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221.
222.
VESICULAR-ARBUSCULAR MYCORRHIZA IN FIELD-GROWN CROPS 总被引:10,自引:6,他引:4
223.
Bathymetric barriers promoting genetic structure in the deepwater demersal fish tusk (Brosme brosme)
HALVOR KNUTSEN PER ERIK JORDE† HANNE SANNÆS A. RUS HOELZEL‡ ODD AKSEL BERGSTAD SERGIO STEFANNI§ TORILD JOHANSEN¶ NILS CHR. STENSETH† 《Molecular ecology》2009,18(15):3151-3162
Population structuring in the North Atlantic deepwater demersal fish tusk ( Brosme brosme ) was studied with microsatellite DNA analyses. Screening eight samples from across the range of the species for seven loci revealed low but significant genetic heterogeneity ( F ST = 0.0014). Spatial genetic variability was only weakly related to geographical (Euclidean) distance between study sites or separation of study sites along the path of major ocean currents. Instead, we found a significant effect of habitat, indicated by significant differentiation between relatively closely spaced sites: Rockall, which is surrounded by very deep water (>1000 m), and the Mid-Atlantic Ridge, which is separated from the European slope by a deep ocean basin, were differentiated from relatively homogeneous sites across the Nordic Seas. Limited adult migration across bathymetric barriers in combination with limited intersite exchange of pelagic eggs and larvae due to site-specific circulatory retention or poor survival during drift phases across deep basins may be reducing gene flow. We regard these limitations to gene flow as the most likely mechanisms for the observed population structure in this demersal species. The results underscore the importance of habitat boundaries in marine species. 相似文献
224.
Abstract. Sympetrinae is the largest subfamily of the diverse dragonfly family Libellulidae. This subfamily, like most libellulid subfamilies, is defined currently by a few wing venation characters, none of which are synapomorphies for the taxon. In this study, we used DNA sequence data from the nuclear locus elongation factor-1α and the mitochondrial loci 16S and 12S rRNA, together with 38 wing venation characters, to test the monophyly of the Sympetrinae and several other libellulid subfamilies. No analysis recovered Sympetrinae as monophyletic, partly because of the position of Leucorrhinia (of the subfamily Leucorrhininae) as a strongly supported sister to Sympetrum (of Sympetrinae) in all analyses. The subfamilies Brachydiplactinae, Leucorrhininae, Trameinae and Trithemistinae were also found not to be monophyletic. Libellulinae was the only subfamily supported strongly as monophyletic. Consistency indices and retention indices of wing venation characters used to define various subfamilies were closer to zero than unity, showing that many of these characters were homoplasious, and therefore not useful for a classification scheme within Libellulidae. 相似文献
225.
The reporting of child sexual abuse (CSA) and physician-patient sexual
relationships (PPSR) are currently the focus of professional, legal and media
attention in several countries. This paper briefly reviews mental health policies
on these issues and reports on a WPA survey of them. While the WPA Madrid
Declaration permits breaching confidentiality for mandatory reporting of CSA
and clearly prohibits PPSR, it is not known how or to what extent these policies
are implemented in WPA Member Societies’ countries. It is also not known
whether policies or laws exist on these topics nationally or to what extent
psychiatrists and the public are aware of them. Representatives of WPA Member
Societies were e-mailed a survey about issues pertaining to CSA and PPSR.
Fifty-one percent of 109 countries replied. All reporting countries had laws
or policies regarding the reporting of CSA, but this was often voluntary (63%)
and without protection for reporting psychiatrists either by law (29%) or
by Member Societies (27%). A substantial number of psychiatric leaders did
not know the law (27%) or their Society’s policy (11%) on these matters.
With respect to PPSR, some reporting countries lacked laws or policies about
PPSR with current (17%) or past (56%) patients. Fewer than half of responding
representatives believed that their Society’s members or the public
were well informed about the laws and policies pertaining to CSA or PPSR.
There is clearly a wide range of laws, policies and practices about CSA and
PPSR in WPA Member Societies’ countries. There is a need in some countries
for laws or supplemental policies to facilitate the protection of vulnerable
child and adult patients through clear, mandatory reporting policies for CSA
and PPSR. Mechanisms to protect and support reporting psychiatrists should
also be developed where they do not already exist. There is also a need in
some countries to develop strategies to improve the education of psychiatrists,
trainees, and the public on these issues. 相似文献
226.
ERIK WESTBERG HANS‐HELMUT POPPENDIECK JOACHIM W. KADEREIT 《Biological journal of the Linnean Society. Linnean Society of London》2010,101(3):526-535
Oenanthe conioides is a lower Elbe endemic plant species growing in the freshwater tidal zone around Hamburg (Germany). Its closest relative Oenanthe aquatica is widely distributed in Eurasia and grows in calm and shallow freshwater. The two species differ in habitat requirements but are otherwise sympatrically distributed, suggesting that ecological divergence has to be maintained in the face of gene flow. In the present study, we investigated ecological differentiation and reproductive isolation in these two species. An amplified fragment length polymorphism analysis found clear genetic differentiation between the two species implying reproductive isolation. A reciprocal transplantation experiment including artificial F1 hybrids showed strong selection against immigrants. In the two parental habitats, the non‐native species are less fit than the native species. Hybrids are less fit in the habitat of Oe. aquatica but perform as well as the native species in the habitat of Oe. conioides. We hypothesize that selection against immigrants is the most important component of reproductive isolation between the two species, and that selection against immigrants is the result of exposure to cold and wind in the tidal habitat of Oe. conioides and to herbivory in the habitat of Oe. aquatica. These results are congruent with a role for differential ecological selection in the formation and maintenance of these two species. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 526–535. 相似文献
227.
1. The mate-locating strategies of Pararge aegeria (L.) males were studied in relation to adult morphology (dorsal wing colour, forewing length, body length and forewing length : body length ratio) and generation.
2. Males locate females either by perching and defending territories, or by patrolling. Individuals were more consistent in their mating strategies than expected by chance.
3. Forewing length : body length ratio was positively correlated with thorax mass : body mass; relatively short-bodied males had relatively heavy thoraxes. Therefore, forewing length : body length ratio was an index of mass allocation.
4. Perching males had higher forewing length : body length ratios and were paler than patrolling males.
5. The higher forewing length : body length ratio was due to the differences in body length and not wing length. Perchers had shorter bodies than patrollers. 相似文献
2. Males locate females either by perching and defending territories, or by patrolling. Individuals were more consistent in their mating strategies than expected by chance.
3. Forewing length : body length ratio was positively correlated with thorax mass : body mass; relatively short-bodied males had relatively heavy thoraxes. Therefore, forewing length : body length ratio was an index of mass allocation.
4. Perching males had higher forewing length : body length ratios and were paler than patrolling males.
5. The higher forewing length : body length ratio was due to the differences in body length and not wing length. Perchers had shorter bodies than patrollers. 相似文献