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121.
Sylvio Redanz Kerstin Standar Andreas Podbielski Bernd Kreikemeyer 《The Journal of biological chemistry》2012,287(43):36111-36122
122.
Kristiansen H Hovstad T Vollan G Faerestrand S 《Indian pacing and electrophysiology journal》2012,12(1):4-14
BackgroundThe conventional right ventricular (RV) lead position in cardiac resynchronization therapy pacemakers (CRT-P) is the RV apex (RV-A). Little is known about electrophysiological stability and associated complications of pacing leads in RV high posterior septal (RV-HS) position in CRT-P.MethodsTwo hundred and thirty-five consecutive CRT-P patients were included from 1999-2010. Pacing thresholds at 0.5 ms and 2.5 V, sensing electrograms and lead impedances were measured at implant and repeated 1,3,6,12,18 and 24 months after CRT-P. Electrophysiological measurements of leads located in RV-A and RV-HS were analyzed retrospectively. Bipolar RV leads were used, including high impedance leads, passive fixation and active fixation.ResultsRV pacing leads were implanted in RV-A (n = 79) and RV-HS (n = 156). Average RV pacing thresholds from CRT implant procedure to 24-month follow-up at 0.5 ms were 0.77 ± 0.69 V in RV-A and 0.71 ± 0.35 V in RV-HS (P = 0.31), and at 2.5 V were 0.06 ± 0.08 ms in RV-A and 0.07 ± 0.05 ms in RV-HS (P = 0.12). Average RV electrogram amplitudes from baseline to 24 months after CRT were 15.3 ± 6.9 mV in RV-A and 12.1 ± 6.0 mV in RV-HS (P = 0.55). Average RV impedances during follow-up were 850 ± 286Ω in RV-A and 618 ± 147Ω in RV-HS (P = 0.57). Similar RV lead revisions between RV-A and RV-HS were observed after 2-year follow-up (P = 0.55).ConclusionsThe RV-HS lead position demonstrated stable and acceptable long-term pacing and sensing function, with rates of complications comparable to conventional RV-A lead position in CRT. The RV-HS lead position is feasible in CRT-P. 相似文献
123.
Inositol monophosphatase (IMPase) family of proteins are Mg(2+) activated Li(+) inhibited class of ubiquitous enzymes with promiscuous substrate specificity. Herein, the molecular basis of IMPase substrate specificity is delineated by comparative crystal structural analysis of a Staphylococcal dual specific IMPase/NADP(H) phosphatase (SaIMPase - I) with other IMPases of different substrate compatibility, empowered by in silico docking and Escherichia coli SuhB mutagenesis analysis. Unlike its eubacterial and eukaryotic NADP(H) non-hydrolyzing counterparts, the composite structure of SaIMPase - I active site pocket exhibits high structural resemblance with archaeal NADP(H) hydrolyzing dual specific IMPase/FBPase. The large and shallow SaIMPase - I active site cleft efficiently accommodate large incoming substrates like NADP(H), and therefore, justifies the eminent NADP(H) phosphatase activity of SaIMPase - I. Compared to other NADP(H) non-hydrolyzing IMPases, the profound difference in active site topology as well as the unique NADP(H) recognition capability of SaIMPase - I stems from the differential length and orientation of a distant helix α4 (in human and bovine α5) and its preceding loop. We identified the length of α4 and its preceding loop as the most crucial factor that regulates IMPase substrate specificity by employing a size exclusion mechanism. Hence, in SaIMPase - I, the substrate promiscuity is a gain of function by trimming the length of α4 and its preceding loop, compared to other NADP(H) non-hydrolyzing IMPases. This study thus provides a biochemical - structural framework revealing the length and orientation of α4 and its preceding loop as the predisposing factor for the determination of IMPase substrate specificity. 相似文献
124.
In regions with thousands of lakes, large scale regional macrophyte surveys are rarely done due to logistical difficulties and high costs. We examined whether remote sensing can be used for regional monitoring of macrophytes in inland lakes using a field study of 13 lakes in Michigan, USA (nine model development lakes and four model testing lakes). Our objectives were: (1) to determine if different levels of macrophyte cover, different growth forms or specific species could be detected using the Landsat-5 TM sensor, and (2) to determine if we could improve predictions of macrophyte abundance and distribution in lakes by including sediment type or measures of water clarity (Secchi disk transparency, chlorophyll a, phytoplankton biovolume, or water color) in our models. Using binomial and multinomial logistic regression models, we found statistically significant relationships between most macrophyte measures and Landsat-5 TM values in the nine model development lakes (percent concordant values: 58–97%). Additionally, we found significant correlations between three lake characteristics and the TM values within lake pelagic zones, despite the inability of these variables to improve model predictions. However, model validation using four lakes was generally low, suggesting caution in applying these models to other lakes. Although the initial model development results suggest that remote sensing is a potentially promising tool for regionally assessing macrophytes, more research is necessary to refine the models in order for them to be applied to unsampled lakes. 相似文献
125.
