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91.
92.
Markus Woischnik Christiane Sparr Sunčana Kern Tobias Thurm Andreas Hector Dominik Hartl Gerhard Liebisch Surafel Mulugeta Michael F Beers Gerd Schmitz Matthias Griese 《BMC cell biology》2010,11(1):1-14
Background
Cryopreservation is the only widely applicable method of storing vital cells for nearly unlimited periods of time. Successful cryopreservation is essential for reproductive medicine, stem cell research, cord blood storage and related biomedical areas. The methods currently used to retrieve a specific cell or a group of individual cells with specific biological properties after cryopreservation are quite complicated and inefficient.Results
The present study suggests a new approach in cryopreservation, utilizing the Individual Cell-based Cryo-Chip (i3C). The i3C is made of materials having appropriate durability for cryopreservation conditions. The core of this approach is an array of picowells, each picowell designed to maintain an individual cell during the severe conditions of the freezing - thawing cycle and accompanying treatments. More than 97% of cells were found to retain their position in the picowells throughout the entire freezing - thawing cycle and medium exchange. Thus the comparison between pre-freezing and post-thawing data can be achieved at an individual cell resolution. The intactness of cells undergoing slow freezing and thawing, while residing in the i3C, was found to be similar to that obtained with micro-vials. However, in a fast freezing protocol, the i3C was found to be far superior.Conclusions
The results of the present study offer new opportunities for cryopreservation. Using the present methodology, the cryopreservation of individual identifiable cells, and their observation and retrieval, at an individual cell resolution become possible for the first time. This approach facilitates the correlation between cell characteristics before and after the freezing - thawing cycle. Thus, it is expected to significantly enhance current cryopreservation procedures for successful regenerative and reproductive medicine. 相似文献93.
Tadesse Dejenie Tsehaye Asmelash Luc De Meester Afework Mulugeta Abreha Gebrekidan Sarah Risch Annemie Pals Katleen Van der Gucht Wim Vyverman Jan Nyssen Jozef Deckers Steven Declerck 《Hydrobiologia》2008,610(1):193-209
The semi-arid highlands of Northern Ethiopia (Tigray) have numerous small reservoirs that have been created by microdams in
an attempt to provide water supply for irrigation and livestock drinking. Although the reservoirs have substantial added value
to residents, their use as water resource is jeopardized by eutrophication and a high occurrence of blooms of toxic cyanobacteria.
So far, there is no systematic information available on the limnological and aquatic ecological characteristics of these dams.
We carried out a standardized survey of 32 reservoirs and assessed a wide set of morphometric, abiotic and biotic variables.
The sampling was performed during two seasons, September–October 2004 (end of the wet season/start of the dry season) and
April–May 2005 (towards the end of the dry season). Using multivariate analysis, we revealed dominating patterns of variable
associations and compared the variability in these patterns among seasons. According to standardized PCA and RDA analyses,
the most important axis of variation was mainly represented by a gradient in nutrients and altitude that was also positively
associated with phytoplankton biomass, suspended matter and oxygen concentration, and negatively with water transparency.
For most variables, correlations between the wet and dry season were weak, which suggests that individual reservoirs behaved
rather differently in their response to seasonal changes. Nevertheless, a Mantel correlation (r = 0.32; P = 0.035) showed a weak but significant overall concordance in the variable association patterns among seasons. A number of
reservoirs became very shallow or fell dry in the dry season, a process that was associated with an increase in suspended
matter and conductivity and a decrease in transparency. These reservoirs contained lower amounts of fish and tended to be
less eutrophic than the deeper, permanent systems, as they had lower levels of phosphorus and chlorophyll-a. With multiple regression analysis, we constructed most parsimonious models in an attempt to explain the variation in key
biotic variables: phytoplankton and cyanobacteria biomass, cladoceran biomass, fish biomass and the abundance of submerged
vegetation. Phytoplankton and fish biomass tended to be positively related with the concentration of total phosphorus, whereas
cladoceran biomass was not associated with nutrient concentrations. The positive association of fish and phytoplankton with
nutrient concentrations suggests a bottom-up control, whereas the absence of an association between zooplankton and nutrient
concentrations may be indicative for top-down control. The biomass of cyanobacteria was negatively related to the biomass
of cladocerans (Daphnia), which likely reflects a top-down effect. Most reservoirs were turbid. The occurrence and abundance of macrophytes tended
to be positively related to water transparency and was negatively associated to TP and the amount of livestock frequenting
the reservoirs. However, macrophytes were not limited to clear-water reservoirs.
