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151.
Ana Paula Souza Caetano Daniela Guimarães Simão Renata Carmo-Oliveira Paulo Eugênio Oliveira 《Plant Systematics and Evolution》2013,299(7):1253-1262
Apomixis, or asexual reproduction through seeds, has been reported for species of the tribe Miconieae, Melastomataceae, but details of the process have yet to be described. We analyzed and compared sporogenesis and gametogenesis in the apomictic Miconia albicans and the sexual M. chamissois. The results point to some differences between species, which were related to the apomictic process. In M. albicans microsporogenesis, problems during meiosis and degeneration of its products led to total pollen sterility, while M. chamissois presented normal bicellular pollen grains in the mature anther. The absence or abnormality of meiosis in M. albicans megasporogenesis led to the formation of an unreduced embryo sac and also to egg cell parthenogenesis, which gave rise to the apomictic embryo. Embryo and endosperm development were autonomous, resulting in seeds and fruits independent of pollination and fertilization. Thus, in this species, apomixis can be classified as diplosporic and obligate. In contrast, meiosis was as expected in the sexual M. chamissois, and led to the development of a reduced embryo sac. Despite the divergent pathways, many embryological characteristics were similar between the studied species and other Melastomataceae and they seem to be conservative character states for the family. 相似文献
152.
Pauline M. Leite Rodrigo S. Gomes Amanda B. Figueiredo Tiago D. Serafim Wagner L. Tafuri Carolina C. de Souza Sandra A. L. Moura Juliana L. R. Fietto Maria N. Melo Fátima Ribeiro-Dias Milton A. P. Oliveira Ana Rabello Luís C. C. Afonso 《PLoS neglected tropical diseases》2012,6(10)
Background
Leishmania (Viannia) braziliensis has been associated with a broad range of clinical manifestations ranging from a simple cutaneous ulcer to destructive mucosal lesions. Factors leading to this diversity of clinical presentations are not clear, but parasite factors have lately been recognized as important in determining disease progression. Given the fact that the activity of ecto-nucleotidases correlates with parasitism and the development of infection, we evaluated the activity of these enzymes in promastigotes from 23 L. braziliensis isolates as a possible parasite-related factor that could influence the clinical outcome of the disease.Methodology/Principal Findings
Our results show that the isolates differ in their ability to hydrolyze adenine nucleotides. Furthermore, we observed a positive correlation between the time for peak of lesion development in C57BL/6J mice and enzymatic activity and clinical manifestation of the isolate. In addition, we found that L. (V.) braziliensis isolates obtained from mucosal lesions hydrolyze higher amounts of adenine nucleotides than isolates obtained from skin lesions. One isolate with high (PPS6m) and another with low (SSF) ecto-nucleotidase activity were chosen for further studies. Mice inoculated with PPS6m show delayed lesion development and present larger parasite loads than animals inoculated with the SSF isolate. In addition, PPS6m modulates the host immune response by inhibiting dendritic cell activation and NO production by activated J774 macrophages. Finally, we observed that the amastigote forms from PPS6m and SSF isolates present low enzymatic activity that does not interfere with NO production and parasite survival in macrophages.Conclusions/Significance
Our data suggest that ecto-nucleotidases present on the promastigote forms of the parasite may interfere with the establishment of the immune response with consequent impaired ability to control parasite dissemination and this may be an important factor in determining the clinical outcome of leishmaniasis. 相似文献153.
Priscila P. Santos Fernando Oliveira Vanessa C. M. P. Ferreira Bertha F. Polegato Meliza G. Roscani Ana Angelica Fernandes Pamela Modesto Bruna P. M. Rafacho Silmeia G. Zanati Annarita Di Lorenzo Luiz S. Matsubara Sergio A. R. Paiva Leonardo A. M. Zornoff Marcos F. Minicucci Paula S. Azevedo 《PloS one》2014,9(12)
Background/Aims
Experimental and clinical studies have shown the direct toxic effects of cigarette smoke (CS) on the myocardium, independent of vascular effects. However, the underlying mechanisms are not well known.Methods
Wistar rats were allocated to control (C) and cigarette smoke (CS) groups. CS rats were exposed to cigarette smoke for 2 months.Results
After that morphometric, functional and biochemical parameters were measured. The echocardiographic study showed enlargement of the left atria, increase in the left ventricular systolic volume and reduced systolic function. Within the cardiac metabolism, exposure to CS decreased beta hydroxy acyl coenzyme A dehydrogenases and citrate synthases and increased lactate dehydrogenases. Peroxisome proliferator-activated receptor alpha (PPARα) and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) were expressed similarly in both groups. CS increased serum lipids and myocardial triacylglycerols (TGs). These data suggest that impairment in fatty acid oxidation and the accumulation of cardiac lipids characterize lipotoxicity. CS group exhibited increased oxidative stress and decreased antioxidant defense. Finally, the myocyte cross-sectional area and active Caspase 3 were increased in the CS group.Conclusion
The cardiac remodeling that was observed in the CS exposure model may be explained by abnormalities in energy metabolism, including lipotoxicity and oxidative stress. 相似文献154.
