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71.
为了提高难溶性药物的溶出速率,采用水热合成法制备了MCM-41和SBA-15两种介孔二氧化硅载体材料,利用浸渍法将模型药茴拉西坦负载于两种载体上.利用扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)、小角X射线衍射(XRD)、N2吸附-脱附、红外光谱(IR)、差热-热重(DTA-TG)对载药前后载体材料的表面形貌、粒径、孔径、孔容、比表面积、晶胞参数、骨架结构等进行测试,结果表明MCM-41和SBA-15具有相同的二维六方孔道结构,孔径及孔容分别为3.49 nm和6.67 nm,载药后的载药量分别为17;和22;,药物以非晶态装载于介孔孔道中没有影响介孔二氧化硅的骨架结构,但使介孔孔容及比表面积都有所降低.通过在不同pH溶出介质中负载于载体上的茴拉西坦与原料药晶体的溶出比较发现,两种载体均能够显著提高茴拉西坦的溶出速率.结合材料表征、载药量及溶出度综合比较,SBA-15载体的载药及释药性能均优于MCM-41载体. 相似文献
72.
Bo Zhang Dr. Jinhui Li Feng Liu Tao Wang Ying Wang Rui Xuan Prof. Guoping Zhang Prof. Rong Sun Prof. Ching-Ping Wong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(50):11715-11724
The practical application of advanced personalized electronics is inseparable from flexible, durable, and even self-healable energy storage devices. However, the mechanical and self-healing performance of supercapacitors is still limited at present. Herein, highly transparent, stretchable, and self-healable poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA)/poly(vinyl alcohol) (PVA)/LiCl polyelectrolytes were facilely prepared by one-step radical polymerization. The cooperation of PAMPSA and PVA significantly increased the mechanical and self-healing capacity of the polyelectrolyte, which exhibited superior stretchability of 938 %, stress of 112.68 kPa, good electrical performance (ionic conductivity up to 20.6 mS cm−1), and high healing efficiency of 92.68 % after 24 h. After assembly with polypyrrole-coated single-walled carbon nanotubes, the resulting as-prepared supercapacitor had excellent electrochemical properties with high areal capacitance of 297 mF cm−2 at 0.5 mA cm−2 and good rate capability (218 mF cm−2 at 5 mA cm−2). Besides, after cutting in two the supercapacitor recovered 99.2 % of its original specific capacitance after healing for 24 h at room temperature. The results also showed negligible change in the interior contact resistance of the supercapacitor after ten cutting/healing cycles. The present work provides a possible solution for the development of smart and durable energy storage devices with low cost for next-generation intelligent electronics. 相似文献
73.
Two LnIII ions are sandwiched by dinuclear CoII building blocks derived from a tris‐triazamacrocyclic ligand bearing pendant carboxylic acid functionality, 1,3,5‐tris((4,7‐bis(2‐carboxyethyl)‐1,4,7‐triazacyclonon‐1‐yl)methyl)‐benzene (H6L), giving rising to two nanoscale heterometallic metal–organic cages formulated as [Co4Ln2(LH2.5)2(H2O)4]·(ClO4)6·NO3·nH2O [Ln = Dy, n = 12 ( 1 ); Ln = Yb, n = 9 ( 2 )], whose internal cavity accommodates a guest NO3? anion. Their hexanuclear cage‐like architectures are maintained both in solution and solid states as confirmed by mass spectrum as well as X‐ray diffraction experiments. These two cages display ligand‐based fluorescence emissions and therefore both were chosen to be operated as fluorescent chemosensors for the detection of nitroaromatic compounds. Attractively, these metal–organic cages allow highly selective and sensitive detection of picric acid (PA) over other nitroaromatics in solution and suspension, and the fluorescence resonance energy transfer (FRET) between the cage probes and PA is mainly responsible for the remarkable detection efficiency. 相似文献
74.
Hui‐Min Lin Jian‐Rong Li Chao Mu Ao Li Xu‐Feng Liu Pei‐Hua Zhao Yu‐Long Li Zhong‐Qing Jiang Hong‐Ke Wu 《应用有机金属化学》2019,33(11)
Five monophosphine‐substituted diiron propane‐1,2‐dithiolate complexes as the active site models of [FeFe]‐hydrogenases have been synthesized and characterized. Reactions of complex [Fe2(CO)6{μ‐SCH2CH(CH3)S}] ( 1 ) with a monophosphine ligand tris(4‐methylphenyl)phosphine, diphenyl‐2‐pyridylphosphine, tris(4‐chlorophenyl)phosphine, triphenylphosphine, or tris(4‐fluorophenyl)phosphine in the presence of the oxidative agent Me3NO·2H2O gave the monophosphine‐substituted diiron complexes [Fe2(CO)5(L){μ‐SCH2CH(CH3)S}] [L = P(4‐C6H4CH3)3, 2 ; Ph2P(2‐C5H4N), 3 ; P(4‐C6H4Cl)3, 4 ; PPh3, 5 ; P(4‐C6H4F)3, 6 ] in 81%–94% yields. Complexes 2 – 6 have been characterized by elemental analysis, spectroscopy, and X‐ray crystallography. In addition, electrochemical studies revealed that these complexes can catalyze the reduction of protons to H2 in the presence of HOAc. 相似文献
75.
