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61.
Summary Serial chromosome studies were performed on four monocytic cell lines established from bone marrow samples of patients suffering from hematopoietic disorders other than leukemia. A spontaneous in vitro transformation towards a malignant phenotype has been found to be related to the karyotype evolution. The correlation between the chromosome changes of these cell lines and those described in human cancer and leukemia is discussed. 相似文献
62.
Werner Wolfgang Alekos Simoni Carla Gentile Ralf Stanewsky 《Proceedings. Biological sciences / The Royal Society》2013,280(1768)
Circadian clocks are endogenous approximately 24 h oscillators that temporally regulate many physiological and behavioural processes. In order to be beneficial for the organism, these clocks must be synchronized with the environmental cycles on a daily basis. Both light : dark and the concomitant daily temperature cycles (TCs) function as Zeitgeber (‘time giver’) and efficiently entrain circadian clocks. The temperature receptors mediating this synchronization have not been identified. Transient receptor potential (TRP) channels function as thermo-receptors in animals, and here we show that the Pyrexia (Pyx) TRP channel mediates temperature synchronization in Drosophila melanogaster. Pyx is expressed in peripheral sensory organs (chordotonal organs), which previously have been implicated in temperature synchronization. Flies deficient for Pyx function fail to synchronize their behaviour to TCs in the lower range (16–20°C), and this deficit can be partially rescued by introducing a wild-type copy of the pyx gene. Synchronization to higher TCs is not affected, demonstrating a specific role for Pyx at lower temperatures. In addition, pyx mutants speed up their clock after being exposed to TCs. Our results identify the first TRP channel involved in temperature synchronization of circadian clocks. 相似文献
63.
The Fo subunits of the Escherichia coli F1Fo-ATP synthase are sufficient to form a functional proton pore 总被引:11,自引:0,他引:11
The assembly of the Fo sector of the Escherichia coli ATP synthase has been studied using both structural and functional criteria for assembly. Cross-linking E. coli minicell membranes containing only the Fo subunits a, b, and c with dithiobis(succinimidyl propionate) (DSP) produces b2 and c2 dimers that are generated by cross-linking membranes containing the assembled holoenzyme. Five plasmids carrying the genes specifying the Fo polypeptides in a bacterial strain lacking all of the unc (ATP synthase) genes show a good correlation between Fo function and the amount of the membrane-bound Fo polypeptides. In this report we revise a conclusion reached previously (Klionsky, D.J., Brusilow, W.S.A., and Simoni, R.D. (1983) J. Biol. Chem. 258, 10136-10143) and present evidence that the Fo subunits alone are sufficient to assemble a functional proton pore. 相似文献
64.
L Bovalini P Lusini S Simoni D Vedaldi L Andreassi F Dall'Acqua P Martelli 《Biochemistry international》1988,16(6):991-998
TMP (4,5',8-trimethylpsoralen) usually employed in PUVA therapy and TMA (4,6,4'-trimethylangelicin), phototherapeutic agent under clinical and biological investigation, show an inhibitory effect of competitive type on the low Km cyclic AMP phosphodiesterase present in rat liver. The two drugs exhibit Ki values of 135 and 320 microM, respectively. 相似文献
65.
Simone Bettini Valeria Franceschini Laura Astolfi Edi Simoni Benedetta Mazzanti Alessandro Martini Roberto P. Revoltella 《Cytotherapy》2018,20(2):189-203
Background
Kanamycin, mainly used in the treatment of drug-resistant-tuberculosis, is known to cause irreversible hearing loss. Using the xeno-transplant model, we compared both in vitro and in vivo characteristics of human mesenchymal stromal cells (MSCs) derived from adult tissues, bone marrow (BM-MSCs) and adipose tissue (ADSCs). These tissues were selected for their availability, in vitro multipotency and regenerative potential in vivo in kanamycin-deafened nod-scid mice.Methods
MSCs were isolated from informed donors and expanded ex vivo. We evaluated their proliferation capacity in vitro using the hexosaminidase assay, the phenotypic profile using flow-cytometry of a panel of surface antigens, the osteogenic potential using alkaline phosphatase activity and the adipogenic potential using oil-red-O staining. MSCs were intravenously injected in deafened mice and cochleae, liver, spleen and kidney were sampled 7 and 30 days after transplantation. The dissected organs were analyzed using lectin histochemistry, immunohistochemistry, polymerase chain reaction (PCR) and dual color fluorescence in situ hybridization (DC-FISH).Results
MSCs showed similar in vitro characteristics, but ADSCs appeared to be more efficient after prolonged expansion. Both cell types engrafted in the cochlea of damaged mice, inducing regeneration of the damaged sensory structures. Several hybrid cells were detected in engrafted tissues.Discussion
BM-MSCs and ADSCs showed in vitro characteristics suitable for tissue regeneration and fused with resident cells in engrafted tissues. The data suggest that paracrine effect is the prevalent mechanism inducing tissue recovery. Overall, BM-MSCs and ADSCs appear to be valuable tools in regenerative medicine for hearing loss recovery. 相似文献66.
