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91.
92.
Milan M. Ćirković 《Foundations of Science》2002,7(4):453-463
A modern assessment of the classical Boltzmann-Schuetz argument for large-scale entropy fluctuations as the origin of our observable cosmological domain is given.The emphasis is put on the central implication of this picture which flatly contradicts the weak anthropic principle as an epistemological statement about the universe. Therefore, to associate this picture with the anthropic principle as it is usually done is unwarranted. In particular, Feynman's criticism of theanthropic principle based on the entropy-fluctuation picture is a product of this semantic confusion. 相似文献
93.
A. Marušić K. Kos A. Stavljenić S. Vukičević 《Cellular and molecular life sciences : CMLS》1993,49(8):693-698
Subcutaneous injection of nonspecific irritants such as magnesium silicate (talc) provokes granulomatous inflammation in the rat. Part of the acute phase response (APR) in these animals is the loss of trabecular bone at sites distant from the site of inflammation. To assess the possible involvement of vitamin D in the bone loss, we studied the development of the acute phase response in vitamin D-deprived rats. The serum APR provoked by subcutaneous inflammation in rachitic rats consisted of hypozincemia, hypercupremia, increased, alkaline phosphatase activity and adrenocorticotropic hormone (ACTH) concentration, and was similar to that in control animals except for the absence of hypoferremia. Control rats with talc-induced subcutaneous inflammation also had splenomegaly and decreased total and mononuclear peripheral blood cell counts, while subcutaneous inflammation did not induce spleen changes in rachitic rats. Subcutaneous inflammation induced the loss of trabecular bone and decreased the osteoblastic cell count in tibial metaphyses in control animals. Rachitic rats had abundant osteoid on trabecular surfaces, and the number of osteoblasts and osteoclasts was comparable to that of the controls. Subcutaneous inflammation did not affect any of the bone parameters in rachitic rats. These results indicate that vitamin D plays an important role in the generation of the acute phase response during inflammation, particularly in the induction of spleen and bone cell changes. The discrepancy of the blood on one hand and bone and spleen indices of the APR on the other, indicate that there may be divergent pathways in the generation of the inflammatory response, some of which may be dependent on vitamin D. 相似文献
94.
Grbić M Van Leeuwen T Clark RM Rombauts S Rouzé P Grbić V Osborne EJ Dermauw W Ngoc PC Ortego F Hernández-Crespo P Diaz I Martinez M Navajas M Sucena É Magalhães S Nagy L Pace RM Djuranović S Smagghe G Iga M Christiaens O Veenstra JA Ewer J Villalobos RM Hutter JL Hudson SD Velez M Yi SV Zeng J Pires-daSilva A Roch F Cazaux M Navarro M Zhurov V Acevedo G Bjelica A Fawcett JA Bonnet E Martens C Baele G Wissler L Sanchez-Rodriguez A Tirry L Blais C Demeestere K Henz SR Gregory TR Mathieu J 《Nature》2011,479(7374):487-492
95.
Seibert MM Ekeberg T Maia FR Svenda M Andreasson J Jönsson O Odić D Iwan B Rocker A Westphal D Hantke M DePonte DP Barty A Schulz J Gumprecht L Coppola N Aquila A Liang M White TA Martin A Caleman C Stern S Abergel C Seltzer V Claverie JM Bostedt C Bozek JD Boutet S Miahnahri AA Messerschmidt M Krzywinski J Williams G Hodgson KO Bogan MJ Hampton CY Sierra RG Starodub D Andersson I Bajt S Barthelmess M Spence JC Fromme P Weierstall U Kirian R Hunter M Doak RB Marchesini S Hau-Riege SP Frank M 《Nature》2011,470(7332):78-81
X-ray lasers offer new capabilities in understanding the structure of biological systems, complex materials and matter under extreme conditions. Very short and extremely bright, coherent X-ray pulses can be used to outrun key damage processes and obtain a single diffraction pattern from a large macromolecule, a virus or a cell before the sample explodes and turns into plasma. The continuous diffraction pattern of non-crystalline objects permits oversampling and direct phase retrieval. Here we show that high-quality diffraction data can be obtained with a single X-ray pulse from a non-crystalline biological sample, a single mimivirus particle, which was injected into the pulsed beam of a hard-X-ray free-electron laser, the Linac Coherent Light Source. Calculations indicate that the energy deposited into the virus by the pulse heated the particle to over 100,000?K after the pulse had left the sample. The reconstructed exit wavefront (image) yielded 32-nm full-period resolution in a single exposure and showed no measurable damage. The reconstruction indicates inhomogeneous arrangement of dense material inside the virion. We expect that significantly higher resolutions will be achieved in such experiments with shorter and brighter photon pulses focused to a smaller area. The resolution in such experiments can be further extended for samples available in multiple identical copies. 相似文献
96.
