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排序方式: 共有387条查询结果,搜索用时 15 毫秒
91.
Early and late passage C-6 glial cell growth: Similarities with primary glial cells in culture 总被引:10,自引:0,他引:10
Dimitra Mangoura MD Ph.D Nikos Sakellaridis M.D Ph.D. Jackeline Jones Antonia Vernadakis 《Neurochemical research》1989,14(10):941-947
Earlier studies in our laboratory have shown that C-6 glial cells in culture exhibit astrocytic properties with increasing cell passage. In this study, we tested the responsiveness of early and late passage C-6 glial cells to various cultures conditions: culture substrata (collagen, poly-L-lysine, plastic), or supplements for the culture medium, DMEM, [fetal calf, or heat inactivated (HI) serum, or media conditioned from mouse neuroblastoma cells (NBCM) or primary chick embryo cultured neurons (NCM)]. Glutamine synthetase (GS) and cyclic nucleotide phosphohydrolase (CNP), astrocytic and oligodendrocytic glial markers, were used. Cell numer and protein content increased exponentially with days in culture regardless of the type of the substratum or cell passage. Differences in cell morphology among the three types of substratum were also reflected on GS activity, which rose by three-fold on culture day 3 for cells grown on collagen; thereafter, GS profiles were similar for all substrata. This early rise in GS is interpreted to reflect differential cell adhesion processes on the substrata; specifically, cell adhesion on the collagen stimulated differentiation into astrocytic phenotype.Analogous to immature glia cells in primary cultures, early passage C-6 glial cells responded to neuronal factors supplied either from NCM or NBCM by expressing reduced GS activity, the astrocytic marker and enhanced CNP activity, the oligodendrocytic marker. Thus, early passage cells can be induced to express either astrocytic or oligodendrocytic phenotype. In accordance with our previous reports on primary glial cells, late passage C-6 cells exhibit their usual astrocytic behavior, responding to serum factors with GS activity. Moreover, whereas NCM or NBCM alone markedly lowered GS activity, a combination with serum restored activity. The present findings confirm our previous observations and further establish the C-6 glial cells as a reliable model to study immature glia.Special issue dedicated to Dr. Paola S. Timiras. 相似文献
92.
Yoshimasa Ito Kimie Fukuyama MD PhD Noboru Horie William L. Epstein 《Molecular and cellular biochemistry》1984,60(2):183-188
Summary Enzymatic activity was investigated in metal-binding proteins from rat epidermal cells. Tris-HCl buffer soluble and KSCN solubilized proteins were extracted stepwise from granular and cornified cells of 2-day old rat epidermis. Each extract was separately applied to a Cu2+ or Zn2– chelate Sepharose 6B column and the proteins were eluted with buffers of different pHs and finally with EDTA solution. Metal chelate-binding proteins were found in both soluble and solubilized proteins but there was a larger amount in the latter. Affinity of the proteins to bind with Cu2+ chelate was greater than that with Zn2+ chelate. In Tris-HCl buffer extract, histidase activity was detected in Cu2+ chelate-binding proteins, but not in Zn2+ chelate-binding proteins. Acid phosphatase, cysteine proteinase, dipeptidase, cathepsin D, -galactosidase, gelatin hydrolase, and superoxide dismutase did not bind to metal chelates although these enzymes, except acid phosphatase, were inhibited by Cu2+, but not by Zn2+. In contrast, KSCN solubilized metal chelate-binding proteins showed plasminogen activator, acid phosphatase, and gelatin and casein hydrolases while histone hydrolase did not bind to either chelate column. Since metal-binding proteins in rat epidermal cells have been shown previously to be histidine- and cysteine-rich proteins concentrated in keratohyalin granules, interaction of metals and the structural proteins with certain enzymes may be involved in the regulation of epidermal cell functions. 相似文献
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Moayad M Aljarabah Neil R Borley James MD Wheeler 《International Seminars in Surgical Oncology : ISSO》2007,4(1):20
Background
appendiceal tumours are rare, they may be encountered unexpectedly in any acute or elective abdominal operation, many of these tumours are not appreciated intraoperatively and are diagnosed only during formal histopathological analysis of an appendicectomy specimen. Herein we present a case of appendiceal adenocarcinoma presenting as left-sided large bowel obstruction, we also review the literature of unusual presentations of appendiceal tumours.Case Presentation
we report a case of left sided large bowel obstruction found to be secondary to an appendiceal adenocarcinoma. The patient presented with abdominal pain, distension and constipation, CT scan showed large bowel obstruction thought to be due to a sigmoid tumour, on laparotomy the appendix was also noted to be abnormal. A low Hartman's was performed with en-bloc total hysterectomy and bilateral salpigo-oophorectomy. A separate ileocaecal resection with end ileostomy was also performed, pathology specimens showed that the primary neoplasm was the appendix with metastasis to the distal sigmoid.Conclusion
appendiceal tumours are rare, they usually present as acute appendicitis, other presentations are far less common.98.
99.
The Stomach, Helicobacter pylori, and Acid Secretion 总被引:1,自引:0,他引:1
100.
Dorsey DA Mascó DH Dikranian K Hyrc K Masciotra L Faddis B Soriano M Gru AA Goldberg MP de Erausquin GA 《Apoptosis : an international journal on programmed cell death》2006,11(4):535-544
Developing neuronal populations undergo significant attrition by natural cell death. Dopaminergic neurons in the substantia
nigra pars compacta undergo apoptosis during synaptogenesis. Following this time window, destruction of the anatomic target
of dopaminergic neurons results in dopaminergic cell death but the morphology is no longer apoptotic. We describe ultrastructural
changes that appear unique to dying embryonic dopaminergic neurons. In primary cultures of mesencephalon, death of dopaminergic
neurons is triggered by activation of glutamate receptors sensitive to alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic
acid (AMPA), and differs ultrastructurally from both neuronal apoptosis or typical excitotoxicity. AMPA causes morphological
changes selectively in dopaminergic neurons, without affecting other neurons in the same culture dishes. Two hours after the
onset of treatment swelling of Golgi complexes is apparent. At 3 h, dopaminergic neurons display loss of membrane asymmetry
(coinciding with commitment to die), as well as nuclear membrane invagination, irregular aggregation of chromatin, and mitochondrial
swelling. Nuclear changes continue to worsen until loss of cytoplasmic structures and cell death begins to occur after 12 h.
These changes are different from those described in neurons undergoing either apoptosis or excitotoxic death, but are similar
to ultrastructural changes observed in spontaneous death of dopaminergic neurons in the natural mutant weaver mouse. 相似文献