全文获取类型
收费全文 | 18409篇 |
免费 | 3585篇 |
国内免费 | 4973篇 |
专业分类
化学 | 14640篇 |
晶体学 | 540篇 |
力学 | 1042篇 |
综合类 | 515篇 |
数学 | 2493篇 |
物理学 | 7737篇 |
出版年
2024年 | 43篇 |
2023年 | 277篇 |
2022年 | 706篇 |
2021年 | 761篇 |
2020年 | 760篇 |
2019年 | 772篇 |
2018年 | 649篇 |
2017年 | 803篇 |
2016年 | 858篇 |
2015年 | 990篇 |
2014年 | 1217篇 |
2013年 | 1539篇 |
2012年 | 1714篇 |
2011年 | 1678篇 |
2010年 | 1481篇 |
2009年 | 1498篇 |
2008年 | 1620篇 |
2007年 | 1452篇 |
2006年 | 1369篇 |
2005年 | 1137篇 |
2004年 | 923篇 |
2003年 | 679篇 |
2002年 | 670篇 |
2001年 | 641篇 |
2000年 | 580篇 |
1999年 | 395篇 |
1998年 | 274篇 |
1997年 | 209篇 |
1996年 | 175篇 |
1995年 | 154篇 |
1994年 | 151篇 |
1993年 | 114篇 |
1992年 | 119篇 |
1991年 | 95篇 |
1990年 | 84篇 |
1989年 | 74篇 |
1988年 | 61篇 |
1987年 | 47篇 |
1986年 | 44篇 |
1985年 | 24篇 |
1984年 | 27篇 |
1983年 | 30篇 |
1982年 | 10篇 |
1981年 | 22篇 |
1980年 | 7篇 |
1979年 | 13篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1965年 | 2篇 |
1959年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
861.
LUO Zha LIU Hao SHEN Wei SHI Kun CHEN Ankang SHENG Libo SUI Yongming ZOU Bo 《高等学校化学研究》2022,38(3):843-846
We used a diamond anvil cell(DAC) to control the deformation of synthesized copper nanorods and silver nanoparticles. And we measured the surface plasmon resonance of copper nanorods and silver nanoparticles, which exhibit redshifts or blueshifts. The surface plasmon resonance shows an abnormal blue shift for both copper nanorods and silver nanoparticles. The solvents of copper nanorods and silver nanoparticles are n-hexane and water, where the pressure loads include quasi-hydrostatic and non-hydrostatic. 相似文献
862.
Huijun Wang Jie Gao Dr. Xiang Xu Dr. Baogen Liu Lingyun Yu Yadong Ren Dr. Rui Shi Prof. Zheng Zeng Prof. Liqing Li 《化学:亚洲杂志》2021,16(9):1118-1129
To investigate the effects of oxygen-containing functional groups on the adsorption of volatile organic compounds (VOCs) with different polarity, oxygen-rich porous carbon materials (OPCs) were synthesized by heat treatment of glucose/potassium oxalate material. The carbon material had a large specific surface area (1697 m2 g−1) and a high oxygen content (18.95 at.%). OPC exhibited high adsorption capacity of toluene (309 mg g−1) and methanol (447 mg g−1). The specific surface area and total pore volume determined the adsorption capacity of toluene and methanol at the high-pressure range, while the oxygen-containing groups became the main factor affecting the methanol adsorption at the low-pressure range due to the hydrogen bond interaction through the density functional theory (DFT) calculations. This study provides an important hint for developing a novel O-doped adsorbent for the VOCs adsorption applications and analyzing the role of oxygen-containing groups in the VOCs adsorption under the low-pressure range. 相似文献
863.
Qianqian Hao Xiuquan Jia Dr. Jiping Ma Mingxia Gao Xiaomeng Fan Jin Gao Prof. Jie Xu 《化学:亚洲杂志》2021,16(11):1388-1391
Organic modifiers have shown promising potential for regulating the activity and selectivity of heterogeneous catalysts via tuning their surface properties. Despite the increasing application of organic modification technique in regulating the redox-acid catalysis of metal oxides, control of the acidity of metal oxide catalysts for enhanced reaction selectivity without sacrificing their redox activity remains a substantial challenge. Herein, we show the successful control of redox-acid catalysis of metal oxides with aprotic tertiary amine modifiers. Robust modification of manganese dioxide catalysts with N,N-dialkylcyclohexylamine selectively blocks the Lewis acid sites, with their redox activity mostly unaffected. This enables efficient synthesis of imines in high to excellent selectivity via aerobic oxidation of structurally diverse aryl amines. 相似文献
864.
Ricardo G. Alvim Petrina Georgala Lucas Nogueira Alexander J. Somma Karan Nagar Jasmine Thomas Laura Alvim Amelia Riegel Christopher Hughes Jie Chen Augusto B. Reis Souhil Lebdai Avigdor Scherz Steven Zanganeh Rui Gardner Kwanghee Kim Jonathan A. Coleman 《Molecules (Basel, Switzerland)》2021,26(12)
Purpose: Vascular targeted photodynamic therapy (VTP) is a nonsurgical tumor ablation approach used to treat early-stage prostate cancer and may also be effective for upper tract urothelial cancer (UTUC) based on preclinical data. Toward increasing response rates to VTP, we evaluated its efficacy in combination with concurrent PD-1 inhibitor/OX40 agonist immunotherapy in a urothelial tumor-bearing model. Experimental design: In mice allografted with MB-49 UTUC cells, we compared the effects of combined VTP with PD-1 inhibitor/OX40 agonist with those of the component treatments on tumor growth, survival, lung metastasis, and antitumor immune responses. Results: The combination of VTP with both PD-1 inhibitor and OX40 agonist inhibited tumor growth and prolonged survival to a greater degree than VTP with either immunotherapeutic individually. These effects result from increased tumor infiltration and intratumoral proliferation of cytotoxic and helper T cells, depletion of Treg cells, and suppression of myeloid-derived suppressor cells. Conclusions: Our findings suggest that VTP synergizes with PD-1 blockade and OX40 agonist to promote strong antitumor immune responses, yielding therapeutic efficacy in an animal model of urothelial cancer. 相似文献
865.
