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961.
Microsatellite DNA polymorphism divergence in Triticum dicoccoides accessions highly resistant to yellow rust 总被引:9,自引:0,他引:9
T. Fahima M. S. Röder A. Grama E. Nevo 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(2):187-195
Stripe rust (yellow rust), caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of wheat throughout the world. Wild emmer wheat, Triticum dicoccoides, the progenitor of cultivated wheat, was found to be a valuable source for novel stripe-rust-resistance genes. The objective
of the present study was to estimate the extent of genetic diversity among the wild emmer wheat accessions, previously identified
as highly resistant to stripe rust, in order to select suitable parents for genetic-mapping studies. Twenty three wheat microsatellite
(WMS) markers were used to detect DNA polymorphism among 21 accessions of T. dicoccoides, which included 19 resistant and two susceptible accessions originating mainly from the center of origin and diversity in
the Upper Galilee and Hermon Mountain in northern Israel. In addition, two Triticum durum and one Triticum aestivum lines were also included in the analysis. The 23 WMS markers used were located on 23 chromosome arms, representing all 14
chromosomes of genomes A and B of wheat, and revealed a total of 230 alleles. The number of alleles ranged from 5 to 18, with
an average of ten alleles per WMS. Genetic dissimilarity values between genotypes, calculated by the WMSderived data, were
used to produce a dendrogram of the relationships among accessions using the unweighted pair-group method with arithmetic
averages (UPGMA). The results showed that all of the wild emmer wheat accessions could be distinguished. Most of the resulting
groups were strongly related to the ecogeographical origin of the accessions, indicating that the genetic diversity of T. dicoccoides is correlated with geographic distribution. The three major groups were the Rosh Pinna group (north of the Sea of Galilee),
the Mount Hermon group (north of the Golan Heights) and Mount Kena’an group (Upper Galilee). The genetic similarity (GS) of
the 21 T. dicoccoides accessions based on WMS results averaged 0.31. As expected, the T. durum and T. aestivum lines were grouped separately from the T. dicoccoides accessions. The results obtained suggest that a relatively small number of microsatellites can be used for the estimation
of genetic diversity in wild material of T. dicoccoides. These results will be useful in the identification of suitable parents for the development of mapping populations for tagging
yellow-rust resistance genes derived from T. dicoccoides. Furthermore, future work could test the adaptive evolutionary significance of microsatellites in natural populations of
wild emmer wheat.
Received: 8 August 1997 / Accepted: 25 August 1997 相似文献
962.
P. K. Subudhi S. Nandi C. Casal S. S. Virmani N. Huang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(6-7):941-949
The cytoplasmic genetic male-sterile (CMS) lines developed at the International Rice Research Institute are valuable in producing
tropical rice hybrids. Efficient use of CMS lines in hybrid rice production will depend on their level of genetic diversity.
Aside from morphological characterization, molecular analysis based on DNA markers can provide information on the genetic
diversity of the germplasm. The Amplified Fragment Length Polymorphism (AFLP) technique was used to fingerprint 71 CMS lines
and four rice cultivars, ‘IR64’, ‘Azucena’, ‘IR74’, and ‘FR13A’. Eleven primer pair combinations specific to the enzymes PstI and MseI were used to generate 530 AFLP markers, 176 of which were polymorphic. Each CMS line revealed a distinct fingerprint. The
AFLP marker-based dendrogram depicted genetic variation among the CMS lines. The CMS lines developed in japonica background
grouped with ‘Azucena’, a japonica cultivar. None of the CMS lines clustered with ‘FR13A’, a flood-tolerant traditional indica
variety. ‘IR64’ was found to be distinct from the other indica CMS lines and clustered with lines developed in its background.
The grouping of CMS lines into a few groups is useful for breeders in selecting genetically diverse CMS lines for hybrid rice
production and in avoiding test crossing every CMS line empirically. This study demonstrated that AFLP is a powerful and reliable
tool in determining the genetic relationships and in producing distinct fingerprints of rice cultivars.
Received: 20 December 1996 / Accepted: 9 October 1997 相似文献
963.
J. Wang K. D. Liu C. G. Xu X. H. Li Q. Zhang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(3):407-412
Wide-compatibility varieties (WCVs) are a special class of rice germplasm that is able to produce fertile hybrids when crossed
to both indica and japonica rice varieties. WCVs may differ greatly in their spectrum and level of compatibility. The objective
of this study was to determine the genetic basis of wide-compatibility conferred by ‘Dular’, a landrace variety from India
that has demonstrated a high level of wide-compatibility in previous studies with a broad range of indica and japonica varieties.
A three-way cross (‘Balilla/Dular//Nanjing 11’) was made and the resulting F1 population evaluated in the field for spikelet fertility. A total of 235 plants from this population was assayed individually
for restriction fragment length polymorphisms (RFLPs) at 159 marker loci covering the entire rice genome at regular intervals.
