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261.
Helene Fast Seefeldt Flemming Hofmann Larsen Nanna Viereck Bernd Wollenweber Sren Balling Engelsen 《Cereal Chemistry》2008,85(4):571-577
Temporal and genotypic differences in bulk carbohydrate accumulation in three barley genotypes differing in the content of mixed linkage β‐(1→3),(1→4)‐D‐glucan (β‐glucan) and starch were investigated using proton high‐resolution, magic angle spinning, nuclear magnetic resonance (1H HR MAS NMR) during grain filling. For the first time, 1H HR MAS NMR spectra of flour from immature barley seeds are analyzed. Spectral assignments are made using two‐dimensional (2D) NMR methods. Both α‐ and β‐glucan biosynthesis were characterized by inspection of the spectra as well as by calibration to the reference methods for starch and β‐glucan content. Starch was quantified with very good calibrations to the α‐(1→4) peak (5.29–5.40 ppm) and the region 3.67–3.83 ppm covering starch glycopyranosidic protons from H5 and H6. In contrast, the spectral inspection of the β‐anomeric region 4.45–4.85 ppm showed unexpected lack of intensity in the high β‐glucan mutant lys5f at seed maturity, resulting in poor calibration to reference β‐glucan content. We hypothesize that the lack of β‐glucan signal in lys5f indicates partial immobilization of the β‐glucan that appears to be either genotypic dependent or water/β‐glucan ratio dependent. 相似文献
262.
Wanchun Zhao Lili Qi Xiang Gao Gaisheng Zhang Jian Dong Qijiao Chen Bernd Friebe Bikram S. Gill 《Euphytica》2010,175(3):343-350
Dasypyrum villosum (L.) Candargy is a diploid, wild relative of bread wheat (Triticum aestivum L.). Previous studies showed that D. villosum chromosome 1V has genes that encode seed storage proteins that may be used to enhance the grain quality of bread wheat. As
a first step in genetic transfer, the present study was initiated to develop compensating Robertsonian translocations involving
wheat chromosome 1D and D. villosum chromosome 1V and to analyze their effects on grain quality. A monosomic 1D stock was crossed with the disomic addition stock
DA1V#3 and the double monosomic plants (20″ + 1D′ + 1V#3′) were self pollinated. Two co-dominant STS markers (BE499250 and
BE591682) polymorphic for the short arm of 1V#3S and two dominant STS markers (BE518358 and BE585781) polymorphic for the
long arm of 1V#3L were developed to screen a large number of progeny to identify plants that had only the 1V#3S or 1V#3L arms.
Five compensating Robertsonian heterozygous translocations, two (plants #56 and #83) for the short arm (T1DL·1V#3S) and three
(plants #7, #123, and #208) for the long arm (T1DS·1V#3L) were identified from 282 F2 plants and confirmed by genomic in situ hybridization and C-banding analyses. Two homozygous translocations T1DL·1V#3S (plants
#14 and #39) were identified from 52 F3 plants derived from F2 plant #83. Four homozygous translocations T1DS·1V#3L (plants #3, #22, #29, and #30) were identified from 68 F3 plants derived from F2 plant #208. The homozygous translocation T1DL·1V#3S had a significantly higher (37.4 ml) and T1DS·1V#3L had significantly
lower (10 ml) Zeleny sedimentation values compared to Chinese Spring wheat (30.7 ml). Our results showed that 1V#3S increased
gluten strength and enhanced wheat quality, but 1V#3L decreased gluten strength and did not enhance wheat quality. 相似文献
263.
