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911.
采用柠檬酸钠辅助的水热方法制备了一系列不同Ca2+含量的Ca2+/Yb3+/Er3+共掺的NaYF4微米片。利用透射电子显微镜(TEM)、X射线衍射分析(XRD)、发光光谱等测量手段对样品进行了形貌、晶相、发光性质的表征。样品在980 nm激光泵浦下,可以观察到强的上转换绿色荧光。在Ca2+的摩尔分数从0增加到8%的过程中,紫外到可见的上转换发光随着Ca2+浓度的增加而显著增强。这是由于Ca2+的掺杂导致了晶体内部的不对称性,同时也提高了晶体的结晶性。 相似文献
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Dan Zhu Yurong Yan Pinhua Lei Bo Shen Wei Cheng Huangxian Ju Shijia Ding 《Analytica chimica acta》2014
A novel electrochemical sensing strategy was developed for ultrasensitive and rapid detection of Salmonella by combining the rolling circle amplification with DNA–AuNPs probe. The target DNA could be specifically captured by probe 1 on the sensing interface. Then the circularization mixture was added to form a typical sandwich structure. In the presence of dNTPs and phi29 DNA polymerase, the RCA was initiated to produce micrometer-long single-strand DNA. Finally, the detection probe (DNA–AuNPs) could recognize RCA product to produce enzymatic electrochemical signal. Under optimal conditions, the calibration curve of synthetic target DNA had good linearity from 10 aM to 10 pM with a detection limit of 6.76 aM (S/N = 3). The developed method had been successfully applied to detect Salmonella as low as 6 CFU mL−1 in real milk sample. This proposed strategy showed great potential for clinical diagnosis, food safety and environmental monitoring. 相似文献
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基于5G基站前向功率控制和波束赋形等关键技术,设计单用户情况下5G基站电磁辐射测试方案。该方案根据电磁辐射功率密度随着距离平方减小的规律布点,可以在一定程度上提高宏基站测试效率。对本文所提监测方案进行现场实测,监测结果远小于国际非电离辐射防护委员会(ICNIRP)标准限值,表明5G基站电磁辐射水平总体可控。利用高频结构仿真器(HFSS)设计5G基站天线模型获取大规模多输入多输出(MIMO)天线阵方向图,基于实际场景电磁参数分析搭建场景,通过射线追踪算法对5G基站的电磁辐射进行预测。预测与监测结果相比误差不大,证明预测方法可靠。 相似文献
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Shi Liang Xian‐Zhu Yang Xiao‐Jiao Du Hong‐Xia Wang Hong‐Jun Li Wei‐Wei Liu Yan‐Dan Yao Yan‐Hua Zhu Yin‐Chu Ma Jun Wang Er‐Wei Song 《Advanced functional materials》2015,25(30):4778-4787
Delivery of small interfering RNA (siRNA) by nanocarriers has shown promising therapeutic potential in cancer therapy. However, poor understanding of the correlation between the physicochemical properties of nanocarriers and their interactions with biological systems has significantly hindered its anticancer efficacy. Herein, in order to identify the optimal size of nanocarriers for siRNA delivery, different sized cationic micellar nanoparticles (MNPs) (40, 90, 130, and 180 nm) are developed that exhibit similar siRNA binding efficacies, shapes, surface charges, and surface chemistries (PEGylation) to ensure size is the only variable. Size‐dependent biological effects are carefully and comprehensively evaluated through both in vitro and in vivo experiments. Among these nanocarriers, the 90 nm MNPs show the optimal balance of prolonged circulation and cellular uptake by tumor cells, which result in the highest retention in tumor cells. In contrast, larger MNPs are rapidly cleared from the circulation and smaller MNPs are inefficiently taken up by tumor cells. Accordingly, 90 nm MNPs carrying polo‐like kinase 1 (Plk1)‐specific siRNA (siPlk1) show superior antitumor efficacy, indicating that 90 nm could either be the optimal size for systemic delivery of siRNA or close to it. Our findings provide valuable information for rationally designing nanocarriers for siRNA‐based cancer therapy in the future. 相似文献
917.
Humidity‐Triggered Self‐Healing of Microporous Polyelectrolyte Multilayer Coatings for Hydrophobic Drug Delivery
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Xia‐Chao Chen Ke‐Feng Ren Jia‐Hui Zhang Dan‐Dan Li Emily Zhao Zhong Jonathon Zhao Zhi‐Kang Xu Jian Ji 《Advanced functional materials》2015,25(48):7470-7477
Layer‐by‐layer (LbL) self‐assemblies have inherent potential as dynamic coatings because of the sensitivity of their building blocks to external stimuli. Here, humidity serves as a feasible trigger to activate the self‐healing of a microporous polyethylenimine/poly(acrylic acid) multilayer film. Microporous structures within the polyelectrolyte multilayer (PEM) film are created by acid treatment, followed by freeze‐drying to remove water. The self‐healing of these micropores can be triggered at 100% relative humidity, under which condition the mobility of the polyelectrolytes is activated. Based on this, a facile and versatile method is suggested for directly integrating hydrophobic drugs into PEM films for surface‐mediated drug delivery. The high porosity of microporous film enables the highest loading (≈303.5 μg cm?2 for a 15‐bilayered film) of triclosan to be a one‐shot process via wicking action and subsequent solvent removal, thus dramatically streamlining the processes and reducing complexities compared to the existing LbL strategies. The self‐healing of a drug‐loaded microporous PEM film significantly reduces the diffusion coefficient of triclosan, which is favorable for the long‐term sustained release of the drug. The dynamic properties of this polymeric coating provide great potential for its use as a delivery platform for hydrophobic drugs in a wide variety of biomedical applications. 相似文献
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针对线性离散多址复用(LDDMA)系统,文章研究在线性迫零(Zero-Force)接收机条件下的多用户选择分集与调度算法。对于用户子集选择算法,遍历搜索是最优的,但它所引起的繁重的计算复杂度,很难在实际中应用。基于此考虑,本文提出三种次优的贪婪选择准则:最大信道增益选择,最大信道容量选择与最大最小后验SNR选择。数值仿真结果表明:最大最小后验SNR准则可以提供较好的BER性能。 相似文献