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51.
Soon-An Ong Li-Ngee Ho Yee-Shian Wong Komalathevi Raman 《Water, air, and soil pollution》2012,223(4):1615-1623
Combinations of sequential anaerobic and aerobic process enhance the treatment of textile wastewater. The aim of this study
was to investigate the treatment of diazo dye Reactive Black 5 (RB5)-containing wastewater using granular activated carbon
(GAC)–biofilm sequencing batch reactor (SBR) as an integration of aerobic and anaerobic process in a single reactor. The GAC–biofilm
SBR system demonstrated higher removal of COD, RB5 and aromatic amines. It was observed that the RB5 removal efficiency improved
as the concentration of co-substrate in the influent increased. The alternative aeration introduced into the bioreactor enhanced
mineralization of aromatic amines. Degradation of RB5 and co-substrate followed second-order kinetic and the constant (k
2) values for COD and RB5 decreased from 0.002 to 0.001 and 0.004 to 0.001 l/mg h, respectively, as the RB5 concentration increased
from 100 to 200 mg/l in the GAC–biofilm SBR system. 相似文献
52.
Background, Aim and Scope The distribution of sediments in estuarine beaches is controlled by the interactions between sediment supply, hydrodynamic
processes and human intervention. The main purpose of this study is to characterize the sediments of Tagus estuarine beaches
in order to understand their origin and to contribute to a better knowledge of the Tagus estuary sediment budget.
Methods Surface sediment samples were collected across beach profiles and sand grain size analysis was performed by dry sieving. Grain
size statistics for the median (d50) and standard deviation (SDM) were obtained using the Moment method. This study was complemented by a qualitative evaluation
of the sediment composition. Cross-shore topographic surveys were conducted for selected sampling sites.
Results Tagus estuarine beach sediments are mainly composed of quartz sand particles which are fine-grained and well sorted near the
mouth of the estuary and medium to coarse-grained and moderately sorted in the inner domain. Compositional results show evidence
of active anthropogenic sediment sources, especially in the coarser fractions.
Discussion The analysis of the textural and compositional characteristics of beach sediments in the inner estuarine domain is compatible
with local sedimentary sources, while a marine signature is present at the mouth and inlet channel sediments. In the inner
domain, differences in the sedimentary processes are represented by the textural characteristics of the sediments, such as
the sorting degree and the gravel content. Sediment characteristics also reflect human intervention in the system, with the
introduction of anthropogenic and allochthonous particles and the mixture of sediments from different sources.
Conclusions The sediments of the inner Tagus estuarine beaches are derived from local Plio-Pleistocene outcrops while inlet and outer
estuary beaches reveal a dominant marine source. Beach textural variability observed in the inner domain is not related to
wave forcing gradients, but mainly to variations in the sedimentary processes along the estuarine margins and to human intervention.
Results show that the Tagus estuarine beaches depended, almost exclusively, on sediment input from local sources until the
last century. With increasing human occupation, sediment transfers became dominated by anthropogenically related activities
mainly connected with the occupation of estuarine margins and dredging.
Recommendations and Perspectives Further studies should extend the present level of knowledge in what concerns sand transport patterns through additional compositional
and geochemical analysis, and the development of new techniques in order to allow the quantitative evaluation of the impact
of human activities on the sediment budget. 相似文献
53.
The mechanism that controls the proportion of cannabichromene (CBC), a potential pharmaceutical, in the cannabinoid fraction
of Cannabis sativa L. is explored. As with tetrahydrocannabinol (THC) and cannabidiol (CBD), CBC is an enzymatic conversion product of the precursor
cannabigerol (CBG). CBC is reported to dominate the cannabinoid fraction of juveniles and to decline with maturation. This
ontogeny was confirmed in inbred lines with different mature chemotypes. A consistent CBC presence was found in early leaves
from a diverse clone collection, suggesting that CBC synthase is encoded by a fixed locus. Morphological variants possessing
a ‘prolonged juvenile chemotype’ (PJC), a substantial proportion of CBC persisting up to maturity, are presented. PJC is associated
with a reduced presence of floral bracts, bracteoles, and capitate-stalked trichomes. Genetic factors causing these features
were independent of the allelic chemotype locus B that was previously postulated and regulates THC and CBD synthesis and CBG accumulation. In contrast to previously described
Cannabis chemotypes, the cannabinoid composition of PJCs showed plasticity in that reduced light levels increased the CBC proportion.
The ability of PJC plants to enable the production of pharmaceutical raw material with high CBC purity is demonstrated. 相似文献
54.
55.
应用化学计量学对近红外光谱数据进行建模是近红外光谱分析中的难点和关键。随着研究的深入,现有分析建模的改进算法和新方法的应用不断出现。本文详细阐述了数据预处理、定性和定量建模优化方法的研究进展。在降噪消噪方法中,小波(WT)变换是最为常用和有效的工具,应用非常广泛。波长优化选择方法是现在研究的重点之一,主要有遗传算法(GA)、无信息变量消除方法(UVE)和连续投影算法(SPA)等。在模型优化算法中,主要是在偏最小二乘法(PLS)、人工神经网络(ANN)和支持向量机(SVM)的基础上提出多种改进算法,能够更加有效地优化模型。但每种算法各具优点的同时也存在着一定的局限性,对于不同类型待测物的数学模型,优化的方法也有所不同,所以在实际应用中将多种数学挖掘方法结合,相互取长补短,将成为今后研究趋势。 相似文献
56.
57.
客车车架的动态特性是影响整车振动舒适性的关键因素。为探讨纵横梁结构对某轻型客车车架动态特性的影响,建立车架的研究性模型,对研究性模型进行多种方案的计算分析,综合各方案的计算结果,确定影响车架动态特性最大的结构特征,以此为基础对原车架进行改进,提高了车架的模态频率。计算结果表明,该研究方法简便有效,可推广应用于对其它结构的研究。 相似文献
58.
59.
盐单胞菌(Halomonas sp.)C6与耐盐有关的可能转座酶A基因长1707bp,编码568个氨基酸,其上游1 ̄171bp DNA区域内含有核糖体结合位点GAGG和类似于大肠杆菌(E.coli)proU、proP和galpI、枯草牙胞杆菌(Bacillus subtilis)白基因gfp为报告基因,启动子探针载体pHN127为载体质粒,通过亚克隆,在pHN127无启动子的gfp基因上游插入了包 相似文献
60.
资源配置从来都处于调整之中,稳定不变的资源配置是没有的。黑龙江省资源相对丰度较高,农业资源环境较好,但资源配置仍存在着不容忽视的问题。形势发展要求应立足于黑龙江省特有的自然、经济以及社会条件,调整农业资源配置方向。 相似文献