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51.
Abstract: Phylogenetic reconstruction of the Upper Barremian ammonite genus Gassendiceras (Gassendiceratinae) was performed using a cladistic analysis incorporating continuous data. Some morphological features were found to vary identically among all the analysed species and therefore carry no phylogenetic information (= symplesiomorphic). The single obtained cladogram allows interpreting the evolution of the Gassendiceras as an anagenetic succession of eight species, in stratigraphic order of appearance, Gassendiceras multicostatum, G. alpinum, G. hoheneggeri, G. rebouleti, G. bosellii, G. quelquejeui, G. coulletae and G. enayi. The clade Pseudoshasticrioceras/Imerites is derived from G. enayi, so the genus Gassendiceras appears to be paraphyletic. But here, we accept this fact as the best evolutive classification. The evolution over time of Gassendiceras is modulated by some processes, which could have constrained the inferred phylogenetic pattern with the drift of the global variability towards the most gracile forms over time. It is tempting to interpret this evolution as a constant selection over time of the Gassendiceras modulated by environmental control due to eustatic variation across a transgressive sequence. Thus, the most peramorphic (gracile) individuals seemed favoured at the expense of those most robust (paedomorphic). 相似文献
52.
Relief of hypoxia by angiogenesis promotes neural stem cell differentiation by targeting glycolysis 下载免费PDF全文
Christian Lange Miguel Turrero Garcia Ilaria Decimo Francesco Bifari Guy Eelen Annelies Quaegebeur Ruben Boon Hui Zhao Bram Boeckx Junlei Chang Christine Wu Ferdinand Le Noble Diether Lambrechts Mieke Dewerchin Calvin J Kuo Wieland B Huttner Peter Carmeliet 《The EMBO journal》2016,35(9):924-941
Blood vessels are part of the stem cell niche in the developing cerebral cortex, but their in vivo role in controlling the expansion and differentiation of neural stem cells (NSCs) in development has not been studied. Here, we report that relief of hypoxia in the developing cerebral cortex by ingrowth of blood vessels temporo‐spatially coincided with NSC differentiation. Selective perturbation of brain angiogenesis in vessel‐specific Gpr124 null embryos, which prevented the relief from hypoxia, increased NSC expansion at the expense of differentiation. Conversely, exposure to increased oxygen levels rescued NSC differentiation in Gpr124 null embryos and increased it further in WT embryos, suggesting that niche blood vessels regulate NSC differentiation at least in part by providing oxygen. Consistent herewith, hypoxia‐inducible factor (HIF)‐1α levels controlled the switch of NSC expansion to differentiation. Finally, we provide evidence that high glycolytic activity of NSCs is required to prevent their precocious differentiation in vivo. Thus, blood vessel function is required for efficient NSC differentiation in the developing cerebral cortex by providing oxygen and possibly regulating NSC metabolism. 相似文献
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Laura J. Schmertmann Laszlo Irinyi Richard Malik Jeff R. Powell Wieland Meyer Mark B. Krockenberger 《Ecology and evolution》2019,9(17):9684-9700
Cryptococcosis is a fungal infection caused by members of the Cryptococcus gattii and C. neoformans species complexes. The C. gattii species complex has a strong environmental association with eucalypt hollows (particularly Eucalyptus camaldulensis), which may present a source of infection. It remains unclear whether a specific mycobiome is required to support its environmental survival and growth. Conventional detection of environmental Cryptococcus spp. involves culture on differential media, such as Guizotia abyssinica seed agar. Next‐generation sequencing (NGS)‐based culture‐independent identification aids in contextualising these species in the environmental mycobiome. Samples from 23 Australian tree hollows were subjected to both culture‐ and amplicon‐based metagenomic analysis to characterize the mycobiome and assess relationships between Cryptococcus spp. and other fungal taxa. The most abundant genera detected were Coniochaeta, Aspergillus, and Penicillium, all being commonly isolated from decaying wood. There was no correlation between the presence of Cryptococcus spp. in a tree hollow and the presence of any other fungal genus. Some differences in the abundance of numerous taxa were noted in a differential heat tree comparing samples with or without Cryptococcus‐NGS reads. The study expanded the known environmental niche of the C. gattii and C. neoformans species complexes in Australia with detections from a further five tree species. Discrepancies between the detection of Cryptococcus spp. using culture or NGS suggest that neither is superior per se and that, rather, these methodologies are complementary. The inherent biases of amplicon‐based metagenomics require cautious interpretation of data through consideration of its biological relevance. 相似文献
56.
