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991.
The Ni/4H-SiC Schottky barrier diodes (SBDs) and transfer length
method (TLM) test patterns of Ni/4H-SiC Ohmic contacts were
fabricated, and irradiated with 1~MeV electrons up to a dose of
3.43× 1014~e/cm-2. After radiation, the forward
currents of the SBDs at 2~V decreased by about 50%, and the
reverse currents at -200~V increased by less than 30%. Schottky
barrier height (φ B ) of the Ni/4H-SiC SBD increased
from 1.20~eV to 1.21~eV under 0~V irradiation bias, and decreased
from 1.25~eV to 1.19~eV under -30~V irradiation bias. The
degradation of φ B could be explained by the variation
of interface states of Schottky contacts. The on-state resistance
(Rs) and the reverse current increased with the dose, which
can be ascribed to the radiation defects in bulk material. The
specific contact resistance (\rhoc) of the Ni/SiC Ohmic
contact increased from 5.11× 105~Ωega.cm2 to 2.97× 10-4~Ωega.cm2. 相似文献
992.
This paper studies the influence of the imperfectness of the contact condition on the torsional wave propagation in the initially stressed (stretched) bi-material compounded circular cylinder. The investigation is carried out within the scope of the piecewise homogeneous body model with the use of the Three-dimensional Linearized Theory of Elastic Waves in Initially Stresses Bodies. The mathematical formulation of the corresponding eigen-value problem is formulated and the solution method for that is developed. The two cases considered are the bi-material compounded cylinder consists of the solid inner and surrounding hollow outer cylinders (Case 1); the bi-material compounded cylinder consists of the hollow inner and surrounding hollow outer cylinders (Case 2). The mechanical relations of the cylinders’ materials are written through the Murnaghan potential. It is proven that the imperfectness of the contact condition does not influence the asymptotic-limit values of the wave propagation velocity. Moreover, the numerical results on the effects of the imperfectness of the boundary condition on the influence of the initial stresses on the wave propagation velocity are presented and discussed. 相似文献
993.
We prove that on a compact manifold, a contact foliation obtained by a smallC
1 perturbation of an almost regular contact flow has at least two closed characteristics. This solves the Weinstein conjecture for contact forms which areC
1-close to almost regular contact forms.Supported in part by NSF Grant DMS 90-01861 相似文献
994.
In this paper, we analyze helices in the secondary structures of the 16S and 23S rRNAs from the statistical physics perspective. The results of the analysis lead to propose a possible mechanism of the RNA folding based on the premise that the structure of RNA may bear a trace of its folding. We show that the frequency distribution of the helix contact order approximately follows a power-law, which implies that helices of large contact orders should inevitably exist. Furthermore, the frequencies of helix contact orders can be characterized by the multifractal. Comprehending the multifractality and the power-law of the distribution of the helix contact orders, we suggest a nearest-preferred helix formation as a mechanism for RNA folding via a random binary multiplicative process. The proposed process was supported by reconstructing the multifractal spectrum based on the transfer matrix theory and the binary tree representation of helices in the secondary structures. This justifies, at least partially if not entirely, the relevance of the proposed process as the kinetics of RNA folding. 相似文献
995.
We consider (,,,)structures of parabolic type on hypersurfaces of dual spaces and study the rank of the affinor . We consider almost contact metric structures of parabolic type of the first kind on hypersurfaces of 4dimensional dual metric space. We study the properties of these structures and give examples of normal, integrable, and Sasakian parabolic structures. 相似文献
996.
采用组合材料方法研究了金属Ni膜厚对Ni/SiC接触性质的影响.16个膜厚均为18 nm的Ni/SiC电极具有较为一致的肖特基接触性质;膜厚从10 nm增加到160 nm,肖特基接触的电流-电压(I-V)曲线随膜厚发生显著变化.分析表明这种变化源于膜厚对理想因子n和有效势垒高度ФB的影响.1000℃快速退火后,这些肖特基接触都转变为欧姆接触,Ni2Si是主要的生成物.I-V曲线测
关键词:
碳化硅
肖特基接触
欧姆接触
组合材料方法 相似文献
997.
本文研究了K模Wˉ1中K的非负偶次数的1上圈问题.利用计算导子在其生成元上作用,获得了简约定理和K模W1ˉ中K的非负偶次数的1上圈,推广了模切触超代数偶部导子. 相似文献
998.
ZnO∶Ga(GZO)透明电极沉积在p-GaN表面,用作透明电流扩展层。直接沉积在p-GaN上的p-GaN/GZO存在较大的势垒,容易形成肖特基接触,而良好的欧姆接触对功率LED器件至关重要。为了降低接触势垒,采用盐酸和氢氧化钠溶液对GaN表面进行去氧化层处理,并对p-GaN/GZO进行退火处理,研究表面处理和退火对p-GaN/GZO接触特性的影响。研究表明:碱性溶液处理有利于降低接触势垒;退火处理后,接触势垒略有增加。 相似文献
999.
1000.
Nitrogen ions were implanted into SiC ceramics by using ion implantation technology (N+-SiC). The surface structure and chemical bonds of N+-SiC ceramics were determined by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and their nanohardness was measured by nanoindenter. The friction and wear properties of the N+-SiC/SiC tribo-pairs were investigated and compared with those of SiC/SiC tribo-pairs in water using ball-on-disk tribo-meters. The wear tracks on the N+-SiC ceramics were observed by non-contact surface profilometer and scanning electron microscope (SEM) and their wear volumes were determined by non-contact surface profilometer. The results show that the N+-SiC ceramics were mainly composed of SiC and SiCN phase and SiN, CC, CN and CN bonds were formed in the implantation layer. The highest hardness of 22.3 GPa was obtained as the N+-SiC ceramics implanted at 50 keV and 1 × 1017 ions/cm2. With an increase in nitrogen ion fluence, the running-in period of N+-SiC/SiC tribo-pairs decreased, and the mean stable friction coefficient decreased from 0.049 to 0.024. The N+-SiC ceramics implanted at 50 keV and 5 × 1017 ions/cm2 exhibited the excellent tribological properties in water. In comparison of SiC/SiC ceramic tribo-pairs, the lower friction coefficient and lower wear rate for the N+-SiC/SiC tribo-pairs were acquired. 相似文献