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971.
972.
Masayuki Suda Naoto Kameyama Aya Ikegami Motohiro Suzuki Naomi Kawamura Yasuaki Einaga 《Polyhedron》2009,28(9-10):1868-1874
We have observed size-reduction induced ferromagnetism and significant photo-magnetic effects in azobezene-thiol-modified gold nanoparticles. When the particle size was reduced to 1.7 nm, ferromagnetism even at room temperature was observed while diamagnetism was dominating with the particle size of 5.0 nm. Furthermore, reducing the particles size to 1.7 nm also gave rise to photo-magnetic properties because the decrease in particle size provided free volume between each of the azobenzene ligands. This photo-magnetic effect could be attributed to photo-induced changes in the values of d-charge losses due to the photoisomerization of azo-ligands, which were accompanied by the inversion of surface dipole values to the opposite sign. 相似文献
973.
Tetsuji Itoh Ryo Ishii Shun-ichi Matsuura Junko Mizuguchi Satoshi Hamakawa Taka-aki Hanaoka Tatsuo Tsunoda Fujio Mizukami 《Colloids and surfaces. B, Biointerfaces》2010,75(2):478-482
We assembled a highly durable conjugate with both a high-density accumulation and a regular array of lipase, by encapsulating it in mesoporous silica (FSM) with alkyltrimethylammonium (CTAB) chains on the surface. The activity for hydrolyzing esters of the lipase immobilized in mesoporous silica was linearly related to the concentration of lipase, whereas that of non-immobilized lipase showed saturation due to self-aggregation at a high concentration. The lipase conjugate also had increased resistance to heating when stayed in the silica coupling with CTAB. In addition, encapsulating the enzyme with FSM coupled CTAB caused the lipase to remain stable even in the presence of urea and trypsin, suggesting that the encapsulation prevented dissociation and denaturing. This conjugate had much higher activity and much higher stability for hydrolyzing esters when compared to the native lipase. These results show that FSM provides suitable support for the immobilization and dispersion of proteins in mesopores with disintegration of the aggregates. 相似文献
974.
UCoAl exhibits attributes of an itinerant 5f-electron metamagnet. It is paramagnetic down to lowest temperatures but the c -axis susceptibility shows a maximum around T max , 20 K. When a field larger than B c , 0.6 T is applied along the c -axis of hexagonal structure a ferromagnetic ordering of U moments is induced at low temperatures. The critical parameters T max and B c are sensitive to alloying and hydrostatic pressure. In the latter case values of both, T max and B c , are increasing with increasing pressure, i.e. metamagnetism is suppressed towards a conventional paramagnetism. We report on results of an experiment with a c -axis uniaxial pressure, which has an opposite influence on T max and B c leading to ferromagnetism in zero field. A scenario of the physics of UCoAl is presented accounting for effects of hydrostatic- and uniaxial-pressure on the lattice and consequences in the 5f-electron delocalization and anisotropy of hybridization-mediated exchange interactions. 相似文献
975.
976.
The vortical flows of an incompressible fluid in a rectangular three-dimensional container with a large spanwise aspect ratio driven by a moving solid lid are studied using a combined compact finite difference (CCD) scheme with high accuracy and high resolution. The study focuses on the change of the steady flow structures in the cavity with Reynolds numbers ranging from 100 to 850. The results of the flow in the cavity with a spanwise aspect ratio 6.55 show that several stable closed streamlines localized near the symmetric plane are found at Re ≥500, while a closed stable streamline is found near the side wall at Re ≤300. The change of the flow pattern present in this system affects the diffusion properties in the flow but seems to have no qualitative effect on the global flow properties which include energy dissipation in the cavity. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
977.
Dai Masui Takuya Kochi Zhen Tang Youichi Ishii Yasushi Mizobe Masanobu Hidai 《Journal of organometallic chemistry》2001,620(1-2):69-79
The heterobimetallic trinuclear sulfido clusters [(Cp*Ir)2(μ3-S)2MCl2] (M=Pd (3), Pt (4); Cp*=η5-C5Me5) were synthesized from the dinuclear hydrogensulfido complex [Cp*IrCl(μ-SH)2IrCp*Cl] (2) and [MCl2(COD)] (COD=cycloocta-1,5-diene), while the reaction of 2 with [Pd(PPh3)4] afforded the cationic trinuclear cluster [(Cp*Ir)2(μ3-S)2PdCl(PPh3)]Cl (5). Clusters 3 and 4 reacted with PPh3 to give a series of mono and dicationic clusters including 5, while the dicationic clusters [(Cp*Ir)2(μ3-S)2M(dppe)][BPh4]2 (M=Pd (9), Pt (10); DPPE=Ph2PCH2CH2PPh2) were obtained by the reaction with dppe followed by anion metathesis. The molecular structures of 5·CH2Cl2, 9·CH3COCH3, and 10·CH3COCH3 were determined by X-ray crystallography. Clusters 3 and 4 were found to catalyze the addition of alcohols to alkynes to give the corresponding acetals. Internal 1-aryl-1-alkynes were transformed by cluster 3 into the corresponding 2,2-dialkoxy-1-arylalkanes with high regioselectivity up to 99:1, while cluster 4 was a much less regioselective catalyst. 相似文献
978.
We study the Newton boundaries of hypersurface singularities from the viewpoint of the theory of filtered blowing-ups. We
can construct counter examples to Reid's conjecture in the -dimensional cases which is related to the problem about the existence of good embedding for the criterion about the rationality
(or the non-rationality). For 3-dimensional case, our examples contains a simple K3 singularity which does not belong to the
famous list consisting of 95 types
Received March 5, 1999; in final form October 28, 1999 / Published online February 5, 2001 相似文献
979.
The oscillation modes of a supersonic circular twin jet and multijet with square configuration where the center-to-center spacing of nozzles was fixed to 1.4 times the nozzle diameter were investigated experimentally. It is found that the twin jet oscillates simultaneously in three different oscillation modes for the pressure ratios of about 4.1. From the acoustical observation, these oscillation modes are identified as one lateral oscillation mode perpendicular to a plane composed of the twin jet axes and two lateral oscillation modes parallel to this plane. For a multijet with a square configuration, only one lateral oscillation mode was observed. In this case, it is observed that when the spacing between two facing sides of the square formed by four jets is stretched, the spacing between the other two sides shrinks and vice versa. 相似文献
980.
T Ishii M Furube S Hirano K Takatori K Iida M Kajiwara 《Chemical & pharmaceutical bulletin》2001,49(12):1507-1511
Liver disease is associated with an abnormal elevation of the plasma concentrations of the aromatic amino acids phenylalanine and tyrosine. The liver is the main site of aromatic amino acid metabolism, particularly the hydroxylation of phenylalanine to tyrosine and further tyrosine degradation. In the present study, we have examined the usefulness of the L-[1-13C]phenylalanine breath test (13C-PheBT) and L-[13C]tyrosine breath test (13C-TyrBT) for the detection of hepatic damage in patients with liver cirrhosis. First, the time courses of 13CO2 excretion after the administration of L-[1-13C]phenylalanine and L-[1-13C]tyrosine were compared. The peak times (the time expressed in minutes at which 13CO2 excretion was maximal) were 20 min in both breath tests, but 13C-TyrBT gave a higher peak than 13C-PheBT. Next, the parameters of 13C-PheBT and 13C-TyrBT were compared with biochemical liver function test values. These parameters were well correlated with several liver blood test values conventionally regarded as measures of hepatocyte functional reserve. Therefore, 13C-PheBT and 13C-TyrBT may be useful to assess the degree and progression of hepatic dysfunction. 相似文献