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71.
72.
应用荧光光谱法研究了牛血清蛋白与荧光增白剂CBS-X、BBU、VBL的相互作用.通过Stern-Volmer方程、Lineweaver-BurK方程和双对数曲线进行计算,研究了FWA对BSA内源荧光的猝灭机制.FWA对BSA内源荧光的猝灭主要为静态猝灭和荧光共振能量转移猝灭.测定了荧光增白剂CBS-X、BBU、VBL对BSA的猝灭常量和扩散常量(283 K),确定了荧光增白剂与BSA结合位点数均为1.根据Frster非辐射能量转移理论,计算了BSA与荧光增白剂分子间的结合距离和能量转移效率.通过测定283 K和298 K时供体与受体分子间结合常量,计算了BSA与荧光增白剂作用的热力学参量.BSA与FWA作用的ΔH<0,ΔS>0,并以此确定了BSA 与荧光增白剂分子主要通过静电力进行作用. 相似文献
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74.
以造纸污泥中提取的木质素和二乙基环氧丙基胺(简称环氧胺单体)为原料,通过接枝共聚反应制备了木质素胺絮凝剂(DL),并确定了最佳合成工艺条件,同时采用傅里叶变换红外光谱(FTIR)对产物结构进行了表征。结果表明,以1.5mo1·L-1NaOH为催化剂,木质素和环氧胺单体的质量比为1:1,于70℃下接枝反应2h时,所得絮凝剂DL对3种模拟染料废水的脱色率分别可达89.66%、74.10%和89.84%,通过比较DL与木质素的絮凝效果以及絮体微观形貌,对DL的絮凝机理进行了初步探讨。 相似文献
75.
Joseph Schwager Nicole Seifert Albine Bompard Daniel Raederstorff Igor Bendik 《Molecules (Basel, Switzerland)》2021,26(18)
Vitamins and bioactives, which are constituents of the food chain, modulate T lymphocyte proliferation and differentiation, antibody production, and prevent inflammation and autoimmunity. We investigated the effects of vitamins (vitamin A (VA), D (VD), E (VE)) and bioactives (i.e., resveratrol (Res), epigallocatechin-3-gallate (EGCG)) on the adaptive immune response, as well as their synergistic or antagonistic interactions. Freshly isolated T lymphocytes from healthy individuals were activated with anti-CD3/CD28 antibodies for 4–5 days in the presence of bioactives and were analyzed by cytofluorometry. Interleukins, cytokines, and chemokines were measured by multiple ELISA. Gene expression was measured by quantitative RT-PCR. Res and EGCG increased CD4 surface intensity. EGCG led to an increased proportion of CD8+ lymphocytes. Anti-CD3/CD28 activation induced exuberant secretion of interleukins and cytokines by T lymphocyte subsets. VD strongly enhanced Th2 cytokines (e.g., IL-5, IL-13), whereas Res and EGCG favored secretion of Th1 cytokines (e.g., IL-2, INF-γ). Res and VD mutually influenced cytokine production, but VD dominated the cytokine secretion pattern. The substances changed gene expression of interleukins and cytokines in a similar way as they did secretion. Collectively, VD strongly modulated cytokine and interleukin production and favored Th2 functions. Resveratrol and EGCG promoted the Th1 response. VA and VE had only a marginal effect, but they altered both Th1 and Th2 response. In vivo, bioactives might therefore interact with vitamins and support the outcome and extent of the adaptive immune response. 相似文献
76.
鱼类的非特异性免疫调节 总被引:16,自引:0,他引:16
介绍了鱼类的非特异性免疫器官及其免疫机制,通过免疫刺激剂可提高鱼类的非特异性免疫力,在仔鱼的特异性免疫器官尚未发育之前,仔鱼对外界病原微生物的抵抗力主要依靠来自母体的抗体和自身的非特异性免疫力,例举免疫刺激剂对提高仔鱼存活率的实验,并探讨了该方法在苗种生产中的应用前景。 相似文献
77.
