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941.
Martin Juckel Primož Koželj Yurii Prots Alim Ormeci Ulrich Burkhardt Andreas Leithe-Jasper Eteri Svanidze 《无机化学与普通化学杂志》2020,646(14):1238-1243
Intermediate valence behavior is frequently observed in materials containing Ce, Yb, Eu, Sm, or Tm. In the current work, we report synthesis and characterization of Yb2Cu9Al8 (Th2Zn17 structure type). Its intermediate valence behavior can be described by an excitation energy Eex/kB = 319 K and a spin fluctuation temperature Tsf = 60 K. The valence state of Yb is estimated to be close to 2.04 for the low-temperature region. The valence gradually evolves to the value of 2.80 at T = 400 K. The specific heat coefficient of γexp = 59 mJ · molYb–1 · K–2 indicates a moderate effective mass enhancement, together with finite density of states at the Fermi level. The latter is also confirmed by the band structure calculations. 相似文献
942.
943.
Optical,Electrochemical, and Magnetic Properties of Pyrrole‐ and Thiophene‐Bridged 5,15‐Diazaporphyrin Dimers
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Satoshi Omomo Yasuhisa Maruyama Prof. Dr. Ko Furukawa Dr. Taniyuki Furuyama Prof. Dr. Haruyuki Nakano Prof. Dr. Nagao Kobayashi Prof. Dr. Yoshihiro Matano 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(5):2003-2010
The first examples of pyrrole‐ and thiophene‐bridged 5,15‐diazaporphyrin (DAP) dimers are prepared through Stille coupling reactions of nickel(II) and copper(II) complexes of 3‐bromo‐10,20‐dimesityl‐5,15‐diazaporphyrin (mesityl=2,4,6‐trimethylphenyl) with the respective 2,5‐bis(tributylstannyl)heteroles. The effects of the heterole spacers and meso nitrogen atoms on the optical, electrochemical, and magnetic properties of the DAP dimers are investigated by UV/Vis absorption spectroscopy, density functional theory calculations, magnetic circular dichroism spectroscopy, cyclic voltammetry, and EPR spectroscopy. The heterole spacers are found to have a significant impact on the electronic transitions over the entire π‐system. In particular, the pyrrole‐bridged DAP dimers exhibit high light‐harvesting potential in the low‐energy visible/near‐infrared region owing to the intrinsic charge‐transfer character of the lowest excitation. 相似文献
944.
945.
946.
Hye Jin Heo Hyoung Kyu Kim Jae Boum Youm Sung Woo Cho In-Sung Song Sun Young Lee Tae Hee Ko Nari Kim Kyung Soo Ko Byoung Doo Rhee Jin Han 《Experimental & molecular medicine》2016,48(8):e254
Mitochondria are crucial for maintaining the properties of embryonic stem cells (ESCs) and for regulating their subsequent differentiation into diverse cell lineages, including cardiomyocytes. However, mitochondrial regulators that manage the rate of differentiation or cell fate have been rarely identified. This study aimed to determine the potential mitochondrial factor that controls the differentiation of ESCs into cardiac myocytes. We induced cardiomyocyte differentiation from mouse ESCs (mESCs) and performed microarray assays to assess messenger RNA (mRNA) expression changes at differentiation day 8 (D8) compared with undifferentiated mESCs (D0). Among the differentially expressed genes, Pdp1 expression was significantly decreased (27-fold) on D8 compared to D0, which was accompanied by suppressed mitochondrial indices, including ATP levels, membrane potential, ROS and mitochondrial Ca2+. Notably, Pdp1 overexpression significantly enhanced the mitochondrial indices and pyruvate dehydrogenase activity and reduced the expression of cardiac differentiation marker mRNA and the cardiac differentiation rate compared to a mock control. In confirmation of this, a knockdown of the Pdp1 gene promoted the expression of cardiac differentiation marker mRNA and the cardiac differentiation rate. In conclusion, our results suggest that mitochondrial PDP1 is a potential regulator that controls cardiac differentiation at an early differentiation stage in ESCs. 相似文献
947.
Crystal Structure Analysis of the Repair of Iron Centers Protein YtfE and Its Interaction with NO
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Dr. Feng‐Chun Lo Chang‐Chih Hsieh Dr. Manuel Maestre‐Reyna Prof. Chin‐Yu Chen Dr. Tzu‐Ping Ko Prof. Yih‐Chern Horng Yei‐Chen Lai Prof. Yun‐Wei Chiang Chih‐Mao Chou Cheng‐Hung Chiang Prof. Wei‐Ning Huang Dr. Yi‐Hung Lin Prof. D. Scott Bohle Prof. Wen‐Feng Liaw 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(28):9768-9776
Molecular mechanisms underlying the repair of nitrosylated [Fe–S] clusters by the microbial protein YtfE remain poorly understood. The X‐ray crystal structure of YtfE, in combination with EPR, magnetic circular dichroism (MCD), UV, and 17O‐labeling electron spin echo envelope modulation measurements, show that each iron of the oxo‐bridged FeII–FeIII diiron core is coordinatively unsaturated with each iron bound to two bridging carboxylates and two terminal histidines in addition to an oxo‐bridge. Structural analysis reveals that there are two solvent‐accessible tunnels, both of which converge to the diiron center and are critical for capturing substrates. The reactivity of the reduced‐form FeII–FeII YtfE toward nitric oxide demonstrates that the prerequisite for N2O production requires the two iron sites to be nitrosylated simultaneously. Specifically, the nitrosylation of the two iron sites prior to their reductive coupling to produce N2O is cooperative. This result suggests that, in addition to any repair of iron centers (RIC) activity, YtfE acts as an NO‐trapping scavenger to promote the NO to N2O transformation under low NO flux, which precedes nitrosative stress. 相似文献
948.
949.
950.
In this paper, an analytical expression to the steam-water dipole orientation parameter is proposed. The calculations have
been carried out under the presumptions that: the electric properties of the water molecules are characterized completely
by a permanent dipole moment and a constant scalar polarizability, that translational fluctuations may be neglected, and that
the positions are orientation-free. The results are presented in the form of continuous and integrable expressions that can
be easily compared to the precedent studies as well as involved in similar analytical models. 相似文献