Xuan Thinh Duong Irina Holmes Ji Li Brett D. Wick Dongyong Yang 《Journal of Functional Analysis》2019,276(4):1007-1060
In this paper we establish the characterization of the weighted BMO via two weight commutators in the settings of the Neumann Laplacian on the upper half space and the reflection Neumann Laplacian on with respect to the weights associated to and respectively. This in turn yields a weak factorization for the corresponding weighted Hardy spaces, where in particular, the weighted class associated to is strictly larger than the Muckenhoupt weighted class and contains non-doubling weights. In our study, we also make contributions to the classical Muckenhoupt–Wheeden weighted Hardy space (BMO space respectively) by showing that it can be characterized via the area function (Carleson measure respectively) involving the semigroup generated by the Laplacian on and that the duality of these weighted Hardy and BMO spaces holds for Muckenhoupt weights with while the previously known related results cover only . We also point out that this two weight commutator theorem might not be true in the setting of general operators L, and in particular we show that it is not true when L is the Dirichlet Laplacian on . 相似文献
76.
A water circulation system with the almost same element composition and socket type was adopted in coral Acropora culture under different seawater pH value conditions and the data of the relationship between boron isotopic compositions of coral and seawater pH value by thermoelectric ionization mass spectrometer were obtained. According to the correlations between αcarb-3 of coral and the pH value of cultured seawater, αcarb-3 was not a constant but related to pH value, indicating that B(OH)3 also incorporated carbonate. Therefore, the theoretical formula could not be used to calculate the seawater pH value from the δ11Bcarb value of the measured marine biological carbonate. The empirical equations obtained experimentally would be an alternative method to calculate the seawater pH value. In addition, the mixed precipitation of CaCO3 and Mg(OH)2 was found in aquaculture tanks with high pH value, and the δ11B of the solid was significantly higher than that of cultured seawater. The result indicated that the presence of Mg(OH)2 had a significant effect on the boron isotope fractionation, which deserved our attention. 相似文献
77.
The trench on a printed circuit board was reconstructed to fabricate a microfluidic framework that allows low-cost production for small quantities and integration with multifunctional elements. An on-chip electrolyte regulator was thus proposed on this platform to analyze diffusion properties in laminar flow. A numerical model was developed, highlighting the interplay between the electrolyte migration and hydrodynamic properties. Solutions with dissolved sodium chloride were simulated and experimentally tested for the regulation of electrical conductivity under the guidance of the normalized Nernst-Planck equation. The diffusion mechanism and the resulting concentration field were demonstrated in detail. This approach provides a satisfactory manufacturing method and a useful tool for integrated microfluidic systems. 相似文献
78.
采用酸浸、磁选酸浸、水淬/研磨酸浸等不同工艺对冷冻法硝酸磷肥生产工艺中的废渣-酸不溶物进行了提纯处理,利用X射线荧光光谱仪(XRF测试)对酸不溶物提纯前后各成分含量的变化进行了分析,从中得出了不同工艺流程对酸不溶物纯度的影响,最终确定了最佳的酸不溶物处理工艺.结果表明:在酸浸实验中,盐酸酸浸效果最佳,可将酸不溶物中SiO2纯度达到82.43;;在酸浸工艺前加入磁选、水淬、研磨的工序均可有效提升酸不溶物的提纯效果;冷冻法硝酸磷肥工艺中酸不溶物最佳的提纯工艺路线为:干燥、筛分、水洗、磁选、研磨、盐酸酸浸,处理后酸不溶物中SiO2纯度达到88.92;,符合微硅粉的生产要求. 相似文献
79.
以La2O3、Al2O3、ZrO2、Cr2O3、CaCO3为原料,通过高温固相反应法制备La1-xCaxAl0.8 Cr0.2O3/CaZrO3(0≤x≤0.2)复相陶瓷材料,分别通过XRD、SEM和EDS等仪器对试样的物相组成和显微结构进行分析,利用紫外可见近红外分光光度计测量其红外吸收曲线.结果 表明:当CaZrO3理论生成量和La1-xCaxAl0.8Cr0.2O3的摩尔比小于0.20时复相陶瓷材料在0.76~2.5 μm的发射率较La0.8 Ca0.2Al0.8Cr0.2O3得到进一步提高,当CaZrO3理论生成量和La1-xCaxAl0.8Cr0.2O3的摩尔比为0.04时发射率最佳. 相似文献
80.