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921.
922.
Summary The morphogenesis of the different types of labiate processes is compared among three species of centric diatoms [Stephanopyxis turns (Greville) Ralfs,Odontella sinensis (Greville) Grunow, andOdontella aurita (Lyngbye) Agardh]. In all species, a cytoplasmic structure,i.e., the labiate process apparatus, situated close to the developing labiate process, appears before the labiate process begins to form and disappears upon its maturation. The possibility that the labiate process apparatus is implicated in the phylogeny of the labiate process is discussed. 相似文献
923.
This report is a comprehensive fine structural analysis of the morphological changes occurring during metamorphosis of the marine hydrozoan Mitrocomella polydiademata. Five stages are recognized during metamorphosis: planulae just prior to settlement, ball and filiform stages, immature polyps, and primary feeding polyps. Settlement and metamorphosis of cnidarian planulae involve such changes as ciliary arrest, discharge of nematocytes, secretion of glandular cells, differentiation of cells, and changes in cell and body shape. 相似文献
924.
Summary The fine structure of the cerebral organs is described in three species of monostiliferous hoplonemerteans. Amphiporus lactifloreus, Paranemertes peregrina and Tetrastemma candidum. There are two distinct groups of sensory cells in the cerebral organs of all three species. The ultrastructure of the sensory elements in these species is consistent with a chemoreceptive function of the dendrites. Incurrent and excurrent channels of the canal are postulated, based on the fine structure of the ciliary axonemes. Flow through the canal is such that each of the two groups of dendrites is downstream from a group of glandular cell outlets and upstream from a group of vesicular cells. It is suggested that the glandular, sensory and vesicular cells form a functional unit in which glandular cells secrete a coating material over the dendrites and vesicular cells actively remove this coating by endocytosis. Vesicular material is also found in glandular cells, where it probably arises in situ through crinophagy. There is no ultrastructural evidence that vesicular material is transferred to the vascular system. Small fibres containing dense vesicles are present among the ciliated cells and may represent an efferent nerve supply controlling the rate of flow through the canal. 相似文献
925.
926.
Hsiao‐Huang Chang Yi‐Chih Chen Chun‐Jung Huang Chia‐Cheng Kuo Yi‐Min Wang Chia‐Wei Sun 《Journal of biophotonics》2020,13(10)
Near‐infrared spectroscopy (NIRS) has been proposed as a noninvasive modality for detecting complications in patients undergoing extracorporeal membrane oxygenation (ECMO), and it can simultaneously reveal the global circulatory status of these patients. We optimized ECMO therapy on the basis of real‐time peripheral NIRS probing. Three patients underwent venoarterial (VA) ECMO and one patient underwent venovenous (VV) ECMO. All patients received peripheral ECMO cannulation with routine distal perfusion catheter placement. We designed an experimental protocol to adjust ECMO blood flow over 1 hour. Hemodynamic responses were measured using NIRS devices attached to the calf at approximately 60% of the distance from the ankle to the knee. HbO2 levels change substantially with adjustments in ECMO flow, and they are more sensitive than HHb levels and the tissue saturation index (TSI) are. NIRS for optimizing ECMO therapy may be reliable for monitoring global circulatory status. 相似文献
927.
928.
Hsu‐Chun Wu Rong‐Chien Lin Hsin‐Yi Hung Chia‐Fen Yeh Jui‐Hua Chu Xiao‐Jun Yang Chiou‐Ju Yao Fa‐Sheng Zou Cheng‐Te Yao Shou‐Hsien Li Fu‐Min Lei 《Zoologica scripta》2011,40(5):468-478
Wu, H.‐C., Lin, R.‐C., Hung, H.‐Y., Yeh, C.‐F., Chu, J.‐H., Yang, X.‐J., Yao, C.‐J., Zou, F.‐S., Yao, C.‐T., Li, S.‐H. & Lei, F.‐M. (2011). Molecular and morphological evidences reveal a cryptic species in the Vinaceous Rosefinch Carpodacus vinaceus (Fringillidae; Aves). —Zoologica Scripta, 40, 468–478. The Vinaceous Rosefinch (Carpodacus vinaceus) is endemic in East Asia with two recognized subspecies –C. v. vinaceus, distributed along the eastern edge of the Tibetan Plateau and the Himalayas, and C. v. formosanus, restricted to Taiwan’s Central Mountain Range. As reflected in a controversial taxonomic history, this vastly disjunctive distribution pattern suggests that the subspecies, having been isolated from each other for a long time, might have diverged, challenging the current taxonomic treatment and calling for possible species delimitation. Sequences of two mitochondrial fragments (mtDNA) and two Z‐linked nuclear loci (zDNA) were used to reconstruct the intraspecific phylogeny of C. vinaceous. The mtDNA tree shows that the two subspecies of the vinaceous rosefinch form two exclusively monophyletic clades. All but one zDNA sequences from the nominate subspecies and C. v. formosanus also formed exclusively monophyletic clades (the exceptional zDNA sequence from C. v. vinaceous formed a weakly supported clade with two outgroup species). Moreover, by conducting quantitative comparisons of morphometric traits and male plumage coloration, we found that the two subspecies exhibit distinguishable morphological differences. All the evidence therefore suggests that C. v. formosanus is a cryptic species and that its taxonomic status should be restored to full species. Molecular dating suggests that the two sibling rosefinches split 1.7 ± 0.2 million years ago, providing a point estimate for the historical connectivity of biota between eastern Tibet‐Himalayas and montane Taiwan. 相似文献
929.
930.
The nervous system of the planula larva of Anthopleura elegantissima consists of an apical organ, one type of endodermal receptor cell, two types of ectodermal receptor cells, central neurons and nerve plexus. Both interneural and neuromuscular synapses are found in the nerve plexus. The apical organ is a collection of about 100 long, columnar cells each bearing a long cilium and a collar of about 10 microvilli. The cilia of the apical organ are twisted together to form an apical tuft. The ciliary rootlets of the apical organ cells are extremely long, reaching to the basal processes of the cells adjacent to the mesoglea. All three types of sensory cells are tall and slender in profile and are identified by the presence of one or more of the following features: microtubules, small vesicles, membrane-bound granules and synapses. The interneurons are bipolar cells with somas restricted to the aboral end, adjacent to the apical organ. All synapses observed are polarized or asymmetrical. A diagram including all the elements of the nervous system is presented and the possible functions of the nervous system are discussed in relation to larval behavior. 相似文献