全文获取类型
收费全文 | 17578篇 |
免费 | 2784篇 |
国内免费 | 2373篇 |
专业分类
化学 | 12855篇 |
晶体学 | 182篇 |
力学 | 1248篇 |
综合类 | 170篇 |
数学 | 2069篇 |
物理学 | 6211篇 |
出版年
2024年 | 55篇 |
2023年 | 335篇 |
2022年 | 492篇 |
2021年 | 573篇 |
2020年 | 638篇 |
2019年 | 623篇 |
2018年 | 469篇 |
2017年 | 489篇 |
2016年 | 818篇 |
2015年 | 700篇 |
2014年 | 964篇 |
2013年 | 1208篇 |
2012年 | 1474篇 |
2011年 | 1479篇 |
2010年 | 1104篇 |
2009年 | 1008篇 |
2008年 | 1155篇 |
2007年 | 979篇 |
2006年 | 895篇 |
2005年 | 896篇 |
2004年 | 697篇 |
2003年 | 648篇 |
2002年 | 723篇 |
2001年 | 631篇 |
2000年 | 475篇 |
1999年 | 457篇 |
1998年 | 373篇 |
1997年 | 335篇 |
1996年 | 345篇 |
1995年 | 262篇 |
1994年 | 268篇 |
1993年 | 195篇 |
1992年 | 187篇 |
1991年 | 168篇 |
1990年 | 117篇 |
1989年 | 103篇 |
1988年 | 75篇 |
1987年 | 42篇 |
1986年 | 64篇 |
1985年 | 44篇 |
1984年 | 25篇 |
1983年 | 32篇 |
1982年 | 22篇 |
1981年 | 17篇 |
1980年 | 12篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1974年 | 10篇 |
1957年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Interactions of the vector breathers for the coupled Hirota system with $$4\times 4$$ 4 × 4 Lax pair
Nonlinear Dynamics - In this paper, we investigate the interactions of the vector breathers for the coupled Hirota system with $$4\times 4$$ Lax pair. Firstly, we give the first-order breather... 相似文献
3.
Donglei Wei Huili Li Chuanqing Yang Jianmin Fu Hou Chen Liangjiu Bai Wenxiang Wang Huawei Yang Lixia Yang Ying Liang 《Journal of polymer science. Part A, Polymer chemistry》2022,60(10):1588-1594
Acridone as a new kind of visible light photocatalyst has been developed to catalyze metal free atom transfer radical polymerization (ATRP). The photocatalyst possess low excited state potential as can undergo an oxidative quenching pathway to initiate ATRP of vinyl monomers. Kinetic study and light on/off reaction demonstrate the “living”/controlled nature of the polymerization by light. Block copolymers can be achieved by using PMMA as macroinitiator to reinitiate polymerization of other vinyl monomers, which shows highly preserved Br chain-end functionality in the synthesized polymers. Moreover, the polymerization can be conducted under air atmosphere as most photocatalysts need anaerobic condition, which may give inspiration of further application of this kind of photocatalyst. 相似文献
4.
Analysis and pharmacokinetic study of polyphyllin H in beagle dog plasma after oral administration of Rhizoma Paridis Extracts by LC‐MS/MS 下载免费PDF全文
5.
6.
7.
8.
We numerically solve the time-dependent Ginzburg–Landau equations for two-gap superconductors using the finite-element technique. The real-time simulation shows that at low magnetic field, the vortices in small-size samples tend to form clusters or other disorder structures. When the sample size is large, stripes appear in the pattern. These results are in good agreement with the previous experimental observations of the intriguing anomalous vortex pattern, providing a reliable theoretical basis for the future applications of multi-gap superconductors. 相似文献
9.
Chao Liu Liying Wang Lin Yang Famei Wang Chunhong Xu Jingwei Lv Guanglai Fu Xianli Li Qiang Liu Haiwei Mu Tao Sun Paul K. Chu 《Physics letters. A》2019,383(25):3200-3206
A single-polarization filter comprising a gold-coated photonic crystal fiber based on surface plasmon resonance is designed and investigated. The pattern matching and coupled polarization characteristics analyzed by the full-vector finite element method (FEM) and losses at 1,540 nm are achieved to 1,016.01739 dB/cm (x-pol core mode) and 33.81917 dB/cm (y-pol core mode). The crosstalk (CT) value of the 1,540 nm band is ?853.12653 dB for fiber length and the bandwidth is 850 nm. The working wavelength of the filter ranges from 1,280 nm to 1,540 nm by varying the diameter of outer air holes (), the diameter of inner air holes (), the metal film thickness (t), as well as the liquid refractive index (n). 相似文献
10.
An N. Le Ruiqi Liang Prof. Dr. Mingjiang Zhong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(35):8177-8189
Mixed-graft block copolymers (mGBCPs) consist of two or more types of polymeric side chains grafted on a linear backbone in a random, alternating, or pseudo-alternating sequence. They can phase-separate with the backbone serving as the interface of the blocks, and the side chains dominate their self-assembly behavior. mGBCPs are an accessible polymer architecture for exploring the idea of encoding polymer properties through the macromolecular architecture, as there are two distinct structural components that can be tuned: the backbone and the side chains. In this Concept article, the current literature on the synthesis of mGBCPs is reviewed, and the advantages and disadvantages of each synthetic method are noted. The self-assembly of mGBCPs is also discussed where possible. Finally, directions for future research on mGBCP synthesis and self-assembly are suggested. 相似文献