Handling editor: L. M. Bini 相似文献
94.
Julia Raykin Taylor E. Forte Roy Wang Andrew Feola Brian C. Samuels Jerry G. Myers Lealem Mulugeta Emily S. Nelson Rudy L. Gleason C. Ross Ethier 《Biomechanics and modeling in mechanobiology》2017,16(1):33-43
Visual impairment and intracranial pressure (VIIP) syndrome is characterized by a number of permanent ophthalmic changes, including loss of visual function. It occurs in some astronauts during long-duration spaceflight missions. Thus, understanding the pathophysiology of VIIP is currently a major priority in space medicine research. It is hypothesized that maladaptive remodeling of the optic nerve sheath (ONS), in response to microgravity-induced elevations in intracranial pressure (ICP), contributes to VIIP. However, little is known about ONS biomechanics. In this study, we developed a custom mechanical testing system that allowed for unconfined lengthening, twisting, and circumferential distension of the porcine ONS during inflation and axial loading. Data were fit to a four-fiber family constitutive equation to extract material and structural parameters. Inflation testing showed a characteristic “cross-over point” in the pressure–diameter curves under different axial loads in all samples that were tested; the cross-over pressure was \(10.3 \pm 0.95\) mmHg (\(\hbox {mean} \pm \hbox {SEM}\)). Large sample-to-sample variations were observed in the circumferential strain, while only modest variations were observed in the circumferential stress. Multiphoton microscopy revealed that the collagen fibers of the ONS were primarily oriented axially when the tissue was loaded. The existence of this cross-over behavior is expected to be neuroprotective, as it would avoid optic nerve compression during routine changes in gaze angle, so long as ICP was within the normal range. Including these observations into computational models of VIIP will help provide insight into the pathophysiology of VIIP and could help identify risk factors and potential interventions. 相似文献
95.
Helen Suzanne Cox Tanja Kubica Daribay Doshetov Yared Kebede Sabine Rüsch-Gerdess Stefan Niemann 《Respiratory research》2005,6(1):134
Background
After the collapse of the Soviet Union, dramatically increasing rates of tuberculosis and multidrug-resistant tuberculosis (MDR-TB) have been reported from several countries. This development has been mainly attributed to the widespread breakdown of TB control systems and declining socio-economic status. However, recent studies have raised concern that the Beijing genotype of Mycobacterium tuberculosis might be contributing to the epidemic through its widespread presence and potentially enhanced ability to acquire resistance.Methods
A total of 397 M. tuberculosis strains from a cross sectional survey performed in the Aral Sea region in Uzbekistan and Turkmenistan have been analysed by drug susceptibility testing, IS6110 fingerprinting, and spoligotyping.Results
Fifteen isolates showed mixed banding patterns indicating simultaneous infection with 2 strains. Among the remaining 382 strains, 152 (40%) were grouped in 42 clusters with identical fingerprint and spoligotype patterns. Overall, 50% of all isolates were Beijing genotype, with 55% of these strains appearing in clusters compared to 25% of non-Beijing strains. The percentage of Beijing strains increased with increasing drug resistance among both new and previously treated patients; 38% of fully-susceptible isolates were Beijing genotype, while 75% of MDR-TB strains were of the Beijing type.Conclusion
The Beijing genotype is a major cause of tuberculosis in this region, it is strongly associated with drug resistance, independent of previous tuberculosis treatment and may be strongly contributing to the transmission of MDR-TB. Further investigation around the consequences of Beijing genotype infection for both tuberculosis transmission and outcomes of standard short course chemotherapy are urgently needed. 相似文献96.
Identification of LBM180, a lamellar body limiting membrane protein of alveolar type II cells, as the ABC transporter protein ABCA3 总被引:8,自引:0,他引:8
Mulugeta S Gray JM Notarfrancesco KL Gonzales LW Koval M Feinstein SI Ballard PL Fisher AB Shuman H 《The Journal of biological chemistry》2002,277(25):22147-22155
97.
