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21.
HIV-particles in spermatozoa of patients with AIDS and their transfer into the oocyte 总被引:11,自引:1,他引:10 下载免费PDF全文
B Baccetti A Benedetto AG Burrini G Collodel EC Ceccarini N Crisa A Di Caro M Estenoz AR Garbuglia A Massacesi P Piomboni T Renieri D Solazzo 《The Journal of cell biology》1994,127(4):903-914
By immunocytochemistry and in situ hybridization at the electron microscopy level, and by the PCR technique, we have shown that HIV-1 binds and enters normal sperm; that viral particles, their antigens, and nucleic acid are present in sperm from HIV-1 infected men; and that such sperm can transfer HIV-1 like particles to normal human oocytes. We also present evidence that a galactosylceramide-like compound is present on the sperm membrane and could function as an alternative receptor for HIV. 相似文献
22.
Unusual pattern of bacterial ice nucleation gene evolution 总被引:5,自引:0,他引:5
Edwards AR; Van den Bussche RA; Wichman HA; Orser CS 《Molecular biology and evolution》1994,11(6):911-920
Bacterial ice nucleation activity (INA+ phenotype) can be traced to the
product of a single gene, ina. A remarkably sparse distribution of this
phenotype within three bacterial genera indicates that the ina gene may
have followed an unusual evolutionary path. Southern blot analyses, coupled
with assays for ice-nucleating ability, revealed that within four bacterial
species an ina gene is present in some strains but absent from others.
Results of hybridization experiments using DNA fragments that flank the ina
gene suggested that the genotypic dimorphism of ina may be anomalous. A
phylogenetic analysis of 16S ribosomal RNA gene sequences from a total of
14 ina+ and ina- bacterial strains indicated that the ina+ bacteria are not
monophyletic but instead phylogenetically interspersed among ina- bacteria.
The relationships of ina+ bacteria inferred from ina sequence did not
coincide with those inferred from the 16S data. These results suggest the
possibility of horizontal transfer in the evolution of bacterial ina genes.
相似文献
23.
Relationship between the golgi apparatus, gerl, and secretory granules in acinar cells of the rat exorbital lacrimal gland 总被引:14,自引:12,他引:2 下载免费PDF全文
The method of secretory granuleformation in the acinar cells of the rat exorbital lacrimal gland was studied by electron microscope morphological and cytochemical techniques. Immature secretory granules at the inner face of the Golgi apparatus were frequently attached to a narrow cisternal structure similar to GERL as described in neurons by Novikoff et al. (Novikoff, P. M., A. B. Novikoff, N. Quintana, and J.-J. Hauw. 1971. J. Cell Bio. 50:859-886). In the lacrimal gland. GERL was located adjacent to the inner Golgi saccule, or separated from it by a variable distance. Portions of GERL were often closely paralleled by modified cisternae of rough endoplasmic reticulum (RER), which lacked ribosomes on the surface adjacent to GERL. Diaminobenzidine reaction product of the secretory enzyme peroxidase was localized in the cisternae of the nuclear envelope, RER, peripheral Golgi vesicles, Golgi saccules, and immature and mature secretory granules. GERL was usually free of peroxidase reaction product or contained only a small amount. Thiamine pyrophosphatase reaction product was present in two to four inner Golgi saccules; occasionally, the innermost saccule was dilated and fenestrated, and contained less reaction product than the next adjacent saccule. Acid phosphatase (AcPase) reaction product was present in GERL, immature granules, and, rarely, in the innermost saccule, but not in the rest of the Golgi saccules. Thick sections of AcPase preparations viewed at 100 kV revealed that GERL consisted of cisternal, and fenestrated or tublular portions. The immature granules were attached to GERL by multiple connections to the tublular portions. These results suggest that, in the rat exorbital lacrimal gland, the Golgi saccules participate in the transport of secretory proteins, and that GERL is involved in the formation of secretory granules. 相似文献
24.
SMM?VerstappenEmail author AR?Poole M?Ionescu LE?King M?Abrahamowicz DM?Hofman JWJ?Bijlsma FPJG?Lafeber the Utrecht Rheumatoid Arthritis Cohort Study group 《Arthritis research & therapy》2005,8(1):R31
Introduction
The objective of this study was to determine whether serum biomarkers for degradation and synthesis of the extracellular matrix of cartilage are associated with, and can predict, radiographic damage in patients with rheumatoid arthritis (RA). 相似文献25.
26.
