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31.
Suzanne M. Watt David J. Gilmore Donald Metcalf Stephen P. Cobbold Trang K. Hoang Herman Waldmann 《Journal of cellular physiology》1983,115(1):37-45
A rat monoclonal antibody, YBM/42, directed against mouse leukocyte common antigen, was used for the analysis and separation of hemopoietic progenitor cells from mouse bone marrow and fetal liver. Cells were fractionated on a FACS-II cell sorter and the resulting subpopulations examined for their morphology and ability to form colonies in agar (for day 7 colonies) and methylcellulose (for day 2 erythroid clones). The antibody bound to all leukocytes, including blast cells and day 7 hemopoietic progenitor cells (day 7 colony forming cells, CFC), but not to erythrocytes or nucleated erythroid cells. This antibody can be used to advantage to enrich for early progenitor cells from mouse fetal liver, in which the majority of cells (70%) are nucleated erythroid cells. In day 12 fetal liver, approximately 10% of all cells bind this antibody strongly and, of these approximately 70% are blast cells. Contained within this positive population are 95% of all day 7 CFC. In the most enriched fraction about 20% of the cells formed day 7 colonies. This represents a 25-fold enrichment over unsorted fetal liver. The negative fractions contain 94% of all cells forming erythroid clones (≥8 cells) on day 2 of culture (day 2 CFU-E). In the most enriched fraction, 20% of the cells are day 2 CFU-E. Day 7 CFC can therefore be well separated from day 2 CFU-E, with good recovery of both cell types, by use of a single label. Day 7 colony forming cells were classified as granulocyte (G-CFC), macrophage (M-CFC), mixed granulocyte/macrophage (GM-CFC), pure erythroid (E), or mixed erythroid (Emix). A high enrichment for multipotential cells is achieved and constitues 3–5% of cells in the most enriched fraction. Most types of day 7 CFC could not be separated with YMB/42, but GM-CFC and M-CFC exhibit a broader distribution than the other CFC with regard to fluorescence intensity. This implicit heterogeneity in GM-CFC and M-CFC is further substantiated by the finding that myeloid progenitors in the different FACS fractions also share a differential reactivity to different sources of growth factors. 相似文献
32.
Summary Four classes of glial cells can be recognized in the central nervous system of turtles and birds on the basis of nuclear characteristics (methylene blue) and external morphology (Golgi technique). It seems likely that astrocytes and ependymal cells have a similar origin and function, but no evidence has been seen to indicate that transitional forms exist between astrocytes and oligodendrocytes or microgliacytes. Ependymal cells in the tectum and forebrain are covered by lamellate excrescences which are absent on cells in the spinal cord. Protoplasmic astrocytes are restricted to the gray matter. In the turtle they have an elongate shape characteristic of primitive elements, but stellate forms typical of mammals predominate in the bird. Fibrous astrocytes are abundant in the white matter. Endfeet are lacking in the turtle except on cells located near the pia; they are common for all elements in the bird and can sometimes be observed to outline the course of capillaries. Oligodendrocytes are identical to mammalian and amphibian forms. Small, round somata and long, thin processes are typical of types I and II while a tubular reticulum or membranous sheath characterizes type IV. The lack of a well defined somata and absence of transitional forms (type III) are compatible with the possibility that type IV is not a true cell type but corresponds to the inner cytoplasmic tongue of myelin. Microgliacytes are present in gray and white matter; they have a smaller overall size in the turtle and young chicken than in adult birds.Supported by a postdoctoral fellowship from the United States National Institutes of Health, NB 28,013-01Al. 相似文献
33.
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35.
FREE NUCLEOTIDES OF THE BRAIN IN VARIOUS MAMMALS 总被引:4,自引:0,他引:4
36.
37.
Suzanne W. T. Batra 《Insectes Sociaux》1966,13(2):87-92
Summary The structure and populations of seven nests ofHalictus scabiosæ were studied in Geneva during July and August, 1964. Cells, containing brood of various ages, were radially arranged along the branching burrows. The one to six females in each nest did not belong to distinct worker and queen castes. This is in contrast to reports of distinct castes in what appears to be the same species from France. Most pollen collectors in the Geneva population were inseminated and some probably laid eggs.
Contribution No. 1303 from the Department of Entomology, The University of Kansas, Lawrence. 相似文献
Zusammenfassung Die Struktur und die Bewohner von sieben Nestern vonHalictus scabiosæ, die im Juli und August 1964 in der Gegend um Genf gesammelt wurden, werden beschrieben. Zellen mit Brut verschiedenen Alters sind entlang verzweigter Gänge radiär angeordnet. Bis zu sechs Weibchen befanden sich in einem einzelnen Nest. Sie waren nicht in Königinnen und Arbeiterinnen differenziert, wie dies von Bienen aus Frankreich berichtet ist, die wahrscheinlich zur selben Art gehören. Die meisten Pollen-Sammlerinnen der Genfer Population waren befruchtet und einige von ihnen legten auch wahrscheinlich Eier.
Résumé La structure et la population de sept nids deHalictus scabiosæ ont été étudiées à Genève durant les mois de juillet et d'août 1964. Des cellules contenant du couvain d'âge différent sont disposées en rayons le long de terriers qui se ramifient. Chaque nid était occupé par une à six femelles qui n'appartenaient pas à une caste distincte d'ouvrières ou de reine. La plupart des abeilles qui collectent le pollen furent inséminées et quelques-unes probablement pondèrent des ufs.
