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41.
Leaf samples were taken from 34 (1998) and 10 (1999) vineyards in five valleys in western Oregon to assess spider mite pests and biological control by predaceous phytoseiid mites. A leaf at a coordinate of every 10 m of border, 5 m into a vineyard, was taken to minimize edge effects; 20 leaves were taken at regular intervals from vineyard centers. Variables recorded at each site included grape variety and plant age, chemicals used, and vegetation next to vineyards. Sites were rated as occurring in agricultural versus riparian settings based on surrounding vegetation types. Multiple linear regressions and a computer genetic algorithm with an information content criterion were used to assess variables that may explain mite abundances. Typhlodromus pyri Scheuten was the dominant phytoseiid mite species and Tetranychus urticae Koch the dominant tetranychid mite species. High levels of T. urticae occurred when phytoseiid levels were low, and low levels of T. urticae were present when phytoseiid levels were high to moderate. T. urticae densities were higher in vineyards surrounded by agriculture, but phytoseiid levels did not differ between agricultural and riparian sites. Phytoseiids had higher densities on vineyard edges; T. urticae densities were higher in centers. Biological control success of pest mites was rated excellent in 11 of 44 vineyards, good in 27, and poor in only six sites. Predaceous mites appeared to be the principal agents regulating spider mites at low levels in sites where pesticides nontoxic to predators were used. Effects of surrounding vegetation, grape variety, growing region, and other factors on mites are discussed.  相似文献   
42.
LIGHT is a member of the tumor necrosis factor superfamily and is the ligand for LT-betaR, HVEM, and decoy receptor 3. LIGHT has a cytotoxic effect, which is further enhanced by the presence of interferon-gamma (IFN-gamma). Although LIGHT/IFN-gamma can activate caspase activity, neither benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone nor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone can completely inhibit LIGHT/IFN-gamma-mediated apoptosis. Moreover, overexpression of Bcl-2 further enhances LIGHT/IFN-gamma-mediated apoptosis. It appears that LIGHT and IFN-gamma act synergistically to activate caspase-3, with the resultant cleavage of Bcl-2, removal of the BH4 domain, leading to conversion of Bcl-2 from an antiapoptotic to a proapoptotic form in p53-deficient hepatocellular carcinoma Hep3BT2 cells. Thus, LIGHT seems to be able to override the protective effect of Bcl-2 and induce cell death. Although benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone and benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone can prevent the cleavage of Bcl-2 by LIGHT/IFN-gamma, they only partially inhibit apoptosis in Hep3BT2 cells that are overexpressing Bcl-2. In contrast, both LIGHT/IFN-gamma-mediated apoptosis and Bcl-2 cleavage are inhibited by free radical scavengers, indicating that free radicals may play an essential role in LIGHT/IFN-gamma-mediated apoptosis at a step upstream of caspase-3 activation. These results suggest that LIGHT signaling may diverge into multiple, separate processes.  相似文献   
43.
ObjectiveTo estimate the impact of preventive chemotherapy on the prevalence and intensity of soil-transmitted helminth (STH) infections, schistosomiasis, and lymphatic filariasis in the Philippines, using systematic review and meta-analysis.MethodsWe included reports reporting prevalence of STH infections, schistosomiasis, or lymphatic filariasis in the Philippines published until 31 March 2021. Peer-reviewed studies were identified in electronic databases. Grey literature reports by the University of the Philippines and the Department of Health were also included. Pooled infection prevalence, before and after the initiation of preventive chemotherapy, stratified by age group, was calculated using the inverse variance heterogeneity model.FindingsA total of 109 reports were included in the review and meta-analysis. Overall prevalence of moderate-heavy intensity Ascaris lumbricoides (6.6%) and Trichuris trichiura (2.7%) infection after initiation of preventive chemotherapy were significantly lower than the prevalence prior to initiation (23.6% for A. lumbricoides and 12.2% for T. trichiura). Prevalence reductions were also found in school and preschool-age children for A. lumbricoides and T. trichiura. Studies conducted after preventive chemotherapy initiation had significantly lower overall prevalence of moderate-heavy intensity schistosomiasis (3.1% vs 0.2%) and of schistosomiasis in school-age children (30.5% vs 1%). Pooled prevalence of lymphatic filariasis prior to preventive chemotherapy initiation was 3.2% across 12 provinces, while currently only two provinces still have prevalence of more than 1%. There were no published studies reporting prevalence of lymphatic filariasis after initiation of preventive chemotherapy. Heterogeneity was high with I2 mostly above 90%.ConclusionThe burden of STH infections and schistosomiasis in children were significantly lower in studies conducted following the initiation of preventive chemotherapy. Eliminating morbidity and interrupting transmission, however, may require expanded control initiatives including community-wide treatment, and improved water, sanitation, and hygiene. Lymphatic filariasis burden has decreased since the implementation of preventive chemotherapy, with all but two provinces having reached the elimination of lymphatic filariasis as a public health problem.  相似文献   
44.
