462-1474
In this paper, we propose a composite Laguerre spectral method for the nonlinear Fokker–Planck equations modelling the relaxation of fermion and boson gases. A composite Laguerre spectral scheme is constructed. Its convergence is proved. Numerical results show the efficiency of this approach and coincide well with theoretical analysis. Some results on the Laguerre approximation and techniques used in this paper are also applicable to other nonlinear problems on the whole line. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
997.
On the decay and blow‐up of solution for coupled nonlinear wave equations with nonlinear damping and source terms 下载免费PDF全文
In this work, we consider a nonlinear coupled wave equations with initial‐boundary value conditions and nonlinear damping and source terms. Under suitable assumptions on the damping terms and source terms and initial data in the stable set, we obtain that the decay estimates of the energy function is exponential or polynomial by using Nakao's method. By using the energy method, we obtain the blow‐up result of solution with some positive or nonpositive initial energy. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
998.
Yongqiao Wang Donghe Pei Xiupeng Cui 《Mathematical Methods in the Applied Sciences》2017,40(18):7151-7161
We introduce the notions of the pseudospherical normal Darboux images for the curve on a lightlike surface in Minkowski 3‐space and study these Darboux images by using technics of the singularity theory. Furthermore, we give a relation between these Darboux images and Darboux frame from the viewpoint of Legendrian dualities. 相似文献
999.
Exact boundary controllability for 1‐D quasilinear wave equations with dynamical boundary conditions 下载免费PDF全文
Yue Wang Günter Leugering Tatsien Li 《Mathematical Methods in the Applied Sciences》2017,40(10):3808-3820
By equivalently replacing the dynamical boundary condition by a kind of nonlocal boundary conditions, and noting a hidden regularity of solution on the boundary with a dynamical boundary condition, a constructive method with modular structure is used to get the local exact boundary controllability for 1‐D quasilinear wave equations with dynamical boundary conditions. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
1000.
Wenyan Chen Xiaoliu Wang Ming Yang 《Mathematical Methods in the Applied Sciences》2017,40(10):3775-3783
Under the shrinking curvature flow with inner normal velocity V = kα(α > 1), it is shown that highly symmetric, locally convex initial curves evolve into a point asymptotically like an multi‐circles. The proof relies on a crucial use of Bonnensen inequality for highly symmetric, locally convex curves. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献