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101.
Sage TL Hristova-Sarkovski K Koehl V Lyew J Pontieri V Bernhardt P Weston P Bagha S Chiu G 《American journal of botany》2009,96(1):183-206
Carpel transmitting tissue is a major floral innovation that is essential for angiosperm success. It facilitates the rapid adhesion, hydration, and growth of the male gametophyte to the female gametophyte. As well, it functions as a molecular screen to promote male gametophytic competition and species-specific recognition and compatibility. Here, we characterize the transmitting tissue extracellular matrix (ECM) and pollen tube growth in basal-relictual angiosperms and test the hypothesis that a freely flowing ECM (wet stigma) was ancestral to a cuticle-bound ECM (dry stigma). We demonstrate that the most recent common ancestor of extant angiosperms produced an ECM that was structurally and functionally equivalent to a dry stigma. Dry stigmas are composed of a cuticle and primary wall that contains compounds that facilitate the adhesion and growth of the male gametophyte. These compounds include methyl-esterified homogalacturonans, arabinogalactan-proteins, and lipids. We propose that transmitting tissue evolved in concert with an increase in cuticle permeability that resulted from modifications in the biosynthesis and secretion of fatty acids needed for cuticle construction. Increased cuticle permeability exposed the male gametophyte to pre-existing molecules that enabled rapid male gametophyte adhesion, hydration, and growth as well as species-specific recognition and compatibility. 相似文献
102.
Man-Koumba Soumahoro Patrick Gérardin Pierre-Yves Bo?lle Joelle Perrau Adrian Fianu Jacques Pouchot Denis Malvy Antoine Flahault Fran?ois Favier Thomas Hanslik 《PloS one》2009,4(11)
Background
Persistent symptoms, mainly joint and muscular pain and depression, have been reported several months after Chikungunya virus (CHIKV) infection. Their frequency and their impact on quality of life have not been compared with those of an unexposed population. In the present study, we aimed to describe the frequency of prolonged clinical manifestations of CHIKV infection and to measure the impact on quality of life and health care consumption in comparison with that of an unexposed population, more than one year after infection.Methodology/Principal Findings
In a retrospective cohort study, 199 subjects who had serologically confirmed CHIKV infection (CHIK+) were compared with 199 sero-negative subjects (CHIK–) matched for age, gender and area of residence in La Réunion Island. Following an average time of 17 months from the acute phase of infection, participants were interviewed by telephone about current symptoms, medical consumption during the last 12 months and quality of life assessed by the 12-items Short-Form Health Survey (SF-12) scale. At the time of study, 112 (56%) CHIK+ persons reported they were fully recovered. CHIK+ complained more frequently than CHIK– of arthralgia (relative risk = 1.9; 95% confidence interval: 1.6–2.2), myalgia (1.9; 1.5–2.3), fatigue (2.3; 1.8–3), depression (2.5; 1.5–4.1) and hair loss (3.8; 1.9–7.6). There was no significant difference between CHIK+ and CHIK– subjects regarding medical consumption in the past year. The mean (SD) score of the SF-12 Physical Component Summary was 46.4 (10.8) in CHIK+ versus 49.1 (9.3) in CHIK– (p = 0.04). There was no significant difference between the two groups for the Mental Component Summary.Conclusions/Significance
More than one year following the acute phase of infection, CHIK+ subjects reported more disabilities than those who were CHIK–. These persistent disabilities, however, have no significant influence on medical consumption, and the impact on quality of life is moderate. 相似文献103.
Kidd JM Graves T Newman TL Fulton R Hayden HS Malig M Kallicki J Kaul R Wilson RK Eichler EE 《Cell》2010,143(5):837-847
Understanding the prevailing mutational mechanisms responsible for human genome structural variation requires uniformity in the discovery of allelic variants and precision in terms of breakpoint delineation. We develop a resource based on capillary end sequencing of 13.8 million fosmid clones from 17 human genomes and characterize the complete sequence of 1054 large structural variants corresponding to 589 deletions, 384 insertions, and 81 inversions. We analyze the 2081 breakpoint junctions and infer potential mechanism of origin. Three mechanisms account for the bulk of germline structural variation: microhomology-mediated processes involving short (2-20 bp) stretches of sequence (28%), nonallelic homologous recombination (22%), and L1 retrotransposition (19%). The high quality and long-range continuity of the sequence reveals more complex mutational mechanisms, including repeat-mediated inversions and gene conversion, that are most often missed by other methods, such as comparative genomic hybridization, single nucleotide polymorphism microarrays, and next-generation sequencing. 相似文献
104.
