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671.
Tamika S. Ragland Melody D. Gossage Michael D. Furtaw Jon P. Anderson David L. Steffens Mary J. Wirth 《Electrophoresis》2019,40(5):817-823
With the growth of the biopharmaceutical industry, there is a need for rapid size‐analysis of proteins on the megaDalton scale. The large pore sizes needed for such separations cannot be easily reached by pushing the current limits of size‐exclusion chromatography or gel electrophoresis. The concept detailed here is the formation of arbitrarily wide pores by packing nonporous colloidal silica in capillaries. This method can be called packed‐capillary electrophoresis, or “pCE”. Electrophoresis of protein standards (11–155 kDa) by pCE, using 345 nm diameter particles in 100 μm diameter capillaries, gives 2x higher resolution than a typical PAGE gel in 1/6 of the time. The electropherograms show that pCE is highly efficient, with half‐micrometer plate heights for all seven standards, giving 105 plates for a 50 mm length. The large pore radius of 65 nm enables baseline resolution of proteins of 0.72, 1.048 and 1.236 MDa in less than 15 min. The short separation time of pCE is attributed to the absence of small pores that restrict protein migration in gels. The pCE separation is applied to the analysis of a stressed pharmaceutical‐grade IgG4 sample, giving unprecedented baseline resolution of monomer, dimer, trimer and tetramer in less than 10 min. 相似文献
672.
Carla Bisi Castellani Oliviero Carugo Menico Rizzi 《Monatshefte für Chemie / Chemical Monthly》1991,122(12):1005-1014
Summary Novel Eu3+ and Tb3+ complexes with a pyrano[2,3-b]pyridine ligand have been synthesized and characterized. The stability constants in 1:1DMF-water were determined. In solution, various tautomeric forms of the free ligand are present, and their equilibrium is influenced by complexation toLn
3+ cations. Both the Eu3+ and Tb3+ complexes present an intense cation luminescence following the ligand excitation in the UV region. The cation emission quantum yields and life-times are discussed with regard to the mechanism of the ligand-to-metal energy transfer process.
Synthese und spektroskopische Eigenschaften von Europium(III) und Terbium(III) Komplexen mit einem Pyrano[2,3-b]pyridin als Ligand
Zusammenfassung Es wurden neue Eu3+- und Tb3+-Komplexe mit einem Pyrano[2,3-b]pyridin-Derivat hergestellt und charakterisiert. Die Stabilitätskonstanten in 1:1DMF-Wasser wurden festgestellt. In Lösung liegen verschiedene tautomere Formen der freien Liganden vor, wobei die entsprechenden Gleichgewichte von der Komplexierung beeinflußt werden. Sowohl die Eu3+- als auch die Tb3+-Komplexe zeigen eine intensive Kationen-Lumineszenz, die auf die Liganden-Anregung im UV folgt. Die Kationen-Emissionsquantenausbeuten und die Lebenszeiten werden im Hinblick auf den Mechanismus des Prozesses beim Ligand-zu-Metall-Energietransfer diskutiert.相似文献
673.
Summary Stability constants and composition of cadmium-glycinate binary complexes were determined using cyclic voltammetry. Furthermore, binary and ternary complex equilibria for chloroacetates and glycinate with cadmium in 0.1M aqueous KNO3 atpH 10.4 and 298 K were investigated. Cadmium forms binary complexes with chloroacetates of low stability and ternary ones with chloroacetate-glycinate of significant stability.
Gleichgewichte in wäßrigen Cadmium-Chloroacetat-Glycinat-Systemen. Untersuchungen mittels zyklischer Voltammetrie
Zusammenfassung Gleichgewichtskonstanten und Zusammensetzung binärer Cadmium-Glycinat-Komplexe wurden mittels zyklischer Voltammetrie bestimmt. Weiters wurden binäre und ternäre Gleichgewichte von Chloroacetaten und Glycinat mit Cadmium in 0.1M KNO3 beipH 10.4 und 298 K untersucht. Cadmium bildet binäre Komplexe geringer Stabilität mit Chloroacetaten und ternäre Komplexe von beträchtlicher Stabilität mit Chloroacetaten und Glycinat.相似文献
674.