Martin Frommhold Arend Heim Mikhail Barabanov Franziska Maier Ralf‐Udo Mühle Sergei M. Smirenski Wieland Heim 《Ecology and evolution》2019,9(24):14430-14441
The selection of a nest site is crucial for successful reproduction of birds. Animals which re‐use or occupy nest sites constructed by other species often have limited choice. Little is known about the criteria of nest‐stealing species to choose suitable nesting sites and habitats. Here, we analyze breeding‐site selection of an obligatory “nest‐cleptoparasite”, the Amur Falcon Falco amurensis. We collected data on nest sites at Muraviovka Park in the Russian Far East, where the species breeds exclusively in nests of the Eurasian Magpie Pica pica. We sampled 117 Eurasian Magpie nests, 38 of which were occupied by Amur Falcons. Nest‐specific variables were assessed, and a recently developed habitat classification map was used to derive landscape metrics. We found that Amur Falcons chose a wide range of nesting sites, but significantly preferred nests with a domed roof. Breeding pairs of Eurasian Hobby Falco subbuteo and Eurasian Magpie were often found to breed near the nest in about the same distance as neighboring Amur Falcon pairs. Additionally, the occurrence of the species was positively associated with bare soil cover, forest cover, and shrub patches within their home range and negatively with the distance to wetlands. Areas of wetlands and fallow land might be used for foraging since Amur Falcons mostly depend on an insect diet. Additionally, we found that rarely burned habitats were preferred. Overall, the effect of landscape variables on the choice of actual nest sites appeared to be rather small. We used different classification methods to predict the probability of occurrence, of which the Random forest method showed the highest accuracy. The areas determined as suitable habitat showed a high concordance with the actual nest locations. We conclude that Amur Falcons prefer to occupy newly built (domed) nests to ensure high nest quality, as well as nests surrounded by available feeding habitats. 相似文献
57.
PHILIP S WANG MATTHIAS ANGERMEYER GUILHERME BORGES RONNY BRUFFAERTS WAI TAT CHIU GIOVANNI DE GIROLAMO JOHN FAYYAD OYE GUREJE JOSEP MARIA HARO YUEQIN HUANG RONALD C KESSLER VIVIANE KOVESS DAPHNA LEVINSON YOSHIBUMI NAKANE MARK A OAKLEY BROWN JOHAN H ORMEL JOSé POSADA-VILLA SERGIO AGUILAR-GAXIOLA JORDI ALONSO SING LEE STEVEN HEERINGA BETH-ELLEN PENNELL SOMNATH CHATTERJI T. BEDIRHAN üSTüN 《World psychiatry》2007,6(3):177-185
Data are presented on patterns of failure and delay in making initial treatment
contact after first onset of a mental disorder in 15 countries in the World
Health Organization (WHO)''s World Mental Health (WMH) Surveys. Representative
face-to-face household surveys were conducted among 76,012 respondents aged
18 and older in Belgium, Colombia, France, Germany, Israel, Italy, Japan,
Lebanon, Mexico, the Netherlands, New Zealand, Nigeria, People''s Republic
of China (Beijing and Shanghai), Spain, and the United States. The WHO Composite
International Diagnostic Interview (CIDI) was used to assess lifetime DSM-IV
anxiety, mood, and substance use disorders. Ages of onset for individual disorders
and ages of first treatment contact for each disorder were used to calculate
the extent of failure and delay in initial help seeking. The proportion of
lifetime cases making treatment contact in the year of disorder onset ranged
from 0.8 to 36.4% for anxiety disorders, from 6.0 to 52.1% for mood disorders,
and from 0.9 to 18.6% for substance use disorders. By 50 years, the proportion
of lifetime cases making treatment contact ranged from 15.2 to 95.0% for anxiety
disorders, from 7.9 to 98.6% for mood disorders, and from 19.8 to 86.1% for
substance use disorders. Median delays among cases eventually making contact
ranged from 3.0 to 30.0 years for anxiety disorders, from 1.0 to 14.0 years
for mood disorders, and from 6.0 to 18.0 years for substance use disorders.
