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31.
Bao Gia Nguyen 《Journal of statistical physics》1987,49(1-2):235-243
A study is made of the gap exponents for percolation processes with the triangle condition in the subcritical region. It is show that the gaps are given by
t
=2 fort=2, 3,. Scaling theory predicts thatP
p
(¦C
0¦S(p))–(p
c
–p) andE
p
(1/¦C
0¦; ¦C
0¦S(p))–(p
c
–p)3, whereS(p) is the typical cluster size. It is found that (p
c
–p)P
p
(|C
0S(p)
1–)(p
c
–p)1–2 and (p
c
–p)3E
p
(1/|C
0|;|C
0|S(p)
1–))(p
c
–p)3–4. 相似文献
32.
33.
采用摩擦氧浓度实验方法, 结合原位观察、扫描电镜、能谱仪和X-射线衍射分析, 系统研究Ti-V-Cr 阻燃钛合金燃烧产物的微观组织形貌、燃烧反应过程的合金元素分布规律及微观机理. 结果表明: Ti-V-Cr 阻燃钛合金燃烧过程发出闪亮耀眼的白光, 具有典型金属燃烧的火焰特征. 燃烧产物主要有TiO2, V2O5和Cr2O3三种氧化物, 该混合氧化物以分散颗粒和致密连续体存在. 分散颗粒为规则的球形; 致密连续燃烧产物的微观组织具有分区特征, 从合金基体至燃烧表面依次为过渡区、热影响区、熔凝区和燃烧区. 其中, 过渡区存在一些微小的颗粒状凸起, 且有一定方向性; 热影响区中形成大量V基固溶体相和少量的Ti基固溶体相, V基固溶体相上存在Ti的含量远高于基体的针状析出物; 熔凝区中, 大量的Ti基固溶体中存在少量的V基固溶体; 燃烧区主要为Ti, V和Cr的氧化物混合物. 热影响区的V基固溶体相降低了Ti元素向熔凝区的迁移速率, 减慢了燃烧区Ti与O的优先反应; 燃烧区形成的TiO2, V2O5和Cr2O3混合氧化物和熔凝区O在Ti中大量固溶共同终止了O向合金基体的继续扩散, 从而使Ti-V-Cr阻燃钛合金表现出优异的阻燃功能性. 相似文献
34.
We show that the evolution equations for a perfect fluid coupled to general relativity in a general lapse and shift, are Hamiltonian relative to a certain Poisson structure. For the fluid variables, a Lie-Poisson structure associated to the dual of a semi-direct product Lie algebra is used, while the bracket for the gravitational variables has the usual canonical symplectic structure. The evolution is governed by a Hamiltonian which is equivalent to that obtained from a canonical analysis. The relationship of our Hamiltonian structure with other approaches in the literature, such as Clebsch potentials, Lagrangian to Eulerian transformations, and its use in clarifying linearization stability, are discussed.Research supported in part by NSF grant MCS 81-08814(A02)Research supported in part by NSF grant MCS 81-07086 相似文献
35.
Structures of Pt clusters on graphene doped with nitrogen, boron, and silicon: a theoretical study 下载免费PDF全文
The structures of Pt clusters on nitrogen-,boron-,silicon-doped graphenes are theoretically studied using densityfunctional theory.These dopants(nitrogen,boron and silicon) each do not induce a local curvature in the graphene and the doped graphenes all retain their planar form.The formation energy of the silicon-graphene system is lower than those of the nitrogen-,boron-doped graphenes,indicating that the silicon atom is easier to incorporate into the graphene.All the substitutional impurities enhance the interaction between the Pt atom and the graphene.The adsorption energy of a Pt adsorbed on the silicon-doped graphene is much higher than those on the nitrogen-and boron-doped graphenes.The doped silicon atom can provide more charges to enhance the Pt-graphene interaction and the formation of Pt clusters each with a large size.The stable structures of Pt clusters on the doped-graphenes are dimeric,triangle and tetrahedron with the increase of the Pt coverage.Of all the studied structures,the tetrahedron is the most stable cluster which has the least influence on the planar surface of doped-graphene. 相似文献
36.
微尺度下壁面粗糙度对面向导热影响研究 总被引:1,自引:0,他引:1
随着空间尺度的缩小,界面对导热的影响就会越来越明显。本文采用非平衡分子动力学模拟方法模拟了壁面的粗糙度对面向导热的影响,并给出微尺度下的粗糙度定义。在模拟中构造了不同的壁面粗糙度,得到了面向热导率随着壁面粗糙度增加而减小的结果。分析认为壁面的镜面反射率随着粗糙度增加而减小,而镜面反射率减小将导致热导率下降. 相似文献
37.
为了提高加速鲁棒特征(SURF)算法的实时性和准确性,本文提出了一种结合AGAST角点检测和改进的SURF特征描绘算法。首先利用AGAST角点检测模板检测特征点,再使用增加对角信息的哈尔小波响应来生成特征点的描述子,之后利用特征袋对产生的描述子进行编码并生成新的特征向量,最后利用支持向量机(SVM)对特征向量进行分类,完成识别。本文以SIFT和SURF算法为对照,分别进行不同视角、光照和尺度的识别实验。实验结果表明,本文算法的平均识别率为98.0%、96.9%、97.1%,平均时间分别为66.1 ms、79.3 ms、41.0 ms,在识别率上较优于SURF算法,所耗时间约是SURF算法的1/3。 相似文献
38.
Ying Jie Shen Rui Jun Lan Yin Chang Zhao Chuan Peng Qian Tong Yu Dai Bao Quan Yao 《Journal of Russian Laser Research》2017,38(6):559-563
We design a continuous-wave Tm:YLF laser with a composite slab crystal end-pumped by two fiber-coupled laser diodes at room temperature. We achieve a maximum continuous wave output power of 105 W for the bonded slab Tm:YLF laser; the corresponding slope efficiency is 47.7% and the optical-to-optical conversion efficiency is 42.0% with respect to the incident pump power. The laser operated at 1,907.5 nm with a beam quality factor of M2 ~3.2 at the highest output power. 相似文献
39.
40.
Most of lasers used for imaging and heating gold nanorods are single-wavelength lasers and their efficiency to interact with different gold nanorods is limited. In this study, we demonstrated that supercontinuum light could be a fast, effective and energy efficient excitation source for heating of gold nanorods. The photothermal effect and the heating speed of gold nanorods illuminated by a supercontinuum light and femtosecond pulses through two-photon excitation are experimentally studied through using transmission electron microscopy images and photoluminescence images of gold nanorods. It is found that the supercontinuum light improves the heating speed by 39 %, and melts 30 % more of gold nanorods compared with the femtosecond pulse excitation approach. The heating speed of gold nanorods by supercontinuum light depends not only on its polarization states, but also on the pulse width and numerical aperture of its focused beam. It has been found that the supercontinuum is more efficient in heating of gold nanorods, making it potentially valuable for clinical applications. 相似文献