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991.
992.
C. Kevers R. Greimers T. Franck B. Bisbis J. Dommes T. Gaspar 《Biologia Plantarum》1999,42(3):321-332
A fully habituated (auxin- and cytokinin-independent) self-regenerating (organo-genic) sugar beet cell line (HO) and a fully
habituated non-organogenic one (HNO) derived from the former one, were analyzed as to their nuclear size and DNA content.
Flow cytometry and image analysis were used and cells of certified diploid leaves of the same sugar beet strain served as
controls. The HNO cells had been shown previously to have many characteristics of cancerous cells. The analyses made on leaves
and HNO cells indicated the presence of only one population of cycling cells. In HO cells, two cycling populations were detected:
the first one had the same DNA content as the leaves while the second one contained two fold more DNA than the first population.
HNO cells showed the higher nuclear size and DNA content. HNO cells also showed evidence of aneuploidy. Thus, nuclear size,
DNA content and ploidy level increase together with the neoplasic progression to culminate in HNO cells with the loss of organogenic
totipotency.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
993.
Michel Génard Jean Dauzat Nicolás Franck Françoise Lescourret Nicolas Moitrier Philippe Vaast Gilles Vercambre 《Trees - Structure and Function》2008,22(3):269-282
Carbon allocation within a plant depends on complex rules linking source organs (mainly shoots) and sink organs (mainly roots
and fruits). The complexity of these rules comes from both regulations and interactions between various plant processes involving
carbon. This paper presents these regulations and interactions, and analyses how agricultural management can influence them.
Ecophysiological models of carbon production and allocation are good tools for such analyses. The fundamental bases of these
models are first presented, focusing on their underlying processes and concepts. Different approaches are used for modelling
carbon economy. They are classified as empirical, teleonomic, driven by source–sink relationships, or based on transport and
chemical/biochemical conversion concepts. These four approaches are presented with a particular emphasis on the regulations
and interactions between organs and between processes. The role of plant architecture in carbon partitioning is also discussed
and the interest of coupling plant architecture models with carbon allocation models is highlighted. As an illustration of
carbon allocation models, a model developed for peach trees, describing carbon transfer within the plant, and based on source–sink
and Münch transport theory is presented and used for analyzing the link between roots, shoots and reproductive compartments.
On this basis, the consequences of fruit load or plant pruning on fruit and vegetative growth can be evaluated. 相似文献
994.
995.
Grégory Simon Madeleine Bouzon Franck Charmantray Virgil Hélaine Bertrand Légeret Philippe Marlière Laurence Hecquet 《Bioorganic & medicinal chemistry letters》2009,19(14):3767-3770
Probes were developed for the in vivo detection of transketolase activity by the use of a complementation assay in Escherichia coli auxotrophs They combine the d-threo ketose moiety recognised by transketolase and the side chain of leucine or methionine. These compounds were donor substrates of yeast transketolase leading to the release of the corresponding α-hydroxyaldehydes which could be converted in E. coli by a cascade of reactions into leucine or methionine required for cellular growth. 相似文献
996.
997.
Minaygninrin Kon Dramane Kaba Jacques Kabor Lian Francesca Thomas Laura Cristina Falzon Mathurin Koffi Cyrille Mambo Kouam Bernardin Ahouty Charlie Franck Alfred Compaor Emmanuel Kouassi NGouan Philippe Solano Eric Fvre Philippe Büscher Veerle Lejon Vincent Jamonneau 《PLoS neglected tropical diseases》2021,15(8)
BackgroundLittle is known about the diagnostic performance of rapid diagnostic tests (RDTs) for passive screening of human African trypanosomiasis (HAT) in Côte d’Ivoire. We determined HAT prevalence among clinical suspects, identified clinical symptoms and signs associated with HAT RDT positivity, and assessed the diagnostic tests’ specificity, positive predictive value and agreement.MethodsClinical suspects were screened with SD Bioline HAT, HAT Sero-K-Set and rHAT Sero-Strip. Seropositives were parasitologically examined, and their dried blood spots tested in trypanolysis, ELISA/Tbg, m18S-qPCR and LAMP. The HAT prevalence in the study population was calculated based on RDT positivity followed by parasitological confirmation. The association between clinical symptoms and signs and RDT positivity was determined using multivariable logistic regression. The tests’ Positive Predictive Value (PPV), specificity and agreement were determined.ResultsOver 29 months, 3433 clinical suspects were tested. The RDT positivity rate was 2.83%, HAT prevalence 0.06%. Individuals with sleep disturbances (p<0.001), motor disorders (p = 0.002), convulsions (p = 0.02), severe weight loss (p = 0.02) or psychiatric problems (p = 0.04) had an increased odds (odds ratios 1.7–4.6) of being HAT RDT seropositive. Specificities ranged between 97.8%-99.6% for individual RDTs, and 93.3–98.9% for subsequent tests on dried blood spots. The PPV of the individual RDTs was below 14.3% (CI 2–43), increased to 33.3% (CI 4–78) for serial RDT combinations, and reached 67% for LAMP and ELISA/Tbg on RDT positives. Agreement between diagnostic tests was poor to moderate (Kappa ≤ 0.60), except for LAMP and ELISA/Tbg (Kappa = 0.66).ConclusionIdentification of five key clinical symptoms and signs may simplify referral for HAT RDT screening. The results confirm the appropriateness of the diagnostic algorithm presently applied, with screening by SD Bioline HAT or HAT Sero-K-Set, supplemented with trypanolysis. ELISA/Tbg could replace trypanolysis and is simpler to perform.Trial registrationClinicalTrials.gov . NCT03356665相似文献
998.
999.
1000.
Bone is a complex system, and could be modeled as a poroelastic media. The aim of this paper is to identify the macroscopic value of the cortical bone permeability coefficient. A simple experimental method was designed in order to determine the permeability coefficient. Two bone samples taken from different ox femurs were filled with water, to place them under internal pressure. The measurements gave both the fluid flow through the lateral surfaces and the internal pressure. The originality of this work is the coupling between an experimental process and a structural computation performed with a finite element method. The mean cortical bone permeability coefficient identified was about k=1.1x10(-13)m(2). This value tends to confirm other values found in the literature, obtained by different methods and often at macroscopic scale. It confirms also the domination of vascular permeability (Haversian and Volkmann's canals). 相似文献