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排序方式: 共有1404条查询结果,搜索用时 15 毫秒
1.
《Animal : an international journal of animal bioscience》2017,11(3):375-381
Ultrasound scanning traits have been adapted in selection programs in many countries to improve carcass traits for lean meat production. As the genetic parameters of the traits interested are important for breeding programs, the estimation of these parameters was aimed at the present investigation. The estimated parameters were direct and maternal heritability as well as genetic correlations between the studied traits. The traits were backfat thickness (BFT), skin+backfat thickness (SBFT), eye muscle depth (MD) and live weights at the day of scanning (LW). The breed investigated was Kivircik, which has a high quality of meat. Six different multi-trait animal models were fitted to determine the most suitable model for the data using Bayesian approach. Based on deviance information criterion, a model that includes direct additive genetic effects, maternal additive genetic effects, direct maternal genetic covariance and maternal permanent environmental effects revealed to be the most appropriate for the data, and therefore, inferences were built on the results of that model. The direct heritability estimates for BFT, SBFT, MD and LW were 0.26, 0.26, 0.23 and 0.09, whereas the maternal heritability estimates were 0.27, 0.27, 0.24 and 0.20, respectively. Negative genetic correlations were obtained between direct and maternal effects for BFT, SBFT and MD. Both direct and maternal genetic correlations between traits were favorable, whereas BFT–MD and SBFT–MD had negligible direct genetic correlation. The highest direct and maternal genetic correlations were between BFT and SBFT (0.39) and between MD and LW (0.48), respectively. Our results, in general, indicated that maternal effects should be accounted for in estimation of genetic parameters of ultrasound scanning traits in Kivircik lambs, and SBFT can be used as a selection criterion to improve BFT. 相似文献
2.
《Chemical Speciation and Bioavailability》2013,25(1-4):75-77
AbstractIn this paper, we describe a series of laboratory experiments which quantify the rate of Cr6+ reduction by Fe0. The main goal of these experiments was to determine the removal efficiency of Cr6+ by iron. The results indicate that Fe0 reduces Cr6+ to Cr3+ under alkaline and slightly acidic conditions. The removal efficiency rises with an increase of the initial concentration of Cr6+ (1 mg/L to 10 mg/L) when the quantity of Fe0 is stable. The removal efficiency increases as the quantity of Fe0 is raised when other conditions are constant. The removal efficiency would not be affected by other inorganic ions unless they were present at very high concentrations. When the initial concentration Cr6+ is 10mg/L and pH is 6.5–7.7, the final concentration of Cr6+ in effluent is less than 0.05 mg/L and the total Fe is less than 0.3 mg/L in effluent. 相似文献
3.
In the Okavango Delta 98–99% of the water from inflow and rainfall is lost to the atmosphere through evapotranspiration. As
a consequence 94% of inflowing solutes are retained within the Delta landscape. This process might be expected to result in
an entirely saline environment, but that is not the case: the surface waters have very low salinity, supporting a typical
freshwater biota. It has been deduced that the numerous islands in the Delta (about 150,000 within an area of 13,500 km2) have been formed through evapotransporative concentration in the groundwater, of infiltrating solutes, followed by precipitation
and volume increase. Evidence of this is the large amount of calcrete in island soils. These islands of 3–10 m thickness with
clayey soils are underlain by fine Kalahari sand to a depth of 200–300 m, which also indicates that they are formed through
surface processes. The infiltration rate of surface water from floodplains and streams into islands is very high, and is predominantly
a lateral process that is unidirectional. Evapotranspiration in the riparian woodland zone cause the ground-waters in the
central area of islands—with halophyte grasslands—to have very high salinities. By use of chloride as a conservative element
the concentration factor between central island groundwater and surface water is calculated to be 500–1,000. This groundwater
is depleted of calcium and magnesium supporting the early deductions that these elements have precipitated as calcrete. There
is also a large depletion of silicate and potassium that probably have precipitated as well forming the clayey soils typical
of the islands. The central island groundwater is dominated by sodium, bicarbonate and dissolved organic matter. The gradual
increase of salinity here causes a periodic let off of this water through a density-driven process to deeper layers. This
process together with island growth through precipitation of solutes are the two major sink processes of inflowing solutes
and explains why the Okavango Delta is at present a freshwater system. The whole island complex is calculated to be 100,000–400,000 years
old while some intensely studied islands may be younger: 80,000–240,000 years. The discrepancy is explained by a biassed selection
of islands currently in flooded areas with better growth conditions. The uniqueness of the Okavango Delta and ideas for future
research are discussed. 相似文献
4.
目的:探讨早期食管癌的浸润深度的临床病理因素。方法:对术前胃镜发现、术后病理证实的55例早期食管癌进行统计,分析早期食管癌内镜下表现、肿瘤分化程度、淋巴转移与浸润深度之间的关系。结果:表面扩散生长型、腔内生长型高度<5mm、双向生长型高度<2mm及壁内生长型深度<0.5mm提示黏膜内癌。腔内生长型高度≥5mm、壁内生长型高度≥0.5mm、双向生长型高度≥2mm及混合生长型提示黏膜下癌。肿瘤分化程度与浸润深度呈负相关。4例淋巴结转移及2例淋巴管癌栓,其中1例为黏膜癌。5例为黏膜下层癌,原位癌均未发生转移。结论:内镜下表现与浸润深度有密切关系,肿瘤恶性程度越高则越易向深层浸润,浸润越深淋巴结转移率越高。 相似文献
5.
