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61.
Dr. Colin R. Groom Dr. Frank H. Allen 《Angewandte Chemie (International ed. in English)》2014,53(3):662-671
The Cambridge Crystallographic Data Centre (CCDC) was established in 1965 to record numerical, chemical and bibliographic data relating to published organic and metal–organic crystal structures. The Cambridge Structural Database (CSD) now stores data for nearly 700 000 structures and is a comprehensive and fully retrospective historical archive of small‐molecule crystallography. Nearly 40 000 new structures are added each year. As X‐ray crystallography celebrates its centenary as a subject, and the CCDC approaches its own 50th year, this article traces the origins of the CCDC as a publicly funded organization and its onward development into a self‐financing charitable institution. Principally, however, we describe the growth of the CSD and its extensive associated software system, and summarize its impact and value as a basis for research in structural chemistry, materials science and the life sciences, including drug discovery and drug development. Finally, the article considers the CCDC’s funding model in relation to open access and open data paradigms. 相似文献
62.
An illustrative example is given to show how various vibrational spectroscopy techniques coupled with two-dimensional (2D) correlation analysis can be effectively utilized in the development of a novel and functional material. Surface-hydrophilic elastomer latex (SHEL) is a material exhibiting rather unusual permanently water-wettable surface feature despite having a soft and rubbery bulk property, which can be successfully analyzed with vibrational spectroscopy. 2D photoacoustic (PAS) IR spectra of a SHEL film indicate the localized surface segregation of long-chain ethoxylate moiety of the oligomeric surfactant used in the preparation of this material. The accumulation of the hydrophilic long-chain ethoxylate produces the high energy polar surface over the hydrophobic bulk phase of SBR copolymer. The persistence of very low water contact angle, even after repeated washing of a SHEL film with an excess amount of water, indicates permanent covalent attachment of long-chain ethoxylate group to the SBR copolymer. 2D Raman spectra generated from the process monitoring of the emulsion copolymerization of SHEL reveal the mechanism of the covalent attachment of long-chain ethoxylate. The reaction involves a separate step of oleyl moiety of the block surfactant reacting with 1,3-butadiene prior to the onset of copolymerization to produce the SBR latex product. 相似文献
63.
Mohammed I. Jeraal Nicholas Holmes Geoffrey R. Akien Richard A. Bourne 《Tetrahedron》2018,74(25):3158-3164
Reaction optimisation and understanding is fundamental for process development and is achieved using a variety of techniques. This paper explores the use of self-optimisation and experimental design as a tandem approach to reaction optimisation. A Claisen-Schmidt condensation was optimised using a branch and fit minimising algorithm, with the resulting data being used to fit a response surface model. The model was then applied to find new responses for different metrics, highlighting the most important for process development purposes. 相似文献
64.
Residence time spectra and material distributions in an operating caprolactam production plant were measured by means of sodium 24, bromine 82 and technetium 99m. The results of the tracerexperiments contributed to an optimization of the plant. 相似文献
65.
Industrially advanced countries and inereasingly also agricultural countries today use radioisotopes as labelled compounds or scaled sources in order to solve their scientific and technological problems. 相似文献
66.
Es wird eine radiometrische Bandwaage zur Koksaustragsmengen-Messung in BHT-Kokereien beschrieben. Voranstellend werden einige analytische Ausdrücke zur theoretischen Behandlung dieses Bandwaagentyps mitgeteilt. Die Waage zeichnet sich durch hohe Stabilität der Anzeige, durch die Möglichkeit des routinemäßigen Umsetzens von Meßstelle zu Meßstelle innerhalb kurzer Zeit und durch einen relativ kleinen Wägefehler (Meßunsicherheit ≦ 2,9%) aus. Die Signalaufbereitung innerhalb der Elektronik erfolgt durchgängig digital unter Verwendung eines Rechnerschaltkreises. 相似文献
67.
68.
Bhagwat PrasadAmit Garg Hardik TakwaniSaranjit Singh 《Trends in analytical chemistry : TRAC》2011,30(2):360-387
Metabolite identification (Met ID) is important during the early stages of drug discovery and development, as the metabolic products may be pharmacologically active or toxic in nature. Liquid chromatography-mass spectrometry (LC-MS) has a towering role in metabolism research.This review discusses current approaches and recent advances in using LC-MS for Met ID. We critically assess and compare various mass spectrometers, highlighting their strengths and limitations. Citing appropriate examples, we cover recent LC and ion sources, isotopic-pattern matching, hydrogen/deuterium-exchange MS, data dependent analyses, MSE, mass defect filter, 2D and 3D approaches for the elucidation of molecular formula, polarity switching, and background-subtraction and noise-reduction algorithms. A flow chart outlines a comprehensive strategy for Met ID, including a focus on reactive metabolites. 相似文献
69.
Morphology development and phase inversion were investigated during dynamic vulcanisation of ethylene–propylene–diene terpolymer (EPDM)/polypropylene (PP) blends. The effects of viscosity ratio and cross-linking reactions were also addressed. EPDM/PP blends were dynamically vulcanised in a Haake batch mixer using resole and SnCl2 as cross-linking agents. The morphology development and cross-linking degree with reaction time were followed by morphology analysis (SEM and TEM) and measurement of EPDM gel content, respectively. For the same reaction time, it was found that the EPDM gel content decreased when the low-molecular-weight EPDM was used. As a result, the morphological development was delayed and the phase-inversion point was shifted to higher reaction times, allowing us to monitor morphological development during a thermoplastic vulcanisate (TPV) preparation. Using the low-molecular-weight EPDM and increasing the PP viscosity accelerated the morphological development, shifting phase-inversion to lower reaction times. While blend composition influenced final TPV morphology, it had a minor effect on the mechanism of morphological development. A correlation between cross-linking degree and morphology development was established. The results obtained allowed to propose a mechanism of morphology development during dynamic vulcanisation of the EPDM/PP blends, including phase inversion. 相似文献
70.
The polyamide 6 (PA6)/isotactic polypropylene (iPP) in situ fibrillation composites are prepared by a novel extrusion die with an assembly of laminating‐multiplying elements (LMEs). The scanning electron micrographs illustrate that the dividing‐multiplying processes in LMEs elongate, break, and stabilize the dispersed PA6 phase in the iPP matrix along the flowing direction (FD). The morphology development of PA6 with different LME numbers greatly affects the rheological properties, crystalline behaviors, and mechanical properties. The dynamic rheological test performed at 195°C shows that the increased spatial restriction of the high‐aspect‐ratio PA6 particles increases the viscoelastic moduli, complex viscosity, and relaxation time. The crystalline analysis reveals that the heterogeneous nucleation becomes predominant and the transcrystalline morphology is observed in those samples produced by more LMEs. The tensile tests indicate that both, breaking strength and elongation, enhanced simultaneously because of the fibrillation of dispersed phase and the improvement in interfacial adhesion between the fibers and the matrix. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献