Astarci P Glineur D Kefer J Renkin J Vanoverschelde JL El Khoury G 《Innovations (Philadelphia, Pa.)》2010,5(2):136-137
Transapical aortic valve implantation requires puncture of the left ventricle apex and insertion of a 32-French delivery sheath. A critical step in the procedure consists of secure closure of the ventricular apex. We describe 2 cases of apical rupture of 42 transapical aortic valve implantations. Furthermore, we describe the use of a newly designed single circular Teflon pledget that can help to avoid this complication. This pledget provides a more secure and uniform shrinkage of the entire apex to close the defect left by the delivery sheath. 相似文献
105.
Nectar-carbohydrate production and composition were investigated by high-performance liquid chromatography and enzymology
in nine species from five tribes of the Brassicaceae. In six species (Arabidopsis thaliana (L.) Heynh., Brassica napus L., B. rapa L., Lobularia maritima (L.) Desv., Raphanus sativus L., Sinapis arvensis L.) that produced nectar from both lateral nectaries (associated with the short stamens) and median nectaries (outside the
long stamens), on average 95% of the total nectar carbohydrate was collected from the lateral ones. Nectar from these glands
possessed a higher glucose/fructose ratio (usually 1.0–1.2) than that from the median nectaries (0.2–0.9) within the same
flower. Comparatively little sucrose was detected in any nectar samples except from Matthiola bicornus (Sibth. et Sm.) DC., which possessed lateral nectaries only and produced a sucrose-dominant exudate. The anatomy of the nectarial
tissue in nectar-secreting flowers of six species, Hesperis matronalis L., L. maritima, M. bicornus, R. sativus, S. arvensis, and Sisymbrium loeselii L., was studied by light and scanning-electron microscopy. Phloem alone supplied the nectaries. However, in accordance with
their overall nectar-carbohydrate production, the lateral glands received relatively rich quantities of phloem that penetrated
far into the glandular tissue, whereas median glands were supplied with phloem that often barely innervated them. All nectarial
tissue possessed modified stomata (with the exception of the median glands of S. loeselii, which did not produce nectar); further evidence was gathered to indicate that these structures do not regulate nectar flow
by guard-cell movements. The numbers of modified stomata per gland showed no relation to nectar-carbohydrate production. Taken
together, the data on nectar biochemistry and nectary anatomy indicate the existence of two distinct nectary types in those
Brassicacean species that possess both lateral and median nectaries, regardless of whether nectarial tissue is united around
the entire receptacle or not. It is proposed that the term “nectarium” be used to represent collectively the multiple nectaries
that can be found in individual flowers.
Received: 21 July 1997 / Accepted: 19 September 1997 相似文献
106.
Isabelle Bonnin Joelle Ronfort † Frederic Wozniak Isabelle Olivieri‡ 《Molecular ecology》2001,10(6):1371-1383
In order to elucidate the mechanisms underlying the large amount of RAPD polymorphism found in 1990 in a population of the selfing annual Medicago truncatula GAERTN. (Fabaceae), we have analysed most of the individuals (n = 363) from the same population 6 years later using microsatellite loci. We confirm the result of the earlier study, namely that this population is very polymorphic and highly subdivided, with approximately 37% of the variance distributed among subpopulations, only 50 m apart one from another. We use standard F-statistics analyses, linkage disequilibria, minimum spanning network, multilocus assignment tests and spatial autocorrelation analyses to test the hypotheses that spatial structure and outcrossing events are involved in maintaining the large amount of genetic diversity at the level of each subpopulation. Interestingly, fine-scale spatial structure could be observed in only one subpopulation suggesting that other mechanisms are acting elsewhere. To the best of our knowledge, this is the first study of fine spatial genetic structure in a predominantly selfing species. 相似文献
107.
