全文获取类型
收费全文 | 2681篇 |
免费 | 180篇 |
专业分类
2861篇 |
出版年
2024年 | 4篇 |
2023年 | 20篇 |
2022年 | 46篇 |
2021年 | 94篇 |
2020年 | 46篇 |
2019年 | 68篇 |
2018年 | 89篇 |
2017年 | 76篇 |
2016年 | 108篇 |
2015年 | 167篇 |
2014年 | 213篇 |
2013年 | 227篇 |
2012年 | 302篇 |
2011年 | 258篇 |
2010年 | 156篇 |
2009年 | 139篇 |
2008年 | 137篇 |
2007年 | 145篇 |
2006年 | 121篇 |
2005年 | 106篇 |
2004年 | 95篇 |
2003年 | 77篇 |
2002年 | 67篇 |
2001年 | 11篇 |
2000年 | 6篇 |
1999年 | 17篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 2篇 |
1994年 | 7篇 |
1993年 | 12篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有2861条查询结果,搜索用时 11 毫秒
51.
Emmanuelle Kesse-Guyot Valentina A. Andreeva Claude Jeandel Monique Ferry Mathilde Touvier Serge Hercberg Pilar Galan 《PloS one》2012,7(12)
Background
Associations between alcohol consumption and cognitive function are discordant and data focusing on midlife exposure are scarce.Objective
To estimate the association between midlife alcohol consumption and cognitive performance assessed 13 y later while accounting for comorbidities and diet.Methods
3,088 French middle-aged adults included in the SU.VI.MAX (1994) study with available neuropsychological evaluation 13 y later. Data on alcohol consumption were obtained from repeated 24h dietary records collected in 1994–1996. Cognitive performance was assessed in 2007–2009 via a battery of 6 neuropsychological tests. A composite score was built as the mean of the standardized individual test scores (mean = 50, SD = 10). ANCOVA were performed to estimate mean differences in cognitive performance and 95% confidence intervals (CI).Results
In women, abstainers displayed lower cognitive scores than did low-to-moderate alcohol drinkers (1 to 2 drinks/day) (mean difference = −1.77; 95% CI: −3.29, −0.25). In men, heavy drinkers (>3 drinks/day) had higher cognitive scores than did low-to-moderate (1 to 3 drinks/day) (mean difference = 1.05; 95% CI: 0.10, 1.99). However, a lower composite cognitive score was detected in male drinkers consuming ≥90 g/d (≈8 drinks/d). A higher proportion of alcohol intake from beer was also associated with lower cognitive scores. These associations remained significant after adjustment for diet, comorbidities and sociodemographic factors.Conclusion
In men, heavy but not extreme drinking was associated with higher global cognitive scores. Given the known harmful effects of alcohol even in low doses regarding risk of cancer, the study does not provide a basis for modifying current public health messages.Trial Registration
ClinicalTrials.gov NCT00272428相似文献52.
53.
Malej Alenka; Mozetic Patricija; Turk Valentina; Terzic Senka; Ahel Marijan; Cauwet Gustave 《Journal of plankton research》2003,25(8):949-966
This study examined the partitioning of organic matter intoparticulate organic carbon (POC) and dissolved organic carbon(DOC) pools in nutrient-enriched enclosures containing naturalplankton from the Gulf of Trieste (northern Adriatic), an areaaffected by mucilage. The strategy of nutrient additions wasto introduce a pulse of new nutrients in concentrations thatmimic natural inputs and to survey community structure and organicmatter fluxes long enough so that plankton became nutrient-limited.Maximal bacterial biomass attained roughly double the initialvalue, while autotrophic carbon increased by nearly an orderof magnitude. The microflagellate-dominated community releasedmore DOC per unit biomass (5.5 ± 7.2 to 50.6 ±28.0 µg C µg Chl a-1 day-1 versus 3.4 ± 3.4to 10.8 ± 4.6 µg C µg Chl a-1 day-1 for diatom-dominatedphytoplankton), POC increase was modest (~300 µg C l-1)and there was little change in DOC. Organic carbon partitioningduring two experiments in which diatoms prevailed was dominatedby POC (>800 µg C l-1) in the exponential growth phasewith an increasing contribution of particulate carbohydratesthat paralleled gradual nutrient depletion. Transition to thestationary phase and the decay of autotrophic communities wereaccompanied by the net accumulation of a carbohydrate-rich DOC. 相似文献
54.
Valentina Mariotti Benedetta Bonfiglioli Silvana Condemi 《Journal of human evolution》2009,56(4):340-354
55.
Francesco Saccoliti Gabriella Angiulli Giovanni Pupo Luca Pescatori Valentina Noemi Madia Antonella Messore 《Journal of enzyme inhibition and medicinal chemistry》2017,32(1):304-310
The study presented here aimed at identifying a new class of compounds acting against Leishmania parasites, the causative agent of Leishmaniasis. For this purpose, the thioether derivatives of our in-house library have been evaluated in whole-cell screening assays in order to determine their in vitro activity against Leishmania protozoan. Among them, promising results have been achieved with compound RDS 777 (6-(sec-butoxy)-2-((3-chlorophenyl)thio)pyrimidin-4-amine) (IC50?=?29.43?µM), which is able to impair the mechanism of the parasite defence against the reactive oxygen species by inhibiting the trypanothione reductase (TR) with high efficiency (Ki 0.25?±?0.18?µM). The X-ray structure of L. infantum TR in complex with RDS 777 disclosed the mechanism of action of this compound that binds to the catalytic site and engages in hydrogen bonds the residues more involved in the catalysis, namely Glu466', Cys57 and Cys52, thereby inhibiting the trypanothione binding and avoiding its reduction. 相似文献
56.
