全文获取类型
收费全文 | 723篇 |
免费 | 84篇 |
出版年
2023年 | 6篇 |
2022年 | 8篇 |
2021年 | 21篇 |
2020年 | 6篇 |
2019年 | 6篇 |
2018年 | 13篇 |
2017年 | 9篇 |
2016年 | 18篇 |
2015年 | 41篇 |
2014年 | 50篇 |
2013年 | 48篇 |
2012年 | 53篇 |
2011年 | 64篇 |
2010年 | 35篇 |
2009年 | 29篇 |
2008年 | 36篇 |
2007年 | 52篇 |
2006年 | 33篇 |
2005年 | 46篇 |
2004年 | 53篇 |
2003年 | 36篇 |
2002年 | 38篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1989年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1973年 | 3篇 |
1959年 | 2篇 |
1958年 | 2篇 |
1953年 | 1篇 |
1951年 | 1篇 |
1950年 | 1篇 |
1938年 | 1篇 |
1923年 | 1篇 |
1892年 | 1篇 |
1855年 | 1篇 |
排序方式: 共有807条查询结果,搜索用时 15 毫秒
1.
Dominique Toussaint-Demylle Jean-Marie Scheiff Stanislas Haumont 《Cell and tissue research》1990,262(1):115-123
Summary Thymic nurse cells (TNC), which are multicellular complexes composed of epithelial cells and thymocytes, were obtained from C3H-mice thymuses. They were described by means of light and electron microscopy. The morphology of epithelial cells forming isolated TNC compared to that of small tissue fragments obtained by enzymatic digestion revealed that TNC could be derived from all parts of the thymus: cortex, corticomedullary junction and medulla, the cortex being their principal source. This variety of origin, the presence of several epithelial cells inside a single TNC, the presence of non-lymphoid cells, and the various locations of eleaved desmosomes confirmed that their aspect in vitro as round and sealed structures can be considered to be an artifact due to the isolation technique used. Indeed, during this procedure, they are formed by a process of wrapping of the epithelial cytoplasm around the tightly associated thymocytes. All three epithelial cell types: cortical reticular cells, medullary reticular cells, and medullary globular cells can form TNC.A portion of this work was presented at the first Thymus Workshop. Rolduc, Netherlands, April, 1988 相似文献
2.
Monique Berthelon Catherine Caillaud Françoise Rey Philippe Labrune Dominique Melle Josué Feingold Jean Frézal Marie-Louise Briard Jean-Pierre Farriaux Pierre Guibaud Hubert Journel Bernard Le Marec Nicole Maurin Jean-Louis Nivelon Henri Plauchu Jean-Marie Saudubray Philippe Tron Jean Rey Arnold Münnich Stanislas Lyonnet 《Human genetics》1991,86(4):355-358
Summary A total of 252 chromosomes from 126 patients with phenylalanine hydroxylase (PAH) deficiencies were analyzed for both mutant genotypes and restriction fragment length polymorphism (RFLP) haplotypes at the PAH locus. The mutant genes studied originated either from Western Europe (116 alleles) or from Mediterranean countries (136 alleles). Only 27% of all mutant alleles were found to carry identified mutations, particularly mutations at codon 252 (2.3%), 261 (7.5%), 280 (6.3%), 408 (3.5%) and at the splice donor site of intron 12 (6.3%). The mutant genotypes were associated with RFLP haplotypes 7, 1, 38, 2 and 3 at the PAH locus respectively. Except for the splice mutation of intron 12, these associations were preferential, but not exclusive, since the other four mutations were found on the background of at least two RFLP haplotypes. These results, together with the observation that 85% of PAH deficient patients are heterozygotes for their mutant genotypes, emphasize the great heterogeneity of PAH deficiencies in Mediterranean countries and hamper systematic DNA testing for carrier status in this population. 相似文献
3.