Antônia E.A. Oliveira Elane S. Ribeiro Maura da Cunha Valdirene M. Gomes Kátia V.S. Fernandes José Xavier-Filho 《Plant Growth Regulation》2004,43(1):57-62
Insulin is a 6 kDa peptide hormone that activates several metabolic processes and cellular growth. Germination studies showed that insulin, vanadyl sulphate (an insulin mimetic compound), tyrphostin (an inhibitor of insulin receptor kinase activity), pinitol (a chiro inositol analogue) and glucose were able to accelerate Canavalia ensiformis (Jack bean) seedling radicle and epicotyl development. Immunofluorescence microscopy analysis showed that proteins binding to insulin, insulin receptor and phosphoserine antibodies are localized in an internal layer of the C. ensiformis seed coat. These results and others previously reported from our laboratory suggest that insulin, insulin receptor and phosphoserine proteins could be components of signalling pathways akin to those present in animals. 相似文献
155.
A C Frantz A D McDevitt L C Pope J Kochan J Davison C F Clements M Elmeros G Molina-Vacas A Ruiz-Gonzalez A Balestrieri K Van Den Berge P Breyne E Do Linh San E O ?gren F Suchentrunk L Schley R Kowalczyk B I Kostka D ?irovi? N ?prem M Colyn M Ghirardi V Racheva C Braun R Oliveira J Lanszki A Stubbe M Stubbe N Stier T Burke 《Heredity》2014,113(5):443-453
Although the phylogeography of European mammals has been extensively investigated
since the 1990s, many studies were limited in terms of sampling distribution, the
number of molecular markers used and the analytical techniques employed, frequently
leading to incomplete postglacial recolonisation scenarios. The broad-scale genetic
structure of the European badger (Meles meles) is of interest as it may
result from historic restriction to glacial refugia and/or recent anthropogenic
impact. However, previous studies were based mostly on samples from western Europe,
making it difficult to draw robust conclusions about the location of refugia,
patterns of postglacial expansion and recent demography. In the present study,
continent-wide sampling and analyses with multiple markers provided evidence for two
glacial refugia (Iberia and southeast Europe) that contributed to the genetic
variation observed in badgers in Europe today. Approximate Bayesian computation
provided support for a colonisation of Scandinavia from both Iberian and southeastern
refugia. In the whole of Europe, we observed a decline in genetic diversity with
increasing latitude, suggesting that the reduced diversity in the peripheral
populations resulted from a postglacial expansion processes. Although MSVAR v.1.3
also provided evidence for recent genetic bottlenecks in some of these peripheral
populations, the simulations performed to estimate the method''s power to
correctly infer the past demography of our empirical populations suggested that the
timing and severity of bottlenecks could not be established with certainty. We urge
caution against trying to relate demographic declines inferred using MSVAR with
particular historic or climatological events. 相似文献
156.
157.
158.
Rafaela Magalhães Brandão Maria das Graças Cardoso Luís Roberto Batista Alex Rodrigues Silva Caetano Ana Carolina Cortez Lemos Maria Alice Martins David Lee Nelson Juliano Elvis De Oliveira 《Letters in applied microbiology》2022,74(5):765-776
Poly(lactic acid) (PLA) nanofibres containing different proportions of the essential oils from Ocimum basilicum L. and Ocimum gratissimum L. were prepared by solution blow spinning method. The essential oils were extracted by hydrodistillation and characterized by gas chromatography. MEV, contact angle, DSC and FTIR were used to characterize the nanofibres. The effect of bioative nanofibres on the growth of the fungus and on the production of ochratoxin A were evaluated using the fumigation test. Linalool, 1·8-cineole and camphor were the principal components of the essential oil from O. basilicum, and eugenol was the principal constituent in the oil from O. gratissimum. An increase in the average diameter of the nanofibres was observed with the addition of the essential oils. The essential oils acted as a plasticizer, resulting in a reduction in the crystallinity of the PLA. The encapsulation of essential oils in PLA nanofibres was verified by FTIR. An effective antifungal and antimicotoxygenic activity against Aspergillus ochraceus and Aspergillus westerdjikiae was observed for the bioative nanofibres. These results confirm the potential of PLA nanofibres containing the essential oils for the control of toxigenic fungi that cause the deterioration of food and are harmful to human health. 相似文献
159.
Debora B. Lima Daniela Rezende-Puker Renata S. Mendonça Marie-Stephane Tixier Manoel G. C. GondimJr. José W. S. Melo Daniel C. Oliveira Denise Navia 《Experimental & applied acarology》2018,76(3):287-310
The accurate characterization of biological control agents is a key step in control programs. Recently, Amblyseius largoensis from Thailand were introduced in Brazil to evaluate their efficiency for the control of the red palm mite, Raoiella indica. The aim of this study was to confirm their identification and to characterize the population from Thailand, comparing it to populations of the Americas and Indian Ocean islands. In addition, a population of A. largoensis from New Caledonia, Oceania, of which DNA sequences were available, was included in phylogenetic analyses. Morphometric data obtained for the population of A. largoensis from Thailand were compared to those of populations from Reunion Island and the Americas through univariate and multivariate analyses. Two DNA fragments were amplified and sequenced: the nuclear ribosomal region ITSS and the mitochondrial 12S rRNA. Haplotypes (12S rRNA) and genotypes (ITSS) were identified and phylogenetic analyses using both fragments were conducted separately and combined using maximum likelihood and the Bayesian information criterion. The integrative approach reveals morphometric and molecular variabilities among populations of A. largoensis and shows that the population identified as A. largoensis collected in Thailand, as well as that from New Caledonia, are conspecific to the populations of the Americas and Indian Ocean islands. Populations from the Americas and Asia are more related to each other than with that from the Indian Ocean islands. Hypotheses to explain this clustering are proposed. Data on the molecular intraspecific variability of this predatory mite from remote areas will be helpful for the development of molecular diagnosis. 相似文献
160.