Luis A. Ebensperger Verónica Quirici Valentina Bunster Cecilia León Juan Ramírez-Estrada Loren D. Hayes 《The Journal of wildlife management》2021,85(7):1344-1354
Species-specific research on free-ranging mammals reveals a diversity of effects of radio-collars on behavior, body condition, and fitness. Although these studies indicate rather limited direct effects, radio-collars may cause effects influenced by socio-ecological conditions. Using a 7-year study on a natural population of group-living degus (Octodon degus), we tested the hypothesis that ecological (food availability, burrow density) and social (group size, group male-to-female ratio) conditions modulate effects of radio-collars on body condition (e.g., body mass, ecto- and endoparasite loads, fecal cortisol metabolites) and direct fitness (litter size, adult survival). We determined the effect of radio-collar use on degus by contrasting the presence or absence of radio-collars, quantifying the effects of the number of days carrying a radio-collar, and the relative mass of radio-collars worn by degus in central Chile between 2009 and 2015. Radio-collar use was not associated with direct effects on litter size, adult survival, or with body mass and fecal cortisol metabolites but was linked to low ecto- and endoparasite loads. These seemingly positive effects may reflect decreased mobility, or a research bias for radio-collaring larger, healthier individuals. There was no evidence that ecological and social conditions modulated radio-collar effects on degu body condition and direct fitness. These findings are consistent with evidence from other mammal studies that reported no appreciable detrimental direct or indirect effects of radio-collars. © 2021 The Wildlife Society. 相似文献
57.
58.
Radi M Crespan E Botta G Falchi F Maga G Manetti F Corradi V Mancini M Santucci MA Schenone S Botta M 《Bioorganic & medicinal chemistry letters》2008,18(3):1207-1211
A series of substituted benzoylamino-2-[(4-benzyl)thio]-1,3,4-thiadiazoles has been discovered as potent Abl tyrosine kinase inhibitors. Molecular docking simulations on the Abl tyrosine kinase were conducted in order to rationalize the SAR of the synthesized inhibitors. The most active compound identified from the enzymatic screening (6a) showed interesting inhibitory activity on Imatinib-sensitive murine myeloid 3B clone and Bcr-Abl-independent Imatinib-resistant leukemia cells. Surprisingly, 6a was also proved to act as differentiating inducers in human promyelocytic leukemia cells (HL-60). 相似文献
59.
Andrea Berruti Roberto Borriello Maria Teresa Della Beffa Valentina Scariot Valeria Bianciotto 《Symbiosis (Philadelphia, Pa.)》2013,61(2):63-76
Camellia japonica L. (Theaceae, Theales) is an acidophilic evergreen flowering shrub and is traded worldwide. Symbiotic associations between the roots of this plant species and arbuscular mycorrhizal fungi (AMF), commonly recognized as natural biofertilizers and biocontrol agents, have been poorly studied so far. The aim of our study was to verify whether the application of nonspecific commercial AMF-based inocula could succeed and improve the growth of C. japonica. An experiment was conducted concerning the application of commercial inocula constituted by a specific AMF isolate (Funneliformis mosseae) or a consortium of different fungi and bacteria as alternatives to fertilization in pot cultivated C. japonica ‘Dr. Burnside’. Several growth parameters, plant nutrition and mycorrhization levels were monitored at the end of plant cultivation. Generally, increases in some macroelements (Ca, Mg, K) and microelements (Cu, Mn, Fe, Zn) were detected in the root system of inoculated camellias, while only Cu and Mn accumulation was increased in the leaves. Plants inoculated with the consortium inoculum exhibited increased chlorophyll content and foliage diameter while plants inoculated with F. mosseae exhibited increased number of flowers. Based on the polymorphism of an 18S rDNA region, we assessed the inoculated AMF that colonized C. japonica roots. The experiments showed that the applied AMF poorly colonized the root system of C. japonica. We suggest that commercial AMF formulations should be more targeted and host-specific in order to successfully colonize the host root and, potentially, fully express their benefits. 相似文献
60.
Valentina Ferrari Alison Tarke Hannah Fields Luca Ferrari Trevor Conley Franco Ferrari Zeynep Koşaloğlu-Yalçın Alessandro Sette Bjoern Peters Colin L. McCarthy Asad Bashey Dimitrios Tzachanis Edward D. Ball Tiffany N. Tanaka Rafael Bejar Thomas A. Lane Antonella Vitiello 《Cytotherapy》2021,23(4):320-328
Therapies that utilize immune checkpoint inhibition work by leveraging mutation-derived neoantigens and have shown greater clinical efficacy in tumors with higher mutational burden. Whether tumors with a low mutational burden are susceptible to neoantigen-targeted therapy has not been fully addressed. To examine the feasibility of neoantigen-specific adoptive T-cell therapy, the authors studied the T-cell response against somatic variants in five patients with myelodysplastic syndrome (MDS), a malignancy with a very low tumor mutational burden. DNA and RNA from tumor (CD34+) and normal (CD3+) cells isolated from the patients’ blood were sequenced to predict patient-specific MDS neopeptides. Neopeptides representing the somatic variants were used to induce and expand autologous T cells ex vivo, and these were systematically tested in killing assays to determine the proportion of neopeptides yielding neoantigen-specific T cells. The authors identified a total of 32 somatic variants (four to eight per patient) and found that 21 (66%) induced a peptide-specific T-cell response and 19 (59%) induced a T-cell response capable of killing autologous tumor cells. Of the 32 somatic variants, 11 (34%) induced a CD4+ response and 11 (34%) induced a CD8+ response that killed the tumor. These results indicate that in vitro induction of neoantigen-specific T cells is feasible for tumors with very low mutational burden and that this approach warrants investigation as a therapeutic option for such patients. 相似文献