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101.
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Four Roccella species, R. canariensis, R. fimbriata, R. montagnei, and R. tuberculata, were found to possess sequence insertions in up to four locations in the first half of the SSU rDNA. Insertions from one of these positions have been classified as group I introns, while the others may represent degenerative forms of group I introns or messenger RNA introns. Two of the insertion-containing taxa, R. canariensis and R. tuberculata, differ only in their dispersal strategy: R. canariensis is sexual, producing only fruiting bodies and R. tuberculata is sterile, producing only vegetative propagules, i.e., soredia. Because insertions occurred in specimens of both taxa, they were used to examine the phylogenetic relationships between and within the two species. The sequence insertions from each of the four positions were aligned and cladistically analyzed separately. Internal transcribed spacers (ITS) were additionally sequenced to study the phylogeny of all R. canariensis and R. tuberculata specimens. Three other Roccella species (R. babingtonii, R. fimbriata, and R. montagnei) and Dirina catalinariae were used as outgroups in this parsimony analysis. Sequence insertions were found to be potentially useful in phylogenetic studies, although due to the sequence dissimilarity, homology relations were difficult to establish above the species level and in some cases even within the species. The phylogenies obtained from the insertion matrices were totally consistent with the ITS data and the insertions were concluded to have been inherited. When the insertion and ITS data were combined for total evidence, R. canariensis and R. tuberculata did not form distinct lineages in the phylogenetic tree, but appeared mixed in well-supported groups containing both sorediate and fertile specimens.  相似文献   
103.
The Touchet River in eastern Washington State is the site of the first causal assessment in the arid Northwest for salmonids using the U.S. Environmental Protection Agency's (USEPA's) Stressor Identification process. Seven candidate causes that affect salmonid density and macroinvertebrate abundance and diversity were considered: toxics, warm water temperature, sedimentation, low dissolved oxygen, alkaline pH, reduced detritus, and reduced habitat complexity. Candidate causes were evaluated using several types of evidence of preceding causation, co-occurrence, sufficiency, and alteration along with evaluation of the consistency of that evidence and consistency with other assessments. Evidence was scored, and the body of evidence was weighed based on credibility, strength, diversity, and coherence. Warm water temperature and sedimentation were highly probable causes of altered biological condition. Low dissolved oxygen and alkaline pH were also a problem for some areas but were less severe than temperature and sediment. Water removal and reduced habitat complexity and canopy cover were not directly causal but could affect sedimentation and temperature. This case study is noteworthy for using assemblage symptomology associated with temperature, sediment, and detritus as a type of evidence and for physiographically matching reference sites for comparisons and evaluation of natural and cumulative anthropogenic stressor gradients in the absence of state biological criteria.  相似文献   
104.
In the past few decades, some novel low‐cost nanostructured devices have been explored for converting solar energy into electrical or chemical energy, such as organic photovoltaic cells, photoelectrochemical solar cells, and solar water splitting cells. Generally, higher light absorption and/or charge separation efficiency are considered as the main reasons for improved performance in a nanostructured device versus a planar structure. However, quantitative analysis and definite experimental evidence remain elusive. Here, using BiVO4 as an example, comparable samples with porous and dense structures have been prepared by a simple method. The porous and dense films are assembled into a solid‐electrolyte bulk and planar heterojunction, respectively. Some quantitative results are obtained by decoupling photon absorption, interfacial charge transfer, and charge separation processes. These results suggest that higher charge separation efficiency is mainly responsible for enhanced performance in a solid‐electrolyte bulk heterojunction. Moreover, we also present visualized evidence to show higher charge separation efficiency comes from a shorter photo‐generated hole diffusion distance in a bulk heterojunction. These results can deepen understanding charge transfer in a bulk heterojunction and offer guidance to design a more efficient low‐cost device for solar conversion and storage.  相似文献   
105.
Objective: Although obesity is increasing in older U.S. adults, treatment is controversial in this age group. We sought to examine evidence concerning obesity's health‐related risks, diagnostic methods, and treatment outcomes in older individuals. Research Methods and Procedures: We searched MEDLINE and Cochrane Library databases, consulted with experts, and examined bibliographies for English language studies discussing obesity in older adults (mean age ≥ 60), published between January 1980 and November 2005. Inclusion criteria were met by 32 longitudinal analyses, seven diagnostic studies, and 17 randomized controlled trial articles. At least two authors independently reviewed and abstracted study design, population, results, and quality information. Results: Correlations between body fat and three anthropometric measures (BMI, waist circumference, waist‐to‐hip ratio) decrease with age but remain clinically significant. Obesity contributes to risk for several cardiovascular endpoints, some cancers, and impaired mobility but protects against hip fracture. The association between obesity and mortality declines as age increases. Intensive counseling strategies incorporating behavioral, dietary, and exercise components promote a weight loss of 3 to 4 kg over 1 to 3.3 years. The loss is linked with improved glucose tolerance, improved physical functioning, reduced incidence of diabetes and a combined hypertension and cardiovascular endpoint, and reduced bone density. Discussion: In older adults, obesity can be diagnosed with standard clinical measures. Intensive counseling can promote modest sustained weight loss, but data are insufficient to evaluate surgical or pharmacological options. Obesity treatment is most likely to benefit individuals with high cardiovascular risk. Limited data suggest possible functional improvement. Treatment should incorporate measures to avoid bone loss.  相似文献   
106.