The use of ribotyping and antibiotic resistance patterns for identification of host sources of Escherichia coli strains 总被引:1,自引:0,他引:1
AIMS: To compare antibiotic resistance and ribotyping patterns ability to identify triplicate isolates sent from a group of 40 Escherichia coli taken from seven host sources. METHODS AND RESULTS: Of the 120 isolates, 22 isolates were resistant to ampicillin, streptomycin, tetracycline and trimethoprim and 98 isolates were susceptible. Antibiotic patterns identified 33 of the triplicates and three of the six groups had isolates from multiple hosts. Ribotyping divided the isolates into 27 ribotype groups with all triplicates grouped into the same ribotype group with one host per group. CONCLUSIONS: Antibiotic susceptibility pattern placed 98 of the isolates in a single group with 50% of the antibiotic susceptibility pattern groups containing multiple host species. Ribotyping groups were host specific with each host having one to seven ribotype groups. SIGNIFICANCE AND IMPACT OF THE STUDY: Antibiotic susceptibility pattern groups have been used for environmental source identification and faecal pollution tracking, however these groups do not always distinguish between host species. Stability of the markers is a potential concern and this system can only be used if antibiotic resistance levels are high in the isolates studied. All isolates have a ribotype group which was stable and like other molecular methods has advantages over antibiotic susceptibility pattern groups which uses a phenotypic method. 相似文献
98.
Million M Maillot C Adelson DA Nozu T Gauthier A Rivier J Chrousos GP Bayati A Mattsson H Taché Y 《Peptides》2005,26(7):1188-1195
We investigated the effects of peripheral injection of sauvagine, a CRF2>CRF1 receptor (corticotropin-releasing factor) agonist compared with CRF, on two sets of tonic colorectal distension (CRDs 30, 40, 50 mmHg, 3-min on/off)-induced visceromotor response (VMR) measured as area under the curve (AUC) of abdominal muscle contraction in conscious female rats. Sauvagine (10 or 20 microg/kg, s.c.) abolished the 226.7+/-64.3% and 90.4+/-38.1% increase in AUC to the 2nd CRD compared with the 1st CRD (performed 30 min before) in female Fisher and Sprague-Dawley (SD) rats, respectively. CRF had no effect while the CRF1 antagonist, antalarmin (20 mg/kg, s.c.), alone or with sauvagine, blocked the enhanced response to the 2nd CRD, performed 60 min after the 1st CRD, and reduced further the AUC by 33.5+/-23.3% and 63.5+/-7.2%, respectively in Fisher rats. These data suggest that peripheral CRF2 receptor activation exerts antinociceptive effects on CRD-induced visceral pain, whereas CRF1 contributes to visceral sensitization. 相似文献
99.
Elizabeth Kebede‐westhead Carolina Pizarro Walter W. Mulbry Ann C. Wilkie 《Journal of phycology》2003,39(6):1275-1282
Growing algae to scrub nutrients from manure presents an alternative to the current practice of land application and provides utilizable algal biomass as an end product. The objective of this study was to assess algal growth, nutrient removal, and nitrification using higher light intensities and manure loading rates than in the previous experiments. Algal turfs, with periphyton mainly composed of green algal species, were grown under two light regimes (270 and 390 μmol photons·m?2· s?1) and anaerobically digested flushed dairy manure wastewater (ADFDMW) loading rates ranging from 0.8 to 3.7 g total N and 0.12 to 0.58 g total P·m?2·d?1. Filamentous cyanobacteria (Oscillatoria spp.) and diatoms (Navicula, Nitzschia, and Cyclotella sp.) partially replaced the filamentous green algae at relatively high ADFDMW loading rates and more prominently under low incident light. Mean algal production increased with loading rate and irradiance from 7.6±2.71 to 19.1±2.73 g dry weight· m?2·d?1. The N and P content of algal biomass generally increased with loading rate and ranged from 2.9%–7.3% and 0.5%–1.3% (by weight), respectively. Carbon content remained relatively constant at all loading rates (42%–47%). The maximum removal rates of N and P per unit algal biomass were 70 and 13 mg·g?1 dry weight·m?2·d?1, respectively. Recovery of nutrients in harvested algal biomass accounted for about 31%–52% for N and 30%–59% for P. Recovery of P appeared to be uncoupled with N at higher loading rates, suggesting that algal potential for accumulation of P may have already been saturated. It appears that higher irradiance level enhancing algal growth was the overriding factor in controlling nitrification in the algal turf scrubber units. 相似文献
100.
Ayele?Lenja Tsegaye?Demissie Bereket?YohannesEmail author Mulugeta?Yohannis 《International breastfeeding journal》2016,11(1):32