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151.
Seroepidemiology of strongyloidiasis in a Thai village 总被引:1,自引:0,他引:1
R W Douce A E Brown C Khamboonruang P D Walzer R M Genta 《International journal for parasitology》1987,17(7):1343-1348
Strongyloidiasis is a potentially fatal disease for which existing methods of diagnosis lack sensitivity. A recently developed ELISA for IgG antibodies against the infective larval stage was used to screen a leprosy resettlement village in an area endemic for strongyloidiasis. The results of the ELISA were compared with the results of stool examination for 177 villagers. Eleven per cent of the village had S. stercoralis present on stool examination and 45% had antibodies detected by ELISA. Eighteen of 21 (85%) villagers with S. stercoralis infection proven by stool examination had positive ELISA values. No cross reactivity with intraluminal parasites was present. Linear correlation between per cent eosinophils and the ELISA revealed a correlation coefficient of 0.402 (P < 0.001). Forty-two days after sucessful treatment in 14 villagers, the IgG antibody levels had decreased (P < 0.001). Leprosy did not affect the sensitivity of the assay. These results suggest that ELISA is a simple, sensitive and specific method for surveying exposure to S. stercoralis in an endemic area. 相似文献
152.
Genta RM 《Parasitology today (Personal ed.)》1986,2(9):241-246
In the highly competitive world of parasites, where survival is indissolubly tied to the presence of suitable hosts in the same ecological niche, Strongyloides stercoralis occupies a unique position. This versatile nematode has developed a successful relationship with two ecosystems, the terrestrial environment and the mammalian body, by becoming facultatively independent of either (Box 1). It requires external maturation for transmission, but it also has the ability to multiply within a single host. It prefers man, but may infect apes, monkeys, dogs and cats. As a human parasite, S. stercoralis establishes self-perpetuating intestinal colonies and negotiates their survival with the host's defense mechanisms. In this article, Robert Genta reviews the immunobiological aspects of this unusual relationship. 相似文献
153.
Raquel Santos Souza Hector Manuel Diaz-Albiter Vivian Maureen Dillon Rod J. Dillon Fernando Ariel Genta 《PloS one》2016,11(3)
Aedes aegypti larvae ingest several kinds of microorganisms. In spite of studies regarding mosquito digestion, little is known about the nutritional utilization of ingested cells by larvae. We investigated the effects of using yeasts as the sole nutrient source for A. aegypti larvae. We also assessed the role of beta-1,3-glucanases in digestion of live yeast cells. Beta-1,3-glucanases are enzymes which hydrolyze the cell wall beta-1,3-glucan polyssacharide. Larvae were fed with cat food (controls), live or autoclaved Saccharomyces cerevisiae cells and larval weight, time for pupation and adult emergence, larval and pupal mortality were measured. The presence of S. cerevisiae cells inside the larval gut was demonstrated by light microscopy. Beta-1,3-glucanase was measured in dissected larval samples. Viability assays were performed with live yeast cells and larval gut homogenates, with or without addition of competing beta-1,3-glucan. A. aegypti larvae fed with yeast cells were heavier at the 4th instar and showed complete development with normal mortality rates. Yeast cells were efficiently ingested by larvae and quickly killed (10% death in 2h, 100% in 48h). Larvae showed beta-1,3-glucanase in head, gut and rest of body. Gut beta-1,3-glucanase was not derived from ingested yeast cells. Gut and rest of body activity was not affected by the yeast diet, but head homogenates showed a lower activity in animals fed with autoclaved S. cerevisiae cells. The enzymatic lysis of live S. cerevisiae cells was demonstrated using gut homogenates, and this activity was abolished when excess beta-1,3-glucan was added to assays. These results show that live yeast cells are efficiently ingested and hydrolyzed by A. aegypti larvae, which are able to fully-develop on a diet based exclusively on these organisms. Beta-1,3-glucanase seems to be essential for yeast lytic activity of A. aegypti larvae, which possess significant amounts of these enzyme in all parts investigated. 相似文献
154.
155.
FA Miles 《Current opinion in neurobiology》1997,7(6):867-871
Observers moving through a texture three-dimensional world experience potentially confusing patterns of optic flow. Recent experiments on monkeys and humans have revealed the existence of rapid, yet cortically mediated, reflex eye movements that automatically single out images in the plane of fixation for stabilization and ignore images that are nearer or further. 相似文献
156.
Rossella Dorati Ida Genta Barbara Colzani Tiziana Modena Giovanna Bruni Giuseppe Tripodo Bice Conti 《AAPS PharmSciTech》2015,16(5):1129-1139
A stability study was performed on ivermectin (IVM)-loaded biodegradable microparticles intended for injection in dogs. The rational was to evaluate the performances upon irradiation of a drug, such as IVM, with a few criticalities with respect to its stability, and toxicity. The goal was to provide valuable information for pharmaceutical scientists and manufacturers working in the veterinary area. The microspheres based on poly(D,L-lactide) and poly-(ε-caprolactone) and loaded with IVM and with the addition of alpha-tocopherol (TCP) as antioxidant were prepared by the emulsion solvent evaporation method and sterilized by gamma irradiation. Microsphere characterization in term of size, shape, polymer, and IVM stability upon irradiation was performed. The results show that the type of polymer significantly affects microsphere characteristics and performances. Moreover, suitably stable formulations can be achieved only by TCP addition.KEY WORDS: alpha-tocopherol, gamma irradiation, ivermectin, microspheres, poly(D,L-lactide), poly-(ε-caprolactone) 相似文献
157.