A Sahaboglu O Paquet-Durand J Dietter K Dengler S Bernhard-Kurz P AR Ekstr?m B Hitzmann M Ueffing F Paquet-Durand 《Cell death & disease》2013,4(2):e488
For most neurodegenerative diseases the precise duration of an individual cell''s death is unknown, which is an obstacle when counteractive measures are being considered. To address this, we used the rd1 mouse model for retinal neurodegeneration, characterized by phosphodiesterase-6 (PDE6) dysfunction and photoreceptor death triggered by high cyclic guanosine-mono-phosphate (cGMP) levels. Using cellular data on cGMP accumulation, cell death, and survival, we created mathematical models to simulate the temporal development of the degeneration. We validated model predictions using organotypic retinal explant cultures derived from wild-type animals and exposed to the selective PDE6 inhibitor zaprinast. Together, photoreceptor data and modeling for the first time delineated three major cell death phases in a complex neuronal tissue: (1) initiation, taking up to 36 h, (2) execution, lasting another 40 h, and finally (3) clearance, lasting about 7 h. Surprisingly, photoreceptor neurodegeneration was noticeably slower than necrosis or apoptosis, suggesting a different mechanism of death for these neurons. 相似文献
27.
28.
In many cases of interspecific kleptoparasitism, hosts developdefensive behaviors to minimize the impact of kleptoparasites.Because vigilance and defensive behaviors are often costly,selection should favor hosts that adjust the amount of investmentneeded to minimize losses to kleptoparasitism. However, examplesof such facultative responses are rare. Here, we investigatethe response of cooperatively breeding pied babblers (Turdoidesbicolor) to the drongo (Dicrurus adsimilis), an avian kleptoparasitethat regularly follows pied babbler groups, often giving alarmcalls to alert the group to predators but also occasionallygiving false alarm calls in order to steal food items. We showthat pied babbler response to drongos varies markedly accordingto babbler group size. In small groups, where there are fewindividuals available to act as sentinels, babblers sentinelless when a drongo is present and respond strongly to drongoalarm calls. However, in large groups, where there are manyindividuals available to participate in predator vigilance,babblers sentinel more often when a drongo is present, rarelyrespond to drongo alarm calls, and aggressively displace drongos,with a consequent decline in the number of successful kleptoparasitismevents. This behavior represent a facultative response to akleptoparasite according to the costs versus benefits of toleratingtheir presence. 相似文献
29.
N. GARCÍA-MAGALLANES F. LUQUE-ORTEGA E. M. AGUILAR-MEDINA R. RAMOS-PAYÁN C. GALAVIZ-HERNÁNDEZ J. G. ROMERO-QUINTANA L. DEL POZO-YAUNER H. RANGEL-VILLALOBOS E. ARÁMBULA-MERAZ 《Journal of genetics》2014,93(2):325-330
Glucose-6-phosphate dehydrogenase deficiency (G6PD) is the most common enzyme pathology in humans; it is X-linked inherited and causes neonatal hyperbilirubinaemia, chronic nonspherocytic haemolytic anaemia and drug-induced acute haemolytic anaemia. G6PD deficiency has scarcely been studied in the northern region of Mexico, which is important because of the genetic heterogeneity described in Mexican population. Therefore, samples from the northern Mexico were biochemically screened for G6PD-deficiency, and PCR-RFLPs, and DNA sequencing used to identify mutations in positive samples. The frequency of G6PD deficiency in the population was 0.95% (n = 1993); the mutations in 86% of these samples were G6PD A?202A/376G , G6PD A?376G/968C and G6PD Santamaria376G/542T . Contrary to previous reports, we demonstrated that G6PD deficiency distribution is relatively homogenous throughout the country (P = 0.48336), and the unique exception with high frequency of G6PD deficiency does not involve a coastal population (Chihuahua: 2.4%). Analysis of eight polymorphic sites showed only 10 haplotypes. In one individual we identified a new G6PD mutation named Mexico DF193A>G (rs199474830), which probably results in a damaging functional effect, according to PolyPhen analysis. Proteomic impact of the mutation is also described. 相似文献
30.
Lucas Bleicher Ricardo Aparicio Fabio M Nunes Leandro Martinez Sandra M Gomes Dias Carolina Migliorini Ana Figueira Auxiliadora Morim Maria Santos Walter H Venturelli Rosangela da Silva Paulo Marcos Donate Francisco AR Neves Luiz A Simeoni John D Baxter Paul Webb Munir S Skaf Igor Polikarpov 《BMC structural biology》2008,8(1):1-13