全文获取类型
收费全文 | 14756篇 |
免费 | 2674篇 |
国内免费 | 2169篇 |
专业分类
化学 | 10906篇 |
晶体学 | 155篇 |
力学 | 869篇 |
综合类 | 150篇 |
数学 | 1905篇 |
物理学 | 5614篇 |
出版年
2024年 | 15篇 |
2023年 | 302篇 |
2022年 | 363篇 |
2021年 | 493篇 |
2020年 | 627篇 |
2019年 | 702篇 |
2018年 | 527篇 |
2017年 | 504篇 |
2016年 | 724篇 |
2015年 | 770篇 |
2014年 | 921篇 |
2013年 | 1132篇 |
2012年 | 1364篇 |
2011年 | 1411篇 |
2010年 | 997篇 |
2009年 | 1017篇 |
2008年 | 1043篇 |
2007年 | 881篇 |
2006年 | 824篇 |
2005年 | 668篇 |
2004年 | 562篇 |
2003年 | 440篇 |
2002年 | 467篇 |
2001年 | 378篇 |
2000年 | 299篇 |
1999年 | 326篇 |
1998年 | 255篇 |
1997年 | 220篇 |
1996年 | 197篇 |
1995年 | 176篇 |
1994年 | 146篇 |
1993年 | 156篇 |
1992年 | 101篇 |
1991年 | 99篇 |
1990年 | 86篇 |
1989年 | 81篇 |
1988年 | 70篇 |
1987年 | 39篇 |
1986年 | 40篇 |
1985年 | 47篇 |
1984年 | 29篇 |
1983年 | 18篇 |
1982年 | 24篇 |
1981年 | 11篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1973年 | 3篇 |
1972年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Let p ∈ [1, ∞), q ∈ [1, ∞), α∈ R, and s be a non-negative integer. Inspired by the space JNp introduced by John and Nirenberg(1961) and the space B introduced by Bourgain et al.(2015), we introduce a special John-Nirenberg-Campanato space JNcon(p,q,s) over Rn or a given cube of R;with finite side length via congruent subcubes, which are of some amalgam features. The limit space of such spaces as p →∞ is just the Campanato space which coincides with the space BMO(the space of functions with bounded mean oscillations)when α = 0. Moreover, a vanishing subspace of this new space is introduced, and its equivalent characterization is established as well, which is a counterpart of the known characterization for the classical space VMO(the space of functions with vanishing mean oscillations) over Rn or a given cube of Rn with finite side length.Furthermore, some VMO-H1-BMO-type results for this new space are also obtained, which are based on the aforementioned vanishing subspaces and the Hardy-type space defined via congruent cubes in this article. The geometrical properties of both the Euclidean space via its dyadic system and congruent cubes play a key role in the proofs of all these results. 相似文献
12.
Li Jun Zheng Dayong Wei Ning Sun Yunfeng Liu Li Yuan Yuan Jiang Qinghua 《Chemistry of Natural Compounds》2022,58(4):650-652
Chemistry of Natural Compounds - A new quassinoid, dehydrobruceantinol B (1), was isolated from the seeds of Brucea javanica, together with two known compounds, bruceantinol (2) and bruceine A (3).... 相似文献
13.
Yuan Xin Zhang Shuren Zhong Xuanmeng Yuan Hao Song Dongfan Wang Xiaoyu Yu Hanyang Guo Zijian 《中国科学:化学(英文版)》2022,65(10):1978-1984
Science China Chemistry - Oncogenic KRAS reprograms pancreatic ductal adenocarcinoma (PDAC) cells to a state that is awfully resistant to apoptosis. An alternative coping strategy is to trigger a... 相似文献
14.
15.
Sun Yuan Luo Shunlong Lei Xiangyun 《International Journal of Theoretical Physics》2021,60(9):3211-3224
International Journal of Theoretical Physics - Gram matrices arise naturally in the consideration of pair-wise overlap of a family of vectors or quantum pure states, and play an important role in... 相似文献
16.
Acta Mathematicae Applicatae Sinica, English Series - This paper proposes a method for modelling volatilities (conditional covariance matrices) of high dimensional dynamic data. We combine the... 相似文献
17.
18.
Wu Peng Wang Yun Li Yang Hu Xuewen Xiu Taoyuan Yuan Dingzhong Liu Yan Wu Zhenyu Liu Zhirong 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(2):553-559
Journal of Radioanalytical and Nuclear Chemistry - In order to reduce the potential toxicity to the environment after treatment of radioactive waste water, an eco-friendly graphene oxide... 相似文献
19.
Peng-Yan Gui Xiao-Hui Yan Wen-Juan Yuan Yuan-Liang Ma Xiao Ding Shuai Liu 《Natural product research》2019,33(19):2830-2836
A new A, D-seco limonoid, named 12-acetyloxyperforatin (1), along with three known ones, were isolated from the leaves of Harrisonia perforata. Their structures were elucidated on the basis of spectroscopic analysis, including extensive NMR techniques and computational modelling. These compounds showed no inhibitory activity against the 11β-HSD1 enzyme. 相似文献
20.
Zhang Yi Huang Peng Long Mei Liu Song Yang Huaming Yuan Shuwen Chang Shi 《中国科学:化学(英文版)》2019,62(1):58-61
An innovative cancer therapy strategy regarding the interface engineering of kaolinite has been designed. The exposed silanol group facilitates more guest species with high dispersion on the supports. Mn_3O_4 magnetic nanoparticles are uniformly distributed on external surfaces of the Kaolin_(C12N)with the Al–O–Mn bond for the detection of the tumor microenvironment by T1-MRI; Doxorubicin(DOX) are loaded in the interlayer space with the electrostatic interaction for chemo-treating; and KI is coated on the outer layer of the nanocomposites based on the electrostatic interaction for thyroid cancer targeting. The synergetic effects and the treatment mechanism enhanced by the interface engineering, KI@DOX-Mn_3O_4-Kaolin_(C12N)can cause remarkably low cell viability(57%, 200 μg/mL), tumor shrinking(75%, 20 μg/kg), and accumulation into the tumor tissues. The novel kaolinite based drug delivery system is expected to incorporate imaging diagnosis, targeted therapy and drug delivery into one single system for postoperative residual thyroid cancer treatment and observation for metastasis of focal area. 相似文献