Pongamia (Millettia pinnata) has been widely studied as a potential feedstock for biodiesel fuel, though little is known about its feasibility at a commercial level. Capital budgeting and cash flow analysis was conducted for a potential Pongamia plantation and crushing plant in Queensland, Australia. For annual seed yields ranging from 20 to 80 kg (in shell) per tree, the delivered cost of Pongamia oil was estimated to be between AUD $2.22 and AUD $0.64 per litre. The seed yield range of 20 to 80 kg per tree is roughly equivalent to between 7 and 29 t per hectare at a planting density of 357 trees per hectare. Major components of the delivered cost of (Pongamia) oil are the capital expenses of land acquisition, plantation establishment and the crushing plant construction. The major operational costs include mechanical harvesting; fertiliser; control of weed, pests and diseases; seed crushing; and freight of oil to a refinery. The cost items with the greatest volume sensitivity are the capital expenses, overheads (consisting mostly of salaries and wages of employees) and the expenses associated with harvesting and crushing operations. These costs could be significantly reduced if the seed yield could be increased. Several scenarios were tested to demonstrate the effect of seed yield and oil price on the profitability and cash flow of the Pongamia enterprise. At most plausible oil prices and seed yields, Pongamia oil is not expected to be economically viable.  相似文献   
45.
46.
In prion diseases, the normal prion protein is transformed by an unknown mechanism from a mainly α-helical structure to a β-sheet-rich, disease-related isomer. In this study, we surprisingly found that a slow, spontaneous α-to-coil-to-β transition could be monitored by circular dichroism spectroscopy in one full-length mouse recombinant prion mutant protein, denoted S132C/N181C, in which the endogenous cysteines C179 and C214 were replaced by Ala and S132 and N181 were replaced by Cys, during incubation in a non-denaturing neutral buffer. No denaturant was required to destabilize the native state for the conversion. The product after this structural conversion is toxic β-oligomers with high fluorescence intensity when binding with thioflavin T. Site-directed spin-labeling ESR data suggested that the structural conversion involves the unfolding of helix 2. After examining more protein mutants, it was found that the spontaneous structural conversion is due to the disulfide-deletion (C to A mutations). The recombinant wild-type mouse prion protein could also be transformed into β-oligomers and amyloid fibrils simply by dissolving and incubating the protein in 0.5 mM NaOAc (pH 7) and 1 mM DTT at 25°C with no need of adding any denaturant to destabilize the prion protein. Our findings indicate the important role of disulfide bond reduction on the structural conversion of the recombinant prion protein, and highlight the special “intrinsically disordered” conformational character of the recombinant prion protein.  相似文献   
47.
Sixteen novel cephalosporin derivatives with activity against methicillin-resistant Staphylococcus aureus (MRSA) are described. The compounds were synthesized using substituted thiopyridones, generated either by cyclization of functionalized precursors, or by direct alkylation of the enolate of 2-methyl substituted pyrones. The most active compound in vitro against a strain of MRSA (A27223) displayed an MIC of 0.5 microg/mL. The most efficacious compound in vivo had a PD50 of 2.1 mg/kg.  相似文献   
48.