信息系统中的可移动Agent 总被引:1,自引:0,他引:1
介绍了可移动Agent的特性,可移动Agent可在异质计算机网络中移动,它能感知网络的状态,监控系统并与其它Agent进行交互,导航模型可以让Agent适应网络的变化并自主制定导航计划,从而方便、有效、智能地完成信息检索的任务. 相似文献
78.
Jifeng Yu Song Li Dianze Chen Dandan Liu Huiqin Guo Chunmei Yang Wei Zhang Li Zhang Gui Zhao Xiaoping Tu Liang Peng Sijin Liu Xing Bai Yongping Song Zhongxing Jiang Ruliang Zhang Wenzhi Tian 《Molecules (Basel, Switzerland)》2022,27(17)
Background: Targeting the CD47/SIRPα signaling pathway represents a novel approach to enhance anti-tumor immunity. However, the crystal structure of the CD47/SIRPα has not been fully studied. This study aims to analyze the structure interface of the complex of CD47 and IMM01, a novel recombinant SIRPα-Fc fusion protein. Methods: IMM01-Fab/CD47 complex was crystalized, and diffraction images were collected. The complex structure was determined by molecular replacement using the program PHASER with the CD47-SIRPαv2 structure (PDB code 2JJT) as a search model. The model was manually built using the COOT program and refined using TLS parameters in REFMAC from the CCP4 program suite. Results: Crystallization and structure determination analysis of the interface of IMM01/CD47 structure demonstrated CD47 surface buried by IMM01. Comparison with the literature structure (PDB ID 2JJT) showed that the interactions of IMM01/CD47 structure are the same. All the hydrogen bonds that appear in the literature structure are also present in the IMM01/CD47 structure. These common hydrogen bonds are stable under different crystal packing styles, suggesting that these hydrogen bonds are important for protein binding. In the structure of human CD47 in complex with human SIRPα, except SER66, the amino acids that form hydrogen bonds are all conserved. Furthermore, comparing with the structure of PDB ID 2JJT, the salt bridge interaction from IMM01/CD47 structure are very similar, except the salt bridge bond between LYS53 in IMM01 and GLU106 in CD47, which only occurs between the B and D chains. However, as the side chain conformation of LYS53 in chain A is slightly different, the salt bridge bond is absent between the A and C chains. At this site between chain A and chain C, there are a salt bridge bond between LYS53 (A) and GLU104 (C) and a salt bridge bond between HIS56 (A) and GLU106 (C) instead. According to the sequence alignment results of SIRPα, SIRPβ and SIRPγ in the literature of PDB ID 2JJT, except ASP100, the amino acids that form common salt bridge bonds are all conserved. Conclusion: Our data demonstrated crystal structure of the IMM01/CD47 complex and provides a structural basis for the structural binding interface and future clinical applications. 相似文献
79.
The dipeptide d-Glu-meso-DAP (iE-DAP) is the minimal structural fragment capable of activating the innate immune receptor nucleotide-binding oligomerization domain protein (NOD1). The meso-diaminopimelic acid (meso-DAP) moiety is known to be very stringent in terms of the allowed structural modifications which still retain the NOD1 activity. The aim of our study was to further explore the chemical space around the meso-DAP portion and provide a deeper understanding of the structural features required for NOD1 agonism. In order to achieve the rigidization of the terminal amine functionality of meso-DAP, isoxazoline and pyridine heterocycles were introduced into its side-chain. Further, we incorporated the obtained meso-DAP mimetics into the structure of iE-DAP. Collectively, nine innovative iE-DAP derivatives additionally equipped with lauroyl or didodecyl moieties at the α-amino group of d-Glu have been prepared and examined for their NOD1 activating capacity. Overall, the results obtained indicate that constraining the terminal amino group of meso-DAP abrogates the compounds’ ability to activate NOD1, since only compound 6b retained noteworthy NOD1 agonistic activity, and underpin the stringent nature of this amino acid with regard to the allowed structural modifications. 相似文献
80.
A nonempty and nonconstant partial recursive function such that any function resembling it is recursively isomorphic to it is called a t-function. It is proved that the domain of any t-function is neither a simple nor a pseudosimple set. 相似文献