全文获取类型
收费全文 | 8237篇 |
免费 | 1177篇 |
国内免费 | 701篇 |
专业分类
化学 | 2686篇 |
晶体学 | 1099篇 |
力学 | 609篇 |
综合类 | 150篇 |
数学 | 3167篇 |
物理学 | 2404篇 |
出版年
2024年 | 6篇 |
2023年 | 84篇 |
2022年 | 122篇 |
2021年 | 217篇 |
2020年 | 253篇 |
2019年 | 202篇 |
2018年 | 173篇 |
2017年 | 260篇 |
2016年 | 370篇 |
2015年 | 263篇 |
2014年 | 434篇 |
2013年 | 644篇 |
2012年 | 464篇 |
2011年 | 602篇 |
2010年 | 535篇 |
2009年 | 570篇 |
2008年 | 590篇 |
2007年 | 576篇 |
2006年 | 576篇 |
2005年 | 456篇 |
2004年 | 416篇 |
2003年 | 361篇 |
2002年 | 280篇 |
2001年 | 208篇 |
2000年 | 217篇 |
1999年 | 159篇 |
1998年 | 166篇 |
1997年 | 162篇 |
1996年 | 87篇 |
1995年 | 87篇 |
1994年 | 96篇 |
1993年 | 67篇 |
1992年 | 52篇 |
1991年 | 62篇 |
1990年 | 48篇 |
1989年 | 37篇 |
1988年 | 37篇 |
1987年 | 27篇 |
1986年 | 20篇 |
1985年 | 36篇 |
1984年 | 22篇 |
1983年 | 9篇 |
1982年 | 13篇 |
1981年 | 11篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1936年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
Jia Fu Qianqian Jia Peida Liang Saisai Wang Huaxin Zhou Liyang Zhang Hong Wang Chunlei Gao Yanni Lv Shengli Han Langchong He 《Journal of separation science》2022,45(14):2498-2507
Cell membrane chromatography is an effective method for screening bioactive components acting on specific receptors in complex systems, which maintains the biological activity of the membrane receptors and improves screening efficiency. However, traditional cell membrane chromatography suffers from poor stability, resulting in a limited life span and low reproducibility, greatly limiting the application of this method. To address this problem, cyanuric chloride-decorated silica gel was used for the covalent immobilization of the cell membranes. Cyanuric chloride reacts with amino groups on the cell membranes and membrane receptors to form covalent bonds. In this way, the cell membranes are not easy to fall off. The column life of the cyanuric chloride-decorated epidermal growth factor receptor/cell membrane chromatography column was extended to more than 8 days, whereas the column life of the normal cell membrane chromatography column dropped sharply in the first 3 days. A cyanuric chloride-decorated epidermal growth factor receptor/cell membrane chromatography online HPLC-IT-TOF-MSn system was applied for screening drug leads from Trifolium pratense L. One potential drug lead, formononetin, which acts on the epidermal growth factor receptor, was screened. Our strategy of covalently immobilizing cell membrane receptors also improved the stability of cell membrane chromatography. 相似文献
72.
Lignin, as an abundant natural polymer with interesting mechanical, antimicrobial, and antioxidant properties, has the possibility to produce numerous chemicals and biofuels of current interest. However, the structural recalcitrance, heterogeneity, and complex extraction methods of lignin can hinder its transformation into value-added materials. Therefore, the research community is exploring innovative bioconversion technologies capable of effectively valorizing lignin. Thus, effective bioconversion and deconstruction methods have been recently studied. In this review, we first define lignin as a versatile raw material considering its characteristics, properties, and abundance. Then, lignin valorization is described in terms of the current opportunities and technical challenges. Finally, we discuss the industrial potential of lignin-derived products such as biofuels, biopolymers, biopesticides, and fertilizers. Those lignin-derived products are highly valuable for the energy and food industries, which are two main sectors challenged by the rapid growth of population, urbanization, and consumption. Thus, progress on lignin valorization would represent significant advancements in the Sustainable Development Goals (SDGs) and circular economy aspects. 相似文献
73.
74.
以抗坏血酸为还原剂,柠檬酸为结构导向剂,一步还原硝酸银,合成了尺寸和形状可调的花状银颗粒。纳米粒子的粒径可在600~1 200 nm范围内调整,表面突起可达到10~25 nm。柠檬酸的化学性质在银纳米粒子合成多级花状银结构的过程中起着至关重要的作用。通过改变柠檬酸或抗坏血酸溶液的用量,银结构的各向异性形貌可以很容易地调节。以制备的多级花状银颗粒作为表面增强拉曼散射(SERS)基底,对浓度为10~(-10)mol·L~(-1)的罗丹明6G(R6G)仍具有较高的检测灵敏度。 相似文献
75.