Quantitative trait locus (QTL) analysis identified 5 loci, located on chromosomes 1, 3, 5, 6 and 8, as having significant
effects on hybrid fertility, which jointly explained 55.5% of the fertility variation in this population. The QTL on chromosome
5 ( f5) showed the largest effect on hybrid fertility, followed by those on chromosomes 6 ( f6), 3 ( f3) and 1 ( f1), with the one on chromosome 8 ( f8) having the smallest effect. Genotypes each composed of an allele from ‘Dular’ and an allele from ‘Nanjing 11’ at four ( f3, f5, f6 and f8) of the five QTLs contributed to the increase of fertility in the population. In contrast, the genotype composed of alleles
from ‘Balilla’ and ‘Nanjing 11’ at the fifth locus ( f1) was in the direction of increasing fertility. Analysis of variance using marker genotypes at the five QTLs as the groups
detected two interactions involving four of the five loci, a 2-locus interaction between f5 and f8 and a 3-locus interaction among f3, f5 and f6. The level of hybrid fertility is the result of complex interactions among these loci. The implication of the present findings
in the utilization of the wide-compatibility of ‘Dular’ in rice breeding programs is also discussed.
Received: 21 October 1997 / Accepted: 30 December 1997 相似文献
964.
Genetic diversity and its relationship to hybrid performance in maize as revealed by RFLP and AFLP markers 总被引:50,自引:0,他引:50
P. Ajmone Marsan P. Castiglioni F. Fusari M. Kuiper M. Motto 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(2):219-227
The challenge to maize breeders is to identify inbred lines that produce highly heterotic hybrids. In the present study we
surveyed genetic divergence among 13 inbred lines of maize using DNA markers and assessed the relationship between genetic
distance and hybrid performance in a diallel set of crosses between them. The parental lines were assayed for DNA polymorphism
using 135 restriction fragment length polymorphisms (RFLPs) and 209 amplified-fragment polymorphisms (AFLPs). Considerable
variation among inbreds was detected with RFLP and AFLP markers. Moreover AFLPs detect polymorphisms more efficiently in comparison
to RFLPs, due to the larger number of loci assayed in a single PCR reaction. Genetic distances (GDs), calculated from RFLP
and AFLP data, were greater among lines belonging to different heterotic groups compared to those calculated from lines of
the same heterotic group. Cluster analysis based on GDs revealed associations among lines which agree with expectations based
on pedigree information. The GD values of the 78 F1 crosses were partioned into general (GGD) and specific (SGD) components. Correlations of GD with F1 performance for grain yield were positive but too small to be of predictive value. The correlations of SGDs, particularly
those based on AFLP data, with specific combining-ability effects for yield may have a practical utility in predicting hybrid
performance.
Received: 15 August 1997 / Accepted: 19 September 1997 相似文献
965.
Sample size for collecting seeds in germplasm conservation: the case of the Lima bean (Phaseolus lunatus L.) 总被引:2,自引:0,他引:2
I. Zoro Bi A. Maquet J. Degreef B. Wathelet J. P. Baudoin 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(1-2):187-194
The design of optimum sampling strategies integrating criteria of efficiency relevant to multilocus models and many target
populations has been investigated with respect to the number of plants and the number of seeds per plant to be sampled for
a Lima bean (Phaseolus lunatus L.) gene pool. This study, using five populations and six polymorphic enzyme loci, shows that the number of plants rather
than the number of seeds collected per plant primarily determines the success of seed sampling, suggesting that plant number
plays an essential part in maintaining the allelic multiplicity of predominantly selfing species like Lima bean. According
to the results, it appears that among Lima bean populations an efficient sampling procedure is achieved by collecting 1–4
seeds from 200 to 300 plants. These sample sizes will retain 8–10 alleles, regardless of their frequencies. When we consider
polymorphism at the 5% level, it is expected that sampling 10–80 plants will collect combinations of 4–8 alleles. Based on
data from genetic and demographic studies, we suggest an efficient sampling scheme for Lima bean germplasm at both population
and geographical levels.
Received: 10 March 1998 / Accepted: 1 April 1998 相似文献
966.
The use of microsatellite markers for detection of genetic diversity in barley populations 总被引:41,自引:0,他引:41
D. Struss J. Plieske 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(1-2):308-315
A barley lambda-phage library was screened with (GA)n and (GT)n probes for developing microsatellite markers. The number of repeats ranged from 2 to 58 for GA and from 2 to 24 for GT. Fifteen
selected microsatellite markers were highly polymorphic for barley. These microsatellite markers were used to estimate the
genetic diversity among 163 barley genotypes chosen from the collection of the IPK Genebank, Germany. A total of 130 alleles
were detected by 15 barley microsatellite markers. The number of alleles per microsatellite marker varied from 5 to 15. On
average 8.6 alleles per locus were observed. Except for GMS004 all other barley microsatellite markers showed on average a
high value of gene diversity ranging from 0.64 to 0.88. The mean value of gene diversity in the wild forms and landraces was
0.74, and even among the cultivars the gene diversity ranged from 0.30 to 0.86 with a mean of 0.72. No significant differences
in polymorphism were detected by the GA and GT microsatellite markers. The estimated genetic distances revealed by the microsatellite
markers were, on average , 0.75 for the wild forms, 0.72 for landraces and 0.70 among cultivars. The microsatellite markers
were able to distinguish between different barley genotypes. The high degree of polymorphisms of microsatellite markers allows
a rapid and efficient identification of barley genotypes.
