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1.
Digital images of ex situ germplasm stored in the Sardinian Germplasm Bank (BG-SAR) were used for the application of image analysis techniques at the Stazione Sperimentale di Granicoltura per la Sicilia. The analysed accessions refer to 148 taxonomic units belonging to 102 genera and 47 families, typical of the Sardinian flora, and of the Mediterranean basin in general.The images of diaspores were acquired by a flatbed scanner and elaborated with a macro specially developed for the morphometric and colorimetric measurements. This method allowed carrying out a database for the characterization of autochthonous germplasm in entry to the bank and the realization of statistic classifiers for the discrimination of genera and species within the following families: Apiaceae, Boraginaceae, Caryophyllaceae, Cistaceae, Fabaceae and Scrophulariaceae. Such classifiers, based on the linear discriminant analysis (LDA) technique and checked by cross-validation, showed a performance included between 74.3% and 96.4%.In addition, for the genus Astragalus, it was possible to elaborate a classifier able to identify very similar taxa of a species complex, obtaining a performance between 83.7% and 100%. Such analysis proved the validity of the methodology also from the taxonomic point of view.Suggestions for subsequent methodological progress, which could offer applications in other research issues, such as ecological analysis, soil seed bank and archaeological botany are proposed.  相似文献   
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The synthesis and characterization of rare-earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) thiocyanate adducts with tripiperidinophosphine oxide (tpppO) with general formula (RE)(SCN)3(tpppO)3 are reported. Conductance measurements in acetonitrile indicate the non-electrolytic nature of the complexes. Infrared absorption spectra evidence that the SCN ion coordinates through the nitrogen atom (isothiocyanate form) and that tpppO coordinates through the phosphoryl oxygen. X-ray powder patterns suggest the existence of three different crystal forms: (1) La; (2) an isomorphous series including Ce, Nd and Pr; and (3) another isomorphous series, including Sm, Gd, Eu, Ho, Er, Tb, Lu and Y. The visible spectra of the Nd adduct and the calculated parameters β = 0.98, b1/2 = 0.072 and δ = 1.06 indicate that the metal-ligand bonds are essentially electrostactic. The emission spectra of the Eu compound showed 5D0 → 7FJ bands (J = 0, 1, 2), suggesting a C3v symmetry for the coordination polyhedron. The lifetime of the 5D0 state is 1.28 ms. The emission spectra of the Tb complex presented 5D4 → 7FJ bands (J = 4, 5, 6) and the Dy complex showed the 4F9/2 → 6H13/2 band. The structure of the Pr complex showed that the coordination polyhedron is a trigonal antiprism, with the isothiocyanate anions in one base and three tpppO ligands in the other. Thermal analyses (TG-DTG) were carried out for the Ce, Nd and Gd adducts. Mass losses start between 250 and 334 °C. The final residues at 1300 °C are the corresponding phosphates.  相似文献   
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 The relative diversity and distinctness of Ethiopian barleys has been investigated using (1) morphology/isozyme/hordein polymorphisms and (2) RFLP markers. In the former a set of 51 landraces from over the whole of Ethiopia was compared with Iranian landraces based on data from previous studies and new hordein data. The two sets of landraces were found to have a comparable diversity. The Ethiopian ones are more diverse morphologically (5 traits), are similar in numbers of alleles per protein locus (17 loci) and in genetic differentiation, but are less diverse in average heterozygosity per locus and degree of polymorphism. However, on the basis of the hordein data the two sources of germplasm are very distinct. The correlation between morphological and protein diversity is very low. In the RFLP study 28 probes evenly distributed across the genome were used to analyse 43 Ethiopian landraces (represented by one single genotype) and to compare them with modern cultivars from North America, Europe and Japan, as well as 3 landraces from Iran, 1 from Nepal, and 1 accession of H. spontaneum from Afghanistan. The major finding was that the Ethiopian germplasm appears to be significantly less diverse than the modern germplasm but that it is genotypically very distinct. The apparent contradiction between a high diversity of useful genes coming from Ethiopia and an apparently low diversity at the DNA level is discussed. Received: 22 July 1996 / Accepted: 26 July 1996  相似文献   
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Abstract.  1. The survival, growth and fecundity of bumblebee colonies are affected by the availability of food resources and presence of natural enemies. Social parasites (cuckoo bumblebees and other bumblebees) can invade colonies and reduce or halt successful reproduction; however, little is known about the frequency of invasion or what environmental factors determine their success in the field.
