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71.
SYNOPSIS. After 1914 protozoologists have generally agreed that Pleistophora gigantea (Thélohan, 1895) Swellengrebel, 1911, Ichthyosporidium giganteum (Thélohan, 1895) Swarczewsky, 1914, and I. phymogenes Caullery and Mesnil, 1905, are identical. Because no polar filament was found in the spores, however, some authors have followed Swarczewsky in considering this species to be a haplosporidan, while others have persisted in thinking it a microsporidan. Using preserved material that Swellengrebel saved from a tumor on which he based his studies, we have found a polar filament in the spores both with the PAS reaction and with the electron microscpe. This new information removes the only basis for the doubt which some authors have entertained, that Thélohan and Sweliengrebel correctly considered the parasite to belong to the Microsporida. Since Pleistophora gigantea is believed to be identical with I. phymogenes, recently selected by Sprague as type species of genus Ichthyosporidium Caullery and Mesnil, 1905, then Ichthyosporidium, originally assigned to the Haplosporida, must be regarded as a microsporidan genus. Whether it is distinct from all other microsporidan genera is a matter needing further consideration. 相似文献
72.
SYNOPSIS. A species of Nosema in the muscles of the North American white shrimp, generally known as Penaeus setiferus but also known as P. fluviatilis, appears identical with type specimens of N. nelsoni Sprague, 1950, in P. aztecus. Its Golgi apparatus, as seen in the sporoblast, is a complex system of cisternae, small vesicles and expanded sacs which plays a major role in spore morphogenesis. It transforms directly into the polaroplast complex, certain membranous investments of the polar filament, the polar sac and perhaps part of the posterior vacuolar system. Probably the polar sac contains the polar cap. The PAS-positive material in both the cap and the filament may be a component of the Golgi complex. This new concept of the Golgi complex supplements our earlier view of spore morphogenesis according to which the polar filament is of nuclear origin. It also reconciles the idea with Vávra's identification of Golgi vesicles associated with the developing polar filament. 相似文献
73.
Immunofluorescent Localization of Vimentin, Prekeratin and Actin during Odontoblast and Ameloblast Differentiation 总被引:1,自引:0,他引:1
HERVÉ LESOT JEAN MARIE MEYER JEAN VICTOR RUCH KLAUS WEBER MARY OSBORN 《Differentiation; research in biological diversity》1982,21(1-3):133-137
The localization of constitutive proteins of different types of cytoskeletal components (prekeratin, vimentin, and actin) was examined in embryonic mouse molars using specific antibodies and immunofluorescence microscopy on frozen sections. Prekeratin and actin were found in the enamel organ. Preameloblasts demonstrated uniform staining, whereas ameloblasts demonstrated an apical accumulation of both prekeratin and actin. Vimentin and actin were observed in the dental papilla. A redistribution of vimentin accompanied the polarization of odontoblasts. A possible transmembranous control of cytoskeletal activities by the extracellular matrix is discussed. 相似文献
74.
JINWEN JIANG SHUBH D. SHARMA SHELLEY NAKAMURA JENG-YU LAI JODY L. FINK VICTOR J. HRUBY MAC E. HADLEY 《Pigment cell & melanoma research》1995,8(6):314-323
Seventeen human melanoma cell (HMC) lines, both melanotic and amelanotic, were incubated in the continuous presence of a potent melanotropic peptide hormone analog, [Nle4,d -Phe7]α-MSH, for 72 hr with daily changes of medium. Only one cell line (HD, melanotic) consistently responded to the hormone analog by increased tyrosinase activity. Three (one melanotic, two amelanotic) of the HMC lines also failed to respond to the peptide by either increased or decreased enzyme activity when incubated continuously in the presence of the peptide for longer periods of time (6,15,27,43 days). The HD cell line, however, again responded with increasingly enhanced basal enzyme activity the longer the cells were incubated in the presence of the melanotropin. One amelanotic cell line (C8161) responded with enhanced enzyme activity when grown to confluency in the continuous presence of the peptide. Basal tyrosinase activity of the C8161 cell line may have increased as cell density in the flasks increased. These results suggest that under conditions of increased cell number, phenotypic expression of tyrosinase activity in so called “amelanotic” (tyrosinase-negative) cells is increased and can be enhanced further by stimulation with a melanotropic peptide. Under conditions of increased cell number, the presence of [Nle4,d -Phe7]α-MSH caused morphological differentiation (shape change); the cells became enlarged and very dendritic. The number of cells in monolayer (surface of the flask) and in the medium were drastically reduced in both melanotic and “amelanotic” cell lines incubated with [Nle4,d -Phe7]α-MSH. The data support other published reports that melanotropic peptides inhibit human melanoma cell growth (proliferation) in vitro, most likely through a cytostatic mechanism. [Nle4,d -Phe7]α-MSH also exhibited a prolonged (residual) inhibitory action on HD cell proliferation. In other words, inhibition of cell growth (proliferation) of the HMCs was evident even several days after removal of the melanotropic peptide from the incubation medium. 相似文献
75.
VICTOR D. VACQUIER BRIGITTE BRANDRIFF CHARLES G. GLABE 《Development, growth & differentiation》1979,21(1):47-60
Acid-dejellied Lytechinus pictus eggs bind few sperm and show decreased fertilizability. Addition of solubilized egg jelly increases sperm binding and fertilizability, presumably by increasing the frequency of the acrosome reaction. However, dejellied Strongylocentrotus purpuratus bind more sperm and show increased fertilizability in the complete absence of soluble egg jelly. Addition of soluble egg jelly greatly decreases fertilizability in S. purpuratus. Such species differences may be the basis for the controversy between Lillie and Tyler on the one hand, who believed that egg jelly increased egg fertilizability; while Loeb and Hagström on the other hand, believed jelly had no effect on, or actually decreased egg fertilizability. 125I-labeling of dejellied S. purpuratus egg surfaces and immunofluorescent studies show that egg jelly persists on the surfaces of acid-dejellied eggs. Egg jelly appears to be a non-removable component of the vitelline layer of this species. 相似文献
76.
77.
A character survey compiling the morphological information of the subfamily Stygnicranainae was carried out. Two new species of Stygnicranaus Roewer, 1913 are described from Colombia and the new genus Agathocranaus is described from Ecuador. All known species of the subfamily are included in a matrix of 46 morphological characters. Parsimony analysis under implied weights recovered a monophyletic Stygnicranainae including Tryferos Roewer, 1931 plus Stygnicranaus and Agathocranaus. However, the usage of the four subfamilies of Cranaidae as currently defined is abandoned because the two largest subfamilies of Cranaidae – Cranainae and Prostygninae – represent paraphyletic groups (grades), whereas Heterocranainae is a superfluous subfamily, including only the genus Heterocranaus Roewer, 1913. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157 , 470–494. 相似文献
78.
79.
Two new species of freshwater ostracods are described from Southern India and their taxonomic validity is discussed. 相似文献
80.