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991.
Zhang Xiaoyong Gao Junfang Wang Jun He Lina Tian Runze Yang Junhong Lu Bohui 《印度化学会志》2022,99(9):100651
We prepared the nanocrystals (NCs) of CdTe, CdTe:Yb, and CdTe:Yb, Mn vis water phase synthesis and examined their structural, morphological, and optical properties. All NCs have a particle diameter of about 2–4 nm, and the monodispersed, uniform spherical, cubic structure of the CdTe NC remains largely unchanged after the doping with Yb and Mn. According to the X-ray diffraction results, the CdTe, CdTe:Yb, and CdTe:Yb, Mn NCs all have a cubic structure, and the diffraction peak of CdTe:Yb NC is at a lower 2θ angle compared with that of the CdTe NC. With the CdTe NC as the reference, the UV–Vis absorption of the CdTe:Yb and the CdTe:Yb, Mn NCs exhibits a blueshift and a redshift, and the emission of CdTe:Yb and CdTe:Yb, Mn has a blueshift of about 12 nm and a redshift of about 73 nm, respectively. The CdTe:Yb, Mn NCs have higher quantum yields than the CdTe:Yb NC, and the quantum yield is the highest when CdTe is doped with 1:1 Mn2+/Yb3+. In addition, both the CdTe:Yb and CdTe:Yb, Mn NCs have a shorter fluorescence lifetime than the CdTe NC. 相似文献
992.
含氮聚合物负载钯络合物的合成及其催化加氢性能的研究 总被引:1,自引:0,他引:1
合成了一系列含氮聚合物金属络合物,考察了它们对1,5,9-环十二碳三烯选择性催化加氢的活性及选择性。研究了同种聚合物中单原子配体与双原子配体对催化剂活性的影响。对不同金属物种、孔结构、温度及压力对加氢活性及选择性的影响也进行了系统的比较。 相似文献
993.
Yang Li Zhen-Hua Ye Chun Lin Xiao-Ning Hu Rui-Jun Ding Li He 《Optical and Quantum Electronics》2013,45(7):641-648
Current–voltage characteristics of HgCdTe photodiodes in the forward bias region have been modeled considering mechanisms including drift-diffusion current, recombination current, metal-semiconductor contact and constant series resistance. Moreover, a fitting method based on the genetic algorithm has been developed to obtain values of related physical parameters from the measured dynamic resistance–voltage curves. Fitting results of $n^+$ -on- $p$ planar devices with different cutoff wavelengths are presented to illustrate the model and method, which are available and promising in acquiring device parameter values and evaluating the electrode contact quality. 相似文献
994.
Ning Tang Bo Shen Kui Han Xiao-Wei He Chun-Ming Yin Zhi-Jian Yang Zhi-Xin Qin Guo-Yi Zhang Tie Lin Wen-Zheng Zhou Li-Yan Shang Jun-Hao Chu 《Applied Physics A: Materials Science & Processing》2009,96(4):953-957
The subband structure and occupation in the triangular quantum well at Al
x
Ga1−x
N/GaN heterointerfaces have been investigated by means of temperature dependent Shubnikov–de Haas (SdH) measurements at low
temperatures and high magnetic fields under illumination. After the illumination of the heterostructures, the total two-dimensional
electron gas concentration increases, and the SdH oscillation amplitudes are enhanced when there is no additional subband
occupation. It is also found that the energy separation between the subbands decreases after the illumination. We suggest
that the illumination decreases the electric field and thus weakens the quantum confinement of the triangular quantum well
at Al
x
Ga1−x
N/GaN heterointerfaces. The GaN layer is thought to be the primary contributor of the excited electrons by the illumination. 相似文献
995.
Yuanyuan Huang Xin FangXiaoxi Lin Huaifeng LiWeiming He Kuo-Wei Huang Yaofeng YuanZhiqiang Weng 《Tetrahedron》2012,68(48):9949-9953
An efficient room temperature copper-catalyzed trifluoromethylation of organotrifluoroborates under the base free condition using an electrophilic trifluoromethylating reagent is demonstrated. The corresponding trifluoromethylarenes were obtained in good to excellent yields and the reaction tolerates a wide range of functional groups. 相似文献
996.
Electrochemical Aziridination by Alkene Activation Using a Sulfamate as the Nitrogen Source 下载免费PDF全文
Jin Li Wenhao Huang Jingzhi Chen Lingfeng He Xu Cheng Guigen Li 《Angewandte Chemie (International ed. in English)》2018,57(20):5695-5698
The first direct aziridination of triaryl‐substituted alkenes was achieved by means of an electrochemical process that could extend to multisubstituted styrenes. Specifically, hexafluoroisopropanol sulfamate was used as a nucleophilic nitrogen source. Mechanistic experiments suggest that this electrochemical process proceeds by stepwise formation of two C?N bonds through reactions between cationic carbon species and the sulfamate. 相似文献
997.
C. Y. He X. Q. Li L. H. Zhu X. G. Wu Y. Liu B. Pan L. H. Li Z. M. Wang G. S. Li Z. Y. Li S. Y. Wang Q. Xu J. G. Wang H. B. Ding J. Zhai 《The European Physical Journal A - Hadrons and Nuclei》2010,43(1):1-4
Up to now, no experimental cross-section data exist for the 67Zn (n,a \alpha) 64Ni reaction in the MeV neutron energy region. In the present work, the cross-section of the 67Zn (n,a \alpha) 64Ni reaction was measured at E
n = 6.0 MeV. Experiments were performed at the Van de Graaff accelerator of Peking University, China. Fast neutrons were produced
through the D (d, n) 3He reaction using a deuterium gas target. Absolute neutron flux was determined by a small 238U fission chamber and a BF3 long counter was used as a neutron flux monitor. A twin gridded ionization chamber was employed as the a \alpha -particle detector and two back-to-back 67Zn samples were used for a \alpha events measurement. Background was measured and subtracted from foreground. The measured cross-section of the 67Zn (n,a \alpha) 64Ni reaction was 7.3 (1±15%) mb at 6.0MeV. The present result was compared with existing evaluations and TALYS code calculations. 相似文献
998.
In this paper, we report a high power cryogenic cooling Tm(6 at.-%),Ho(0.5 at.-%):YLF laser end-pumped by a 19-fiber-coupled-diodes module with the central wavelength of 792 nm at 20°. The highest continuouswave power of 3.6 W at 2.051 μm is attained under pumping power of 13.6 W, corresponding to opticaloptical conversion efficiency of 26%, and the slope efficiency is larger than 30%. The threshold power is only about 0.16 W because of the long lifetime, large effective emission cross section, and low re-absorption in Tm,Ho:YLF crystal. 相似文献
999.
Four rate enhancing cases of nitroxide‐mediated living free‐radical polymerizations are simulated by the Monte Carlo method to investigate the effects of parameters on kinetics and molecular weight distribution of the resulting polymers. In all cases the equilibrium between growing and dormant chains shifts in favor of the growing chains under corresponding reaction conditions. The polymerization rates are therefore increased substantially without much loss in control of molecular weight and distribution of the products. The optimization of rate‐enhancement in living free‐radical polymerization is also discussed. 相似文献
1000.
含氨基,羟基吸附剂对胆红素的吸附 总被引:16,自引:0,他引:16
本文分别合成了含氨基和羟基的高分子吸附剂,并对它们对胆红素的吸附性能进行了研究。实验表明,经3小时的吸附后,含氨基和含羟基的吸附剂对胆红素的吸附率可达80%以上,对其吸附胆红素的性能和机理进行了探讨。 相似文献