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81.
82.
Stability of tokamak plasmas with internal transport barriers against high n ideal magnetohydrodynamic ballooning mode 下载免费PDF全文
A ballooning mode equation for tokamak plasma, with the toroidicity and the Shafranov shift effects included, is derived for a shift circular flux tokamak configuration. Using this equation, the stability of the plasma configuration with an internal transport barrier (ITB) against the high n (the toroidal mode number) ideal magnetohydrodynamic (MHD) ballooning mode is analysed. It is shown that both the toroidicity and the Shaftanov shift effects are stabilizing. In the ITB region, these effects give rise to a low shear stable channel between the first and the second stability regions. Out of the ITB region towards the plasma edge, the stabilizing effect of the Shaftanov shift causes the unstable zone to be significantly narrowed. 相似文献
83.
有随机模拟方法研究了化学昆沌模型的介观动力学。对该混沌模型的系综模拟发现,在这种不稳定运动中存在强烈的内部涨落,然而由于混沌运动整体上的稳定性,使得系综中的代表点被限制在混沌吸引子上,并且单个代表点形成的随机轨道很好地保持了确定性混沌吸引子的基本特征。 相似文献
84.
85.
86.
建立了双层有机发光二极管中载流子在有机层界面复合的无序跳跃理论模型.由于有机分子材料的空间及能带结构的无序性,采用刚体模型处理有机层界面问题是不恰当的,而采用无序跳跃模型比较合理.复合效率及复合电流由载流子跳跃距离、有机层界面的有效势垒高度及该界面处的电场强度分布所决定:在双层器件ITO/α-NPD/Alq3/Al中,当所加电压小于19.5V时,复合效率随着载流子跳跃距离的增加而增加,而大于19.5V时,复合效率随着其距离的增加而减少;复合效率随着有机层界面有效势垒高度的增加而增加;
关键词:
有机层界面
双层有机发光二极管
复合效率
有效势垒高度
无序跳跃模型 相似文献
87.
建立了在单层有机发光二极管中电场强度不太大(E≤104Vcm)的情况下,载流子注入、传输和复合的理论模型.通过求解非线性Painleve方程得出了电场强度随坐标变化的解析函数关系式以及电流密度随电压变化关系,给出了电流密度以及器件的复合效率在不同的载流子迁移率情况下随电压变化关系图像.结果表明,复合效率受载流子迁移率影响较大,在器件中多数载流子应具有较低的迁移率,而少数载流子应具有较高的迁移率,这样有利于载流子的注入和传输,从而可提高发光效率.并且得出当空穴迁移率大于电子迁移率时,复合区域偏向阴极,反之亦
关键词:
单层有机发光二极管
复合效率
迁移率 相似文献
88.
Hao Wang Robert M. Straubinger John M. Aletta Jin Cao Xiaotao Duan Haoying Yu Jun Qu 《Journal of the American Society for Mass Spectrometry》2009,20(3):507-519
Protein arginine (Arg) methylation serves an important functional role in eucaryotic cells, and typically occurs in domains
consisting of multiple Arg in close proximity. Localization of methylarginine (MA) within Arg-rich domains poses a challenge
for mass spectrometry (MS)-based methods; the peptides are highly charged under electrospray ionization (ESI), which limits
the number of sequence-informative products produced by collision induced dissociation (CID), and loss of the labile methylation
moieties during CID precludes effective fragmentation of the peptide backbone. Here the fragmentation behavior of Arg-rich
peptides was investigated comprehensively using electron-transfer dissociation (ETD) and CID for both methylated and unmodified
glycine-/Arg-rich peptides (GAR), derived from residues 679–695 of human nucleolin, which contains methylation motifs that
are widely-represented in biological systems. ETD produced abundant information for sequencing and MA localization, whereas
CID failed to provide credible identification for any available charge state (z=2–4). Nevertheless, CID produced characteristic
neutral losses that can be employed to distinguish among different types of MA, as suggested by previous works and confirmed
here with product ion scans of high accuracy/resolution by an LTQ/Orbitrap. To analyze MA-peptides in relatively complex mixtures,
a method was developed that employs nano-LC coupled to alternating CID/ETD for peptide sequencing and MA localization/characterization,
and an Orbitrap for accurate precursor measurement and relative quantification of MA-peptide stoichiometries. As proof of
concept, GAR-peptides methylated in vitro by protein arginine N-methyltransferases PRMT1 and PRMT7 were analyzed. It was observed that PRMT1 generated a number of monomethylated (MMA) and
asymmetric-dimethylated peptides, while PRMT7 produced predominantly MMA peptides and some symmetric-dimethylated peptides.
This approach and the results may advance understanding of the actions of PRMTs and the functional significance of Arg methylation
patterns. 相似文献
89.
Y. M. Dan Y. R. Zhao Y. Liu S. S. Qu 《Journal of Thermal Analysis and Calorimetry》2006,84(3):531-534
The two complexes, [Ln(Ala)2(Im)(H2O)](ClO4)3 (Ln=Pr,
Gd), were synthesized and characterized. Using a solution-reaction isoperibol
calorimeter, standard enthalpies of reaction of two reactions: LnCl3⋅6H2O(s)+2Ala(s)+Im(s)+3NaClO4(s)=[Ln(Ala)2(Im)(H2O)](ClO4)3(s)+3NaCl(s)+5H2O(l) (Ln=Pr, Gd),
at T=298.15 K, were determined to be (39.26±0.10)
and (5.33±0.12) kJ mol–1 , respectively.
Standard enthalpies of formation of the two complexes at T=298.15
K, ΔfHΘm
{[Ln(Ala)2(Im)(H2O)](ClO4)3(s)} (Ln=Pr, Gd),
were calculated as –(2424.2±3.3) and –(2443.4±3.3)
kJ mol–1 , respectively. 相似文献
90.
Wensheng Huang Chunhai Yang Wanyun Qu Shenghui Zhang 《Russian Journal of Electrochemistry》2008,44(8):946-951
In this work, an electrochemical method for the determination of malachite green was developed on the basis of enhancement
effect of an anionic surfactant: sodium dodecyl benzene sulfonate. It is found that the oxidation peak current of malachite
green at carbon paste electrode significantly increases in the presence of low concentration of sodium dodecyl benzene sulfonate
in pH 6.5 phosphate buffer, suggesting that sodium dodecyl benzene sulfonate shows obvious enhancement effect for the determination
of malachite green. The experimental parameters, such as supporting electrolyte, kind of surfactant, concentration of sodium
dodecyl benzene sulfonate and accumulation time, were optimized, and then a sensitive and convenient electrochemical method
was proposed for the determination of malachite green. The oxidation peak current is proportional to the concentration of
malachite green over the range from 8.0 × 10−9 to 5.0 × 10−7 mol l−1, and the detection limit is 4.0 × 10−9 mol l−1 after 5 min of accumulation. Finally, this new method was successfully employed to detect malachite green in fish samples.
Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 8, pp. 1019–1024.
The text was submitted by the authors in English. 相似文献