Zusammenfassung Die Anhäufung von Glykogen in der Großhirnrinde von Goldhamstern und Ratten wurde im Bereich peritraumatischer Astrozytenproliferation histochemisch, elektronenmikroskopisch und biochemisch untersucht.Die elektronenmikroskopischen Befunde ergeben klare Aufschlüsse über zelluläre Lokalisation und morphologische Eigenschaften des Depotkohlenhydrates. Massen von 150–400 Å großen Partikeln lagern im Grundplasma der reaktiven Astrozyten; sie sind nach Behandlung mit Bleihydroxyd (Kontrasterhöhung) deutlich darstellbar. Die Vermehrung dieser Partikel ist bereits nach 24 Std in den perikapillären Fußstücken nachweisbar, breitet sich auf einen Großteil des Cytoplasmas einschließlich der das Neuropil durchsetzenden Fortsätze aus und erreicht nach 1–2 Wochen gewöhnlich ihren Höhepunkt. In mehrere Monate alten Glianarben finden sich filamentfreie Cytoplasmabezirke von astrozytären Faserbildnern, die zahlreiche Polysaccharidpartikel enthalten. Örtliche Beziehungen der Glykogenanhäufungen zum Mitochondrienbest and und zum endoplasmatischen Reticulum lassen sich in den reaktiv veränderten Astrozyten nicht feststellen. Auffällige eigenartige, große Lamellenkörper, in deren Zentrum häufig Glykogengranula konzentriert sind, kommen in den Frühstadien der reaktiven Veränderungen der Astrozyten vor. Diese Lamellenkörper entstehen durch Umformung von Golgizonen.Hirnrindengewebe von Ratten, das umfangreiche peritraumatische astrozytäre Reaktionen aufwies, wurde biochemisch untersucht. Nach Ablauf von 24 Std bis 30 Tagen wurden in diesem Gewebe die Glukose, das freie und gebundene Glykogen, die Milchsäure, die Laktatdehydrogenaseaktrvität, der Gesamtstickstoff und die Proteine bestimmt und mit den Werten des normalen Gewebes verglichen. Als wesentlicher Befund ist ein ansehnlicher Anstieg des gebundenen Glykogens in der alterierten Hirnrinde festzustellen. Der Gehalt an freiem Glykogen bleibt dagegen nahezu unverändert.Als wahrscheinlichste Ursache der Glykogenanhäufung im Perikaryon reaktiver Astrozyten wird eine Störung der metabolischen Beziehung zwischen diesen Gliaelementen und den Nervenzellen in Betracht gezogen. Schädigung und Untergang von Neuronen sowie der nachfolgende Gewebsumbau beeinträchtigen die Funktion der Astrozyten als metabolische Bindeglieder zwischen Nervenzellen und Blutstrombahn. Bei unverminderter Glukosezufuhr wird ein unverwertbarer Teil dieser Substanz in Form von Glykogenoproteiden im Cytoplasma der Astrozyten stark vermehrt abgelagert. Für diese Deutung spricht auch der Anstieg von Laktatwerten bei unveränderter Aktivität der Laktatdehydrogenase in dem Gewebe, das reaktive Makrogliaformen enthält.
Summary The accumulation of glycogen in reactive astrocytes in the cerebral cortex of syrian hamsters and rats following a trauma was studied with the electron microscope and with histochemical and biochemical methods.The localization of carbonhydrate deposits within cellular components is achieved by electron microscopic techniques. Discrete particles in the cytoplasm of the reactive astrocytes measuring 150–400 Å show a high contrast by lead hydroxide staining. An increase in the number of these particles can be readily demonstrated after 24 hours in the pericapillary pedicles of the astrocytes. In later stages these particles seem to extend in the cytoplasm of the astrocytes and their processes. The accumulation reaches its highest point after 1 to 2 weeks. Several months later in the old scars the filament-free cytoplasmic areas of the fibrous astrocytes are abundantly loaded with polysaccharide particles.Topographic relations of glycogen accumulations to mitochondria and the endoplasmic reticulum were not observed in the reactive astrocytes. The appearance of peculiar, large, lamellar bodies in the early reactive astrocytes is very remarkable. In the center of these bodies a concentration of glycogen granules often occurs. These lamellar bodies are produced by a transformation of Golgi-apparatus.In order to study the biochemical correlates an extensive peritraumatic astrocyte reaction was induced in the cerebral cortex of rats. In the course with a range from 24 hours to 30 days, glucose, free and bound glycogen, lactic acid, lactate dehydrogenase activity, total nitrogen as well as protein in the peritraumatic tissue were determined and compared with the values of the normal tissue. As a significant result a considerable increase of bound glycogen takes place in the altered cerebral cortex. On the other hand, the content of free glycogen remains almost unchanged. As a probable cause of the glycogen accumulation in the perikaryon of the reactive astrocytes, a disturbance in the metabolic interrelationship between these glial elements and neurons is taken into consideration.The alterations of neurons impairs the function of the astrocytes as metabolic connecting links between neurons and blood stream. With continued glucose supply an unutilized part of this substance is stored in the cytoplasm in the form of glycogenproteid. This interpretation is supported by the fact that the lactate values increase without changes of the lactate dehydrogenase activity.
