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101.
Three new methods for large scale synthesis of electronic grade trimethylgallium and trimethylindium are presented. These methods are based on direct synthesis of trialkylgallium compounds from the Ga/Mg alloy or the mixture of this metals and alkyl halides, RX. The first method consists in the cleavage of the stable trimethylgallium-diethyl ether adduct by heating it in the mixture with ether of higher boiling point. The second one is the reaction of the mixture of Ga and Mg with methyl iodide in a high boiling ether solvent such as diisoamyl ether, i-Am2O. The third method consist in preliminary formation of the stable adducts of trimethylgallium or trimethylindium and alkali metal fluorides from their etherates, followed by removing ethers and thermal decomposition of adducts to yield free trimethylgallium or trimethylindium respectively.  相似文献   
102.
Summary. Two novel compounds, [Co(phen)3]2V4O12·phen·22H2O (1) and [Ni(phen)3]2 V4O12·phen·22H2O (2), were prepared from KVO3–1,10-phenanthroline (phen)–Co(NO3)2, resp. NiCl2–H2O reaction systems. The compounds 1 and 2 are isomorphous and crystallize in triclinic system, space group P-1. Their crystal structures are formed by two types of layers parallel to 001: a cationic one consisting of [MII(phen)3]2+ ions and an anionic one containing the cyclic V4O12 4– anions. The solvate phenanthroline and crystal water molecules are located in the cationic and anionic layers, respectively. The IR spectra of 1 and 2 are consistent with the presence of the cyclic V4O12 4– anions in the complexes.Received November 13, 2002; accepted (revised) February 3, 2003 Published online June 2, 2003  相似文献   
103.
Acid hydrolysis of [Ru(5)(CO)(15)(mu(4)-PN(i)Pr(2))] (2) or protonation of the anionic PO cluster [Ru(5)(CO)(15)(mu(4)-PO)](-) (3) affords the hydroxyphosphinidene complex [Ru(5)(CO)(15)(mu(4)-POH)].1.[H(2)N(i)()Pr(2)][CF(3)SO(3)], which cocrystallizes with a hydrogen-bonded ammonium triflate salt. Reaction of [Ru(5)(CO)(15)(mu(4)-PN(i)Pr(2))] (2) with bis(diphenylphosphino)methane (dppm) leads to [Ru(5)(CO)(13)(mu-dppm)(mu(4)-PN(i)Pr(2))] (4). Acid hydrolysis of 4 leads to the dppm-substituted hydroxyphosphinidene [Ru(5)(CO)(13)(mu-dppm)(mu(4)-POH)] (5), which is analogous to 1, but unlike 1, can be readily isolated as the free hydroxyphosphinidene acid. Compound 5 can also be formed by reaction of 3 with dppm and acid. The cationic hydride cluster [Ru(5)(CO)(13)(mu-dppm)(mu(3)-H)(mu(4)-POH)][CF(3)SO(3)] (6) can be isolated from the same reaction if chromatography is not used. Compound 4 also reacts with HBF(4) to form the fluorophosphinidene cluster [Ru(5)(CO)(13)(mu-dppm)(mu(4)-PF)] (7), while reaction with HCl leads to the mu-chloro, mu(5)-phosphide cluster [Ru(5)(CO)(13)(mu-dppm)(mu-Cl)(mu(5)-P)] (8).  相似文献   
104.
105.
We have developed a family of high-performance capillary DNA sequencing instruments based on a novel multicolor fluorescent detection technology. This technology is based on two technical innovations: the multilaser excitation of fluorescence of labeled DNA fragments and the "color-blind" single-photon detection of modulated fluorescence. Our machines employ modern digital and broadband techniques that are essential for achieving superior instrument performance. We discuss the design and testing results for several versions of the automated single lane DNA sequencers, as well as our approach to scaling up to multilane instruments.  相似文献   
106.
107.
