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991.
Genetic diversity is reduced from wild soybean to cultivars and from landraces to modern varieties. However, intraspecies
genetic diversity loss between characters or phenotypes also existed in wild soybean. We revealed the phylogenic relationship
of character types in Chinese wild soybean using 42 SSR markers. We conjectured that white flower, no-seed bloom, grey pubescence,
and four seed coat colours were evolutionarily acquired phenotypes. There were a small decrease (∆H = 0.1–6.46%) of gene diversity
and a moderate reduction (∆Na = 10.81–53.54%) of number of alleles but a violent loss (80.74–98.59%) of unique alleles in the acquired phenotypes. Our
results seemed to suggest that ovoid and elliptic leaves were differentiated at the earliest and subsequently lanceolate leaf
appeared before the domestication of soybeans within wild soybean, and that G. gracilis type was another earliest type, maybe emerged since the appearance of soybeans or it was concomitant with the domestication
of soybean. 相似文献
992.
993.
Understanding the mechanism and key controlling factors of nitrification in highly acidic soils is important from both ecological
and environmental perspectives. Many acid soils are also characterized by vegetation that produces polyphenolic and terpene
compounds that inhibit microbial activity. We investigated the potentially ameliorative effects of lime, charcoal, and urea
additions on soil nitrification and carbon substrate utilization (using the MicroResp method). Four soils were studied from
widely different environments but with similar pH and inputs of phytochemicals to determine the relative effects of these
potentially controlling factors. The addition of charcoal had no significant effect on net nitrification, but charcoal significantly
increased soil basal respiration and altered C substrate utilization in the two Scottish soils. Urea greatly increased nitrification
in both the Chinese soils, but there was no effect of urea on nitrification in the two Scottish soils. Lime application increased
nitrification in all the soils except for the Chinese mixed forest soil. Multivariate analysis of the C source utilization
data revealed that lime altered C substrate utilization more than urea or charcoal in these highly acidic soils. Our results
suggest that acid-tolerant nitrifiers do exist in these soils and have potential for high activity, and pH (lime addition)
and N-substrate (urea) most often increased nitrification. However, no single factor controlled nitrification in every soil,
suggesting an interaction between abiotic and nitrifier community composition as a result of land use and soil type interactions. 相似文献
994.
Alejandra G. Vovides Jorge López-Portillo Yoav Bashan 《Biology and Fertility of Soils》2011,47(5):567-576
Microbial processes are key elements in determining the productivity of mangroves, and reductions in these processes reflect
the loss of microbial biodiversity and function due to fabricated disturbances. Because nitrogen is a major limiting nutrient
for the productivity of these ecosystems, the goal of this study was to determine profiles of inorganic nitrogen combined
with several environmental parameters, all in relation to the degree of long-term hydraulic impairment of a tropical, monospecific
black mangrove (Avicennia germinans) forest that showed degradation ranging from total loss of mangrove cover to no disturbance. N2-fixation, oxygen levels, and nitrite contents decreased significantly with the severity of the disturbance, and almost null
levels were reached in the completely degraded zone, whereas salinity achieved very high values. Concomitantly, total N, ammonium,
and P contents and ammonia volatilization increased significantly. Pore-water temperature and pH increased moderately. Other
soil physical properties (sand, silt, clay, organic matter, and total C), which varied among the sampling sites, were not
correlated with the level of disturbance. Principal component analyses, including environmental and biological parameters,
suggested that the most significant finding was the considerable loss of N2-fixation with increasing impairment, which was concomitant with significant increases in volatilization of ammonia and salinity.
The results show that microbial N-cycling processes are highly sensitive to salinity and to man-made disturbances that modify
the water level and flow. 相似文献
995.
Since autumn-sown faba beans possess several advantages including higher seed yield over the spring cultivars, the study was
aimed to screen and select cold tolerant accessions of faba beans (Vicia faba L.) and compare these to wild species in the highland of the west Mediterranean region, Turkey. A total of 114 accessions
of Vicia species including 109 accessions of faba bean, three accessions of narbon bean (V. narbonensis L.) and two accessions of V. montbretii Fisch. et C.A. Mey. were screened for cold tolerance at seedling stage in two successive years, 2005–2006 and 2006–2007 growth
seasons. Accessions were evaluated for cold tolerance using a 1 (Highly cold tolerant)-5 (Highly cold susceptible) visual
scale. Considerable variation was found for cold tolerance and some agronomical characteristics in faba beans. Wild relatives
of faba bean were found to be more tolerant to cold than those of cultivated faba beans. Although some pigmented accessions
were free from freezing damage at −9.6°C without snow cover, accessions with white flowers were damaged. The proposed screening
technique could easily be used to evaluate many faba bean accessions for cold tolerance. To increase yield, it was concluded
that the cold tolerant accessions with high yield could be grown as autumn-sown crop in the target environment. 相似文献
996.