Contribution No. 1303 from the Department of Entomology, The University of Kansas, Lawrence. 相似文献
38.
Grazyna Adamus Z. Suzanne Zam Scotts Emerson Paul A. Hargrave 《In vitro cellular & developmental biology. Plant》1989,25(12):1141-1146
Summary We present a practical method for the rescue of previosly stable hybridoma clones which increases the proportion of desired
cells in the population before cloning by limiting dilution. When the antibody activity of a culture supernatant was lower
than that previously obtained, a precloning distribution at a density of 10 cells per microtiter well greatly improved the
chances of obtaining a single active clone by subsequent limiting dilution. The Poisson distribution model was used to evaluate
the method. Probabilities calculated clearly demonstrate the advantage of this precloning distribution step when attempting
to isolate a hydridoma cell line that is relatively rare in a population.
This work was supported in part by grants EY 06225 and EY 06226 from the National Eye Institute of the National Institutes
of Health, Bethesda, MD and by an unrestricted departmental award from Research to Prevent Blindness, Inc. 相似文献
39.
Characterization of Opioid Receptors in Cultured Neurons 总被引:1,自引:1,他引:0
Pierre J.-J. Vaysse R. Suzanne Zukin Kay L. Fields John A. Kessler 《Journal of neurochemistry》1990,55(2):624-631
The appearance of mu-, delta-, and kappa-opioid receptors was examined in primary cultures of embryonic rat brain. Membranes prepared from striatal, hippocampal, and hypothalamic neurons grown in dissociated cell culture each exhibited high-affinity opioid binding sites as determined by equilibrium binding of the universal opioid ligand (-)-[3H]bremazocine. The highest density of binding sites (per mg of protein) was found in membranes prepared from cultured striatal neurons (Bmax = 210 +/- 40 fmol/mg protein); this density is approximately two-thirds that of adult striatal membranes. By contrast, membranes of cultured cerebellar neurons and cultured astrocytes were devoid of opioid binding sites. The opioid receptor types expressed in cultured striatal neurons were characterized by equilibrium binding of highly selective radioligands. Scatchard analysis of binding of the mu-specific ligand [3H]D-Ala2,N-Me-Phe4,Gly-ol5-enkephalin to embryonic striatal cell membranes revealed an apparent single class of sites with an affinity (KD) of 0.4 +/- 0.1 nM and a density (Bmax) of 160 +/- 20 fmol/mg of protein. Specific binding of (-)-[3H]bremazocine under conditions in which mu- and delta-receptor binding was suppressed (kappa-receptor labeling conditions) occurred to an apparent single class of sites (KD = 2 +/- 1 nM; Bmax = 40 +/- 15 fmol/mg of protein). There was no detectable binding of the selective delta-ligand [3H]D-Pen2,D-Pen5-enkephalin. Thus, cultured striatal neurons expressed mu- and kappa-receptor sites at densities comparable to those found in vivo for embryonic rat brain, but not delta-receptors. 相似文献
40.
Hillary A. Hahm Margot M. Ip Kathleen Darcy Jennifer D. Black Wendy K. Shea Suzanne Forczek Masami Yoshimura Takami Oka 《In vitro cellular & developmental biology. Plant》1990,26(8):803-814
Summary A serum-free primary culture system is described which allows normal rat mammary epithelial cells (RMECs) embedded within
a reconstituted basement membrane to undergo extensive growth and functional differentiation as detected by synthesis and
secretion of the milk products casein and lipid. RMECs isolated from mammary glands of immature virgin rats were seeded within
an extracellular matrix preparation derived from the Engelbreth-Holm-Swarm sarcoma and cultured in a serum-free medium consisting
of Dulbecco's modified Eagle's medium-F12 containing insulin, prolactin, progesterone, hydrocortisone, epidermal growth factor,
bovine serum albumin, transferrin, and ascorbic acid. Casein synthesis and secretion were documented at the electron microscopic
level as well as by an enzyme-linked immunosorbent assay (ELISA) assay using a polyclonal antibody against total rat caseins.
Numerous secretory vesicles with casein micelles were noted near the apical surface of the RMECs, and secreted casein was
observed in the lumen. These ultrastructural data were confirmed by the ELISA assay which showed that microgram amounts of
casein per well were synthesized by the RMECs and that the amount of casein increased with time in culture. Using immunoblot
analysis it was demonstrated that the full complement of casein proteins was synthesized. In addition to casein protein, β-casein
mRNA levels were shown to increase with time. Synthesized lipid was detected at both the light and electron microscopic levels.
Phase contrast photomicrographs demonstrated extensive intracellular lipid accumulation within the ductal and lobuloalveolarlike
colonies, and at the electron micrograph level, lipid droplets were predominantly localized near the apical surface of the
RMECs. The lipid nature of these droplets was verified by oil red O staining. Results from this study demonstrate that RMECs
from immature virgin rats proliferate extensively and rapidly develop the capacity to synthesize and secrete casein and lipid
when grown within a reconstituted basement membrane under defined serum-free conditions. This unique system should thus serve
as an excellent model in which the regulation of mammary development and gene expression can be investigated.
This work was supported by grants CA 33240 and CA 35641 and by core grant CA 24538 from the National Institutes of Health,
Bethesda, MD. 相似文献