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111.
Junko Fukutomi Yuko Adachi Akari Kaneko Atsuomi Kimura Hideaki Fujiwara 《Journal of inclusion phenomena and macrocyclic chemistry》2007,58(1-2):115-122
The inclusion complex formation of 4-sulfothiacalix[4]arene sodium salt (STCAS) and Xe has been investigated by using hyperpolarized
129Xe NMR spectroscopy. Our new continuous-flow type hyperpolarizing system has advantageous capabilities that can supply hyperpolarized
gases continuously and directly to a sample solution in a NMR tube. Consequently saturated Xe concentration in the aqueous
solution of STCAS is maintained during the NMR experiment, and 129Xe NMR spectra can be obtained in remarkably short time. STCAS concentration dependence of 129Xe chemical shift has been analyzed in an elaborated way by a computer method as well as a simple graphic method that we have
proposed. The association constant K:13.6±0.8 M−1 at 25 °C was obtained, and further analysis of the temperature dependence has successfully given thermodynamic parameters
of enthalpy (ΔH) and entropy (ΔS) for the inclusion complex formation: ΔH = −11.9±1.9 kJ mol−1 and ΔS = −17.4±5.8 JK−1 mol−1. The energetic aspects of complex formation are discussed from the size effect and from the molecular theory of standard
entropy, and a release of definite number of water molecules from STCAS cavity is suggested in the inclusion complex formation
with Xe. 相似文献
112.
By attaching condenser plates directly to the tensile specimen, creep rates of β-CuZn single crystals have been measured by the capacitance change in the strain-rate range of 10−7 to 10−5 s−1 and at temperatures between 0.7 and 17 K using a 3He cryostat. Slope of the temperature variation of the stress to give a constant strain-rate decreases below 5 K and seems to level off at 0 K. The strain-rate sensitivity becomes almost constant below 2 K. The conventional activation analysis showed that an ARRHENIUS type strain-rate equation breaks down drastically below 5 K. For an effective temperature T* which gives 2 K at 0 K and asympototically coincides with the testing temperature at 5 K, the experimental results can be fitted to the ARRHENIUS strain-rate equation with an activation enthalpy ΔH(τ) for the PEIERLS mechanism. The above result is interpreted in terms of the quantum-mechanical oscillation of the dislocations. 相似文献
113.
114.
115.
Takuya Hashimoto 《Tetrahedron letters》2010,51(4):761-8145
FeCl3/AgOTf-catalyzed hydroarylation of propiolic acid with electron-rich arenes such as mesitylene, tetramethylbenzene, and pentamethylbenzene in trifluoroacetic acid proceeded to give 3-arylpropenoic acids in moderate to high yields. The same reactions with anisole and 1,4-dimethoxybenzene afforded double hydroarylation products, 3,3-diarylpropionic acids. 相似文献
116.
117.
Akiko Hashimoto Takehiro Yamanaka Takeji Takamura-Enya 《Journal of nanoparticle research》2017,19(12):402
Fullerene is a well-known carbon nanomaterial, which can be potentially used for drug manufacture or delivery. Despite several successful examples of utilizing fullerene derivatives as drug candidate materials, their low water solubility under physiological conditions negatively affects the cell penetration efficiency after treatment. In this work, we successfully synthesized two fullerene derivatives with covalently attached fluorescein and boron dipyrromethene (BODIPY) fluorophore moieties, which exhibited cellular uptake and intracellular localization. While both fluorophores decreased their fluorescence intensity in the vicinity of fullerene, the cellar uptake of the fluorescein-modified fullerene was detected via fluorescence microscopy observations. Moreover, decreases in the fluorescence intensities of the intact fluorescein and BODIPY species were observed when both fluorophores and fullerene coexisted in aqueous media. 相似文献
118.
Fujikawa Y Akiyama K Nagao T Sakurai T Lagally MG Hashimoto T Morikawa Y Terakura K 《Physical review letters》2002,88(17):176101
The structure of Ge(105)-(1 x 2) grown on Si(105) is examined by scanning tunneling microscopy (STM) and first-principles calculations. The morphology evolution with an increasing amount of Ge deposited documents the existence of a tensile surface strain in Si(105) and its relaxation with increasing coverage of Ge. A detailed analysis of high-resolution STM images and first-principles calculations produce a new stable model for the Ge(105)-(1 x 2) structure formed on the Si(105) surface that includes the existence of surface strain. It corrects the model developed from early observations of the facets of "hut" clusters grown on Si(001). 相似文献
119.
Kitajima M Hashimoto K Yokoya M Takayama H Aimi N Sakai SI 《Chemical & pharmaceutical bulletin》2000,48(10):1410-1412
A new gluco indole alkaloid, 3,4-dehydro-5-carboxystrictosidine, was obtained from Peruvian U?a de Gato (Cat's Claw, original plant: Uncaria tomentosa) together with two known gluco indole alkaloids. This compound was the first example of isolation of a gluco monoterpenoid indole alkaloid having a 3,4-dihydro-beta-carboline ring system from nature. A characteristic feature of the compound was the quick replacement of the methylene hydrogens on C-14 with deuterium that was observed when it was dissolved in CD3OD. We demonstrated a similar proton-deuterium exchange on a model compound, 1-methyl-3,4-dihydro-gamma-carboline, in CD3OD solution. 相似文献
120.
Hayashi M Hashimoto Y Yamamoto Y Usuki J Saigo K 《Angewandte Chemie (International ed. in English)》2000,39(3):631-633
Convenient access to cyclopentenones is provided by catalytic intra- and intermolecular Pauson - Khand reactions in the presence of octacarbonyldicobalt and tributylphosphane sulfide (see scheme). In contrast to other reactions of this type, they proceed under mild conditions (70 degrees C, 1 atm CO), and commercially available [Co(2)(CO)(8)] can be used without further purification. 相似文献