Zhi-Yong Hu Wei Hua Shun-Mou Huang Han-Zhong Wang 《Genetic Resources and Crop Evolution》2011,58(6):875-887
The complete nucleotide sequence of the rapeseed (Brassica napus L.) chloroplast genome (cpDNA) was determined. The 152,860 bp cpDNA contained a pair of 26,035 bp inverted repeat regions
(IR), which are separated by small and large single copy regions (SSC and LSC) of 83,030 and 17,760 bp, respectively. The
major portion (56.4%) of the B. napus cpDNA consists of gene coding regions, while intergenic spacers make up 43.6% of the complete genome. The average AT content
of the B. napus cpDNA is 63.7% and for the LSC, SSC and IR region is 65.9, 70.8 and 57.7%, respectively. Fifteen genes contained one intron,
while three genes had two introns. In total, 86 simple sequence repeats were identified. The detailed comparison of the B. napus with one of its putative parents, B. rapa L. cpDNA indicated that the two species were highly similar. The entire gene pool and relative positions of 113 individual
genes were identical to those of B. rapa cpDNA. The sequence divergence analysis of B. napus and B. rapa showed only 0.133% in the coding regions, 0.275% in the intron regions, and 0.348% in the intergenic spacer regions. The
phylogenies based on 61 protein coding genes from 48 cpDNA sequences provided strong support for monophyly of many major classes
of angiosperms and provided support that Amborella could be a sister to all other angiosperms. Our analysis also supported that B. napus is the closest species to B. rapa and B. rapa could be the mathernal parent of B. napus cv. zy036. 相似文献
997.
Simonetta Bullitta Sandro Dettori Manuela Manchinu Maria Rosaria Filigheddu Giovanna Piluzza 《Genetic Resources and Crop Evolution》2011,58(7):1007-1020
Considering the very high socio economic value of cork oak (Quercus suber L.) in Mediterranean areas, a better knowledge of local genetic resources is necessary in order to reach a good balance between
the conservation issues and the need of an efficient cork production network. In such frame, local germplasm of Q. suber from the main cork production areas of Sardinia was analysed for DNA and isozyme polymorphisms and for cork quality in relation
to some environmental parameters. A total number of 24 sample stands of cork oak were selected, representing typical vegetation,
sylvicultural and cork quality features within the eight identified cork growing areas in Sardinia. Considerable variation
was found between cork oak stands of the different areas. Results of the principal component analysis performed on the cork
quality data and environmental characters of the eight areas, showed that the first three components explain 72.2% of the
variation. The major characters involved in this differentiation were cork quality characters such as dimensional recover,
moisture and Mg content of the cork and also elevation of stands m a.s.l. for the first component. The second component appears
to be determined by some climatic parameters (average annual temperature and average of the minimum temperatures of coldest
month) and by the Fe and Zn in the cork. For the third component, major characters involved in differentiation are average
annual rainfall, bark thickness and Ca content in the cork. 相似文献
998.
Organic fractions from farm yard manure (FYM), vermicompost, municipal sludge, mustard cake, and surface soil of West Bengal,
which was arsenic (As)-contaminated, were extracted and fractionated into fulvic and humic acid (FA and HA, respectively)
fractions following standard procedures. These HA and FA samples were characterized by pH-potentiometric titrations, viscometric
measurements and visible spectrophotometry. The stability constant (logK) of the complexes formed by these natural with As in aqueous phase was evaluated by the ion-exchange method. The logK values suggest that the organo-As complexes were quite stable. The release isotherm of As from the HA/FA complexes extracted
from vermicompost and FYM was assayed in the presence of molybdate, nitrate, phosphate, sulfate and borate. The greatest tendency
to displace As from the complexes was shown by sulfate, molybdite, and nitrate. 相似文献
999.
Nalini Mallikarjuna S. Senthilvel David Hoisington 《Genetic Resources and Crop Evolution》2011,58(6):889-907
Groundnut, an important crop of many countries of the world, is susceptible to a range of diseases and pests. High levels
of resistances are not available in the cultivated gene pool as the crop is said to have a narrow genetic base. Narrow genetic
base is attributed to the evolution of the crop which took place by the combination of A and B genome species, and later doubling
their chromosome number, giving rise to tetraploid cultivated groundnut. Direct utilization of cross-compatible wild relatives,
which are diploids, to broaden the genetic base and introduction of useful traits, is not a straight-forward process due to
ploidy differences between the cultivated species and wild relatives. Hence amphiploids and autotetraploids were created by
not only combining the putative genomes, but many other A and B genome species, thus producing a highly variable population
of tetraploid groundnuts also called new sources of Arachis hypogaea. This study describes the development and characterization of newly generated tetraploid groundnuts and the level of molecular
diversity as assessed by DArT markers. 相似文献
1000.
Legumes have been shown to increase growth and P uptake of the following cereal. This could, in part, be due to nutrients
released by the decomposing legume residues. To investigate the effect of P added with legume residues on wheat growth, P
uptake and arbuscular mycorrhizal (AM) colonisation, a number of experiments were conducted with different legume residues
added to a soil with low P availability under conditions in which N was not limiting. Young and mature faba bean shoots (FYS,
FMS) and mature chickpea shoots (CP) were added to soil at different rates (0.5–2%, w/w) with the P concentration being the greatest in the young faba bean shoots and least in the mature chickpea residues. Other
treatments included addition of inorganic P at different rates (0–80 mg P kg−1). Available P, growth and P uptake and AM colonisation of wheat were measured after 6 weeks. As expected, inorganic P addition
increased growth and P uptake but decreased AM colonisation. The effect of the residues was more complex. AM colonisation
was not correlated with available P in the soil amended with residues, whereas there was significant negative correlation
between available P and AM colonisation in the treatments with inorganic P. Addition of FYS increased wheat shoot growth and
P uptake and decreased AM colonisation. However, FMS and CP addition not only decreased wheat growth and P uptake but also
AM colonisation despite low soil P availability. It is concluded that addition of some legume residues can improve the growth
of subsequent cereals, but others have a negative effect on wheat growth and AM colonisation which cannot be explained solely
by soil P availability. 相似文献