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91.
92.
Yanmin Yang Chao Mi Fuyun Jiao Xianyuan Su Xiaodong Li Linlin Liu Jiao Zhang Fang Yu Yanzhou Liu Yaohua Mai 《Journal of the American Ceramic Society》2014,97(6):1769-1775
Yb3+/Er3+ codoped La2S3 upconversion (UC) phosphors have been synthesized using high‐temperature solid‐state method. Under 971‐nm excitation, the maximum luminescence power can reach 0.64 mW at the excitation power density of 16 W/cm2 and an absolute power yield of 0.36% was determined by an absolute method at the excitation power density of 3 W/cm2, and the quantum yield of La2S3:Yb3+, Er3+ (green ~0.18%, red ~0.03%, integration ~0.21) was comparable to that of NaYF4:Yb3+, Er3+ nanocrystals (integration ~0.005–0.30). Frequency upconverted emissions from two thermally coupled excited states of Er3+ were recorded in the temperature range 100–900 K. The maximum sensitivity of temperature sensing is 0.0075 K?1. As the excitation power density increases, the temperature of host materials rapidly rises and the top temperature can reach to 600 K. Given the intense UC emission, high sensitivity, as well as good photothermal stability, La2S3:Yb3+/Er3+ phosphor can become a promising composite material for photothermal ablation of cancer cells possessing the functions of temperature sensing and in vivo imaging. 相似文献
93.
Single phase multiferroic BiFeO3 (BFO) ceramics were synthesized with controllable amount of Fe2+ and oxygen vacancies in a very wide concentration range. Double ferroelectric hysteresis loops are observed in fresh BFO ceramics at room temperature without any aging processes. Detailed study shows that this is due to the defect dipoles which have preferential orientations antiparallel to the direction of spontaneous polarization, providing a driving force for domain back-switching. The dielectric constant of BFO could be enormously enhanced by 100 times by increasing the Fe2+ content, employing a polaronic relaxation process. 相似文献
94.
对水样中呋喃丹和甲萘威的高效液相色谱标准检测方法进行了改进,水样使用0.45 mm滤膜过滤后直接进样200μL,以甲醇∶乙腈∶水=20∶20∶60为流动相,流量为1 mL/min,采取等梯度淋洗,荧光检测器激发波长为330 nm,吸收波长为465 nm。改进方法对呋喃丹和甲萘威的加标回收率分别为87.5%~98.6%、89.3%~105.2%,最低检出浓度分别为0.002 mg/L、0.001 mg/L,可用于水中呋喃丹和甲萘威的分析。 相似文献
95.
96.
影响标机贴标质量的因素探讨 总被引:1,自引:0,他引:1
本文系统地阐述了人、机器、商标纸、玻璃瓶和粘贴剂等5种因素对贴标机贴标质量的影响,分析了常见的标机故障,并提出排除措施. 相似文献
97.
Robert F. DeJaco Matheus Dorneles de Mello Huong Giang T. Nguyen Mi Young Jeon Roger D. van Zee Michael Tsapatsis Joern Ilja Siepmann 《American Institute of Chemical Engineers》2020,66(4):e16868
In this work, batch-adsorption experiments and molecular simulations are employed to probe the adsorption of binary mixtures containing ethanol or a linear alkane-1,n-diol solvated in water or ethanol onto silicalite-1. Since the batch-adsorption experiments require an additional relationship to determine the amount of solute (and solvent) adsorbed, as only the bulk liquid reservoir can be probed directly, molecular simulations are used to provide a relationship between solute and solvent adsorption for input to the experimental bulk measurements. The combination of bulk experimental measurements and simulated solute–solvent relationship yields solvent and solute loadings that are self-consistent with simulation alone, and allow for an assessment of the various assumptions made in the literature. At low solution concentrations, the solute loading calculated is independent of the assumption made. At high concentrations, a negligent choice of assumption can lead to systematic overestimation or underestimation of calculated solute loading. 相似文献
98.
Charge recombination in reaction center (RC) of photosystem II(PS II) is regarded as the location of 685 nm delayed fluorescence
(DF). The mechanism of 730 nm component appearing in the DF spectrum for chloroplast was studied by various spectral analysis
methods. Experimental results of the DF spectrum at different chloroplast concentration show that the intensity of peaks at
685nm and 730 nm ascends with the chloroplast concentration increasing when the concentration is relatively low. When the
concentration increases to the level of 7.8μg/ml, a maximum intensity of the peak at 685 nm appears but the intensity of 730
nm peak still increases. The peak at 730 nm finally reaches a maximum intensity at the chloroplast concentration of 31.2 μg/ml
while the intensity of the 685 nm peak has apparently fallen down. The results of absorption spectrum show that the ratios
of A685 to A730 keep almost constant with the increasing of chloroplast concentration. Furthermore, the excitation spectrum
for 730 nm fluorescence shows that the 685nm light has high excitation efficiency. These results indicate that the 730 nm
component of DF spectrum is the fluorescence of chlorophyll in PS I RC excited by 685 nm DF. Meanwhile, this can be further
verified by the invariability of DF spectrum at different delay time (1 second∼9 seconds).
This research is supported by the National Natural Science Foundation of China (60378043), and supported by the Opening Foundation
of the Key Laboratory of Opto-Electronic Technology and Intelligent Control (Lanzhou Jiaotong University), Ministry of Education
(K04108) 相似文献
99.
为了测定水闸混凝土底板与水泥土搅拌桩体之间的抗剪强度,设计了现场大型原位直接剪切试验方法,用以模拟工程实际。通过对4个加固处理后的水泥土搅拌桩体施加不同的垂直应力,变形达到相对稳定后进行水平剪切试验。针对不同垂直应力下的抗剪强度结果,采用最小二乘法,求解得到抗剪强度参数凝聚力为21.2 kPa,内摩擦角为26.7°。现场试验结果表明,在设计荷载作用下的综合摩擦系数达到设计要求,水泥土搅拌桩具有较好的抵抗闸室底板滑动破坏的特性。 相似文献
100.
Mai Bay Stie Johan Ring Gtke Ioannis S. Chronakis Jette Jacobsen Hanne Mrck Nielsen 《International journal of molecular sciences》2022,23(3)
The sublingual mucosa is an attractive route for drug delivery, although challenged by a continuous flow of saliva that leads to a loss of drug by swallowing. It is of great benefit that drugs absorbed across the sublingual mucosa avoid exposure to the harsh environment of the gastro-intestinal lumen; this is especially beneficial for drugs of low physicochemical stability such as therapeutic peptides. In this study, a two-layered hybrid drug delivery system was developed for the sublingual delivery of the therapeutic peptide desmopressin. It consisted of peptide-loaded mucoadhesive electrospun chitosan/polyethylene oxide-based nanofibers (mean diameter of 183 ± 20 nm) and a saliva-repelling backing film to promote unidirectional release towards the mucosa. Desmopressin was released from the nanofiber-based hybrid system (approximately 80% of the loaded peptide was released within 45 min) in a unidirectional manner in vitro. Importantly, the nanofiber–film hybrid system protected the peptide from wash-out, as demonstrated in an ex vivo flow retention model with porcine sublingual mucosal tissue. Approximately 90% of the loaded desmopressin was retained at the surface of the ex vivo porcine sublingual mucosa after 15 min of exposure to flow rates representing salivary flow. 相似文献