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11.
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The experiments were designed to determine the influence of the upper respiratory tract (URT) on liquid flow in the fetal trachea. This flow probably influences pulmonary distension, which is thought to be a major determinant of prenatal lung development. In six fetal sheep the URT could be bypassed by connecting the lower trachea, via an external flowmeter, to a cannula in the amniotic sac. In confirmation of our earlier findings, when the URT was in circuit, the mean rate of tracheal efflux was greater during episodes of fetal breathing movements (FBM) [mean 13.8 +/- 2.6 (SE) ml/h] than during apneic periods (mean 3.2 +/- 1.0 ml/h). When the URT was bypassed there was a reversal of net tracheal flow during FBM episodes (mean 19.6 +/- 5.6 ml/h toward the lungs); during apnea there was a much greater rate of efflux (mean 33.1 +/- 10.2 ml/h) than when the URT was in circuit. Nonlabor uterine contractions were associated with an increased rate of efflux during apnea only when the URT was bypassed. We conclude that during fetal life the URT imposes an essentially unidirectional flow of pulmonary liquid away from the lungs, preventing ingress of amniotic fluid and maintaining constancy of composition of liquid in the developing airways. By retarding outward flow during periods of apnea and thoracic compression and by preventing net influx during episodes of FBM, the URT has the probable effect of maintaining the volume and composition of liquid in the fetal airways within narrow limits. 相似文献
13.
Experiments were conducted in 8 chronically-catheterized fetal sheep at 125-135 days gestation in order to determine the effect of exogenously administered lactic acid to the fetus on fetal heart rate, blood pressure, breathing movements (FBM), electrocortical activity (ECOG), plasma immunoreactive (IR-ACTH) and cortisol concentrations. When fetal arterial pH decreased from 7.37 +/- 0.01 during the control period to 7.20 +/- 0.01, there was an initial bradycardia followed by tachycardia but no change in blood pressure. The amplitude of FBM increased 2-fold initially in association with an increase in PCO2 from 47.9 +/- 2.1 mmHg to 58.8 +/- 3.6 mmHg at 5 min into the lactate infusion. There was no change in the incidence of FBM or low-voltage ECOG and there was no change in the plasma concentrations of IR-ACTH and cortisol with the infusion of lactate. We conclude that the major effects of acutely elevating circulatory lactate concentrations in fetal sheep are to increase the amplitude of FBM and to cause an initial bradycardia followed by a tachycardia. 相似文献
14.
Premelting at the surface of ice crystals is caused by factors such as temperature, radius of curvature, and solute composition. When polycrystalline ice samples are warmed from well below the equilibrium melting point, surface melting may begin at temperatures as low as -15 degrees C. However, it has been reported (. Biophys. J. 65:1853-1865) that when polycrystalline ice was warmed in a differential scanning calorimetry (DSC) pan, melting began at about -50 degrees C, this extreme behavior being attributed to short-range forces. We show that there is no driving force for such premelting, and that for pure water samples in DSC pans curvature effects will cause premelting typically at just a few degrees below the equilibrium melting point. We also show that the rate of warming affects the slope of the DSC baseline and that this might be incorrectly interpreted as an endotherm. The work has consequences for DSC operators who use water as a standard in systems where subfreezing runs are important. 相似文献
15.
Laura A. Steenhuis Maaike H. Nauta Claudi L. H. Bocking Gerdina H. M. Pijnenborg 《PloS one》2015,10(10)
AimsThe aim of this study was to examine whether non-verbal therapies are effective in treating depressive symptoms in psychotic disorders.Results10 RCTs were included, of which three were of high quality according to the CTAM. The direct evidence demonstrated a significant effect on the reduction in depressive symptoms relative to treatment as usual (TAU), in favor of overall non-verbal therapy (ES: -0.66, 95% C.I. = -0.88, -0.44) and music therapy (ES: -0.59, 95% C.I. = -0.85, -0.33). Combining both direct and indirect evidence, yoga therapy (ES: -0.79, 95% C.I. = -1.24, -0.35) had a significant effect on depressive symptoms, and occupational therapy (ES: 1.81, 95% C.I. = 0.81, 2.81) was less effective, relative to TAU. Exercise therapy did not show a significant effect on depressive symptoms in comparison to TAU (ES: -0.02 95% C.I. = -0.67, 0.62). Due to inconsistency of study evidence, the indirect effects should be interpreted cautiously.ConclusionsNon-verbal therapies appear to be effective in reducing depressive symptomatology in psychotic disorders, in particular music therapy and yoga therapy. 相似文献
16.
