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901.
Heung Joon Yang Carole-Ann Cole Nobuo Monji Allan S. Hoffman 《Journal of polymer science. Part A, Polymer chemistry》1990,28(1):219-226
N-isopropylacrylamide and N-acryloxysuccinimide have been copolymerized in various mixtures of terrahydrofuran and toluene using azobisisobutyronitrile as initiator. Polymerization has been conducted for 24 h at 50°C under a slightly positive pressure of nitrogen. The copolymers were assayed for active ester content by measuring the UV absorbance (259 nm) of N-hydroxysuccinimide anion, generated by reacting the copolymers with N-isopropylamine in dimethylformamide and dissolving the resulting mixture in 0.1M HEPES buffer, pH 7.5. The molecular weight and its distribution have been estimated by gel permeation chromatography. The active ester content was found to be equivalent to the comonomer feed ratio, and the major factor controlling the molecular weight was the ratio of tetrahydrofuran to toluene. Thus, the number of active esters per polymer chain could be controlled by adjustment of the comonomer feed ratio and the ratio of tetrahydrofuran to toluene. Monomer reactivity ratios for copolymerization of N-isopropylacrylamide with N-acryloxysuccinimide were also estimated. These copolymers are useful for immobilizing binding ligands such as antibodies for subsequent thermally induced precipitation immunoassays and bioseparation processes. 相似文献
902.
3,4—亚甲二氧基苯甲酸锡酯的合成及表征 总被引:3,自引:0,他引:3
3,4-亚甲二氧基苯甲酸及其取代物与三苯基氢氧化锡或二丁基化锡反应合成了5个锡酯,通过元素分析,IR和^1HNMR对其进行了表征。 相似文献
903.
The layered perovskites Sr2TiO4 and Sr2SnO4 are more active and selective for the oxidative coupling of methane at 1073 K than the corresponding perovskites SrTiO3 and SrSnO3. The role of the surface oxygen species for this reaction is discussed. 相似文献
904.
基于Mn(Ⅱ)对试剂2-(8'-羟基喹啉-5'-磺基-7'-偶氮基)-1-羟基-8-氨基一萘二磺酸(以下简称HQSAH)分解反应的催化作用,提出了锰的荧光催化动力学分析新方法,其λex/em=230/415nm,适宜酸度范围为pH11.0~12.0,Mn(Ⅱ)含量在0~0.08μg/mL呈线性关系,该法用于分析铸造铝合金中的痕量锰,效果良好。还初步探讨了反应机制,确定了反应动力学方程,测定了反应速率和活化能。 相似文献
905.
906.
The fluorimetric determination of mercury ions with o-vanillin-8-aminoquinoline (OVAQ) in aqueous solutions was investigated. Hg(II) could react with the fluorescent reagent OVAQ
(λex/em = 278/314 nm) to form a nonfluorescent complex in an ethanol-water medium of pH 6.00. The linear range of the proposed method
was from 2.5 to 80 μg/L, and the detection limit was 0.80 μg/L. The interferences of 24 foreign ions were also studied. The
method was successfully applied to the determination of Hg(II) in sludge.
The text was submitted by the authors in English. 相似文献
907.
若干3d过渡金属的硫代脯氨酸配合物 总被引:4,自引:0,他引:4
合成了七个新的过渡金属的硫代脯氨酸(tcH)配合物,它们分别是:[M(tc)_2](M=Mn(Ⅱ),Co((Ⅱ))和Ni(Ⅱ)),[Ni(tc)(Ac)(H_2O)],[Ni(tc)(tcH)(H_2O)]NO_3·H_2O,[Ni(tc)(Py)_2(H_2O)NO_3和[Fe(tc)_2(Cl)(H_2O)]。上述配合物的磁化率,摩尔电导,热量分析,红外及电子光谱数据表明,它们都具有八面体构型,tcH主要通过亚氨氮和羧基氧原子与金属键合。文章对这些配合物的可能结构作了初步的讨论。 相似文献
908.
The oxygen reduction reaction (ORR) at neutral pH in various aqueous chloride-containing solutions was investigated voltammetrically. In particular, the ORR was performed in high chloride containing aqueous media including authentic and synthetic seawater under oxygen saturated conditions and compared with that in aqueous nitrate and perchlorate media. The experimental voltammograms revealed a two-electron process forming hydrogen peroxide in low chloride media. In contrast, high concentration chloride solutions, including both synthetic and authentic seawater showed an increase of overpotential, accompanied by a splitting of the voltammetric peak into two one-electron features indicating the formation of superoxide in the first step and its release from the silver-solution interface. The implications for silver nanoparticle toxicology are discussed given the markedly greater toxicity of superoxide over peroxide and the high levels of chloride in biological media as well as in seawater.Superoxide produced at silver electrode in seawater. 相似文献
909.
[reaction: see text] Reactions of alkylmercury chlorides with arene manganese tricarbonyl complexes in the presence of NaI led to the formation of the addition-reduction products. The mechanism was postulated to be the alkyl radical addition to ArMn(CO)3+ cation to form the corresponding 17 valence electron intermediate, which was then reduced by alkylmercury chloride via a singlet electron transfer process to afford the product and regenerate an alkyl radical. 相似文献
910.
含苯氧基萘并萘醌和偶氮苯双变色基化合物的合成和性质 总被引:2,自引:0,他引:2
通过6-氯-5,12-萘并萘醌与4-羟基偶氮苯及其衍生物的反应合成了3种含苯氧基萘并萘醌和偶氮苯光致变色基的双变色基化合物,6-[4-(苯偶氮基)苯氧基]-5,12-萘并萘醌(5),6-[4-(p-乙氧基苯偶氮基)苯氧基]-5,12-萘并萘醌(6)和6-[4-(p-硝基苯偶氮基)苯氧基]-5,12-萘并萘醌(7).这些化合物的苯氧基萘并萘醌变色基的UV诱导光致变色性较弱;基于氨与苯氧基萘并萘醌ana显色体的不可逆反应,化合物5和6DMSO溶液在365nm紫外光辐照光稳态(PSS)下的ana醌式摩尔分数估计分别为22%和17%.这些结果说明,苯偶氮基对苯氧基萘并萘醌变色基的光致变色性质有着极强的影响.另一方面,与4-羟基偶氮苯母体不同,这些双变色基化合物在DMSO中偶氮苯变色基的顺式异构体是相对稳定的 相似文献