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61.
Ionizing radiations, which have already been utilized for the sterilization of medical supplies as well as gas fumigation, should be the final candidate to decontaminate “hybrid” biomaterials containing bio-active materials including enzymes because irradiation induces neither heat nor substances affecting the quality of the materials and our health. In order to check the feasibility of 60Co-gamma rays on these materials, we selected commercial proteases including papain and bromelain hybridized with commercial activated chitosan beads and demonstrated that these enzyme-hybrids suspended in water showed the significant radiation durability of more than twice as much as free enzyme solution at 25-kGy irradiation. Enhanced thermal and storage stability of the enzyme hybrids were not affected by the same dose level of irradiation, either, indicating that commercial irradiation sterilization method is applicable to enzyme hybrids without modification. 相似文献
62.
Yamamoto Y Ishii J Nishiyama H Itoh K 《Journal of the American Chemical Society》2004,126(12):3712-3713
The Ru(II)-catalyzed [2+2+2] cyclotrimerization of alkynylboronates, propargyl alcohol, and terminal alkynes proceeded chemo- and regioselectively to give rise to arylboronates, which were subjected to Suzuki-Miyaura cross-coupling with aryliodides to afford highly substituted biaryls in 53-76% yields. 相似文献
63.
Hiromu Hayashi 《Catalysis Surveys from Japan》1999,3(1):43-52
Additive telluromolybdates, MoO3·2TeO2 and MIIO·TeO2·MoO3 (MIITeMoO6; MII = Co, Mn, Zn), converted ethyl lactate selectively to pyruvate in a vaporphase fixedbed flow system at 250–300 °C. A synergy in activity was observed for binary TeO2–MoO3, and crystalline Te2MoO7 was suggested as the active species. The Rietveld analysis of powder XRD patterns of ternary CoTeMoO6 revealed the layer structure quite different from that of the reference Te2MoO7, but tellurium was again located adjacent to molybdenum linked through lattice oxygen. 相似文献
64.
Brown coals have a considerable number of acidic functional groups of which the main component is carboxyl groups, and the acidity has a wide distribution. In this paper, changes of the acidity distribution were examined by aqueous titration when brown coal was heat-treated to control its acidity distribution. For Loy Yang brown coal from Australia dried at 50 degrees C under vacuum (LY50), the acid dissociation constant, Ka, was distributed over a wide pKa range between 2 and 9. Then, using Gaussian functions, the acidity distribution was divided into four groups, which were characterized by average pKa values: average pKa value of 3.8 (hereafter referred to as Group A), 5.2 (Group B), 6.8 (Group C), and 8.3 (Group D). Among them, Groups A, B, and C were assigned to carboxyl groups. From the changes of the number of carboxyl groups when brown coal was heat-treated up to 400 degrees C, it was found that the way of decrease was different among these acidic groups. The decrease of the amount of carboxyl groups in Group C was significant, and at 325 degrees C most of them disappeared. On the other hand, the carboxyl groups in Group A remained even at a high temperature of 400 degrees C. We estimated approximately the structures around carboxyl groups for LY50 and their structural changes by heat treatment using the known pKa values for simple carboxylic acids and the pKa values calculated by the MOPAC program for complicated carboxylic acids. 相似文献
65.
Kakinoki K Yamane K Yamamoto M Teraoka R Sugimoto I Matsuda Y 《Chemical & pharmaceutical bulletin》2005,53(9):1092-1096
TiO(2) has been widely used in pharmaceutical products, and it also has been used as a photocatalyst. In this study, the influence of photocatalytic activity on the stability of solid-state mequitazine, an H(1)-blocker, was investigated. The photo-degradation of mequitazine with TiO(2) occurred under irradiation with both light sources. The degree of degradation of mequitazine with anatase was higher than that of rutile. The degradation was significantly enhanced with increasing relative humidity. The relationship between the apparent degradation rate constant and water vapor pressure could be clearly described by a simple power law. The major photo-degradation products of mequitazine, resulting from photocatalytic activity of TiO(2), were mequitazine-S-oxide and mequitazine-sulphone. A remarkable degradation of mequitadine occurred with addition of TiO(2), and its photocatalytic activity was controlled by water vapor pressure. The photo-degradation of mequitazine with TiO(2) is a different process from mequitazine without TiO(2), because mequitazine-S-oxide and mequitazine-sulphone are not formed with normal photo-degradation of mequitazine. 相似文献
66.
Kondo T Kaneko Y Taguchi Y Nakamura A Okada T Shiotsuki M Ura Y Wada K Mitsudo TA 《Journal of the American Chemical Society》2002,124(24):6824-6825
Pyranopyrandiones were prepared by a novel ruthenium-catalyzed carbonylative dimerization of cyclopropenones via C-C bond cleavage. For example, treatment of dipropylcyclopropenone with a catalytic amount of Ru3(CO)12 and NEt3 in THF under 15 atm of carbon monoxide at 140 degrees C for 20 h gave a novel functional monomer, 3,4,7,8-tetrapropylpyrano[6,5-e]pyran-2,6-dione, in an isolated yield of 81%. Unsymmetrically substituted pyranopyrandiones were also obtained by ruthenium-catalyzed carbonylative coupling of cyclopropenones with alkynes under similar reaction conditions. 相似文献
67.
The enantioselective Reformatsky reaction of PhCHO was achieved by the use of trifluoromethylated amino alcohols as chiral ligands to afford the corresponding optically active β-hydroxy ester with up to 90% ee. 相似文献
68.
A synthesis of 1,2,5,6-tetrahydro-4H-benzo[3,4]cyclohepta[1,2-e]imidazo[1,2-c]pyrimidine (XII) having a novel ring system is described. Antidepressive activity of XII and its precursors VII-X was screened by inhibitory action of reserpine-induced hypothermia. 相似文献
69.
Chiral β-dimethylaminoalkylphosphines were prepared starting with amino acids, (S)-alanine, (S)-phenylalanine, (R)-phenylglycine, (S)-valine, and (R)-tert-leucine. The chiral phosphines were found to be highly efficient ligands for a nickel catalyzed asymmetric Grignard cross-coupling reaction (38~94% optical yield). 相似文献
70.
To elucidate the mechanism(s) of the relieving effect of saline on cephaloridine (CER) nephrotoxicity, rats were given CER in equal quantity (1 g/kg body weight; i.v.), but at two different concentrations (4 and 25%) in saline. Urinary excretion of glucose, which was investigated as an index for renal proximal tubular injury, revealed that the renal damage was less in the 4% CER 25 ml/kg group than in the 25% CER 4 ml/kg group. As to urinary excretions of CER, sodium, potassium and water, no significant differences were observed between the two groups in the first 2 h, but chloride in the 4% CER 25 ml/kg group showed higher values than in the 25% CER 4 ml/kg group. Plasma concentrations of sodium, potassium, chloride and CER, did not show any definite distinctions between the two groups. At the time-point of 20 min after the CER administration, renal CER content was significantly lower in the 4% CER 25 ml/kg group than in the 25% CER 4 ml/kg group. These results suggest that the sodium ion which is needed for cellular trapping of CER is competitively expended for cellular entry of the chloride ion in the kidney, and that the relieving effect of the saline on CER nephrotoxicity is ascribable to the loaded quantity of chloride ion. 相似文献