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991.
Compartments in a marine food web associated with phylogeny, body mass, and habitat structure 总被引:1,自引:0,他引:1
Enrico L. Rezende Eva M. Albert Miguel A. Fortuna Jordi Bascompte 《Ecology letters》2009,12(8):779-788
A long-standing question in community ecology is whether food webs are organized in compartments, where species within the same compartment interact frequently among themselves, but show fewer interactions with species from other compartments. Finding evidence for this community organization is important since compartmentalization may strongly affect food web robustness to perturbation. However, few studies have found unequivocal evidence of compartments, and none has quantified the suite of mechanisms generating such a structure. Here, we combine computational tools from the physics of complex networks with phylogenetic statistical methods to show that a large marine food web is organized in compartments, and that body size, phylogeny, and spatial structure are jointly associated with such a compartmentalized structure. Sharks account for the majority of predatory interactions within their compartments. Phylogenetically closely related shark species tend to occupy different compartments and have divergent trophic levels, suggesting that competition may play an important role structuring some of these compartments. Current overfishing of sharks has the potential to change the structural properties, which might eventually affect the stability of the food web. 相似文献
992.
Anna Rull Fernando Rodríguez Gerard Aragons Judit Marsillach Raúl Beltrn Carlos Alonso-Villaverde Jordi Camps Jorge Joven 《Cytokine》2009,48(3):273-279
To assess the role of monocyte chemoattractant protein-1 (MCP-1/CCL2) in the development of fatty liver, we have used LDLr−/− mice as an animal model of high-fat, high-cholesterol diet-induced liver steatosis. The rapid dietary induction of hepatic mRNA MCP-1 expression was paralleled by a concomitant increase in plasma MCP-1 that was strongly associated with the degree of liver steatosis. Hepatocytes showed an intense immunoreactivity for MCP-1 that was mainly located surrounding the hepatic lipid droplets. The intake of cholesterol also increased the concentration of MCP-1 in liver homogenates. This was accompanied by a differential expression of members of the PPAR family. Additionally, complete MCP-1 deficiency prevents the development of liver steatosis in LDLr−/− mice and partial deficiency is accompanied by a certain protective effect. Our data also suggest that MCP-1 may be important in the regulation of hepatic insulin resistance and may represent a link between inflammation and metabolic diseases. We conclude that dietary cholesterol upregulation of hepatic MCP-1 may help to understand the role of circulating MCP-1 in conditions where liver derangements are clinically important and in the association of liver steatosis with the metabolic syndrome. 相似文献
993.
Josep Garre-Olmo Margarita Flaqué Jordi Gich Teresa Osuna Pulido Josefina Turbau Natalia Vallmajo Marta Vi?as Secundí López-Pousa Registry of Dementia of Girona Study Group 《BMC neurology》2009,9(1):5
Background
Traditional epidemiological studies do not allow elucidating the reality of referral and diagnosis patterns of dementia in routine clinical practice within a defined territory. This information is useful and necessary in order to plan and allocate healthcare resources. This paper presents the results from a dementia case registry based on epidemiological surveillance fundamentals. 相似文献994.
Jesús de Pedro-Cuesta Javier Virués-Ortega Saturio Vega Manuel Seijo-Martínez Pedro Saz Fernanda Rodríguez Angel Rodríguez-Laso Ramón Reñé Susana Pérez de las Heras Raimundo Mateos Pablo Martínez-Martín Ignacio Mahillo-Fernandez Secundino López-Pousa Antonio Lobo Llinàs Jordi Reglà Jordi Gascón Francisco José García Manuel Fernández-Martínez Raquel Boix Félix Bermejo-Pareja Alberto Bergareche Julián Benito-León Ana de Arce José Luis del Barrio 《BMC neurology》2009,9(1):1-9
Background
To diagnose multiple sclerosis (MS), evidence for dissemination in space and time is required. There is no clear definition on how symptoms and signs of a patient indicate clinical dissemination in space. To provide a uniform approach on this subject, a clinical classification system was described recently differentiating patients with mono- and multifocal clinical presentation. Here we assess the predictive value of clinically defined dissemination in space at first presentation for time to clinically definite MS (CDMS).Methods
Four hundred and sixty-eight patients with a first episode suggestive of MS were classified as clinically mono- or multifocal by two neurologists blinded to magnetic resonance imaging (MRI) results. These patients were part of the BENEFIT study in which 292 patients were randomized to interferon beta-1b (IFNB-1b) and 176 to placebo. By using Kaplan-Meier statistics the risk for CDMS was studied in mono- and multifocal patients of the placebo group, both with and without taking into account MRI measures of potential prognostic relevance.Results
Time to CDMS was similar in monofocal and multifocal patients. In monofocal patients, the risk for CDMS over 2 years was significantly higher when ≥ 9 T2 lesions or at least one Gd-enhancing lesion were present at the first event or 3 or 6 months after the first event. In patients with multifocal presentation, these MRI measures had no significant added value in predicting time to CDMS.Conclusion
These data indicate that a carefully performed neurological assessment of symptoms and signs, combined with lesions on MRI, is important for defining the risk of conversion to CDMS.Trial Registration
The Benefit trial has been registered under NCT00185211 http://www.clinicaltrials.gov 相似文献995.
