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851.
肖友鹏 《人工晶体学报》2022,51(7):1270-1274
硫化亚锗(GeSe)具有合适的禁带宽度、高的吸收系数和高的载流子迁移率等优异的光电特性,且组分简单、低毒和储量丰富,特别适合作为光伏吸收材料。本文基于新型太阳电池吸收层材料GeSe构筑了结构为金属栅线/AZO/i-ZnO/CdS/GeSe/Mo/玻璃的薄膜太阳电池,分别模拟分析了缓冲层和吸收层的厚度、掺杂浓度,以及吸收层体缺陷密度对器件性能的影响。经过优化CdS缓冲层厚度和掺杂浓度以及GeSe吸收层厚度和掺杂浓度,器件获得高达27.59%的转换效率。这些结果表明GeSe基薄膜太阳电池有成为高效光伏器件的潜力。  相似文献   
852.
This study analyzes the productive structure of Portugal in the period 2013–2017, using indicators of localization and specialization applied to 308 Portuguese local authorities. From an empirical approach using a threshold model, the following indicators are used: (i) localization quotient; (ii) specialization coefficient; (iii) Theil entropy index; (iv) rate of industrialization; and (v) the density of establishments by business size. The selected period 2013–2017 is due to the available data concerning firms located per local authority, and the choice of threshold model is justified through the possibility of assessing the non-linear effects of specialization and diversification on productivity, considering, in simultaneous terms, different regimes per business size. Estimation of the threshold model identified a positive, statistically significant relation between industrialization and productivity. Similarly, the terms of interaction between exports and diversification, and between the former and higher education institutions, shows a catalyzing effect of productivity. In addition, the most specialized micro-firms affect productivity significantly and positively, while the least specialized have the opposite effect. Small, less specialized companies have a significant and negative effect on productivity, contrasting with less specialized, medium-sized companies, which affect productivity positively. For large firms, the impact on productivity is negative for both high and low levels of specialization, reinforcing the need to fill existing gaps in strategic diversification, as well as the vertical and horizontal integration of the activities of production chains with high value added.  相似文献   
853.
Abstract

The technique of thermally induced phase separation (TIPS) is favorable for the fabrication of a porous scaffold due to a number of advantages. In this work the poly(L-lactide-co-glycolide-co-ε-caprolactone) (PLLGC) terpolymer was synthesized by melt copolymerization and porous scaffolds thereof from its solution in 1,4-dioxane were fabricated by using the TIPS method. The effects of fabrication parameters, including polymer concentration and freezing temperature, on the morphology, pore size and mechanical properties were studied. The results showed that the average pore size of the PLLGC porous scaffold increased with a decrease in PLLGC concentration and the pore size resulting from freezing at 4?°C (about 20–100?μm) was significantly larger than for other samples (20–50?μm) frozen at lower temperatures. The porosity of the scaffolds decreased with increasing PLLGC concentration or decreasing freezing temperature. On the other hand, the compressive strength of the scaffolds increased with the increase of PLLGC concentration or the decrease of freezing temperature, as would be expected. The present results can be applied in design to control the processing parameters of TIPS for a scaffold with desired pore morphology.  相似文献   
854.
本文以具有重要催化应用前景的Ni/CeO2体系为例,借助17O固体核磁共振波谱技术,根据表面氧物种17O NMR信号的变化,尝试分析了Ni/CeO2表面层中镍离子的含量.分析结果显示,10% NiCe-500和20% NiCe-300两种Ni/CeO2样品表面第一和第二金属离子层中Ni离子的含量分别位于9%~17%和8%~15%范围内.这一方法或可推广至研究其它一系列顺磁掺杂氧化物的表面掺杂含量.  相似文献   
855.
现有的光学溶解氧浓度检测方法中光路及电路结构复杂,本文提出了一种单路光源的频域荧光寿命的溶解氧检测方法.采用单路光源的光学结构实现水体溶解氧浓度的检测,简化了光路及电路结构,改进了溶解氧浓度检测算法,降低了整体检测过程的计算量.设计对比实验对方法进行验证,实验结果表明:单光源的频域荧光寿命的检测方法与DOP1光学溶解氧分析仪相比,在0~9mg/L范围内,实际检测误差降低至0.04mg/L;衡量稳定性的检测标准偏差为0.007mg/L,同比降低了36%;采用快速傅里叶变换以及改进的溶解氧浓度计算方法,配合优化的电路及光路结构,在达到90%稳态时响应时间平均缩短了12s,浓度上升和下降时的响应速度分别提升为40%和28%.该方法具有较好的检测精度、稳定性以及响应速度.  相似文献   
856.