Liu Jie Zou Zhengguang Zhang Shuchao Zhang Huanhuan 《Journal of Solid State Electrochemistry》2021,25(2):387-410
Journal of Solid State Electrochemistry - LiNi0.8Co0.1Mn0.1O2 (NCM811), as one of the most promising cathode materials for lithium ion batteries, has gained a huge market with its obvious... 相似文献
866.
将194例小肝癌患者纳入小肝癌组,185例肝细胞结节患者纳入结节组,所有患者均行MRI扩散加权成像(DWI-MRI),评估患者在DWI-MRI上的形态学表现及ADC值,检测患者血清AFP水平,比较不同检测方法诊断小肝癌的准确度、灵敏度、特异度。结果显示,应用DWI-MRI联合血清AFP诊断小肝癌的特异度、灵敏度和准确度均显著高于单独应用DWI-MRI,或血清AFP(P<0.05)。表明DWI-MRI联合血清AFP对小肝癌的诊断价值显著,可为病情评估提供切实可行的参考。 相似文献
867.
Jun-Jie Shi Qi-Hui Jiang Tian-Ning Zhang Hao Sun Wen-Wen Shi Hendra Gunosewoyo Fan Yang Jie Tang Tao Pang Li-Fang Yu 《Molecules (Basel, Switzerland)》2021,26(5)
Sigma-1 (σ-1) receptor agonists are considered as potential treatment for stroke. TS-157 is an alkoxyisoxazole-based σ-1 receptor agonist previously discovered in our group. The present study describes TS-157 profile in a battery of tests for cerebral ischemia. Initial evaluation demonstrated the compound’s safety profile and blood–brain barrier permeability, as well as its ability to induce neurite outgrowth in vitro. The neurite outgrowth was shown to be mediated via σ-1 receptor agonism and involves upregulation of ERK phosphorylation (pERK). In particular, TS-157 also significantly accelerated the recovery of motor function in rats with transient middle cerebral artery occlusion (tMCAO). Overall, the results herein support the notion that σ-1 receptor agonists are potential therapeutics for stroke and further animal efficacy studies are warranted. 相似文献
868.
Xue Li Xinfeng Tan Qingshuang Chen Xiaoling Zhu Jing Zhang Jie Zhang Baolei Jia 《Molecules (Basel, Switzerland)》2021,26(8)
Prodigiosin is a red pigment produced by Serratia marcescens with anticancer, antimalarial, and antibacterial effects. In this study, we extracted and identified a red pigment from a culture of S. marcescens strain ZPG19 and investigated its effect on the growth performance and intestinal microbiota of Kunming mice. High-performance liquid chromatography/mass spectrometry revealed that the pigment had a mass-to-charge ratio (m/z) of 324.2160, and thus it was identified as prodigiosin. To investigate the effect of prodigiosin on the intestinal microbiota, mice (n = 5) were administered 150 μg/kg/d prodigiosin (crude extract, 95% purity) via the drinking water for 18 days. Administration of prodigiosin did not cause toxicity in mice. High-throughput sequencing analysis revealed that prodigiosin altered the cecum microbiota abundance and diversity; the relative abundance of Desulfovibrio significantly decreased, whereas Lactobacillus reuteri significantly increased. This finding indicates that oral administration of prodigiosin has a beneficial effect on the intestinal microbiota of mice. As prodigiosin is non-toxic to mouse internal organs and improves the mouse intestinal microbiota, we suggest that it is a promising candidate drug to treat intestinal inflammation. 相似文献
869.
In order to alleviate the contradiction between injectability of the profile control agent and its profile control performance, a novel core‐shell heterogeneous structure colloidal particles (CSA) were synthesized, and the mechanism of self‐aggregation plugging was proposed. Cross‐linking inside the nanoparticles and chain‐growth polymerization via capturing acrylamide in the aqueous phase result in the formation of core‐shell heterogeneous structures as proved by TEM observation and XPS analysis. Moreover, CSA nanoparticles exhibit good hydrophilic properties, outstanding thermal stability and limited expansion capacity. Effects of different metal cations and surface group on the self‐aggregation time of CSA nanoparticles were systematically studied. Results showed that divalent cations contributed to more significant aggregation of CSA nanoparticles in comparison to monovalent cations. The increasing cations concentration and valency decreased the thickness of electric double layer, which lead to a decrease in the zeta potential. Core flooding test shows that the injection of nanoparticles which diameter is much smaller that of pore‐throats into the target reservoir can not only successfully enter the depth of porous media, but also effectively block the high permeability areas by the formation of self‐aggregation particle clusters. This study provides a new method for the equilibrium between nanoparticles injectivity and in‐depth profile control of nanoparticles. 相似文献
870.
Zhao Xiaolong Chen Changkun Shi Congling Chen Jie Chen Qingzhong Zhao Dongyue 《Journal of Thermal Analysis and Calorimetry》2021,143(4):3245-3256
Journal of Thermal Analysis and Calorimetry - In this paper, a three-dimensional simulation has been performed to investigate the potential consequences of flammable vapor explosion in a tunnel... 相似文献