  相似文献   
49.
It is unclear whether a single, brief, 15-minute episode of background anesthesia already modulates delayed secondary processes after experimental brain injury. Therefore, this study was designed to characterize three anesthesia protocols for their effect on molecular and histological study endpoints. Mice were randomly separated into groups that received sevoflurane (sevo), isoflurane (iso) or an intraperitoneal anesthetic combination (midazolam, fentanyl and medetomidine; comb) prior to traumatic brain injury (controlled cortical impact, CCI; 8 m/s, 1 mm impact depth, 3 mm diameter). Twenty-four hours after insult, histological brain damage, neurological function (via neurological severity score), cerebral inflammation (via real-time RT-PCR for IL6, COX-2, iNOS) and microglia (via immunohistochemical staining for Iba1) were determined. Fifteen minutes after CCI, the brain contusion volume did not differ between the anesthetic regimens (sevo = 17.9±5.5 mm3; iso = 20.5±3.7 mm3; comb = 19.5±4.6 mm3). Within 24 hours after injury, lesion size increased in all groups (sevo = 45.3±9.0 mm3; iso = 31.5±4.0 mm3; comb = 44.2±6.2 mm3). Sevo and comb anesthesia resulted in a significantly larger contusion compared to iso, which was in line with the significantly better neurological function with iso (sevo = 4.6±1.3 pts.; iso = 3.9±0.8 pts.; comb = 5.1±1.6 pts.). The expression of inflammatory marker genes was not significantly different at 15 minutes and 24 hours after CCI. In contrast, significantly more Iba1-positive cells were present in the pericontusional region after sevo compared to comb anesthesia (sevo = 181±48/mm3; iso = 150±36/mm3; comb = 113±40/mm3). A brief episode of anesthesia, which is sufficient for surgical preparations of mice for procedures such as delivering traumatic brain injury, already has a significant impact on the extent of secondary brain damage.  相似文献   
50.
Following traumatic brain injury (TBI) neuroinflammatory processes promote neuronal cell loss. Alpha-melanocyte-stimulating hormone (α-MSH) is a neuropeptide with immunomodulatory properties, which may offer neuroprotection. Due to short half-life and pigmentary side-effects of α-MSH, the C-terminal tripeptide α-MSH(11–13) may be an anti-inflammatory alternative. The present study investigated the mRNA concentrations of the precursor hormone proopiomelanocortin (POMC) and of melanocortin receptors 1 and 4 (MC1R/MC4R) in naive mice and 15 min, 6, 12, 24, and 48 h after controlled cortical impact (CCI). Regulation of POMC and MC4R expression did not change after trauma, while MC1R levels increased over time with a 3-fold maximum at 12 h compared to naive brain tissue. The effect of α-MSH(11–13) on secondary lesion volume determined in cresyl violet stained sections (intraperitoneal injection 30 min after insult of 1 mg/kg α-MSH(11–13) or 0.9% NaCl) showed a considerable smaller trauma in α-MSH(11–13) injected mice. The expression of the inflammatory markers TNF-α and IL-1β as well as the total amount of Iba-1 positive cells were not reduced. However, cell branch counting of Iba-1 positive cells revealed a reduced activation of microglia. Furthermore, tripeptide injection reduced neuronal apoptosis analyzed by cleaved caspase-3 and NeuN staining. Based on the results single α-MSH(11–13) administration offers a promising neuroprotective property by modulation of inflammation and prevention of apoptosis after traumatic brain injury.  相似文献   
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