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71.
Three species that Navás described - Leucochrysa (Nodita) azevedoi Navás, 1913, Leucochrysa (Nodita) camposi (Navás, 1933) and Leucochrysa (Nodita) morenoi (Navás, 1934) - have received recent taxonomic attention. All three have many similar external features; indeed Navás himself, as well as subsequent authors, have confused the species with each other. Here, (a) misidentifications are corrected; (b) a neotype of Leucochrysa azevedoi is designated; (c) Leucochrysa (Nodita) morenoi, previously synonymized with Leucochrysa (Nodita) camposi, is recognized as a valid species [Reinstated status] All three species are redescribed and illustrated, with special emphasis on the types. Leucochrysa (Nodita) azevedoi was found to be relatively common in agricultural areas along Brazil's Atlantic coast. The two other species are known only from their type localities: Leucochrysa (Nodita) camposi - coastal Ecuador, and Leucochrysa (Nodita) morenoi - Quito, Ecuador.  相似文献   
72.
Rhinocerotids are particularly abundant and diversified in Neogene deposits of the Indian subcontinent, but their systematics is far from being well defined. Based on the revision of old collections and new findings from the Early Miocene of the Bugti Hills and Zinda Pir, Pakistan, ‘Aceratherium blanfordi Lydekker, 1884’ is a chimera, consisting of two dentally convergent but postcranially distinct rhinocerotid taxa: Pleuroceros blanfordi and Mesaceratherium welcommi sp. nov. Postcranial features appear to be much more diagnostic than craniodental morphology in this case. A phylogenetic analysis based on 282 morphological characters scored for 28 taxa (four outgroups and ingroup including both taxa of interest and a ‘branching group’) strengthens this statement and supports Pleuroceros and Mesaceratherium as monophyletic genera within Rhinocerotinae. Both genera are recognized for the first time outside Europe. In the Bugti Hills, P. blanfordi and M. welcommi are part of an exceptionally diversified rhinocerotid fauna, with up to nine species associated in the same locality (Kumbi 4f). This rhinocerotid assemblage confirms the earliest Miocene age (Agenian/Aquitanian) of the upper member of the Chitarwata Formation as a whole. Coeval homotaxic rhinocerotid faunas from Europe (France, Czech Republic) and East Africa (Uganda, Kenya) support broad and sustainable rhinocerotid interchanges amongst South Asia, Europe, and Africa under compatible environmental conditions throughout earliest Miocene times. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 139–194.  相似文献   
73.
Bis(2-hydroxy-3-tert-butyl-5-methylphenyl)methane (bis-phenol) is the most potent inhibitor of the (Ca2+ + Mg2+)-ATPase of skeletal muscle sarcoplasmic reticulum yet identified. The compound behaves as a reversible, tight-binding inhibitor with apparent Ki = 0.3 microM. Butylated hydroxytoluene, butylated hydroxyanisole, and 4-nonylphenol are also effective inhibitors. These observations are of particular interest in light of the widespread use of such phenolic antioxidants and stabilizers in the food industry and in the manufacture of rubbers and plastics and the ease with which the compounds are extracted into organic solvents.  相似文献   
74.
Hydroelectric reservoirs can stratify, producing favorable conditions for mercury methylation in the hypolimnion. The methylmercury (MeHg) can be exported downstream, increasing its bioavailability below the dam. Our objective was to assess the mercury levels in plankton, suspended particulate matter (SPM) and fish collected upstream (UP) and downstream (DW) from the Reservatório de Samuel dam, an Amazonian reservoir that stratifies during half of the year. Mercury concentrations in both SPM and plankton were similar between the two sites, which could indicate there are no conditions favoring methylation at the moment of sampling (absence of stratification). Almost all mercury found in the muscle of fishes was in organic form, and differences of mercury levels between sites were dependent on the fishes trophic level. Herbivores showed similar mean organic mercury levels (UP = 117 μg g?1; DW = 120 μg g?1; n = 12), whereas omnivores (UP = 142 μg g?1; DW = 534 μg g?1; n = 27) and carnivores (UP = 545 μg g?1; DW = 1,366 μg g?1; n = 69) showed significantly higher values below the dam. The absence of a reservoir effect in herbivores is expected, since they feed on grassy vegetation, near the riverbanks, which is not much influenced by mercury in aquatic systems. On the other hand, the higher mercury levels below the dam observed for omnivores and carnivores suggest a possible influence of the reservoir since they feed on items that could be contaminated by MeHg exported from upstream. The results highlight the necessity of assessing areas downstream of reservoirs.  相似文献   
75.
Journal of Plant Research - In mixed-ploidy populations, newly formed polyploids initially occur at low frequencies when compared to diploids. However, polyploidy may lead to morphological and...  相似文献   
76.
A Brazilian strain of Penicillium verrucosum was cultivated under different conditions in a two-step process, in order to verify the influence of nutrients, and of time periods of pre-fermentative and fermentative steps on the biosynthesis of metabolites. Extracellular and intracellular extracts were obtained from each culture in the four different production media used. Chemical profiles of the extracts were obtained by HPLC. Extract trypanocidal activities against trypomastigote forms of Trypanosoma cruzi were evaluated. The time period of incubation in the pre-fermentative and fermentative media, as well as the different nutrients tested, qualitatively and quantitatively modified the production of secondary metabolites by P. verrucosum, and the extract trypanocidal activities.  相似文献   
77.
78.
Mannosylglycerate (MG) is a common compatible solute found in thermophilic and hyperthermophilic prokaryotes. In this study we characterized a mesophilic and bifunctional mannosylglycerate synthase (MGSD) encoded in the genome of the bacterium Dehalococcoides ethenogenes. mgsD encodes two domains with extensive homology to mannosyl-3-phosphoglycerate synthase (MPGS, EC 2.4.1.217) and to mannosyl-3-phosphoglycerate phosphatase (MPGP, EC 3.1.3.70), which catalyze the consecutive synthesis and dephosphorylation of mannosyl-3-phosphoglycerate to yield MG in Pyrococcus horikoshii, Thermus thermophilus, and Rhodothermus marinus. The bifunctional MGSD was overproduced in Escherichia coli, and we confirmed the combined MPGS and MPGP activities of the recombinant enzyme. The optimum activity of the enzyme was at 50 degrees C. To examine the properties of each catalytic domain of MGSD, we expressed them separately in E. coli. The monofunctional MPGS was unstable, while the MPGP was stable and was characterized. Dehalococcoides ethenogenes cannot be grown sufficiently to identify intracellular compatible solutes, and E. coli harboring MGSD did not accumulate MG. However, Saccharomyces cerevisiae expressing mgsD accumulated MG, confirming that this gene product can synthesize this compatible solute and arguing for a role in osmotic adjustment in the natural host. We did not detect MGSD activity in cell extracts of S. cerevisiae. Here we describe the first gene and enzyme for the synthesis of MG from a mesophilic microorganism and discuss the possible evolution of this bifunctional MGSD by lateral gene transfer from thermophilic and hyperthermophilic organisms.  相似文献   
79.