Nicolas Rouhier Eric Gelhaye Pierre-Eric Sautiere Annick Brun Pascal Laurent Denis Tagu Joelle Gerard Elisabeth de Faÿ Yves Meyer Jean-Pierre Jacquot 《Plant physiology》2001,127(3):1299-1309
A sequence coding for a peroxiredoxin (Prx) was isolated from a xylem/phloem cDNA library from Populus trichocarpa and subsequently inserted into an expression plasmid yielding the construction pET-Prx. The recombinant protein was produced in Escherichia coli cells and purified to homogeneity with a high yield. The poplar Prx is composed of 162 residues, a property that makes it the shortest plant Prx sequence isolated so far. It was shown that the protein is monomeric and possesses two conserved cysteines (Cys). The Prx degrades hydrogen peroxide and alkyl hydroperoxides in the presence of an exogenous proton donor that can be either thioredoxin or glutaredoxin (Grx). Based on this finding, we propose that the poplar protein represents a new type of Prx that differs from the so-called 2-Cys and 1-Cys Prx, a suggestion supported by the existence of natural fusion sequences constituted of a Prx motif coupled to a Grx motif. The protein was shown to be highly expressed in sieve tubes where thioredoxin h and Grx are also major proteins. 相似文献
108.
The sensitivity to electric foot shock strees of the dopaminergic system projecting to the frontal cortex was investigated in Balb/c and C57 BL/6 mice. Changes in the activity of the dopaminergic neurons were estimated by measuring DOPAC and DA levels in the frontal cortex using a radioenzymatic method. The DOPAC/DA ratio was enhanced in both strains as soon as 2 min after the beginning of the strees but the effect was much more pronounced in the Balb/c than in the C57 BL/6 mice. The difference was even more important after 6 min of stress since the DOPAC/DA ratios were respectively 380 and 200% the corresponding control values. These changes were related both to an increase of DOPAC levels and a reduction of those of DA. This difference in the reactivity of the mesocortical dopaminergic neurons could partly contribute to some of the distinct behavioral responses of these two strains of mice. A preliminary communication of these results was made at the 7th International Congress of Pharmacology (Paris, July 1978). 相似文献
109.
Anti human M2 type and anti human L type pyruvate kinase sera allowed us to distinguish two groups of pyruvate kinase in man. Erythrocyte and liver (L type) enzymes on the one hand were inhibited by anti L and not all by anti M2 serum; pyruvate kinase from all the other tissues on the other hand were inhibited by anti M2 and not at all by anti L serum. This latter group represent the M type pyruvate kinase isozymes. The M type isozymes have been studied by electrofocusing in thin layer acrylamide-ampholine gel. In adult tissues 4 types of isozymes were found, designated, from acid to alkaline pH, as M2 (predominant form in spleen, leukocytes, lung...), M3, M4 and M1 (predominant form in muscle and brain). In foetal tissues an extra band M2, called M2f, more anodic than M2, was added to the previously described isozymes. Except in brain (in which the isozymes M2, M3, M4 and M1 were found), the most anodic bands (M2f, M2 and M3) were predominant in all the foetal tissues. The isozymes M2f and M2 seem therefore to be the original M type pyruvate kinase forms from which the other isozymes issue. The rate of each isozyme seems to depend on tissue factors characterizing the state of differentiation of some tissues, as indicated by the ability of adult muscle extracts to change the isozymes M2 and M3 into more cathodic forms. 相似文献
110.
J Caroff E Girin D Alix C Cann-Moisan J Sizun L Barthelemy 《Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie》1992,314(10):451-454
The study of 33 cerebrospinal fluids of infants victims of sudden death shows a very significant increase of the metabolites of dopamine and serotonin. These determinations, compared to a control group, indicate a failure, concerning these two neurotransmitters, which could induce a cardiorespiratory seizure. This failure has likely a multifactorial origin. 相似文献