应用遥感技术评估了印度北部Pali Gad山地流域过去几十年里土地利用/土地覆盖变化及其造成的土壤侵蚀程度,并基于摩根参数模型(Morgan Parametric Model)的方法来测定土壤的侵蚀程度;结果表明,由于不同的坡向受到太阳光照的不同可以引起土地覆盖的变迁;海拔和坡度已不再是阻碍人们获取自然资源的因素,人们的活动范围正转移到更高的海拔和更陡峭的坡度;揭示了土地利用/土地覆盖变化对土壤侵蚀进程有着直接的影响。 相似文献
126.
Assessing photosynthetic efficiency in an experimental mangrove canopy using remote sensing and chlorophyll fluorescence 总被引:2,自引:0,他引:2
Caroline J Nichol Uwe Rascher Shizue Matsubara Barry Osmond 《Trees - Structure and Function》2006,20(1):9-15
This study examined the ability of the photochemical reflectance index (PRI) to track changes in effective quantum yield (Δ
F/F
m
′), non-photochemical quenching (NPQ), and the xanthophyll cycle de-epoxidation (DPS) in an experimental mangrove canopy.
PRI was correlated with (Δ F/F
m
′) and NPQ over the 4-week measurement period and over the diurnal cycle. The normalised difference vegetation index (NDVI)
was not correlated with any aspect of photochemical efficiency measured using chlorophyll fluorescence or xanthophyll pigments.
This study demonstrated that photochemical adjustments were responsible for controlling the flow of energy through the photosynthetic
apparatus in this mangrove forest canopy rather than canopy structural or chlorophyll adjustments. 相似文献
127.
Application of remote sensing to site characterisation and environmental change analysis of North African coastal lagoons 总被引:8,自引:6,他引:2
M. H. Ahmed B. M. El Leithy J. R. Thompson R. J. Flower M. Ramdani F. Ayache S. M. Hassan 《Hydrobiologia》2009,622(1):147-171
This article describes the use of satellite imagery for identifying key environmental characteristics within three North African
coastal lagoons (Merja Zerga, Morocco; Ghar El Melh, Tunisia and Lake Manzala, Egypt) and for detecting the major environmental
changes within these environments. A combination of Landsat MSS, Landsat TM, Landsat ETM+ and ASTER imagery was acquired for
the three sites for a period covering the last three decades (1972–2004). Following geometric correction and enhancement,
the interpretation of the most recent image acquired for each of the three lagoons provides important insights into their
current conditions. For Merja Zerga, these include the distribution of the largest channels which drain extensive inter-tidal
mudflats and the two major depositional features associated with sources of freshwater. The distribution of marginal aquatic
vegetation is highlighted as is the intensive use of the surrounding landscape for agriculture. Intensive agriculture around
Ghar El Melh is also indicated. The influence of the Mejerda River, which was diverted away from the lagoon over 100 years
ago, is shown to persist as a residual area of deltaic deposits in shallow water that has been eroded over time. Coastal processes
including the direction of the alongshore sediment transport and the influence of engineering work associated with port construction
can also be recognised. Within Lake Manzala, vegetated islands divide the lake into a series of sub-basins which can be clearly
distinguished. The large influence of human activities within this lake can be identified and include reclamation for agriculture
and the conversion of parts of the lake bed for fish farms. The historical images available for the three lagoons provide
important insights into decadal scale changes, which have been greatest at Lake Manzala. Since the early 1970s large parts
of the lake, in particular in the southwest where the shoreline has migrated northwards, have been reclaimed. Major engineering
works, such as the El Salam Canal and road embankments, are shown to have resulted in significant lake change. The distribution
of emergent vegetation within the lake has also changed. Classification of images for this lake into open water, vegetation
and land enables the quantification of these changes. Between 1973 and 2003, the lake declined in area by approximately 50%.
