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961.
Arnold V. Hallare Thomas-Benjamin Seiler Henner Hollert 《Journal of Soils and Sediments》2011,11(1):141-173
Purpose
Sediments serve as integral and dynamic parts of our aquatic systems. Within the last 15 to 20 years, however, the scientific community has begun noticing deterioration of sediment quality at an alarming rate worldwide. Sediments are now harboring hazardous pollutants that can directly influence water quality, thereby creating very stressful conditions for aquatic life. As a consequence, global efforts were initiated in the early 1970s, to find ways to assess sediment quality. Because of their obvious ecological and economic significance, fish have remained a major taxonomic group for appraising the general quality of aquatic systems. However, for sediment risk assessment, fish have lagged behind invertebrates due to their mobility and generally, pelagic lifestyle. To our knowledge, this is the first paper that comprehensively presents and reviews the versatile role of fish in assessing the state of health of aquatic sediments. 相似文献962.
Purpose
Boric acid was applied in an earthworm field test according to ISO 11268-3 as a possible alternative for the currently used reference substances that may no longer be available in the near future. 相似文献963.
Hong Jie Di Keith C. Cameron Ju-Pei Shen Chris S. Winefield Maureen O’Callaghan Saman Bowatte Ji-Zheng He 《Journal of Soils and Sediments》2011,11(3):432-439
Purpose
Methanotrophs are an important group of methane (CH4)-oxidizing bacteria in the soil, which act as a major sink for the greenhouse gas, CH4. In grazed grassland, one of the ecologically most sensitive areas is the animal urine patch soil, which is a major source of both nitrate (NO3 −) leaching and nitrous oxide (N2O) emissions. Nitrification inhibitors, such as dicyandiamide (DCD), have been used to mitigate NO3 − leaching and N2O emissions in grazed pastures. However, it is not clear if the high nitrogen loading rate in the animal urine patch soil and the use of nitrification inhibitors would have an impact on the abundance of methanotrophs in grazed grassland soils. The purpose of this study was to determine the effect of animal urine and DCD on methanotroph abundance in grazed grassland soils. 相似文献964.
Carbon and nitrogen storage in plant and soil as related to nitrogen and water amendment in a temperate steppe of northern China 总被引:1,自引:0,他引:1
Fu-Mei Lü Xiao-Tao Lü Wei Liu Xu Han Guang-Ming Zhang De-Liang Kong Xing-Guo Han 《Biology and Fertility of Soils》2011,47(2):187-196
We conducted a field-manipulated experiment to assess whether changes in precipitation and nitrogen (N) deposition alter ecosystem
carbon (C) and N storage. Both C and N pools of plant and soil were monitored when urea-N (17.5 g N m−2) and water (increasing mean annual precipitation by 50%) were added to a temperate steppe. After 2 years of treatments, both
N and water addition significantly increased soil inorganic N availability by 125% and 62% during the growing season. While
water addition significantly increased ecosystem C storage by 6% and N storage by 8%, N addition showed significant effects
on neither of them. There were no interactions between N and water addition to affect both total C and N storage in this ecosystem,
though they did interact to affect several individual pools (e.g., aboveground biomass N pool, litter C, and N pool). Results
from the present study indicate that water availability is more important than N availability for C sequestration and that
increasing precipitation will favor C sequestration in this semi-arid grassland. 相似文献
965.
David Borchers Tiago Marques Thorvaldur Gunnlaugsson Peter Jupp 《Journal of Agricultural, Biological & Environmental Statistics》2010,15(3):346-361
Distance sampling methods assume that distances are known but in practice there are often errors in measuring them. These
can have substantial impact on the bias and precision of distance sampling estimators. In this paper we develop methods that
accommodate both systematic and stochastic measurement errors. We use the methods to estimate detection probability in two
surveys with substantial measurement error. The first is a shipboard line transect survey in the North Sea in which information
on measurement error comes from photographically measured distances to a subset of detections. The second is an aerial cue-counting
survey off Iceland in which information on measurement error comes from pairs of independently estimated distances to a subset
of detections. Different methods are required for measurement error estimation in the two cases. We investigate by simulation
the properties of the new estimators and compare them to conventional estimators. They are found to perform better than conventional
estimators in the presence of measurement error, more so in the case of cue-counting and point transect estimators than line
transect estimators. An appendix on the asymptotic distributions of conditional and full likelihood estimators is available
online. 相似文献
966.