Background

Detailed analysis of the dynamic interactions among biological, environmental, social, and economic factors that favour the spread of certain diseases is extremely useful for designing effective control strategies. Diseases like tuberculosis that kills somebody every 15 seconds in the world, require methods that take into account the disease dynamics to design truly efficient control and surveillance strategies. The usual and well established statistical approaches provide insights into the cause-effect relationships that favour disease transmission but they only estimate risk areas, spatial or temporal trends. Here we introduce a novel approach that allows figuring out the dynamical behaviour of the disease spreading. This information can subsequently be used to validate mathematical models of the dissemination process from which the underlying mechanisms that are responsible for this spreading could be inferred.

Methodology/Principal Findings

The method presented here is based on the analysis of the spread of tuberculosis in a Brazilian endemic city during five consecutive years. The detailed analysis of the spatio-temporal correlation of the yearly geo-referenced data, using different characteristic times of the disease evolution, allowed us to trace the temporal path of the aetiological agent, to locate the sources of infection, and to characterize the dynamics of disease spreading. Consequently, the method also allowed for the identification of socio-economic factors that influence the process.

Conclusions/Significance

The information obtained can contribute to more effective budget allocation, drug distribution and recruitment of human skilled resources, as well as guiding the design of vaccination programs. We propose that this novel strategy can also be applied to the evaluation of other diseases as well as other social processes.  相似文献   
80.

Background

Ezrin is a cytoskeletal protein that is involved in tumor growth and invasion. It has been suggested that Ezrin expression plays an important role in tumor metastasis. This study is aimed to investigate the clinicopathological significance of Ezrin overexpression in gastric adenocarcinomas.

Methods

Ezrin protein expression was examined by immunohistochemistry in 26 normal gastric mucosa, 32 dysplasia, and 277 gastric adenocarcinomas. The relationship between Ezrin expression and the clinicopathological features of gastric cancers was analyzed. In addition, a gastric cancer cell line, MKN-1, was also used for immunofluorescence staining to evaluate the distribution of Ezrin protein.

Results

Ezrin protein located in the cytoplasm and/or membrane in the migrating gastric cancer cells, and it mainly concentrated at the protrusion site; however, only cytoplasmic distribution was observed in the non-migrating cancer cells by immunofluorescence staining. The positive rate of Ezrin protein expression was significantly higher in gastric adenocarcinoma and dysplasia compared with that in the normal gastric mucosa. Moreover, expression frequency of Ezrin protein increased significantly in lymph node metastasis and late clinical stages. Consistently, strong expression of Ezrin was significantly correlated with poor prognosis of gastric cancer.

Conclusion

The detection of Ezrin expression can be used as the marker for early diagnosis and prognosis of gastric adenocarcinoma.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2303598677653946  相似文献   
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