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排序方式: 共有416条查询结果,搜索用时 15 毫秒
331.
Alemayehu H. Bedane Mladen Eić Madjid Farmahini-Farahani Huining Xiao 《Cellulose (London, England)》2016,23(3):1537-1552
The theory of mass transport in porous media is of fundamental importance for different applications such as food, paper packaging, textiles, and wood for building materials. In this study, a theoretical water vapor transport model has been developed for cellulose-based materials, such as paper and regenerated cellulose film. Pore diffusivities were determined from the dynamic moisture breakthrough experiments comprising a stack of paper sheets and regenerated cellulose films in a configuration similar to a packed adsorption column. Other mass transfer parameters were determined from transient moisture uptake rate measurements. The model incorporates pore and surface diffusion as a lump parameter into a variable effective diffusion coefficient. The mass transport, involving both pore and surface diffusions, is evaluated independently. The theoretical water vapor transmission rates (WVTRs) obtained from the model were compared with experimentally determined WVTRs measured under steady-state conditions. The theoretical model, based on intrinsic diffusion, stipulates higher WVTR values compared to the experimental results. However, the theoretical water vapor transfer rates agree well with the experimental results when external mass transfer resistance is incorporated in the model. 相似文献
332.
Tatsuya Tsukamoto 《Proceedings of the American Mathematical Society》2000,128(6):1859-1867
Recently it has been proved that if and only if two knots and have the same value for the Vassiliev invariant of type two, then can be deformed into by a finite sequence of clasp-pass moves. In this paper, we determine the difference of the values of the Vassiliev invariant of type three between two knots which can be deformed into each other by a clasp-pass move.
333.
334.
Kitamura Y Mori K Yamamoto M Nozaki A Saito M Tsukamoto I Mifune M Saito Y 《Chemical & pharmaceutical bulletin》2008,56(9):1364-1366
In order to explore the capability of metal porphyrins as an alternative of horseradish peroxidase (HRP), HRP-like activity of three manganese-porphyrins (Mn-Ps) and three Mn-octabromo-porphyrins (Mn-OBPs) was examined in both aqueous and immobilized states. It was found that Mn(3+)-octabromotetrakis(1-methyl-pyridinium-4yl)porphine (Mn-OBTMPyP) has an activity of at least 90% of HRP in an aqueous solution. Mn-OBTMPyP exhibited a catalytic activity even in the presence of hydrogen peroxide without suicide reaction. In addition, Mn-OBTMPyP was revealed to function as an alternative to HRP in the quantitative determination of serum uric acid. These results are of great interest because they indicate that metal-octabromo-porphyrins possibly include promising candidates of artificial enzyme capable of substituting for HRP. 相似文献
335.
Janus纳米粒子的结构设计和简易合成是Pickering乳液界面催化的关键. 本文通过在Pickering乳液保护法中操纵共轭亚油酸的自组装、 自交联性和弱还原性, 合成了Janus型自交联吸附胶束修饰的纳米Fe3O4 (SCA-Fe3O4), 并在其表面原位还原金后, 合成了Janus型催化剂Au-SCA-Fe3O4, 考察其同时作为乳化剂和催化剂在乳液界面催化苯甲醇氧化生成苯甲醛的性能. 结果表明, 该Janus纳米粒子的金修饰量(质量分数)仅为0.66%, 兼具乳化性、 催化性和磁响应性. Au-SCA-Fe3O4可制备外观稳定(100 μm)和热稳定(90 ℃)的苯甲醇/水型Pickering乳液, 可显著提高互不相溶反应物与催化剂间的接触面积, 使其催化活性达到均匀纳米催化剂的2倍和非乳液催化时的3倍, 其在界面的不可转动性使苯甲醛的选择性高于99.9%, 避免了苯甲醛被过度氧化成苯甲酸. 相似文献
336.
Equilibrium data and diffusion characteristics of propane and propylene were determined on mesoporous adsorbents modified
with an organic molecule (APTES) and/or impregnated with AgNO3, in order to obtain a separation by adsorption via π-complexation.
Adsorption capacities were determined by a gravimetric technique, while diffusion characteristics were evaluated by the ZLC
technique. The equilibrium isotherms data showed that the modification with an organic molecule will weaken the π-interaction between Ag+ and double C=C bond. On the other hand slightly higher adsorption capacities for propylene (about 1.5 mol/kg) were obtained
for the sample prepared by a direct impregnation with larger amounts of AgNO3 (M4 sample).