Summary A new method for applying the electron microscope autoradiography to negatively stained specimens is presented.Free ribosomes and ribosome crystals, labeled with 3H-uridine, have been isolated from the rat liver and from the whole hypothermic chick embryo, respectively. The samples, fixed and negatively stained with uranyl acetate, have been treated for autoradiography with the Kodak NTE nuclear emulsion.This method allows to obtain autoradiograms characterized by a very high resolution power of well stained specimens.The perspectives of this new field of ultrastructural investigation are discussed. 相似文献
67.
68.
R. Casalotti L. Simoni M. Belledi G. Barbujani 《Proceedings. Biological sciences / The Royal Society》1999,266(1432):1959
Gradients of allele frequencies have long been considered the main genetic characteristic of the European population, but mitochondrial DNA diversity seems to be distributed differently. One Alu insertion (YAP), five tetranucleotide (DYS19, DYS389B, DYS390, DYS391 and DYS393) and one trinucleotide (DYS392) microsatellite loci of the Y chromosome were analysed for geographical patterns in 59 European populations. Spatial correlograms showed clines for most markers, which paralleled the gradients previously observed for two RFLP polymorphisms. Effective separation times between populations were estimated from genetic distances at microsatellite loci. Even after correcting for the possible effects of continuous local gene flow, the most distant Indo-European-speaking populations seem to have separated no more than 7000 years ago. The clinal patterns and the estimated, recent separation times between populations jointly suggest that Y-chromosome diversity in Europe largely reflects a directional demic expansion, which is unlikely to have occurred before the Neolithic period. 相似文献
69.
S. M. Sirchia I. Garagiola C. De Andreis L. Pedranzini F. Poli F. R. Grati B. Diomelli G. Simoni 《Luminescence》1998,13(5):303-305
Minisatellite analysis is commonly used in forensic disputes but can also be applied to the investigation of cell contamination. Such a problem arises, for example, when transplantation is performed. The presence of contamination has been investigated by other authors using radioactive methods. In the present study we describe a method that allows the detection of contamination with high sensitivity without using radioactive substances. Our technique is based on the use of polymerase chain reaction (PCR) amplification of minisatellite sequences (VNTR), followed by chemiluminescent detection. In particular, biotin-labelled dCTP is included in the PCR mixture and detection of PCR products is obtained following the CSPD chemiluminescent protocol (Southern-Light Nucleic Acid Detection Systems). We applied this method to artificial mixes of DNA of two individuals with alleles of different sizes. We performed progressive dilutions of an individual DNA into the other's DNA and revealed a contamination of 1 in 2500 cells. We also tested our technique searching for maternal contamination in cord blood samples in 60 cases and revealed a 18.3% contamination. The technique that we set up proves to be a very sensitive one which could be applied not only to the detection of maternal cells in cord blood but also in studying any other kind of contamination. © 1998 John Wiley & Sons, Ltd. 相似文献
70.
Nicole Kresge Robert D. Simoni Robert L. Hill 《The Journal of biological chemistry》2009,284(25):e7-e8
Enzymatic Carboxyl Activation of Amino Acids(Hoagland, M. B., Keller, E. B., and Zamecnik, P. C. (1956) J. Biol. Chem. 218, 345–358)Mahlon Bush Hoagland was born in Boston, Massachusetts in 1921. He attended Harvard University and graduated in 1943. Knowing that he wanted to be a surgeon, Hoagland then enrolled at Harvard Medical School. However, he was diagnosed with tuberculosis, and his poor health prevented him from becoming a surgeon when he received his M.D. in 1948. Instead, he accepted a research position at Massachusetts General Hospital. In 1953, he became a postdoctoral fellow with Journal of Biological Chemistry (JBC) Classic author Fritz Lipmann (1) at Huntington Laboratories (also at Massachusetts General Hospital), and a year later, he moved to an adjoining laboratory to work on protein synthesis with JBC Classic author Paul Zamecnik (2).Open in a separate windowMahlon HoaglandInspired by Lipmann''s insights into acyl activation mechanisms, Hoagland used a cell-free system created by Zamecnik that carried out net peptide bond formation using 14C-amino acids (3) to uncover the mechanism of amino acid activation. As reported in the JBC Classic reprinted here, he isolated an enzyme fraction that, in the presence of ATP and amino acids, catalyzed the first step in protein synthesis: the formation of aminoacyl adenylates or activated amino acids. Using data from analysis of this fraction, Hoagland presented a scheme for amino acid activation in his Classic paper.A few years later, Zamecnik and Hoagland discovered a molecule that is essential for protein synthesis: tRNA. This discovery is the subject of the Zamecnik Classic (2).After the discovery of tRNA, Hoagland spent the next year (1957–1958) at Cambridge University''s Cavendish laboratories working with Francis Crick. During that year he traveled to France to visit the Institute Pasteur in Paris. Experiments begun at the Institute would, by 1960, lead to the discovery of messenger RNA (mRNA).When he returned to the United States, Hoagland was appointed associate professor of microbiology at Harvard Medical School. He remained there until 1967 when he accepted a position as professor at Dartmouth Medical School. In 1970, he became the director of the Worcester Foundation for Experimental Biology, a Massachusetts research institute founded by his father. He retired in 1985 and currently lives in Thetford, Vermont.Hoagland has received several awards and honors in recognition of his contributions to science. These include the 1976 Franklin Medal, the 1982 and 1996 Book Awards from the American Medical Writers Association, and membership in the American Academy of Arts and Sciences and the National Academy of Sciences. 相似文献