Genta PR Eckert DJ Gregorio MG Danzi NJ Moriya HT Malhotra A Lorenzi-Filho G 《Journal of applied physiology (Bethesda, Md. : 1985)》2011,111(5):1315-1322
The critical closing pressure (Pcrit) is the airway pressure at which the airway collapses and reflects the anatomical contribution to the genesis of obstructive sleep apnea. Pcrit is usually determined during non-rapid eye movement sleep at night, but has been determined under midazolam sedation during the day in the absence of sleep stage monitoring. Indeed, little is known about the effects of midazolam on sleep architecture. Moreover, deeper sedation with midazolam can decrease upper airway muscle activity and increase collapsibility compared with natural sleep. Pcrit under sedation has not been systematically compared with the usual method performed during natural sleep. Therefore, this study aimed to test the hypothesis that Pcrit following low doses of midazolam during the day would be comparable to Pcrit measured during natural sleep in the same patient. Fifteen men (age 54 ± 10 yr, body mass index 30 ± 4 kg/m(2)) with obstructive sleep apnea underwent a baseline standard overnight polysomnogram (apnea-hypopnea index 38 ± 22 events/h, range: 8-66 events/h), and Pcrit was determined during natural sleep and following midazolam. Sleep induction was obtained with low doses of midazolam (2.4 mg, range 2.0-4.4 mg), and sleep architecture was comparable to natural sleep. Natural sleep and induced sleep Pcrit were similar (-0.82 ± -3.44 and -0.97 ± 3.21 cmH(2)O, P = 0.663) and closely associated (intraclass correlation coefficient = 0.92; 95% confidence interval, 0.78-0.97, P < 0.001). Natural and midazolam-induced Pcrit correlated with obstructive sleep apnea severity, indicating that both Pcrit measures provided meaningful physiological information. Pcrit determined during the day with sleep induction is similar to natural overnight sleep and is a valid alternative approach in which to determine Pcrit. 相似文献
158.
Malatesta M Giagnacovo M Costanzo M Conti B Genta I Dorati R Galimberti V Biggiogera M Zancanaro C 《European journal of histochemistry : EJH》2012,56(2):e20
Chitosan-based nanoparticles (NPs) deserve particular attention as suitable drug carriers in the field of pharmaceutics, since they are able to protect the encapsulated drugs and/or improve their efficacy by making them able to cross biological barriers (such as the blood-brain barrier) and reach their intracellular target sites. Understanding the intracellular location of NPs is crucial for designing drug delivery strategies. In this study, fluorescently-labelled chitosan NPs were administered in vitro to a neuronal cell line, and diaminobenzidine (DAB) photoconversion was applied to correlate fluorescence and transmission electron microscopy to precisely describe the NPs intracellular fate. This technique allowed to demonstrate that chitosan NPs easily enter neuronal cells, predominantly by endocytosis; they were found both inside membrane-bounded vesicles and free in the cytosol, and were observed to accumulate around the cell nucleus. 相似文献
159.
160.
Mitochondrial DNA sequence variation in the spruce budworm species complex (Choristoneura: Lepidoptera) 总被引:5,自引:0,他引:5
A combination of polymerase-chain-reaction amplification and automated DNA
sequencing was used to survey variation in a species complex of pest
insects, the spruce budworms (Choristoneura fumiferana species group), and
an outgroup species, C. rosaceana. We sequenced an mtDNA region of 1,573 bp
that extends from the middle of cytochrome oxidase subunit I (COI) through
tRNA leucine (UUR) to the end of cytochrome oxidase subunit II. In
addition, we examined levels of intraspecific variation within a 470-bp
region of the COI gene. Choristoneura fumiferana clearly represented the
oldest lineage within its species group, with 2.7%-2.9% sequence divergence
from the other species. In contrast, the four remaining species (C. pinus,
C. biennis, C. occidentalis, and C. orae) had closely related or identical
mtDNA, with < 1% divergence among most of their haplotypes. Despite its
older lineage and widespread geographic distribution, C. fumiferana showed
significantly lower intraspecific genetic diversity than did C.
occidentalis. Choristoneura orae shared haplotypes with C. occidentalis and
C. biennis, and species-level separation of these three species was not
supported. Two divergent, uncommon haplotypes were also found in C.
occidentalis and C. biennis. The divergent haplotype in C. biennis had an
unusually high number of inferred amino acid replacements, suggesting
selective differences between mitochondrial DNA haplotypes.
Transition:transversion ratios in Choristoneura paralleled those found in
Drosophila; transition:transversion ratios were highest in closely related
sequences but decreased with increasing sequence divergence. Nucleotide
composition showed an A+T bias that was near the high end of the range
known for insects. This work illustrates the potential utility of direct
DNA sequencing in assessing population structures, species limits, and
phylogenetic relationships among organisms that have not previously been
subjected to DNA analysis.
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