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81.
Tao Zhang Qingxue Ji Jiayi Song Haiming Li Xing Wang Haiqiang Shi Meihong Niu Tingting Chu Fengshan Zhang Yanzhu Guo 《Molecules (Basel, Switzerland)》2022,27(22)
The poor water solubility, large particle size, and low accessibility of cellulose, the most abundant bioresource, have restricted its generalization to carbon dots (CDs). Herein, nitrogen and sulfur co-doped fluorescent carbon dots (N, S-CDs) were hydrothermally synthesized using cellulose nanocrystals (CNC) as a carbon precursor, exhibiting a small particle size and excellent aqueous dispersion. Thiourea was selected as a nitrogen and sulfur dopant to introduce abundant fluorescent functional groups into N, S-CDs. The resulting N, S-CDs exhibited nanoscale size (6.2 nm), abundant functional groups, bright blue fluorescence, high quantum yield (QY = 27.4%), and high overall yield (16.2%). The excellent optical properties of N, S-CDs endowed it to potentially display a highly sensitive fluorescence “turn off” response to rutin. The fluorescence response for rutin allowed a wide linear range of 0–40 mg·L−1, with a limit of detection (LOD) of 0.02 μM, which revealed the potential of N, S-CDs as a rapid and simple sensing platform for rutin detection. In addition, the sustainable and large-scale production of the N, S-CDs in this study paves the way for the successful high-value utilization of cellulose. 相似文献
82.
Yizhao Chai Xuesong Xie Zhangxing He Guangyi Guo Pinji Wang Zhenyue Xing Bingan Lu Shuquan Liang Yan Tang Jiang Zhou 《Chemical science》2022,13(39):11656
Reversibility and stability are considered as the key indicators for Zn metal anodes in aqueous Zn-ion batteries, yet they are severely hindered by uncontrolled Zn stripping/plating and side reactions. Herein, we fabricate a bulk phase ZnIn alloy anode containing trace indium by a typical smelting–rolling process. A uniformly dispersed bulk phase of the whole Zn anode is constructed rather than only a protective layer on the surface. The Zn deposition can be regarded as instantaneous nucleation due to the adsorption of the evenly dispersed indium, and formation of the exclusion zone for further nucleation can be prevented at the same time. Owing to the bulk phase structure of ZnIn alloy, the indium not only plays a crucial role in Zn deposition, but also improves the Zn stripping. Consequently, the as-designed ZnIn alloy anode can sustain stable Zn stripping/plating for over 2500 h at 4.4 mA cm−2 with nearly 6 times smaller voltage hysteresis than that of pure Zn. Moreover, it enables a substantially stable ZnIn//NH4V4O10 battery with 96.44% capacity retention after 1000 cycles at 5 A g−1. This method of regulating the Zn nucleation by preparing a Zn-based alloy provides a potential solution to the critical problem of Zn dendrite growth and by-product generation fundamentally.A ZnIn alloy anode with trace indium is obtained by smelting–rolling method. The Zn deposition could be regarded as instantaneous nucleation that can alleviate the effect of deposition layer for the diffusion zone and suppresses dendrite growth. 相似文献
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阐述了教育部高等学校力学基础课程教学指导委员会历经12年组织的全国历届基础力学青年教师讲课比赛内容与要求、比赛办法、比赛组织程序和组织原则等概况,以及比赛中呈现的各种有益现象与存在的问题,进一步分析了全国普通高等学校基础力学课程教学现状与教学质量状况.希望通过这些分析对基础力学教学未来以及质量监控等提供一些经验与方法,并得以在普通高等学校基础力学教学中推广和借鉴. 相似文献
87.
Xuan Shi Yu Sun Junhui Liu Wencai Liu Yan Xing Zhilong Xiu Yuesheng Dong 《Molecules (Basel, Switzerland)》2023,28(1)
Chemical epigenetic regulation (CER) is an effective method to activate the silent pathway of fungal secondary metabolite synthesis. However, conventional methods for CER study are laborious and time-consuming. In the meantime, the overall profile of the secondary metabolites in the fungi treated by the CER reagent is not well characterized. In this study, suberohydroxamic acid (SBHA), a histone deacetylase inhibitor, was added to a culture of Aspergillus aculeatus DL1011 and a new strategy based on LC-MS/MS analysis integrated with various metabolomic tools (MetaboAnalyst, MS-DIAL, SIRIUS and GNPS) was developed to characterize the profile of induced metabolites. As a result, 13.6%, 29.5% and 27.2% of metabolites were identified as newly biosynthesized, increasing and decreasing in abundance by CER, respectively. The structures of the 18 newly induced secondary metabolites were further identified by the new strategy to demonstrate that 72.2% of them (1 novel compound and 12 known compounds) were first discovered in A. aculeatus upon SBHA treatment. The accuracy of the new approach was confirmed by purification and NMR data analysis of major newly biosynthesized secondary metabolites. The bioassay showed that the newly biosynthesized compounds, roseopurpurin analogues, showed selective activities against DPPH scavenging, cytotoxicity and SHP1 inhibition. Our research demonstrated that CER was beneficial for changing the secondary metabolic profile of fungi and was an effective means of increasing the diversity of active metabolites. Our work also supplied a metabolomic strategy to characterize the profile changes and determine the newly induced compounds in the secondary metabolites of fungi treated with the chemical epigenetic regulator. 相似文献
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研究了真空状态下保温60 min不同退火温度对镜面纯铁的表面粗糙度、表面形貌及晶粒取向的影响。结果表明:在纯铁的多晶型性转变温度点以下,面均方根粗糙度随退火温度的升高而缓慢增大;在多晶型性转变温度及以上发生突变,从面均方根粗糙度为4~5 nm的镜面突变到700 nm;用扫描电子显微镜(SEM)观察样品表面,发现在810 ℃出现再结晶细小晶粒。研究了原材料及860~960 ℃之间几个温度点的X射线衍射{200}晶面极图,结果发现:晶粒在860 ℃开始择优取向,随温度升高,取向越来越明显;再结晶对表面粗糙度的影响不大,晶粒的择优取向使得晶粒在不同方向的膨胀系数不同,以及多晶型性转变导致体积的变化使得晶粒之间挤压造成晶粒之间的凹凸不平和表面较深较粗的晶界,这是造成粗糙度突变的主要原因。 相似文献
90.
针对半导体器件、电路、电子系统的高功率微波效应,提出了一套全新的多层次多物理场协同计算方法。该算法基于半导体器件的物理结构模型,联立并求解由电磁场、半导体物理和热力学方程构成的多物理场方程组,实现了器件级高功率微波效应的仿真;通过器件多物理场仿真和电路仿真的协同计算完成电路级效应仿真;最后进行电路效应和电磁环境的协同计算,获取由多个电路、外壳封装、孔缝和线缆等组成的电子系统的高功率微波效应数据。介绍了该算法的原理和流程,以商业PIN二极管为例,计算了该器件及组成限幅器电路的温度效应、正向恢复特性、半封闭腔体内空间微波辐射等效应,通过与实验测试的对比验证了算法的正确性,同时对效应现象给出了物理机理解释。 相似文献