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51.
52.
Two low-temperature-tolerant mutants of the Dendranthema × grandiflorum (Ramat.) Kitamura cultivar ‘Puck’ derived from an x-radiated tissue culture system were compared, as vegetatively growing plants, to ‘Puck’ ssfor several physiological properties under low-temperature conditions. So far, the low-temperature tolerance of the mutants has been defined as the capacity to flower earlier under low temperature conditions (8—15°C) the wild type. All three lines were not chilling sensitive in the vegetative state and were able to acclimatize and to develop freezing tolerance. Differences between ‘Puck’ and the mutants were found but could not be related to the low-temperature tolerance of the mutants in the generative phase. Levels of the amino acid proline increased during the hardening process, reaching the highest level in the cultivar ‘Puck’. No evidence could be obtained that proline is causally involved in the cold-hardening process. Freezing-induced membrane injury was found to decrease with cold hardening (0—28 days) but the two mutants did not show a greater capacity to acclimatize and cold harden than the original cultivar ‘Puck’. 相似文献
53.
This study was aimed at the induction of morphological mutations for increasing genetic variability and making available additional genetic markers for linkage studies in chickpea (Cicer arietinum L.). A wilt‐resistant, well‐adapted chickpea cultivar of central India,‘JG 315’(Jawahar gram 315), was used for the induction of mutations. Seeds presoaked in distilled water for 2 h were treated with ethyl methane sulphonate (EMS) using six different concentrations (0.1, 0.2, 0.3, 0.4, 0.5 and 0.6%) and two different durations (6 and 8 h). Several morphological mutants were identified in M2. One of the mutants, isolated from a treatment of 0.3% EMS for 8 h, had five to nine large leaflets per leaf in comparison with 11‐17 normal‐sized leaflets per leaf observed in the parental cultivar ‘JG 315′. The mutant was designated broad‐few‐leaflets. Many leaves of this mutant showed a cluster of three to five overlapping leaflets at the terminal end. The other mutant, designated outwardly curved wings, was isolated from the 0.5% EMS treatment for 6 h. In this mutant, the wings were curved outwards, exposing the keel petal, while the wings in typical chickpea flowers are incurved and enclose the keel. The lines developed from the broad‐few‐leaflets and outwardly curved wings mutants were named JGM 4 (Jawahar gram mutant 4) and JGM 5, respectively. Inheritance studies indicated that each of these mutant traits is governed by a single recessive gene. The gene for broad‐few‐leaflets was designated bfl and the gene for outwardly curved wings was designated ocw. The locus bfl was found to be linked with the locus lg (light green foliage) with a map distance of 18.7 ± 6.3 cM. 相似文献
54.
Summary A population of 198 chromosome-doubled haploid lines of spring barley was scored for segregation in locus ml-o (powdery mildew reaction) on chromosome 4 and in the linked loci s (rachilla hair length) and ddt (reaction to the insecticide DDT) on chromosome 7. They were also tested in a disease-free field trial for the agronomic traits: grain yield, thousand grain weight, lodging, and necrotic leaf spotting. The three mutagen-induced resistance genes ml-o5, ml-o6 (from Carlsberg II) and ml-10 (from Foma) showed no detectable differences with respect to effects on agronomic traits. They all conferred a four per cent reduction in grain yield caused mainly by lower thousand grain weight, and an increase in necrotic leaf spotting. The two original mutants of Carlsberg II had additional mutant genes affecting agronomic traits. Lines with gene S (long hair) had on average a three per cent higher thousand grain weight than those with s. The alleles in locus ddt showed no association with the agronomic traits. It is concluded i) that the associations between the three ml-o alleles and agronomic traits are caused by pleiotropy, ii) that ml-o resistant, high-yielding lines may be selected, and iii) that the association between gene s and thousand grain weight may be due to genetic linkage.Abbreviations DH-lines
chromosome-doubled haploid lines 相似文献
55.
The flower colour of Gerbera, an important ornamental cut flower, is derived from carotenoids and flavonoids. The knowledge of enzymological and genetic control of flavonoid biosynthesis is still incomplete. The present paper summarizes the results obtained at our institute between 1981 and 1993. The material for the investigation of phenotypic segregation and segregation of flavonoids after chromatographic analysis came from 408 progenies of controlled crosses. Phenotypic segregation analysis showed acyanic genotypes to be homozygous recessive and recessive epistatic over cyanic genotypes, respectively. This was confirmed by the existence of two loci controlling steps in biosynthesis (fht, dfr or ans) showing recessive mutants and complementary gene action after crosses. Flavone formation is effected by one dominant allele (fns+); dominant and recessive genotypes are now available. Regarding anthocyanidin inheritance, an unusual epistasis of 4′-hydroxylation (pelargonidin formation) over 3′,4′-hydroxylation (cyanidin formation) was observed. Final proof of the postulated gene actions will come from enzymological and molecular biological investigations of the chemogenetically defined Gerbera genotypes now available. 相似文献
56.