Cappellari M McDermid RM Alatalo K Blitz L Bois M Bournaud F Bureau M Crocker AF Davies RL Davis TA de Zeeuw PT Duc PA Emsellem E Khochfar S Krajnović D Kuntschner H Lablanche PY Morganti R Naab T Oosterloo T Sarzi M Scott N Serra P Weijmans AM Young LM 《Nature》2012,484(7395):485-488
Much of our knowledge of galaxies comes from analysing the radiation emitted by their stars, which depends on the present number of each type of star in the galaxy. The present number depends on the stellar initial mass function (IMF), which describes the distribution of stellar masses when the population formed, and knowledge of it is critical to almost every aspect of galaxy evolution. More than 50 years after the first IMF determination, no consensus has emerged on whether it is universal among different types of galaxies. Previous studies indicated that the IMF and the dark matter fraction in galaxy centres cannot both be universal, but they could not convincingly discriminate between the two possibilities. Only recently were indications found that massive elliptical galaxies may not have the same IMF as the Milky Way. Here we report a study of the two-dimensional stellar kinematics for the large representative ATLAS(3D) sample of nearby early-type galaxies spanning two orders of magnitude in stellar mass, using detailed dynamical models. We find a strong systematic variation in IMF in early-type galaxies as a function of their stellar mass-to-light ratios, producing differences of a factor of up to three in galactic stellar mass. This implies that a galaxy's IMF depends intimately on the galaxy's formation history. 相似文献
97.
Jelena Petrović 《Cellular and molecular life sciences : CMLS》1977,33(7):887-888
Summary
3H-Indole acetic acid bound to cytosol proteins of embryonic chicken liver in vitro to an average capacity of at least 20 pmoles/mg binding protein. The auxin-binding protein complexes could be resolved into 4 major zones by anion exchange chromatography; they sedimented at 3–7 S in sucrose density gradients, and were also heterogenous in agarose gel electrophoresis. 相似文献
98.
Zusammenfassung Wiederholte Injektionen von menschlichem -Globulin in der ersten Nachgeburtsperiode, führte bei Kücken zu immunologischer Toleranz gegenüber diesem Antigen. 相似文献
99.
Résumé Chez le rat intoxiqué par des doses léthales de phosphamidone, la consommation in vitro d'oxygène des tranches du cortex cérébral stimulées par KCl est plus élevée que celles des témoins ou des rats intoxiqués au paraoxon ou au TEPP. 相似文献
100.
V. Varagić M. Krstić S. Stepanović S. Hajduković 《Cellular and molecular life sciences : CMLS》1963,19(12):647-648
Résumé 24 et 48 h après irradiation- (900 r) la quantité de 5-hydroxytryptamine dans l'intestin du rat n'a pas changé de manière significative. La quantité de 5-hydroxytryptamine dans la rate du rat, exprimée par g de tissu frais a augmenté. Le prétraitement avec de la cystéamine abaisse nettement la quantité de 5-hydroxytryptamine dans la rate, après l'irradiation. 相似文献