Clinical and molecular heterogeneity of phenylalanine hydroxylase deficiencies in France 总被引:20,自引:10,他引:10
下载免费PDF全文
![点击此处可从《American journal of human genetics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Franoise Rey Monique Berthelon Catherine Caillaud Stanislas Lyonnet Vronique Abadie Flicienne Blandin-Savoja Josu Feingold Jean-Marie Saudubray Jean Frzal Arnold Munnich Jean Rey 《American journal of human genetics》1988,43(6):914-921
RFLPs of 68 normal and 74 mutant alleles at the phenylalanine hydroxylase (PAH) locus were determined in 37 French kindreds. A total of 23 haplotypes, including 18 normal and 16 mutant alleles, were observed. Two-thirds of all mutant alleles were confined within only four haplotypes, while the last third was accounted for by 12 haplotypes, including eight haplotypes absent from Caucasian pedigrees reported thus far. Several mutant haplotypes were present in typical phenylketonuria only, others were present in variants only, and some were present in both. In addition, a particular mutant haplotype (haplotype 2) was found to harbor different mutations in our series, resulting in either typical phenylketonuria or in mild hyperphenylalaninemias. The diploid combination of so many mutant haplotypes in PAH-deficient patients and of compound heterozygosity at the PAH locus in southern Europe might account for the broad spectrum of individual phenotypes observed in France. 相似文献
4.
The reaction of protected 1,2-anhydro-α-d-gluco- and β-d-manno-pyranoses with alkyl and phenyl organocuprates afforded the corresponding C-glycosyl compounds in acceptable to high yield. Complete stereocontrol was obtained, leading respectively to the β-d or the α-d anomer. With the perbenzylated manno derivative, deoxygenation at C-2 was achieved in high yield, affording 2-deoxy-α-d-C-glycosyl compounds. 相似文献
5.
(1) Exposure of phospholipids at the outer surface of activated and control platelets was studied by incubation with a mixture of phospholipase A2 from Naja naja and bee venom, solely or in combination with sphingomyelinase from Staphylococcus aureus, using conditions under which cell lysis remained below 10%. (2) Incubation with phospholipase A2 alone revealed a markedly increased susceptibility of the phospholipids in platelets activated by a mixture of collagen plus thrombin, by the SH-oxydizing compound diamide, or by calcium ionophore A23187, as compared to control platelets or platelets activated separately by collagen or thrombin. (3) Collagen plus thrombin, diamide, and ionophore treated platelets revealed an increased exposure of phosphatidylserine at the outer surface accompanied by a decreased exposure of sphingomyelin, as could be concluded from incubations with a combination of phospholipase A2 and sphingomyelinase. These alterations were much less apparent in platelets activated either by thrombin or by collagen alone. (4) The increased exposure of phosphatidylserine in activated platelets is accompanied by an increased ability of the platelets to enhance the conversion of prothrombin to thrombin by coagulation factor Xa, in the presence of factor Va and calcium. (5) It is concluded that the altered orientation of the phospholipids in the plasma membrane of platelets activated by collagen plus thrombin, by diamide, or by calcium ionophore, is the result of a transbilayer movement. Moreover, the increased exposure of phosphatidylserine in platelets stimulated by the combined action of collagen and thrombin might be of considerable importance for the hemostatic process. 相似文献
6.
Alain Coulombe Isabel Ann Lefèvre Isabelle Baro Edouard Coraboeuf 《The Journal of membrane biology》1989,111(1):57-67
Summary Ca2+- and Ba2+-permeable channel activity from adult rat ventricular myocytes, spontaneously appeared in the three single-channel recording configurations: cell-attached, and excised inside-out or outside-out membrane patches. Single-channel activity was recorded at steady-state applied membrane potentials including the entire range of physiologic values, and displayed no rundown in excised patches. This activity occurred in irregular bursts separated by quiescent periods of 5 to 20 min in cell-attached membrane patches, whereas in excised patch experiments, this period was reduced to 2 to 10 min. During activity, a variety of kinetic behaviors could be observed with more or less complex gating patterns. Three conductance levels: 22, 45 and 78 pS were routinely observed in the same excised membrane patch, sometimes combining to give a larger level. These channels were significantly permeable to divalent cations and showed little or no permeability to potassium or sodium ions. The inorganic blockers of voltage-gated Ca channels, cobalt (2mm), cadmium (0.5mm) or nickel (3mm), had no apparent effect on these spontaneous unitary currents carried by barium ions. Under 10–5
m bay K 8644 or nitrendipine, the activity was clearly increased in about half of the tested excised inside-out membrane patches. Both dihydropyridines enhanced openings of the larger conductance level, which was only very occasionally seen under control conditions. When the single-channel activity became sustained under 5×10–6
m Bay K 8644, it was possible to calculate the mean unitary current at different membrane potentials and show that the mean current value increased with membrane potential. 相似文献
7.