Stefan Engelhardt Rainer Matyssek Bernd Huwe 《European Journal of Forest Research》2009,128(6):621-631
Ecosystem analysis is typically done by determination of species composition, structural exploration, determination of matter
and energy fluxes and/or system analyses based on deterministic or probabilistic/stochastic model approaches. However, regarding
ecosystem dynamics, temporal structure, information content, complexity of signals, and their modifications when subsequently
passing through different subsystems, have not intensively been studied to date. Structure in time series characterised by
information and complexity measures may provide additional, powerful tools to analyse state and dynamics of ecosystems. Along
their path through ecosystem compartments, e.g., hydrological signals are transformed in several ways, comprising changes
in randomness, autocorrelation structures, and smoothness. Thus, time series analyses with complexity and information measures
are of interest for a holistic understanding of ecosystem behaviour and early indications of natural and anthropogenic disturbances
of ecosystems such as ecosystem degradation and climate change. Further, these measures provide additional criteria for the
calibration of model parameters, tests of model validity, and determination of the necessary degree of complexity of process
models. In this paper, we present the outcome from applications of information and complexity measures to hydrological time
series in two climatically different forest ecosystems in South Germany and southern Ecuador. Information and complexity measures
are different for different parameters but ecosystems of the same type such as mountain forests exhibit similar behaviour.
We hypothesise that complexity of hydraulic time series increases with the number of abiotic and biotic variables involved
in the generating process of the time series. Thus, complexity should reach a minimum in the precipitation signal which is
controlled by abiotic, atmospheric factors only, and reach a maximum in the root zone where the interaction of abiotic and
biotic variables is high. Hydrological time series under study cover the sequence of hydrological signals from open precipitation,
throughfall, sapflow, water fluxes in the soil compartment and system discharge. We detected pronounced data aggregation and
transformation effects of hydrological signals along their path through subsystems in terms of information propagation. We
further found similar patterns in different ecosystems of the same general type. As a result of intensive abiotic and biotic
interactions, a pronounced maximum of complexity was found in the moisture signal of the soil compartment. 相似文献
264.
Sabine H. G. Stenkamp Manuel S. Becker Bernd H. E. Hill Rolf Blaich Astrid Forneck 《Euphytica》2009,165(1):197-209
This project studied the genetic variation of the periclinal grape chimera Pinot Meunier, its natural occurring mutations
(loss of trichomes on leaf surfaces) and the German Pinot noir clone Samtrot. Eleven Pinot Meunier clones of French, Italian
and foremost German origin, Pinot Meunier mutations of differing ages and with various dispersions of hairless sectors as
bud-, shoot- and complete vine mutations and six Samtrot clones were investigated with amplified fragment length polymorphisms
(AFLPs) and microsatellites (SSRs). SSR-analysis proved chimerism of all Pinot Meunier clones tested and confirmed identical
genotype for all hairless mutations and Samtrot clones at the analyzed loci. Clonal variation was shown by AFLP-analysis yielding
a total of 670 bands out of 18 primer combinations of which 161 were polymorphic. Pinot Meunier, Samtrot and the naturally
occurring hairless Pinot Meunier mutations could be significantly differentiated. Most of interclonal varying AFLP fragments
(mean 1.5% per sample) originated within the groups of Samtrot or Pinot Meunier mutations, whereas intraclonal identity was
highest within the Pinot Meunier clones. According to the analysis of molecular variance (AMOVA), variation among wild type
and mutated Pinot Meunier leaf halves is significantly smaller than between phenotypically identical Samtrot and Pinot Meunier
mutants. Average gene diversity calculated on variability of loci reduced from Samtrot (0.040 ± 0.023) towards Pinot Meunier
(0.025 ± 0.013) clones. 相似文献
265.
Betulinic acid, isolated in substantial amounts from stem barks of five distinct species of Uapaca could be considered as an important chemotaxomic marker of the Uapaca genus. It inhibited Trypanosoma brucei GAPDH with an IC(50) value of 240 microM and has been shown to be a competitive reversible inhibitor (Ki=200+/-10 microM) of this enzyme with respect to its cofactor NAD(+). 相似文献
266.
The relationship between amount of a nutrient in soil and its concentration in solution, the buffer curve, is usually non‐linear. However, most models that calculate nutrient transport in the soil and nutrient uptake by the plant often assume a linear buffer curve because of simpler programming. In this paper a model is presented that uses the Freundlich function to describe the non‐linear buffer curve in the soil. It has been shown that calculated uptake and depletion curves were not influenced by the shape of the buffer curve. In a sensitivity analysis the buffer capacity, soil solution concentration, soil water content, soil impedance factor, maximum influx and the curvature of the Freundlich function were varied and the influence on calculated uptake was studied. The buffer capacity in general had a minor influence and the linearity or non‐linearity of the buffer capacity had under no circumstances an influence on calculated uptake. Thus, the use of a linear buffer curve in transport models does not lead to a significant error in the results. 相似文献
267.