2. We used 48 experimental colonies of the bumblebee Bombus terrestris , and manipulated both resource availability at the landscape scale and date of colony founding, to explore invasion rates of social parasites and their effect on the performance of host colonies.
3. Proximity to abundant forage resources (fields of flowering oilseed rape) and early colony founding significantly increased the probability of parasite invasion and thus offset the potential positive effects of these factors on bumblebee colony performance.
4. The study concludes that optimal colony location may be among intermediate levels of resources and supports schemes designed to increase the heterogeneity of forage resources for bumblebees across agricultural landscapes.  相似文献   
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The range of uses of a conservation area by a nearby population was quantified by questionnaires applied to residents of Santa Helena county, Brazil. Of the 312 responses compiled, 71.2% of the residents acknowledged the presence of a conservation unit within the county limits while only 59.3% of the respondents had participated in some recreational or leisure outdoor activity within the unit. Activities cited by respondents included games (11.7%), beach visits (11.4%), cross-country walks (9.4%), and fishing (8.3%). A possible visitor fee to improve infrastructure within the area was approved by 64.9% of the interviewees. Suggested visitor fee varied from 50 cents to two dollars.  相似文献   
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Attention is increasingly being given to genetic resources in the deep seabed beyond the limits of national jurisdiction owing to their considerable potential scientific and economic value. At the same time, there are concerns that the increased demand for these genetic resources may result in their unsustainable collection or even in the extinction of species in the deep seabed. At present there is no specific legal framework governing these resources in international law. Thus, this article explores the relevant rules of international law applicable to the conservation and sustainable use of genetic resources in the deep seabed.  相似文献   
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The sustainability of breeding activities in 15 pig farming systems in five European countries was evaluated. One conventional and two differentiated systems per country were studied. The Conventional systems were the standard systems in their countries. The differentiated systems were of three categories: Adapted Conventional with focus on animal welfare, meat quality or environment (five systems); Traditional with local breeds in small-scale production (three systems) and Organic (two systems). Data were collected with a questionnaire from nine breeding organisations providing animals and semen to the studied farming systems and from, on average, five farmers per farming system. The sustainability assessment of breeding activities was performed in four dimensions. The first dimension described whether the market for the product was well defined, and whether the breeding goal reflected the farming system and the farmers’ demands. The second dimension described recording and selection procedures, together with genetic change in traits that were important in the system. The third dimension described genetic variation, both within and between pig breeds. The fourth dimension described the management of the breeding organisation, including communication, transparency, and technical and human resources. The results show substantial differences in the sustainability of breeding activities, both between farming systems within the same category and between different categories of farming systems. The breeding activities are assessed to be more sustainable for conventional systems than for differentiated systems in three of the four dimensions. In most differentiated farming systems, breeding goals are not related to the system, as these systems use the same genetic material as conventional systems. The breeds used in Traditional farming systems are important for genetic biodiversity, but the small scale of these systems renders them vulnerable. It is hoped that, by reflecting on different aspects of sustainability, this study will encourage sustainable developments in pig production.  相似文献   
10.
BackgroundThe rare earth elements (REE) are non-essential elements for plants. They stimulate plant growth at low doses, but at high levels are phytotoxic. There are differences in concentrations of REE in various organs of the same plant species, but the normalized REE patterns can be very similar in samples of the same species collected in different locations. Here we compare normalized REE curves in above-ground samples of Juncus effusus L. (common rush, soft rush) collected from sites with different land-use types.MethodsThe concentrations of rare earth elements were measured in 55 shoot samples of J. effusus L. The samples were collected from 15 sampling sites located in the Holy Cross Mts., south-central Poland and analyzed with the use of inductively coupled plasma mass spectrometry (ICP-MS). The results were normalized to the North American Shale Composite and anomalies of different elements were calculated.ResultsTotal REE concentrations varied from 0.028 mg/kg to 2.7 mg/kg. The samples were enriched in the light REE (from La to Eu) with the highest concentrations of La and Ce. The North American Shale Composite (NASC)-normalized REE curves were roughly similar in all samples except for two samples collected in the acid mine drainageaffected areas.ConclusionAll samples showed positive europium anomalies in NASC-normalized REE concentration patterns. The most probable explanation of this is that the uptake and translocation of Eu in J. effusus (and possibly in other wetland plants) is caused by a short-term decrease of the redox potential in a rhizosphere favoring reduction of Eu3+ to Eu2+ and thus enhancing Eu mobility in the soil-plant environment.  相似文献   
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