Diffusion runs confirmed that the propane desorption rate on M4 sample was much higher compared to propylene. This evidence
leads to a potential application of that adsorbent material for a kinetic separation. 相似文献
337.
Shouquan Huo Ji‐cheng Shi Ei‐ichi Negishi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2002,114(12):2245-2247
338.
Namihira T. Tsukamoto S. Wang D. Hori H. Katsuki S. Hackam R. Akiyama H. Shimizu M. Yokoyama K. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2001,29(4):592-598
A short duration of 100-ns pulsed power has been used to remove nitric oxide (NO) in a mixture of nitrogen, oxygen, water vapor, and NO, simulating flue gases from a power station. The effects of the gas flow rate, the reactor length, and the pulse repetition rate on the percentage of NO removal and its energy efficiency are reported. The percentage of NO removal at a fixed gas flow rate increased with increasing pulse repetition rate due to the increased energy into the discharge. At a fixed pulse rate, the removal of NO increased with decreasing gas flow rate due to the increased residence time of the gas in the discharge reactor, thus facilitating the creation of increased radicals of O and N which then decreased NO. The energy removal efficiency of NO (in mol/kWh) decreased with increasing gas flow rate and increasing removal ratio of NO. The removal of NO increased with increasing energy density (J/I), input into the discharge at different reactor length 相似文献
339.
Catalytic generation of hydrogen by applying fluorinated-metal hydrides as catalysts 总被引:2,自引:0,他引:2
S. Suda Y.-M. Sun B.-H. Liu Y. Zhou S. Morimitsu K. Arai N. Tsukamoto M. Uchida Y. Candra Z.-P. Li 《Applied Physics A: Materials Science & Processing》2001,72(2):209-212
Metal–hydrogen complexes such as NaAlH4, KBH4, and NaBH4 are known as high H-content materials. The highly reactive natures of these materials against moist air and water can be
easily stabilized in aqueous KOH and NaOH solutions. Accordingly, it is required to develop catalysts suitable for generating
hydrogen from the stabilized metal–hydrogen complexes in alkaline solutions.
This work is aimed at developing catalysts that can generate hydrogen from such solutions with considerably high kinetics
under moderate temperature and pressure conditions.
We have found that Mg2Ni, a typical high-temperature hydriding alloy, exhibits excellent functions as a catalyst for the hydrolysis of BH4
--ion-containing solutions. The fluorination-treatment (F-treatment) effects on granular particles of Mg2Ni and Mg2NiH4 are reported in this paper.
Received: 13 November 2000 / Accepted: 14 November 2000 / Published online: 9 February 2001 相似文献
340.
祝向荣 沈鸿烈 沈勤我 李铁 邹世昌 Koichi Tsukamoto Mamoru Okutomi Takeshi Yanagisaw Noboru Higuchi 《物理学报》1999,48(13):40-46
用固相反应法制备了二元掺杂的镧锰氧化物La0.67(Ca0.6Ba0.4)0.33MnOz(LCBMO)立方多晶体材料,研究了其磁特性和庞磁电阻特性,并与用类似方法制备的一元掺杂的La0.67Ca0.33MnOz(LCMO)及La0.67Ba0.33MnOz(LBMO)的庞磁电阻特性进行了比较.研究表明,LCBMO的居里温度TC为312K,介于LCMO和LBMO的TC(分别为280,362K)之间,其金属-半导体转变温度Tp和μ0H=0.6T下的磁电阻(MR)峰值温度Tm分别为306,298K,接近于其TC,也介于LCMO和LBMO的Tp和Tm之间.μ0H=0.6T下,在各自的Tm处,LCMO,LCBMO和LBMO的庞磁电阻值分别达到41%,24.7%和8%,但在室温(300K)处,LCBMO的MR值仍达到20%,远大于LCMO和LBMO的值(分别为2.0%和2.4%).研究还发现,在温度远低于Tm时,LCMO仍保持一定的磁电阻效应,而LCBMO和LBMO的磁电阻温度降低而增加,这些低温磁电阻特性与材料的结构特征(如晶界和致密度)有关.
关键词: 相似文献