This paper presents an improved synthesis of 4,7-dibromobenzo[d][1,2,3]thiadiazole from commercially available reagents. According to quantum-mechanical calculations, benzo[d][1,2,3]thiadiazole (isoBTD) has higher values of ELUMO and energy band gap (Eg), which indicates high electron conductivity, occurring due to the high stability of the molecule in the excited state. We studied the cross-coupling reactions of this dibromide and found that the highest yields of π-spacer–acceptor–π-spacer type compounds were obtained by means of the Stille reaction. Therefore, 6 new structures of this type have been synthesized. A detailed study of the optical and electrochemical properties of the obtained π-spacer–acceptor–π-spacer type compounds in comparison with isomeric structures based on benzo[c][1,2,5]thiadiazole (BTD) showed a red shift of absorption maxima with lower absorptive and luminescent capacity. However, the addition of the 2,2′-bithiophene fragment as a π-spacer resulted in an unexpected increase of the extinction coefficient in the UV/vis spectra along with a blue shift of both absorption maxima for the isoBTD-based compound as compared to the BTD-based compound. Thus, a thorough selection of components in the designing of appropriate compounds with benzo[d][1,2,3]thiadiazole as an internal acceptor can lead to promising photovoltaic materials.  相似文献   
108.
The exact cellular and molecular mechanisms of multiple sclerosis and other autoimmune diseases have not been established. Autoimmune pathologies are known to be associated with faults in the immune system and changes in the differentiation profiles of bone marrow stem cells. This study analyzed various characteristics of experimental autoimmune encephalomyelitis (EAE) in 2D2 mice. Differentiation profiles of six hematopoietic stem cells of bone marrow were found to significantly differ in 2D2 male and female mice during the spontaneous development of EAE. In addition, we found various properties of B and T cells, CD4+ and CD8+ lymphocytes in blood and several organs (bone marrow, spleen, thymus, and lymph nodes) of 2D2 male and female mice to be considerably different. These changes in hematopoietic stem cells differentiation profiles and level of lymphocyte proliferation in various organs of 2D2 mice were found to induce the production of IgGs against DNA, myelin basic protein, and myelin oligodendrocyte glycoprotein, increasing the number of autoantibodies hydrolyzing these substrates. We compared the changes of these immunological and biochemical parameters in 2D2 mice with those of mice of two other lines (Th and C57BL/6), also prone to spontaneous development of EAE. Some noticeable and even extreme variations were found in the time-related development of parameters between male and female mice of 2D2, Th, and C57BL/6 lines. Despite some differences, mice of all three lines demonstrated the changes in hematopoietic stem cells profiles, lymphocyte content, and production of catalytic autoantibodies. Given that these changes are harmful to mice, we believe them to cause the development of experimental autoimmune encephalomyelitis.  相似文献   
109.
The simulated moving bed (SMB) technology is a proven tool for efficient separation of binary mixtures. However, relying on isocratic conditions limits the applicability of the classical SMB approach when considering the field of bioseparations. Here, the use of gradients opens up new possibilities. A gradient in a SMB process can be established by using different solvent strengths in the incoming feed and desorbent streams, resulting in two internal plateaus of elution strength. Thus, compared to the conventional process, the overall amount of solvent needed can be reduced, productivity can be increased and more concentrated product streams can be obtained. In this contribution, two case studies will be presented. At first, the separation of bovine IgG from lysozyme will be analyzed as a model system. Antibodies are a common target substance in bio-chromatography, as therapeutic monoclonal antibodies are among the most promising biopharmaceuticals. Using adsorption data obtained from single-column experiments, an appropriate SMB process was designed and implemented. The second target component is the active dimeric form of the bone morphogenetic protein-2 (BMP-2). This protein was isolated from a renaturation solution, which also contained its inactive monomeric form as well as other undefined proteins from the bacterial production strain. A 3-zone open-loop gradient-SMB approach was used successfully for both separations.  相似文献   
110.
The aim of this study was to obtain quantitative characteristics of the ultraviolet absorption spectra as the molecular absorptivity at the wavelength of maximum absorbance. Organic as well as inorganic compounds were explored. A gas chromatography—ultraviolet absorption instrument has been used in the quantitative study of molecular ultraviolet absorption spectra in the vapour phase. The wavelength range studied was between 168 and 330?nm. The absorbance of 170 compounds was determined relative to perchloroethylene and their molecular absorptivities were calculated. For various groups of compounds, these relative absorptivities varied within two to three orders of magnitude. Standard curves were linear within four orders of magnitude from limit of quantification up to an absorption value of 1.5 absorbance units. The noise level was 3?×?10?5 absorbance units peak to peak at a bandwidth of 1.7?nm and a wavelength range from 180 to 330?nm was preferred. The detection limit for mesitylene was calculated to be 2 pg/s and for naphthalene 1 pg/s with 4?s store cycle time.  相似文献   
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