镧系元素双1:11系列杂多蓝的红外光谱和紫外光谱研究 总被引:1,自引:0,他引:1
本文首次系统研究了镧系元素钼采双1:11系列两子杂多蓝KzHy(Ln(XMo11O3902).nH2O(X=P,Ln=La,Ce,Pr,Nd,Sm,Gd;X=Si,Ln=Ce,Pr,Sm,Tb,Dy)的红外光谱和紫外光谱,对特征峰进行指认,并与还原前的杂多酸盐进行比较,发现有的特征峰出现小的位移,有的峰强度稍有变化,所以得出结论,还原前后,杂多阴离子结构基本不变,但有轻微的畸变。 相似文献
675.
Reinhard Hasselbring Iring Leichtweis Mathias Noltemeyer Herbert W. Roesky Hans-G. Schmidt Axel Herzog 《无机化学与普通化学杂志》1993,619(9):1543-1550
New Complexes of Titanium with Silylated Aminoiminophosphorane and Sulfodiimide Ligands TiCl4 forms a 1 : 1 adduct with S(NSiMe3)2 to give compound 1 and with Me2S(NSiMe3)2 compound 2 , respectively. The reaction of TiCl4 with Ph2S(NSiMe3)2 yields the disubstituted compound Ph2S(NTiCl3)2X4THF 3 which crystallizes in space group P1 . Reaction of TiCl4 with (Me3Si)2NPPh2NPPh2NSiMe3 leads to an exchange of one silyl group with a TiCl3 moiety. In this molecule the Ti-atom is only four-coordinated. The compound crystallizes in the space group P21/c. No chelate complexes are formed by reactions of CpTiCl3, Cp*TiCl3 and Cp*TiF3 with Ph2P(NSiMe3)2H, this is shown by X-ray structural analysis of Cp*TiCl2NPPh2NHSiMe3 6 . Crystals of 6 are obtained in space group P1 . 相似文献
676.
H. Werner 《Angewandte Chemie (International ed. in English)》1968,7(12):930-941
Kinetic studies of substitution reactions of carbonylmetals and of carbonylmetal derivatives in which other ligands (n or π donors) besides CO are bound to the metal atom have recently attracted great interest, and the results of these investigations throw a new light on theoretical and preparative problems. The substitution mechanism is determined mainly by steric and electronic factors. 相似文献
677.
678.
Henri Brunner 《Angewandte Chemie (International ed. in English)》1971,10(4):249-260
The preparation and resolution of asymmetric organometallic compounds of the transition series with four different ligands on the metal atom are described. Some of the optically active complexes retain their configuration, while others undergo racemization in solution. Their properties and reactions are discussed. Centers of asymmetry at transition metal atoms can also be detected on the basis of the magnetic nonequivalence of diastereotopic groups. Information about the configurational stability of such compounds can be obtained by investigation of the temperature dependence of the nuclear magnetic resonance spectra. 相似文献
679.
四水顺丁烯二酸镍配合物晶体是由苹果酸和碳酸镍反应制得的。在这一体系中,加热时苹果酸转化为马来酸并与镍离子络合物成标题配合物。本文测定了该配合物的电子吸收光谱和光声光谱,并用配位场理论定地解释了其光谱性质,得到了配合物的晶场参数及中心离子的轨道能级。理论结果与实验结果的互洽表明了配合物晶体结构与电子结构的一致。 相似文献
680.
Synthesis, Crystal Structure, Electronic Structure, Spectroscopic and Magnetic Properties of [VOCl2{P(SiMe3)3}2]: A Phosphane Complex with a Disordered VOCl2 Group VOCl3 reacts with P(SiMe3)3 to form blue green crystals of [VOCl2{P(SiMe3)3}2] ( 1 ). The X-ray crystal structure analysis of 1 (cubic space group P213: a = 1541.4(1) pm, Z = 4) reveals a slightly distorded trigonal bipyramidal coordination environment for the disordered vanadium(IV) center. Density functional calculations on the compound [VOCl2{P(SiH3)3}2] ( 2 ) are in accord with this observation. 1 has been characterized by ESR, vibrational (IR and Raman) and electronic absorption spectroscopy and magnetic measurements. The ESR spectra of 1 in a toluene solution (293 K and frozen solution at 6 K) exhibit hyperfine interactions of the unpaired electron with the 51V center (I = 7/2) and the 31P centers (I = 1/2) of the two equivalent phosphane ligands. The ligand-field transitions of the VOCl2{P}2 chromophore observed in the electronic absorption spectrum have been assigned on the basis of density functional calculations on 2 . 相似文献