Received: 26 November 1997 / Accepted: 19 January 1998 相似文献
967.
AFLP genetic maps of Eucalyptus globulus and E. tereticornis 总被引:8,自引:0,他引:8
C. M. Marques J. A. Araújo J. G. Ferreira R. Whetten D. M. O’Malley B.-H. Liu R. Sederoff 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(6-7):727-737
Amplified fragment length polymorphism (AFLP) analysis is a rapid and efficient technique for detecting large numbers of
DNA markers in eucalypts. We have used AFLP markers in a two-way pseudo-testcross strategy to generate genetic maps of two
clones of different Eucalyptus species (E. tereticornis and E. globulus). Of 606 polymorphic fragments scored, 487 segregated in a 1 : 1 ratio, corresponding to DNA polymorphisms heterozygous in
one parent and null in the other. In the maternal E. tereticornis map, 268 markers were ordered in 14 linkage groups (919 cM); the paternal E. globulus map had 200 markers in 16 linkage groups (967 cM). Results from PGRI software were compared with MAPMAKER. The average density
of markers was approximately 1 per 3.9 cM. Framework markers were ordered with an average confidence level of 90%, covering
80–100% of the estimated Eucalyptus genome size. In order to investigate the homologies between the E. tereticornis and the E. globulus genetic linkage maps, we included 19 markers segregating 3 : 1 in the analysis. Some homeologous linkage groups were recognized.
The linkage data developed in these maps will be used to detect loci controlling commercially important traits.
Received: 17 July 1997 / Accepted: 13 October 1997 相似文献
968.
Genetic evidence of closed life-cycles for some coral reef fishes within Taiaro Lagoon (Tuamotu Archipelago, French Polynesia) 总被引:2,自引:0,他引:2
Taiaro Lagoon has no permanent or regular connection with the ocean (ingress is restricted to episodes of high sea-level
and/or strong wave action) raising the question of how fish populations with normally dispersive larvae are maintained inside
this lagoon. We compared the genetic population structures of two coral reef fishes, Acanthurus triostegus and Chaetodon ulietensis, present on both sides of the atoll rim to determine whether there is evidence of reproductive isolation. Genetic surveys
showed that the lagoonal and oceanic populations were statistically different at five loci (AAT
*
-3, GDA
*, HPD
*, MDH
* and SDH
*) in A. triostegus and three loci (PGI-2*, IDH
* and PGD
*) in C. ulietensis, producing high F
st values of 0.055 and 0.021, respectively. Our genetic and demographic data on these species suggest that both may be completing
their life-cycles inside the lagoon, which leads us to question the common assumption that coral reef fishes require oceanic
conditions for larval development.
Accepted: 28 August 1997 相似文献
969.
Transgenic Japanese lawngrass (Zoysia japonica Steud.) plants regenerated from protoplasts 总被引:14,自引:0,他引:14
Transgenic Japanese lawngrass (Zoysia japonica Steud.) plants were generated by means of polyethylene glycol (PEG)-mediated direct gene transfer into protoplasts. The plasmid
pBC1 was used to deliver the hygromycin phosphotransferase (hph) and β-glucuronidase (gus) genes into protoplasts. Selection with a high concentration (400 mg/l) of hygromycin yielded a number of resistant calli
and about 400 plants were generated. Polymerase chain reaction (PCR) and Southern hybridization analyses revealed that all
of then plants tested contained introduced genes. The gus gene regulated by the maize alcohol dehydrogenase-1 (Adh 1) promoter was expressed in the leaves and roots of transgenic Japanese lawngrass plants.
Received: 13 December 1996 / Revision received: 9 June 1997 / Accepted: 2 September 1997 相似文献
970.
Timentin as an alternative antibiotic for suppression of Agrobacterium tumefaciens in genetic transformation 总被引:3,自引:0,他引:3
The effects of timentin on shoot regeneration of tobacco (Nicotiana tabaccum) and Siberian elm (Ulmus pumila L.) and its use for the suppression of Agrobacterium tumefaciens in Agrobacterium-mediated genetic transformation were determined. Timentin is a mixture of ticarcillin and clavulanic acid, and at concentrations
of 200–500 mg/l with ratios of ticarcillin:clavulanic acid of 50:1 and 100:1, it had little effect on shoot regeneration of
tobacco or Siberian elm. Timentin was as effective in suppressing A. tumefaciens as carbenicillin and cefatoxime at concentrations commonly used in transformation. The disarmed A. tumefaciens strain LBA4404 in infected tobacco leaf tissues was visually undetectable after three subcultures on medium with 500 mg/l
of timentin and 250 mg/l carbenicillin. Timentin was stable in solid agar medium and remained effective for at least 70 days,
but was unstable when stored as a mixed stock solution or as separate ticarcillin and clavulanic acid stock solutions at –20°C
or –80°C freezer for 4 weeks. Timentin may be an alternative antibiotic for the effective suppression of A. tumefaciens in genetic transformation.
Received: 8 September 1997 / Revision received: 19 November 1997 / Accepted: 2 December 1997 相似文献