Summary Glume cultures of monogenic recessive mutants PGTSLS1 (Plant Genetics triticale selection large spike 1) and PGTSLG2 (Plant Genetics triticale selection long grain 2) were employed along with their parent PGTS control (Plant Genetics triticale selection control) and their F1 and F2 progenies, to determine the genetic basis of plant regeneration in hexaploid triticale. The mutant PGTSLS1 exhibited greater efficiency of plant regeneration (22.4%) followed by PGTS control (7.6%) and PGTSLG2 did not exhibit any regeneration. All the three F1's exhibited plant regeneration frequency on par with that of control (6.9–7.3%), suggesting dominant nature of control genotype over the isogenic mutants. The F2 results suggested that genetic control over the high frequency regeneration of PGTSLS1 was monogenic recessive in nature, and genetic control over the recalcitrant nature of PGTSLG2 also was monogenic recessive. The F2 of the cross PGTSLS1 × PGTSLG2 segregated into four classes. Of the 114 F2 plants, 19 showed no regeneration, 70 of them exhibited 6–8% regeneration, 20 of them 19–24% regeneration, and 5 of them exhibited highest frequency regeneration (57–60%). These observations suggest dihybrid segregation for regeneration. The highest frequency of plant regeneration (57–60%) exhibited by 5 F2 plants may be due to the interaction of non-allelic genes in recessive condition. These results clearly demonstrate the association of at least two genes with plant regeneration in hexaploid triticale. 相似文献
57.
D. R. Knott 《Euphytica》1990,50(2):155-158
Summary Eight stem rust (Puccinia graminis tritici Eriks. and Henn.) resistant lines (designated TICENA lines) that had been selected by Veiga et al. (1981) following gamma radiation of BH-1146 wheat (Triticum aestivum L.) were studied. Six of the lines were resistant to race 15B-1 of stem rust and susceptible to race 56, and proved to carry the gene Sr7a. TICENA 4 carries two unidentified genes, each giving resistance to one of the two races. TICENA 10 carries Sr6, Sr7a and an unidentified gene giving resistance to race 56 but not 15B-1. The results raise doubts about the supposed origin of the lines as mutants. 相似文献
58.
E. J. Knights 《Euphytica》1993,69(3):163-166
Summary A spontaneous fasciated mutant was detected in the chickpea cv. Amethyst. It was characterised by broad, strap-like stems, irregular leaf arrangement and clustering of pods towards the stem apices. F2 and F3 segregations showed that fasciation was controlled by a single, recessive gene for which the symbol fas is proposed. Field trials comparing the fasciated mutant with its non-fasciated isoline showed that fasciation was associated with lower yield, larger seeds, delayed flowering and increased lodging. 相似文献
59.
Summary The effect of the fruit ripening mutants rin, gr, nor and Nr on storage life and pigmentation was investigated in homozygous material, in heterozygous F1 combinations between the mutants with the colour mutant hp and with the normal cv. Kewalo. Crosses with nor showed a 3-to 5-fold increase in storage life in comparison with the normal cv. or with hp. Maximum pigmentation of the fruits of crosses with nor was pale-red with vineripened fruit and pink with fruit harvested at the breaker stage and ripened on the shelf. The ripening inhibitory effect of rin in the different F1 combinations was less pronounced than that of nor, and the colour of the fruits was improved. Fruits of the F1 cross between rin and nor showed greatly improved storage life and developed pink or pale red colour. Most heterozygotes with hp showed improved pigmentation. Problems anticipated in utilizing ripening mutants in breeding for improved keeping quality are discussed. 相似文献
60.
Many spontaneous and a large number of induced mutants that show altered nodulation pattern have been isolated in pea, soybean,
common bean, faba bean, chickpea, groundnut and pigeonpea. Available information on nodulation mutants in these crops is summarised.
The importance of nodulation mutants in basic studies on plant-microbe symbiotic interactions, nitrogen fixation and breeding
of cultivars with higher yield and nitrogen fixation rate are examined. The nodulation mutants, after inoculation with specific
bacterial strains or a number of different strains, show either: no nodulation (nod-), few nodules (nod+/-), ineffective nodulation
(fix-), hyper nodulation (nod++) or hypernodulation even in the presence of otherwise inhibitory nitrate levels (nts). No
spontaneous hypernodulation or nts mutants have been found, all have been induced in independent experiments using different
cultivars of pea, soybean and common bean after mutagenising seeds. Most nodulation mutants show monogenic recessive inheritance,
though semi-dominant and dominant inheritance is also reported. Nodule number is controlled by a process known as autoregulation;
hypernodulating mutants show relaxed autoregulation. By grafting shoots of hypernodulating soybean mutant on normal nodulating
soybean, mungbean and hyacinth bean, presence of a common, translocatable signal has been shown. Nodulation mutants have contributed
to the understanding of the genetic regulation of host-symbiont interactions, nodule development and N fixation. Initially,
the hypernodulating mutants were found to be poor in yield. Using the induced hypernodulating mutant, a new soybean cultivar
‘Nitrobean 60’, has been released in Australia. This cultivar is reported to have given 15% higher yield over cv. ‘Bragg,’
and contributed a higher amount of fixed N to the following cereal crop in rotation. Prospects of using the nodulation mutants
in developing grain legume cultivars that combine high yield with high residual N, within the bioenergetic constraints, for
developing sustainable cropping systems are examined.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献