Failure and delays in treatment seeking were generally greater in developing
countries, older cohorts, men, and cases with earlier ages of onset. These
results show that failure and delays in initial help seeking are pervasive
problems worldwide. Interventions to ensure prompt initial treatment contacts
are needed to reduce the global burdens and hazards of untreated mental disorders. 相似文献
58.
Winkler K Scharnagl H Tisljar U Hoschützky H Friedrich I Hoffmann MM Hüttinger M Wieland H März W 《Journal of lipid research》1999,40(3):447-455
The genetic polymorphism of apolipoprotein E (apoE) is associated with the age of onset and relative risk of Alzheimer's disease (AD). In contrast to apoE3, the wild type allele, apoE4 confers an increased risk of late-onset AD. We demonstrate that the beta-amyloid peptide isoforms Abeta (1-28), Abeta (1-40), and Abeta (1-43) compete for the cellular metabolism of apoE3 and apoE4 containing beta-very low density lipoproteins. An antibody raised against Abeta (1-28) cross-reacted with recombinant apoE. Epitope mapping revealed positive amino acid clusters as common epitopes of Abeta (13 through 17; HHQKL) and apoE (residues 144 through 148; LRKRL), both regions known to be heparin binding domains. Abeta in which amino acids 13 through 17 (HHQKL) were replaced by glycine (GGQGL) failed to compete with the cellular uptake of apoE enriched betaVLDL.These observations indicate that Abeta and apoE are taken up into cells by a common pathway involving heparan sulfate proteoglycans. 相似文献
59.
Functional complementation of human centromere protein A (CENP-A) by Cse4p from Saccharomyces cerevisiae 总被引:4,自引:0,他引:4 下载免费PDF全文
Wieland G Orthaus S Ohndorf S Diekmann S Hemmerich P 《Molecular and cellular biology》2004,24(15):6620-6630
We have employed a novel in vivo approach to study the structure and function of the eukaryotic kinetochore multiprotein complex. RNA interference (RNAi) was used to block the synthesis of centromere protein A (CENP-A) and Clip-170 in human cells. By coexpression, homologous kinetochore proteins from Saccharomyces cerevisiae were then tested for the ability to complement the RNAi-induced phenotypes. Cse4p, the budding yeast CENP-A homolog, was specifically incorporated into kinetochore nucleosomes and was able to complement RNAi-induced cell cycle arrest in CENP-A-depleted human cells. Thus, Cse4p can structurally and functionally substitute for CENP-A, strongly suggesting that the basic features of centromeric chromatin are conserved between yeast and mammals. Bik1p, the budding yeast homolog of human CLIP-170, also specifically localized to kinetochores during mitosis, but Bik1p did not rescue CLIP-170 depletion-induced cell cycle arrest. Generally, the newly developed in vivo complementation assay provides a powerful new tool for studying the function and evolutionary conservation of multiprotein complexes from yeast to humans. 相似文献
60.
The aim of the present study was to test whether rapid accumulation of solutes in response to salinity in leaf tissues of barley (Hordeum vulgare L.) contributes to recovery and maintenance of residual elongation growth. Addition of 100 mM NaCl to the root medium caused an immediate reduction close to zero in elongation velocity of the growing leaf 3. After 20–30 min, elongation velocity recovered suddenly, to 40–50% of the pre-stress level. Bulk osmolality increased first, after 60 min, significantly in the proximal half of the elongation zone. Over the following 3 days, osmolality increases became significant in the distal half of the elongation zone, the adjacent, enclosed non-elongation zone and finally in the emerged portion of the blade. The developmental gradient and time course in osmolality increase along the growing leaf was reflected in the pattern of solute (Cl, Na and K) accumulation in bulk tissue and epidermal cells. The partitioning of newly accumulated solutes between epidermis and bulk tissue changed with time. Even though solute accumulation does not contribute to the sudden and partial growth recovery 20–30 min after exposure to salt, it does facilitate residual growth from 1 h onwards. This is due to a high sink strength for solutes of the proximal part of the growth zone and its ability to accumulate solutes rapidly and at high rates.Abbreviations EDX analysis
Energy-dispersive X-ray analysis
- LEV
Leaf elongation velocity
- LVDT
Linear variable differential transformer
- REGR
Relative elemental growth rate 相似文献