应用作者提出的非连续变形计算力学模型粘弹性分析方法对具体的多体系统在动力外荷载作用下的响应进行了数值模拟,探讨了系统中物体的粘性阻尼对整个系统的变形、应力和接触应力等的影响。与通用软件ABAQUS的计算结果进行了比较研究,两种方法所得到的结果基本一致,但所发展的方法克服了ABAQUS中接触应力分段均匀分布的缺陷,因而所得到的接触应力较为合理,同时也说明了所提出的方法为由刚体、弹性体和粘弹性体所构成的复杂多体系统的数值分析提供了有力的工具。  相似文献   
857.
部分水解聚丙烯酰胺柠檬酸铝体系临界交联浓度的研究   总被引:6,自引:0,他引:6  
采用落球粘度计、核孔膜过滤、动态光散射 (DLS)和2 7Al NMR法 ,研究了高分子量、低浓度的部分水解聚丙烯酰胺 (HPAM)与柠檬酸铝 (AlCit)体系形成交联聚合物溶液 (LPS)的临界交联浓度 .研究结果表明 ,HPAM AlCit体系在聚合物浓度较低时 ,溶液中主要发生形成交联聚合物线团 (LPC)的交联反应 ,此时形成的是LPS ,聚合物浓度增加到某一临界值后 ,体系中形成线团后 ,存在线团间的交联 ,此时形成的是弱凝胶 .不同方法所测得的HPAM AlCit体系的临界交联浓度基本相同 ,对于粘均相对分子质量为 1 4× 10 7的HPAM ,在NaCl浓度为 2 0 0 0mg L ,交联比 2 0∶1时形成的交联体系 ,其临界交联浓度在 2 0 0~ 30 0mg L间 .  相似文献   
858.
高效液相色谱法对吗啡、杜冷丁、安定的同步测定   总被引:6,自引:0,他引:6  
王越  田薇  黄锋 《色谱》1999,17(4):399-400
利用高效液相色谱法同时分析测定了血液中吗啡、杜冷丁、安定的质量浓度。分析柱为C18,流动相为V(甲醇):V(25mmol/LKH2PO4)=90:10,检测波长为285nm。样品血液pH8.5~9.4时,用V(氯仿):V(异丙醇)=9:1溶液提取,以氮气吹干有机溶剂后用流动相溶解残渣进样分析。线性范围为0.05~50mg/L,最小检出质量浓度为0.05mg/L,日内与日间精密度CV<6%。  相似文献   
859.
本文研究了某些铁-硫原子簇络合物紫外-可见光谱220~230nm吸收带λ_(max)的浓度效应,△λnm随络合物结构对称性增加而减小,随浓度基数增大而变大的变化关系,该类型络合物紫外-可见光谱吸收峰的归属;计算了Fe~Ⅱ分裂能△值;配体上的取代基效应,以及在二氯甲烷等溶剂中的溶剂效应。  相似文献   
860.
We provide here a general view on the interactions of surfactants with viruses, with a particular emphasis on how such interactions can be controlled and employed for inhibiting the infectivity of enveloped viruses, including coronaviruses. The aim is to provide to interested scientists from different fields, including chemistry, physics, biochemistry, and medicine, an overview of the basic properties of surfactants and (corona)viruses, which are relevant to understanding the interactions between the two. Various types of interactions between surfactant and virus are important, and they act on different components of a virus such as the lipid envelope, membrane (envelope) proteins and nucleocapsid proteins. Accordingly, this cannot be a detailed account of all relevant aspects but instead a summary that bridges between the different disciplines. We describe concepts and cover a selection of the relevant literature as an incentive for diving deeper into the relevant material. Our focus is on more recent developments around the COVID-19 pandemic caused by SARS-CoV-2, applications of surfactants against the virus, and on the potential future use of surfactants for pandemic relief. We also cover the most important aspects of the historical development of using surfactants in combatting virus infections. We conclude that surfactants are already playing very important roles in various directions of defence against viruses, either directly, as in disinfection, or as carrier components of drug delivery systems for prophylaxis or treatment. By designing tailor-made surfactants, and consequently, advanced formulations, one can expect more and more effective use of surfactants, either directly as antiviral compounds or as part of more complex formulations.  相似文献   
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