Wavefront shaping can compensate the wavefront distortions in deep tissue focusing, leading to an improved penetration depth. However, when using the backscattered signals as the feedback, unexpected compensation bias may be introduced, resulting in focusing position deviations or even no focus in the illumination focal plane. Here we investigated the reliability of wavefront shaping based on coherent optical adaptive technique in deep tissue focusing by measuring the position deviations between the foci in the illumination focal plane and the epi‐detection plane. The experimental results show that when the penetration depth reaches 150 μm in mouse brain tissue (with scattering coefficient ~22.42 mm?1) using a 488 nm laser and an objective lens with 0.75 numerical aperture, the center of the real focus will deviate out of one radius range of the Airy disk while the optimized focus in the epi‐detection plane maintained basically at the center. With the penetration depth increases, the peak to background ratio of the focus in the illumination focal plane decreases faster than that in the epi‐detection plane. The results indicate that when the penetration depth reaches 150 μm, feedback based on backscattered signals will make wavefront shaping lose its reliability, which may provide a guidance for applications of non‐invasive precise optogenetics or deep tissue optical stimulation using wavefront shaping methods. A, Intensity distribution in the epi‐detection plane and the illumination focal plane before and after correction, corresponding to brain sections with 250 and 300 μm thickness, respectively. Scale bar is 2 μm. B, Averaged focusing deviations in the epi‐detection plane (optimized) and the illumination focal plane (monitored) after compensation. The unit of the ordinate is one Airy disk diameter. Black dashed line represents one Airy disk radius. Bars represent the SE of each measurement set. 相似文献
6.
Dong-Hee Kang David Tsao Fan Wang-Cahill Steve Rock A. P. Schwab M. K. Banks 《Bioremediation Journal》2008,12(1):32-45
The potential for plants to minimize leachate volume and reduce cyanide and fluoride concentrations in groundwater was evaluated. High fluoride and soluble salts in the leachate induced chlorosis or necrosis in the leaf margins on green ash (Fraxinus pennsylvanica), yellow poplar (Liriodendron tulipifera), and bald cypress (Taxodium distichum). Hybrid willow (Salix Willow hybrid), sycamore (Platanus sp.), and black willow (Salix nigra) had high rates of transpiration and root growth during the study period. Cyanide in the leachate was removed by plant metabolic processes whereas fluoride accumulated in the leaves. Cyanide and fluoride in landfill leachate can be decreased through phytoremediation. 相似文献
7.
Joon Chul Lee Do Yun Kim Duk Jae Oh Ho Nam Chang 《Biotechnology and Bioprocess Engineering》2008,13(5):560-565
A rCHO cell line of DUKX origin 26*-320, producing recombinant antibody against the human platelet, was cultivated in a two-stage
depth filter perfusion system (DFPS) for 20 days in order to attain high recombinant antibody concentration. The productivity
of the first stage DFPS bioreactor reached 53 times that of the batch culture in a controlled stirred tank reactor and was
showed 12.1 mg/L antibody concentration at a perfusion rate of 6.0 d−1. Glucose concentration in the first DFPS was maintained at 1.5 g/L to avoid cell damage in the perfusion culture. A second
stage DFPS system was attached to the first DFPS, which resulted in a low glucose concentration of 0.02 g/L and a high antibody
concentration of 23.9 mg/L. The two-stage depth filter perfusion culture yielded 60% higher product concentration than the
batch and 49-fold higher productivity of 69.3 mg/L/d in comparison with that (1.4 mg/L/d) in a batch system. Furthermore,
antibody concentration of the second stage was 97% higher than that of the first stage, and the antibody productivities were
comparable to that of the first stage. This two-stage DFPS system also showed potential for higher titer production of recombinant
antibody and high volumetric productivity for long-term culture of bio-pharmaceutical substances. 相似文献
8.
Hydrogeochemical evolution and risk assessment of human health in a riverbank filtration site,northeastern China 总被引:1,自引:0,他引:1
Intensive agriculture and industrial activities have resulted in contamination in rivers and groundwater quality, which threatens human health. In this study, we used comprehensive physiochemical indicators to assess the quality of groundwater used for drinking and irrigation in addition to the potential risks to local residents in a riverbank filtration site. Human health risks through drinking water intake and dermal contact were also estimated. Moreover, we analyzed the spatial distribution regularities of health risk values in a riverbank filtration site. The assessment results revealed that NH4–N, NO2–N, F?, Mn, and As are main contaminants affecting groundwater quality and that 62% of the total samples is suitable for a variety of purposes. All groundwater in the study area is suitable for irrigation based on the sodium adsorption ratio (SAR), residual sodium carbonate (RSC), Na percentage (%Na), and U.S. Salinity Laboratory (USSL) and Wilcox diagrams. The health risk assessment suggests that residents in the study area are at high health risk, and women and children face higher risk than men in both non-carcinogenic and carcinogenic risks. The spatial distribution regularities of health risk values suggest that the human health risk value of each groundwater sample is different in the study area and has certain regularity. Therefore, effective measurements must be taken to address the groundwater contamination and to reduce the human health risks. 相似文献
9.
Wetlands of recent Dutch embankments 总被引:2,自引:2,他引:0
Wetlands of new embankments are characterized with respect to soil and hydrological regime and the processes of desalination
and vegetation succession. Soil- and height gradients, the lack of local drainage and the generally low nutrient content provide
conditions for dynamic mesoseries (groundwatertable low in summer, saturated in winter) and locally for stable mesoseries (relatively high in summer, saturated in winter).
Relations between vegetation and herbivores (gees, ducks, cattle) are discussed. 相似文献
10.