Changes at Merja Zerga over the last three decades include reconfiguration of the marine outlet and the expansion of the internal
delta at the end of the Nador Canal. The images of this site clearly demonstrate the intensification of agriculture around
the lagoon. The most marked changes evident within the images of Ghar El Melh concern the sand bars that separate the lagoon
from the sea. Geomorphological processes operating within the coastal zone have resulted in the straightening of the bars
with central sections migrating out towards the sea. Remote sensing is established as a promising application for detecting
the quantitative surface cover changes in coastal lagoons and their near landscapes.
Guest editors: J. R. Thompson & R. J. Flower
Hydro-ecological Monitoring and Modelling of North African Coastal Lagoons 相似文献
128.
Spatial and temporal deforestation dynamics in protected and unprotected dry forests: a case study from Myanmar (Burma) 总被引:1,自引:0,他引:1
Melissa Songer Myint Aung Briony Senior Ruth DeFries Peter Leimgruber 《Biodiversity and Conservation》2009,18(4):1001-1018
Tropical dry forests are more threatened, less protected and especially susceptible to deforestation. However, most deforestation
research focuses on tropical rain forests. We analyzed spatial and temporal changes in land cover from 1972 through 2005 at
Chatthin Wildlife Sanctuary (CWS), a tropical dry forest in Myanmar (Burma). CWS is one of the largest protected patches of
tropical dry forest in Southeast Asia and supports over half the remaining wild population of the endangered Eld’s deer. Between
1973 and 2005, 62% of forest was lost at an annual rate of 1.86% in the area, while forest loss inside CWS was only 16% (0.45%
annually). Based on trends found during our study period, dry forests outside CWS would not persist beyond 2019, while forests
inside CWS would persist for at least another 100 years. Analysis of temporal deforestation patterns indicates the highest
rate of loss occurred between 1992 and 2001. Conversion to agriculture, shifting agriculture, and flooding from a hydro-electric
development were the main deforestation drivers. Fragmentation was also severe, halving the area of suitable Eld’s deer habitat
between 1973 and 2001, and increasing its isolation. CWS protection efforts were effective in reducing deforestation rates,
although deforestation effects extended up to 2 km into the sanctuary. Establishing new protected areas for dry forests and
finding ways to mitigate human impacts on existing forests are both needed to protect remaining dry forests and the species
they support. 相似文献
129.
Gregory J. Doucette Christina M. Mikulski Kelly L. Jones Kristen L. King Dianne I. Greenfield Roman Marin III Scott Jensen Brent Roman Christopher T. Elliott Christopher A. Scholin 《Harmful algae》2009,8(6):880-888
The ability to detect harmful algal bloom (HAB) species and their toxins in real- or near real-time is a critical need for researchers studying HAB/toxin dynamics, as well as for coastal resource managers charged with monitoring bloom populations in order to mitigate their wide ranging impacts. The Environmental Sample Processor (ESP), a robotic electromechanical/fluidic system, was developed for the autonomous, subsurface application of molecular diagnostic tests and has successfully detected several HAB species using DNA probe arrays during field deployments. Since toxin production and thus the potential for public health and ecosystem effects varies considerably in natural phytoplankton populations, the concurrent detection of HAB species and their toxins onboard the ESP is essential. We describe herein the development of methods for extracting the algal toxin domoic acid (DA) from Pseudo-nitzschia cells (extraction efficiency >90%) and testing of samples using a competitive ELISA onboard the ESP. The assay detection limit is in the low ng/mL range (in extract), which corresponds to low ng/L levels of DA in seawater for a 0.5 L sample volume acquired by the ESP. We also report the first in situ detection of both a HAB organism (i.e., Pseudo-nitzschia) and its toxin, domoic acid, via the sequential (within 2–3 h) conduct of species- and toxin-specific assays during ESP deployments in Monterey Bay, CA, USA. Efforts are now underway to further refine the assay and conduct additional calibration exercises with the aim of obtaining more reliable, accurate estimates of bloom toxicity and thus their potential impacts. 相似文献
130.
The proteolysis of cheese whey with the aid of immobilized enzymes is an attractive alternative for this by-product of the
dairy industry. Among some possible applications for whey protein hydrolysates, one may cite their use as protein source for
individuals with reduced capacity of digestion, or with genetic metabolic disorders (phenylketonuria patients, for instance).
The multipurpose plant that processes whey is named here as a cheese whey biorefinery. This work presents the remote control
and monitoring of the whey biorefineries using the Internet. In an integrated environment, the web application also enables
simulation and economic analyses of the process. This technology might allow small companies to access a remote “engineering
centre”, with know-how on plant design and advanced control techniques. The idea can also be extended to large dairy companies,
providing the remote control of geographically spread sites of production. 相似文献