Ignacio García-Bocanegra Meritxell Simon-Grifé Jitender P. Dubey Jordi Casal Gerard E. Martín Oscar Cabezón Anselmo Perea Sonia Almería 《Parasitology international》2010,59(3):421-426
Serum samples from 2970 (1400 sows, 1570 fattening) pigs, from 100 farms in the 10 main swine production regions in Spain were tested for antibodies against T. gondii by the modified agglutination test (MAT). Antibodies to T. gondii (MAT 1:25 or higher) were detected in 492 pigs (16.6%, 9.7% in fattening pigs and 24.2% in sows). The herd prevalence was 85.0% (95% CI: 78–92) and within-farm prevalence ranged from 2.9% to 92.8% (median = 17.6%). Statistically significant differences were observed among sampling regions with seroprevalence significantly higher in pigs from Valencia Community (27.3%), Extremadura (23.3%) and Catalonia (21.2%). A generalized estimating equations model indicated that the risk factors associated with T. gondii seroprevalence were: age, sows compared to fattening pigs (OR = 2.9; 95% CI = 1.83–4.53), lack of rodent control (OR = 1.9; 95% CI = 1.04–3.60) and presence of cats (OR = 1.6; 95% CI = 1.12–2.34). The seroprevalence observed in the present study indicates a widespread, although variable, exposure to T. gondii among domestic pigs in Spain, which might have important implications for public health. Management measures including control of rodents and cats on the farms could help to reduce the observed prevalence levels in Spain. 相似文献
996.
Laura Picas M. Teresa Montero J.L. Vázquez-Ibar Pierre-Emmanuel Milhiet Jordi Hernández-Borrell 《生物化学与生物物理学报:生物膜》2010,1798(5):1014-12784
We report the insertion of a transmembrane protein, lactose permease (LacY) from Escherichia coli (E. coli), in supported lipid bilayers (SLBs) of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG), in biomimetic molar proportions. We provide evidence of the preferential insertion of LacY in the fluid domains. Analysis of the self-assembled protein arrangements showed that LacY: (i) is inserted as a monomer within fluid domains of SLBs of POPE:POPG (3:1, mol/mol), (ii) has a diameter of approx. 7.8 nm; and (iii) keeps an area of phospholipids surrounding the protein that is compatible with shells of phospholipids. 相似文献
997.
Oriol Arteaga Adolf Canillas Joaquim Crusats Zoubir El-Hachemi Gerald E. JellisonJr. Jordi Llorca Josep M. Ribó 《Origins of life and evolution of the biosphere》2010,40(1):27-40
We present an experimental approach to the study of the chirality of three CM2 meteorite solid samples by direct measurement
of the optical activity (circular birefringence; CB). The measurements are based on transmission two modulator generalized
ellipsometry in conjuction with microscope optics to map the CB of the samples. In spite of the complexity of such optical
analysis, these first results indicate the presence of optically active areas in the meteorite solid matrix. In the case of
the Murchison sample the statistics of the CB mapping shows a bimodal distribution with a bias to negative CB values. The
composition of the active areas probably corresponds to serpentines and other poorly identified phyllosilicate phases. The
results are compatible with the hypothesis that in a mineral-based scenario for the origin of life a CB sign bias in the chiral
fractures originated by mechanical and flow shear gradients on clays could be later transferred to the reactions of the absorbed
organic compounds. 相似文献
998.
999.
Prevalence of neutralizing antibodies to West Nile virus in Eleonora's Falcons in the Canary Islands
Gangoso L Grande JM Llorente F Jiménez-Clavero MÁ Pérez JM Figuerola J 《Journal of wildlife diseases》2010,46(4):1321-1324
Birds are the major amplifying host for West Nile virus (WNV), a flavivirus that may affect humans and transmitted by bloodsucking vectors. Eleonora's Falcons (Falco eleonorae) migrate to the Canary Islands annually from WNV-endemic regions. To investigate the possible role of Eleonora's Falcons in the circulation of WNV, we measured WNV-specific antibodies in 81 falcons captured in 2006. None of the nestlings but 14.8% of the adults had WNV-neutralizing antibodies. RT-PCR did not detect flaviviruses in nonculicine ectoparasites (n=231) of the falcons. These findings suggest that WNV infection did not occur locally, but rather on the wintering grounds or during migration. 相似文献
1000.
Aging is associated with an accrual of body fat, progressive development of insulin resistance and other obesity comorbidities that contribute to decrease life span. Caloric restriction (CR), which primarily affects energy stores in adipose tissue, is known to extend life span and retard the aging process in animal models. In this study, a proteomic approach combining 2‐DE and MS was used to identify proteins modulated by aging and CR in rat white adipose tissue proteome. Proteomic analysis revealed 133 differentially expressed spots, 57 of which were unambiguously identified by MS. Although CR opposed part of the age‐associated protein expression patterns, many effects of CR were on proteins unaltered by age, suggesting that the effects of CR on adipose tissue are only weakly related to those of aging. Particularly, CR and aging altered glucose, intermediate and lipid metabolism, with CR enhancing the expression of enzymes involved in oxalacetate and NADPH production, lipid biosynthesis and lipolysis. Consistently, insulin‐β and β3‐adrenergic receptors were also increased by CR, which denotes improved sensitivity to lipogenic/lipolytic stimuli. Other beneficial outcomes of CR were an improvement in oxidative stress, preventing the age‐associated decrease in several antioxidant enzymes. Proteins involved in cytoskeleton, iron storage, energy metabolism and several proteins with novel or unknown functions in adipose tissue were also modulated by age and/or CR. Such orchestrated changes in expression of multiple proteins provide insights into the mechanism underlying CR effects, ultimately allowing the discovery of new markers of aging and targets for the development of CR‐mimetics. 相似文献