新药Zorifertinib是阿斯利康公司针对非小细胞肺癌(NSCLC)脑转研发的一种表皮生长因子酪氨酸激酶抑制剂(EGFR-TKI),对EGFR 19外显子缺失和EGFR 21外显子L858R突变有高选择性和高抑制性,相较于其他EGFR-TKIs的突出优势是具有优秀的血脑屏障渗透性。临床研究表明Zorifertinib可以在脑内达到等同血浆的药物浓度,有效抑制脑内肿瘤生长,减少脑内肿瘤面积,并且预防脑内肿瘤形成。本文将对该新药的作用机制、研发历程、药代动力学、临床研究和安全性进行综述,为广大研究者以及今后的临床应用提供参考。 相似文献
76.
Sodium metal anodes have attracted significant attention due to their high specific capacity,low redox potential and abundant resources.However,the dendrites and unstable solid electrolyte interphase(SEI)of sodium anodes restrict the development of sodium metal batteries.This review includes the recent progress on the Na anode protection in sodium metal batteries.The strategies are summarized as modified three-dimensional current collectors,artificial solid electrolyte interphases,and electrolyte modifications.Conclusions and perspectives are envisaged for the further understanding and development of Na metal anodes. 相似文献
77.
纳米二氧化硅(SiO2)颗粒以其高硬度、高比表面积、高稳定、价格合理等优势被广泛应用于复合材料的制备中,获得的SiO2/聚合物复合材料通常具有优良的机械性能、很好的热稳定性以及增强的光学和电性能。近年来,随着聚合诱导自组装(PISA)的提出与发展,研究者们基于PISA发展了多种制备不同形貌聚合物纳米粒子的简便方法,为制备SiO2/聚合物复合材料提供了新的思路。作者调研了近十年来基于PISA制备SiO2/聚合物复合材料的相关研究,按照SiO2与聚合物的结合作用和复合机理的不同,创新性地将SiO2/聚合物复合材料的制备分为物理包封法、化学接枝法、超分子作用法和原位生长法。本综述重点论述复合材料的合成方法、主要性能及用途,同时分析各种复合方法的优缺点并对制备方法的未来发展做出展望,以期为相关领域科研工作者提供更清晰的脉络和更丰富的启示。 相似文献
78.
A novel electrochemical detection approach for platelet-derived growth factor(PDGF) via "sandwich"structure is reported in this paper. 3D-4MgCO_3 Mg(OH)_2 4H_2O-Au NPs inorganic hybrid composite was utilized as immobilized substrate for sensitive PDGF detection and Pt-Au bimetallic nanoparticles were labelled on PDGF aptamer to indirectly detect PDGF for the first time. The proposed aptasensor exhibited a high catalytic efficiency towards reduction of H_2O_2, hence the sensitive detection of PDGF was achieved.Results showed that the aptasensor exhibited excellent linear response to PDGF, in the range of 0.1 pg/m L–10 ng/m L(4 fmol/L–400 pmol/L), with detection limit of 0.03 pg/m L(1.2 fmol/L). 相似文献
79.
《Electroanalysis》2017,29(12):2832-2838
In this study, a bimetallic nanomaterial‐based electrochemical immunosensor was developed for the detection of carcinoembryonic antigen (CEA) and vascular endothelial growth factor (VEGF) cancer biomarkers at the same time. CEA and VEGF biomarkers are indicators for colon and breast cancers and stomach cancers, respectively. During the study, gold nanoparticle (AuNp), lead nanoparticle (PbNp), copper nanoparticle (CuNp) and magnetic gamma iron(III)oxide (γFe2O3 Np) were synthesized, characterized and used together for the first time in the structure of an electrochemical biosensor based on anti‐CEA and anti‐VEGF. For this purpose, Au SPE based sandwich immunosensor was fabricated by using labeled anti‐CEA (labeled with Pb+2) and labeled anti‐VEGF (labeled with Cu+2). As a result, CEA and VEGF biomarkers were detected following the oxidation peaks of label metals (Pb+2 and Cu+2) by using differential pulse voltammetry. After the experimental parameters were optimized, the linear range was found in the concentration range between 25 ng/mL and 600 ng/mL with the relative standard deviation (RSD) value of (n=3 for 600 ng/mL) 3.33 % and limit of detection (LOD) value of 4.31 ng/mL for CEA biomarker. On the other hand, the linear range was found in the concentration range between 0.2 ng/mL and 12.5 ng/mL with the RSD value of (n=3 for 12.5 ng/mL) 5.31 % and LOD value of 0.014 ng/mL for VEGF biomarker. Lastly, sample application studies for synthetic plasma sample and interference studies with dopamine, ascorbic acid, BSA, cysteine and IgG were carried out. 相似文献
80.
Mauduit与Sárkzy在一系列论文中研究了κ元序列的伪随机性.本文通过对模pq剩余类环Z_(pq)进行分割,进而结合离散对数的方法,构造了一大族长度为pq的伪随机κ元序列,并证明其具有很好的伪随机性. 相似文献