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41.
Reserve effects and natural variation in coral reef communities 总被引:2,自引:0,他引:2
42.
Edward EE Gabeler Richard van Hillegersberg Randolph G Statius van Eps Wim Sluiter Elma J Gussenhoven Paul Mulder Hero van Urk 《BMC cardiovascular disorders》2002,2(1):16-12
Background
Balloon injury (BI) of the rat carotid artery (CCA) is widely used to study intimal hyperplasia (IH) and decrease in lumen diameter (LD), but CCA's small diameter impedes the evaluation of endovascular therapies. Therefore, we validated BI in the aorta (AA) and iliac artery (CIA) to compare it with CCA.Methods
Rats underwent BI or a sham procedure (control). Light microscopic evaluation was performed either directly or at 1, 2, 3, 4 and 16 weeks follow-up. The area of IH and the change in LD (LD at 16 weeks minus LD post BI) were compared.Results
In the BI-groups the area of IH increased to 0.14 ± 0.08 mm2 (CCA), 0.14 ± 0.03 mm2 (CIA) and 0.12 ± 0.04 mm2 (AA) at 16 weeks (NS). The LD decreased with 0.49 ± 0.07 mm (CCA), compared to 0.22 ± 0.07 mm (CIA) and 0.07 ± 0.10 mm (AA) at 16 weeks (p < 0.05). The constrictive vascular remodelling (CVR = wall circumference loss combined with a decrease in LD) was -0.17 ± 0.05 mm in CIA but absent in CCA and AA. No IH, no decrease in LD and no CVR was seen in the control groups.Conclusions
BI resulted in: (1.) a decrease in LD in CCA due to IH, (2.) a decrease in LD in CIA due to IH and CVR, (3.) no change in LD in AA, (4.) Comparable IH development in all arteries, (5.) CCA has no vasa vasorum compared to CIA and AA, (6.) The CIA model combines good access for 2 F endovascular catheters with a decrease in LD due to IH and CVR after BI. 相似文献43.
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The experimental determination of difference profiles for the study of large zone transport processes by scanning molecular sieve chromatography is described. Using the difference profile method, the progesterone-induced purple glycoprotein of the porcine uterus was found to exist as monomeric units in high ionic environment, with a partition coefficient of 0.269, partition cross-section of 0.488, partition radius of 25 A and a molecular weight of 33,500 g/mole. The technique was further applied in examining the association-dissociation properties of oxyhemoglobin. In a high tonic environment, the partition coefficient was found to be 0.365 for dimer and the partition cross-section, 0.419; for the tetramer in low ionic strength solution, the partition coefficient was 0.275 and the partition cross-section 0.377, with a dissociation constant of 1.03 x 10(-6) mole/l. This new technique should prove applicable in (1) readily locating the centroid positions of transport boundary profiles at the lowest practible protein concentration limits, (2) demonstrating the characteristic boundary shape and concentration-dependent centroid position for an interacting solute, (3) determining the axial dispersion coefficient characteristic of solute turbulence within the gel matrix, and (4) distinguishing the boundary between low and high ionic strength solvent phases in the gel column. 相似文献
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48.
McAlister GC Phanstiel DH Brumbaugh J Westphall MS Coon JJ 《Molecular & cellular proteomics : MCP》2011,10(5):O111.009456
Beam-type collisional activation dissociation (HCD) offers many advantages over resonant excitation collision-activated dissociation, including improved identification of phosphorylated peptides and compatibility with isobaric tag-based quantitation (e.g. tandem mass tag (TMT) and iTRAQ). However, HCD typically requires specially designed and dedicated collision cells. Here we demonstrate that HCD can be performed in the ion injection pathway of a mass spectrometer with a standard atmospheric inlet (iHCD). Testing this method on complex peptide mixtures revealed similar identification rates to collision-activated dissociation (2883 versus 2730 IDs for iHCD/CAD, respectively) and precursor-product-conversion efficiency comparable to that achieved within a dedicated collision cell. Compared with pulsed-q dissociation, a quadrupole ion trap-based method that retains low-mass isobaric tag reporter ions, iHCD yielded isobaric tag for relative and absolute quantification reporter ions 10-fold more intense. This method involves no additional hardware and can theoretically be implemented on any mass spectrometer with an atmospheric inlet. 相似文献
49.
Lionfish (Pterois volitans/miles) have invaded the majority of the Caribbean region within five years. As voracious predators of native fishes with a broad habitat distribution, lionfish are poised to cause an unprecedented disruption to coral reef diversity and function. Controls of lionfish densities within its native range are poorly understood, but they have been recorded in the stomachs of large-bodied Caribbean groupers. Whether grouper predation of lionfish is sufficient to act as a biocontrol of the invasive species is unknown, but pest biocontrol by predatory fishes has been reported in other ecosystems. Groupers were surveyed along a chain of Bahamian reefs, including one of the region's most successful marine reserves which supports the top one percentile of Caribbean grouper biomass. Lionfish biomass exhibited a 7-fold and non-linear reduction in relation to the biomass of grouper. While Caribbean grouper appear to be a biocontrol of invasive lionfish, the overexploitation of their populations by fishers, means that their median biomass on Caribbean reefs is an order of magnitude less than in our study. Thus, chronic overfishing will probably prevent natural biocontrol of lionfishes in the Caribbean. 相似文献
50.
Louis W. Botsford Daniel R. Brumbaugh Churchill Grimes Julie B. Kellner John Largier Michael R. O’Farrell Stephen Ralston Elaine Soulanille Vidar Wespestad 《Reviews in Fish Biology and Fisheries》2009,19(1):69-95
A substantial shift toward use of marine protected areas (MPAs) for conservation and fisheries management is currently underway.
This shift to explicit spatial management presents new challenges and uncertainties for ecologists and resource managers.
In particular, the potential for MPAs to change population sustainability, fishery yield, and ecosystem properties depends
on the poorly understood consequences of three critical forms of connectivity over space: larval dispersal, juvenile and adult
swimming, and movement of fishermen. Conventional fishery management describes the dynamics and current status of fish populations,
with increasing recent emphasis on sustainability, often through reference points that reflect individual replacement. These
compare lifetime egg production (LEP) to a critical replacement threshold (CRT) whose value is uncertain. Sustainability of
spatially distributed populations also depends on individual replacement, but through all possible paths created by larval
dispersal and LEP at each location. Model calculations of spatial replacement considering larval connectivity alone indicate
sustainability and yield depend on species dispersal distance and the distribution of LEP created by species habitat distribution
and fishing mortality. Adding MPAs creates areas with high LEP, increasing sustainability, but not necessarily yield. Generally,
short distance dispersers will persist in almost all MPAs, while sustainability of long distance dispersers requires a specific
density of MPAs along the coast. The value of that density also depends on the uncertain CRT, as well as fishing rate. MPAs
can increase yield in areas with previously low LEP but for short distance dispersers, high yields will require many small
MPAs. The paucity of information on larval dispersal distances, especially in cases with strong advection, renders these projections
uncertain. Adding juvenile and adult movement to these calculations reduces LEP near the edges in MPAs, if movement is within
a home-range, but more broadly over space if movement is diffusive. Adding movement of fishermen shifts effort on the basis
of anticipated revenues and fishing costs, leading to lower LEP near ports, for example. Our evolving understanding of connectivity
in spatial management could form the basis for a new, spatially oriented replacement reference point for sustainability, with
associated new uncertainties. 相似文献