Introduction
Equilibrium passive samplers consisting of 55-μm polyoxymethylene (POM) and 170-μm polydimethylsiloxane were tested for the analysis of polychlorinated dibenzodioxin/furan (PCDD/F) in the pore water and overlying water of the Frierfjord, a bay in southern Norway. This fjord is heavily polluted with PCDD/Fs due to emissions from a former Mg smelter. 相似文献967.
Patrizia Erre Innocenza Chessa Concepción Muñoz-Diez Angjelina Belaj Luis Rallo Isabel Trujillo 《Genetic Resources and Crop Evolution》2010,57(1):41-54
The genetic relationships within and between wild and cultivated olives were examined and clarified in an isolated and restricted
area, such as the Mediterranean island of Sardinia. Wild (21 individuals) and cultivated olive trees (22 local cultivars from
a germplasm collection and 35 ancient trees) were genotyped by means of 13 SSR loci. Five cases of synonymy were observed
and nine distinct genotypes were identified in the collection. Five novel genotypes were also detected among the ancient trees.
Differences on the allelic composition and heterozygosity levels were found between wild and cultivated trees. Model-based
clustering method classified the olive trees into two major gene pools: (a) wild genotypes and (b) local cultivars from the
collection and from heritage olives. Regarding the cultivated plant material, we observed that: (a) most of the Sardinian
cultivars shared the same allelic profiles with the ancient cultivated trees and (b) the majority of these cultivars and all
the novel genotypes were not related to any other cultivars included in this study. These findings as well as the detection
of unique alleles and a certain wild genetic background at some cultivars revealed by the Bayesian analysis may indicate their
autochthonous origin. The synonymy cases found between local cultivars and Italian mainland cultivars indicate interchange
of genetic material among these growing areas, suggesting thus a possible allochthonous origin. The information obtained can
assist in the management of an olive collection and sheds some light on the survival of true oleasters and the origin of Sardinian
cultivars. 相似文献
968.
969.
Alagarsamy Karthikeyan Anandaraj Madhanraj Shunmugiah Karutha Pandian Manikandan Ramesh 《Genetic Resources and Crop Evolution》2011,58(5):769-782
Randomly amplified polymorphic DNA (RAPD) fingerprinting approach was applied to assess genetic diversity in different accessions
of rejuvenating and intellect-promoting ancient ayurvedic medicinal herb Bacopa monnieri (L.) Pennell collected from four Southern Indian states, along with in vitro micropropagated samples maintained in the laboratory
for 5 years. With the 10 analyzed primers, 110 distinct bands, in the size range of 250–870 bp were observed, and among which
14 (12.72%) were polymorphic. Among the random primers used, only OPD 02 generated highest percentage of polymorphism with
30.77. Whereas OPD 08 generated a maximum of 18 amplified bands, but with only 1% polymorphism. Cluster analysis done on the
basis of similarity co-efficient generated from RAPD profiles indicated all the accessions were divided into two sub-groups
based on genetic distances under one major cluster. Major cluster is only the lone loose group of the Bm.2 collected from
Kerala (KER) and in vitro micropropagated plant (IVMP) maintained in the lab. The other sub-group consisted of Bm.1 and Bm.3
collected from Tamil Nadu (TN) and Andhra Pradesh (AP) respectively, which are genetically similar and showed similarity with
accessions from Karnataka Bm.4 (KK). These two sub-groups were joined together at 0.66 genetic distance level. Overall, the
levels of genetic similarity within the accessions varied from 0.24 to 0.80, the matrix ranged from 0.36 to 0.80, with a mean
value of 0.68 indicating genetic similarity at low level. 相似文献
970.
Comparison of phosphorus fractions and alkaline phosphatase activity in sludge,soils, and sediments 总被引:1,自引:0,他引:1
Chunsheng Xie Jie Tang Jie Zhao Donglei Wu Xinhua Xu 《Journal of Soils and Sediments》2011,11(8):1432-1439