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81.
H. Meier E. Zimmerhackl W. Albrecht D. ßösche W. Hecker P. Menge A. Ruckdeschel E. Unger G. Zeitler 《Mikrochimica acta》1970,58(4):733-743
Zusammenfassung Die hochspannungselektrophoretische Wanderung der Halogenokomplexe der Platinmetalle und weiterer anorganischer Ionen wird bei Anwendung von Polycarbonsäuren (Oxalsäure, Bernsteinsäure, Apfelsäure, Weinsäure und Zitronensäure) als Elektrolyt untersucht und der Einfluß des pH-Werts und der Konzentration der Substanzen auf die Wanderung geprüft. Es wird festgestellt, daß die auf die abgestufte Komplexbildungstendenz der Polycarbonsäuren (Zitronensäure > Weinsäure Apfelsäure > Bernsteinsäure) rückführbaren Unterschiede der Wanderungsgeschwindigkeiten für die Trennung anorganischer Gemische gut einzusetzen sind. Für die Chlorokomplexe der Platinmetalle wird eine Abstufung der Beweglichkeiten in der Reihe Ir Pt Os > Rh > > Pd > Ru (> Rh) gefunden.
The high voltage electrophoretic separation of inorganic ions with special consideration of the platinum metals
Summary The high voltage eleetrophoretic migration of the halogen complexes of the platinum metals and other inorganic ions was studied with the employment of the polycarboxylic acids (oxalic, succinic, malic, tartaric, citric) as electrolyte, and the influence of the pH-value and the concentration of the substances on the migration investigated. It was found that the differences in the migration velocities, which may be traced back to the graded complex-forming tendency of the polycarboxylic acids (citric > tartaric malic > > succininic) can be used to good advantage in the separation of inorganic mixtures. With respect to the chlorocomplexes of the platinum metals, a decrease in the mobilities was discovered in the series Ir > Pt > Os > > Rh > Pd > Ru (>Rd).相似文献
82.
The syntheses of p-substituted 2-methyl-4-phenylbuten(1)-carboxylic acid derivatives are described, using Blanc's chloromethylation reaction, the Friedel-Crafts alkylation of unsaturated ketones or the Meerwein arylation; the formed intermediates react in subsequent steps to the title compounds. 相似文献
83.
Mass spectra of 3,6,20β-trihydroxypregnanes differ greatly, depending upon the nature of the A/B ring fusion and the positions of the hydroxy groups. Of all the isomers only 3α,6β,20β-trihydroxy-5β-pregnane produces an intense, structurally significant, ion at m/e 263. For 3β,6α,20β-trihydroxy-5α-pregnane an ion of m/e 141 is typical. 相似文献
84.
Detlef Günther Albrecht v. Quadt Ronny Wirz Herve Cousin Volker J. Dietrich 《Mikrochimica acta》2001,136(3-4):101-107
Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used as a complementary technique to X-ray fluorescence
(XRF), for multi-element analysis of geological samples fused with lithium-tetraborate Li2B4O7). Different calibration strategies using external non-matrix matched reference materials were investigated. Various internal
standards were tested, including the use of Li from the flux, and the use of the naturally occurring internal standards, Si
or Ca. The use of a naturally occurring standard is not as efficient as this required a prior analysis of the samples using
XRF. The obtained values for the analysis of geological reference materials were compared with consensus literature values,
and satisfactory agreement was found. Laser pits, which were formed, had a diameter of 80 μm and 3–5 replicates on each fused
disc were measured. The reproducibility of the method was better than 10% for concentrations above 1 μg/g and better than
15% for lower concentrations. The use of Li as the internal standard offers the possibility of multi-element determinations
in geological samples, which have an unknown composition when the laser ablation analysis is carried out. However, using the
calculated stoichiometric composition of the lithium-tetraborate for the calculation of the Li concentration leads to a constant
deviation from the recommended values. Therefore, it was necessary to determine the Li concentration within each sample batch
using at least one lithium tetraborate fused geological reference material. This resulting Li concentration in the beads was
then used for all subsequent samples in a run. Limits of detection, reproducibility, deviation from reference values indicate
the potential of LA-ICP-MS for such bulk analysis without matrix matched calibration standards. 相似文献
85.
Rodríguez G Albrecht M Schoenmaker J Ford A Lutz M Spek AL van Koten G 《Journal of the American Chemical Society》2002,124(18):5127-5138
The reactivity of the bifunctionalized ligand NC(Br)N-I 1 [IC(6)H(2)(CH(2)NMe(2))(2)-3,5-Br-4] has been studied as a versatile synthon for organic and/or organometallic synthesis. Chemoselective metalation (M = Pd, Pt, Li) at the C(aryl)-I or C(aryl)-Br bonds was achieved by choosing the appropriate metal precursors. In this way a series of Pt(II) and Pd(II) complexes were prepared that have a second functional group available for further reactions. These Pt(II) and Pd(II) complexes were subjected to a wide range of organic and organometallic reactions, revealing the remarkable stability of their M-C sigma-bond and opening an easy route for the synthesis of mono- and (hetero)bimetallic building blocks. The scope of the chemistry of such building blocks shows that they are good candidates for use in the synthesis of dendrimers, bioorganometallic systems, or polymetallic materials. The X-ray crystal structures of the most representative complexes (2, 3a, 19, 20, and 24) are also reported. 相似文献
86.
The label-free time-resolved reflectometric interference spectroscopy has been used to study the interaction of the human
estrogen receptor alpha (ERa) and different types of ligands. Different possible sensor surface coatings including various
estrogen derivatives were evaluated for their suitability for detection of ERa. The determination of the kinetic and thermodynamic
constants was carried out for the interaction in the heterogeneous phase as well as for the interaction in homogeneous phase.
In addition, the affinity of 11 ligands ranging from natural hormones and pharmaceuticals to endocrine disrupting chemicals
(EDCs) has been determined with this label-free assay format. 相似文献
87.
88.
89.
Shyjumon Ibrahimkutty Daniel Issenmann Stefan Schleef Anke‐Susanne Müller Yves‐Laurent Mathis Biliana Gasharova Erhart Huttel Ralph Steininger Jörg Göttlicher Tilo Baumbach Albrecht Bartels Christof Janke Anton Plech 《Journal of synchrotron radiation》2011,18(4):539-545
A high‐repetition‐rate pump–probe experiment is presented, based on the asynchronous sampling approach. The low‐α mode at the synchrotron ANKA can be used for a time resolution down to the picosecond limit for the time‐domain sampling of the coherent THz emission as well as for hard X‐ray pump–probe experiments, which probe structural dynamics in the condensed phase. It is shown that a synchronization of better than 1 ps is achieved, and examples of phonon dynamics of semiconductors are presented. 相似文献
90.
Hirnet A Schroeder K Blügel S Torrelles X Albrecht M Jenichen B Gierer M Moritz W 《Physical review letters》2002,88(22):226102
Sb induces on Ge(113) a c(2 x 2) reconstruction in which Sb breaks one Ge-Ge bond and occupies an interstitial site, in contrast to Sb adsorption on other Si or Ge surfaces. Sb saturates the three dangling bonds per unit cell of the (113) surface inducing a large strain which is released by occupation of the interstitial site. Two neighboring Sb at interstitial sites form a dimer. The structure has been determined by x-ray diffraction, applying direct methods, and ab initio density-functional-theory calculations. The adsorption geometry and the high binding energy lead one to expect that Sb cannot be used as a surfactant for the growth of Si/Ge layers on the (113) surface. 相似文献