The life on the Earth experienced periodically not only significant impoverishments (mass extinctions), but also remarkable rises in diversity. Two recent biodiversity curves and new information on glaciations, sea- level, and plate tectonics, permit to extend our knowledge on the latters. Four Palaeozoic major radiations in the marine realm are identified. They include the early Cambrian (PZMR1), Ordovician (PZMR2), Early Devonian (PZMR3), and mid-Permian (PZMR4) events. PZMR1 occurred immediately after the major end-Proterozoic glaciations, when global sea-level rose with low-magnitude fluctuations and huge well-connected oceans provided a peculiar space for biological innovations. PZMR2 happened at a time of unique sea-level highstand and well-connected watermasses. PZMR3 coincided with a relative sea-level lowstand, which, together with the presence of elongated island chains, might have enhanced the radiation by a rapid dispersal of organisms across shallow oceans and along connected shorelines. PZMR4 occurred at the end of the outstanding planetary-scale Late Palaeozoic glaciation. Generally, the Palaeozoic major radiations in the marine realm did not have an ultimate cause and did not occur in a similar palaeoenvironmental setting. The molecular clock approach suggests a possible link between the DNA-dated divergences of marine invertebrates and the identified major radiations.  相似文献   
107.
Recent models support the idea of sympatric speciation as a result of the joint effects of disruptive selection and assortative mating. We present experimental data, testing models of speciation through frequency‐dependent selection. We show that under high competition on a mixture of resources/hosts, strains of the Seed beetle, Callosobruchus maculatus, change their host fidelity and evolve a more generalistic behaviour in resource utilization among females. The change in host fidelity did not result in disruptive selection and was not followed by assortative mating. This means that only one of three fundamental prerequisites for sympatric speciation evolved as a result of the frequency‐dependent selection. We conclude that for this process to work, a shift to a novel food resource as a result of selection must also lead to a loss of preference for the original resource such that individuals are only able to use either one of the two.  相似文献   
108.
ObjectivesThe coverage policies of many commercial insurers in the United States do not include coverage of stereotactic radiosurgery (SRS) for intractable epilepsy despite recent Level I evidence supporting its efficacy. We sought to assess the efficacy of an evidence-based methodology in obtaining coverage approval of SRS for intractable epilepsy.Patients and MethodsThe clinical policy guidelines from five of the largest United States commercial insurers were reviewed for their language regarding coverage of SRS for epilepsy. An evidence-based questionnaire was created for temporal lobe epilepsy and extratemporal lobe epilepsy based on recent evidence. Telephone interviewers of Insurers assessed the likelihood of SRS coverage for an epilepsy patient meeting the clinical inclusion criteria in the questionnaire. This likelihood was assessed numerically based on interviewee response (2 = yes, 1 = dependent on peer-to-peer, 0 = no).ResultsOf the five policy guidelines, none included literature more recent than 2017. For TLE, 3/5 insurance companies indicated likely SRS coverage; 2/5 indicated peer-to-peer discussion dependence for patients meeting questionnaire criteria for a score of 8/10. For extratemporal TLE, 2/5 companies indicated likely SRS coverage and 3/5 indicated peer-to-peer discussion dependence for a total score of 7/10.ConclusionCreation of an evidence-based methodology in approaching commercial insurers greatly increased the likelihood of SRS coverage for an indication (intractable epilepsy) widely perceived as investigational. These results should pave the way for epilepsy patients to receive coverage should they be appropriate SRS candidates.  相似文献   
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Although studies describing molecular‐based phylogenies within tardigrades are now frequently being published, this is not the case for studies combining molecular and morphological characters. Tardigrade phylogeny is still based, from a morphological point of view, almost exclusively on chitinous structures and little attention has been given to detecting and using novel morphological data. Consequently, we analysed the musculature of seven tardigrade species belonging to the main phyletic lines by confocal laser scanning microscopy and compared these morphological results with new molecular analyses (18S+28S rRNA genes). Finally, we analysed all the data with a total evidence approach. A consilience in the phylogenetic relationships among orders and superfamilies of tardigrades was obtained among the evolutionary trees obtained from morphological, molecular and total evidence approaches. Comparative analysis on the musculature allowed the identification of serial homologies and repeated metameric patterns along the longitudinal animal body axis. A phenomenon of mosaic evolution was detected in musculature anatomy, as dorsal musculature was found to be highly modified with respect to the other body muscle groups, probably related to the evolution of dorsal cuticular plates. An understanding of tardigrade musculature anatomy will give fundamental information to understand the evolution of segmental pattern within Panarthropoda. © 2013 The Linnean Society of London  相似文献   
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