Stanislas Tomavo Jean-Francois Dubremetz Ralph T. Schwarz 《Biology of the cell / under the auspices of the European Cell Biology Organization》1993,78(3):155-162
In this study we describe the biochemical features of the Toxoplasma gondii tachyzoite surface glycoprotein, gp23, demonstrating that it is attached to the parasite membrane by a glycosyl-phosphatidyl inositol anchor. Gp23 was metabolically labeled with tritiated palmitate, myristate, ethanolamine, inositol, glucosamine, mannose and galactose, as expected for a GPI-anchor structure. Gp23 was released from the surface of living parasites after treatment with phosphatidyl inositol-specific phospholipase C (PI-PLC) and the resulting water-soluble protein was immunoprecipitated with a monoclonal antibody specific for gp23. The GPIcore glycan was generated after aqueous-HF dephosphorylation followed by nitrous acid deamination and its carbohydrate structure was analyzed using selective exo- and endoglycosidase treatments. Finally, the phosphatidylinositol moiety of gp23 was characterized using PI-PLC and phospholipase A2 (PLA2) digestions. Our cumulative data suggest that gp23 of T gondii tachyzoites contains a modified GPI-backbone similar to the mammalian Thy-1 anchor, consisting of a conserved core structure (ethanolaminePO4-6-Manαl-2-Manαl-6-Manαl-4-GIcNαl-6-PI) bearing β-linked N-acetylgalactosamine residue(s). 相似文献
8.
Edouard Nice Bruno Catimel Martin Lackmann Steven Stacker Andrew Runting Andrew Wilks Nicos Nicola Antony Burgess 《Letters in Peptide Science》1997,4(2):107-120
The isolation of related genes with evolutionary conserved motifs by the application ofpolymerase chain reaction-based molecular biology techniques, or from database searchingstrategies, has facilitated the identification of new members of protein families. Many of theseprotein molecules will be involved in protein–protein interactions (e.g. growth factors,receptors, adhesion molecules), since such interactions are intrinsic to virtually every cellularprocess. However, the precise biological function and specific binding partners of these novelproteins are frequently unknown, hence they are known as orphan molecules.Complementary technologies are required for the identification of the specific ligands orreceptors for these and other orphan proteins (e.g., antibodies raised against crude biologicalextracts or whole cells). We describe herein several alternative strategies for the identification,purification and characterisation of orphan peptide and protein molecules, specifically thesynergistic use of micropreparative HPLC and biosensor techniques. 相似文献
9.
A microanalytic study of particles transport across the alveoli: role of blood platelets 总被引:5,自引:0,他引:5
J P Berry B Arnoux G Stanislas P Galle J Chretien 《Biomedicine / [publiée pour l'A.A.I.C.I.G.]》1977,27(9-10):354-357
Following intratracheal injection of particles of colloidal gold (30 nm) in the rat, particles in the blood platelets of the alveolar capillaries can rapidly be observed. The presence of the gold is confirmed by microanalysis. The role of this phenomenon in pulmonary clearance is discussed. 相似文献
10.
Ulrich Dobramysl Iris Katharina Jarsch Yoshiko Inoue Hanae Shimo Benjamin Richier Jonathan R. Gadsby Julia Mason Alicja Szaapak Pantelis Savvas Ioannou Guilherme Pereira Correia Astrid Walrant Richard Butler Edouard Hannezo Benjamin D. Simons Jennifer L. Gallop 《The Journal of cell biology》2021,220(4)
Assemblies of actin and its regulators underlie the dynamic morphology of all eukaryotic cells. To understand how actin regulatory proteins work together to generate actin-rich structures such as filopodia, we analyzed the localization of diverse actin regulators within filopodia in Drosophila embryos and in a complementary in vitro system of filopodia-like structures (FLSs). We found that the composition of the regulatory protein complex where actin is incorporated (the filopodial tip complex) is remarkably heterogeneous both in vivo and in vitro. Our data reveal that different pairs of proteins correlate with each other and with actin bundle length, suggesting the presence of functional subcomplexes. This is consistent with a theoretical framework where three or more redundant subcomplexes join the tip complex stochastically, with any two being sufficient to drive filopodia formation. We provide an explanation for the observed heterogeneity and suggest that a mechanism based on multiple components allows stereotypical filopodial dynamics to arise from diverse upstream signaling pathways. 相似文献