The influence of temperature (T) and water potential (ψ) on the denitrification potential, C and N mineralization and nitrification were studied in organic and mineral horizons of an acid spruce forest soil. The amount of N2O emitted from organic soil was 10 times larger than from the mineral one. The maximum of N2O emission was in both soils at the highest water potential 0 MPa and at 20°C. CO2 production in the organic soil was 2 times higher than in mineral soil. Net ammonification in organic soil was negative for most of the T‒ψ variations, while in mineral soil it was positive. Net nitrification in organic soil was negative only at the maximum water potential and temperature (0 MPa, 28°C). The highest rate was between 0 and −0.3 MPa and between 20 and 28°C. In mineral soil NO3− accumulated at all T‒ψ variations with a maximum at 20oC and −0.3 MPa. We concluded that in organic soil the immobilization of NH4+ is the dominant process in the N‒cycling. Nevertheless, decreasing of total N mineralized at 0 MPa and 20—28oC can be explained by denitrification. 相似文献
268.
Christian Hoffmann Manfred Renger Mieczyslaw Hajnos Zofia Sokolowska Grzegorz Jozefaciuk Bernd Marschner 《植物养料与土壤学杂志》1999,162(6):653-659
Veränderungen in Rieselfeldböden während eines Säulenversuchs mit unterschiedlichen Beregnungslösungen. 1. Physikochemische Eigenschaften der Festphase In einem 2.5 Jahre dauernden Säulenexperiment wurden die physikochemischen Eigenschaften von zwei Sandböden, eines genutzten sowie eines ehemaligen Rieselfeldes, untersucht. Die Böden wurden gekalkt, beziehungsweise mit unterschiedlichen Beregnungslösungen beaufschlagt. Die Menge an austauschbaren basischen Kationen sowie die Basensättigung beider Böden veränderte sich deutlich während des Experiments. Diese Veränderungen wurden durch Boden-pH-Änderungen verursacht. Die spezifische Oberfläche und die Kationenaustauschkapazität dieser Standorte hängen vom Gehalt an organischer Substanz im Bodenprofil ab. Die Oberflächenladungsdichte war — unabhängig von der Tiefe — in beiden Böden gleich. 相似文献
269.
This review reports on research of the last ten years to find the primary target enzyme for chloroacetamides. As could be shown first with the green alga Scenedesmus, the formation of very‐long‐chain fatty acids (VLCFAs) is severely impaired. Subsequently, in short‐term experiments, labelled malonate or stearate could be incorporated into leaf discs of cucumber, barley or leek seedlings. While the formation of ‘normal’ long‐chain fatty acids (up to C18) was not influenced, phytotoxic chloroacetamides strongly inhibited the synthesis of VLCFAs of C20, 22 and 24, with I50 values of 10–100 nM . Inhibition depends on the amide structure and on stereospecificity. Also cafenstrole or recently developed tetrazolinones and phosphosulfonates were found active to inhibit fatty‐acid elongation. Subsequently, a cell‐free elongase assay was developed using a microsomal preparation from leek seedlings (Allium porrum L), [14C]malonyl‐CoA and C18, 20, or C22 acyl‐CoA primer substrates. All elongation steps were strongly affected by those phytotoxic herbicides which were also active in vivo. The inhibitors form a tight‐binding complex with the condensing elongase enzyme system which develops with time and lowers the I50 values markedly. Apparently, a nucleophilic attack of the inhibitor takes place at the specific target enzyme. Acyl‐CoA elongation inhibition is correlated with growth inhibition of the intact cell. Due to the low I50 values and the specific inhibition, we assume that impaired VLCFA‐formation is the primary phytotoxic impact of chloroacetamides and functionally related structures. © 2000 Society of Chemical Industry 相似文献
270.