Kate L E Phillips Neil Chiverton Anthony LR Michael Ashley A Cole Lee M Breakwell Gail Haddock Rowena AD Bunning Alison K Cross Christine L Le Maitre 《Arthritis research & therapy》2013,15(6):R213
Introduction
The aims of these studies were to identify the cytokine and chemokine expression profile of nucleus pulposus (NP) cells and to determine the relationships between NP cell cytokine and chemokine production and the characteristic tissue changes seen during intervertebral disc (IVD) degeneration.Methods
Real-time q-PCR cDNA Low Density Array (LDA) was used to investigate the expression of 91 cytokine and chemokine associated genes in NP cells from degenerate human IVDs. Further real-time q-PCR was used to investigate 30 selected cytokine and chemokine associated genes in NP cells from non-degenerate and degenerate IVDs and those from IVDs with immune cell infiltrates (‘infiltrated’). Immunohistochemistry (IHC) was performed for four selected cytokines and chemokines to confirm and localize protein expression in human NP tissue samples.Results
LDA identified the expression of numerous cytokine and chemokine associated genes including 15 novel cytokines and chemokines. Further q-PCR gene expression studies identified differential expression patterns in NP cells derived from non-degenerate, degenerate and infiltrated IVDs. IHC confirmed NP cells as a source of IL-16, CCL2, CCL7 and CXCL8 and that protein expression of CCL2, CCL7 and CXCL8 increases concordant with histological degenerative tissue changes.Conclusions
Our data indicates that NP cells are a source of cytokines and chemokines within the IVD and that these expression patterns are altered in IVD pathology. These findings may be important for the correct assessment of the ‘degenerate niche’ prior to autologous or allogeneic cell transplantation for biological therapy of the degenerate IVD. 相似文献17.
Vincent EJ Jassey Geneviève Chiapusio Philippe Binet Alexandre Buttler Fatima Laggoun‐Défarge Frédéric Delarue Nadine Bernard Edward AD Mitchell Marie‐Laure Toussaint André‐Jean Francez Daniel Gilbert 《Global Change Biology》2013,19(3):811-823
Peatlands contain approximately one third of all soil organic carbon (SOC). Warming can alter above‐ and belowground linkages that regulate soil organic carbon dynamics and C‐balance in peatlands. Here we examine the multiyear impact of in situ experimental warming on the microbial food web, vegetation, and their feedbacks with soil chemistry. We provide evidence of both positive and negative impacts of warming on specific microbial functional groups, leading to destabilization of the microbial food web. We observed a strong reduction (70%) in the biomass of top‐predators (testate amoebae) in warmed plots. Such a loss caused a shortening of microbial food chains, which in turn stimulated microbial activity, leading to slight increases in levels of nutrients and labile C in water. We further show that warming altered the regulatory role of Sphagnum‐polyphenols on microbial community structure with a potential inhibition of top predators. In addition, warming caused a decrease in Sphagnum cover and an increase in vascular plant cover. Using structural equation modelling, we show that changes in the microbial food web affected the relationships between plants, soil water chemistry, and microbial communities. These results suggest that warming will destabilize C and nutrient recycling of peatlands via changes in above‐ and belowground linkages, and therefore, the microbial food web associated with mosses will feedback positively to global warming by destabilizing the carbon cycle. This study confirms that microbial food webs thus constitute a key element in the functioning of peatland ecosystems. Their study can help understand how mosses, as ecosystem engineers, tightly regulate biogeochemical cycling and climate feedback in peatlands 相似文献
18.
Afiniki B Zarafi AM Emechebe AD Akpa O Alabi 《Archives Of Phytopathology And Plant Protection》2013,46(1):11-17
The effect of various levels of nitrogen (0.0, 30.0, 60.0, 120.0) and phosphorus (0.0, 6.5, 13.0, 36.0) on the incidence and severity of downy mildew of pearl millet and yield of two pearl millet varieties (Zango and GB8375) were studied under field conditions in 2000 and 2001 respectively. Both nitrogen and phosphorus significantly increased incidence and severity of the disease in the two varieties. Grain yield and 1000 grain weight of the varieties also increased with nitrogen and phosphorus levels. 相似文献
19.
Travis G. Gerwing Elmar Plate Jess Kidd Jesse Sinclair Christopher W. Burns Shane Johnson Steven Roias Cameron McCulloch Robert C. Bocking 《Restoration Ecology》2020,28(3):623-631
The Kaouk River estuary is located on the northwest coast of Vancouver Island, British Columbia, Canada, in the Treaty Settlement Lands of the Ka:'yu:'k't'h'/Che:k'tles7et'h First Nations. Stretching across the widest point of this estuary is a causeway providing road access to Fair Harbour. This causeway was observed to decrease habitat connectivity throughout the estuary, specifically limiting juvenile salmon access to high‐quality rearing habitat in the tidal marsh. As such, the causeway was breached in 2019 and a bridge was installed. Juvenile salmon were observed using the new connection and were captured both up and downstream of the causeway immediately following breaching. Postbreach water chemistry (dissolved oxygen, pH, salinity, and temperature) near the causeway was recorded within the range of values observed throughout the estuary. Use of the breach by juvenile salmon and homogenized water chemistry indicate the project succeeded in improving habitat connectivity within the Kaouk River estuary and has enhanced juvenile salmon access to 2.7 km2 of wetland rearing habitat. 相似文献
20.
Irene Zelner Kelly Kenna James F. Brien Alan Bocking Richard Harding David Walker Gideon Koren 《PloS one》2013,8(3)