全文获取类型
收费全文 | 653篇 |
免费 | 48篇 |
专业分类
701篇 |
出版年
2023年 | 7篇 |
2022年 | 8篇 |
2021年 | 15篇 |
2020年 | 8篇 |
2019年 | 12篇 |
2018年 | 19篇 |
2017年 | 7篇 |
2016年 | 13篇 |
2015年 | 25篇 |
2014年 | 28篇 |
2013年 | 35篇 |
2012年 | 37篇 |
2011年 | 50篇 |
2010年 | 40篇 |
2009年 | 20篇 |
2008年 | 36篇 |
2007年 | 31篇 |
2006年 | 39篇 |
2005年 | 38篇 |
2004年 | 29篇 |
2003年 | 31篇 |
2002年 | 17篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1975年 | 5篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 7篇 |
1968年 | 3篇 |
1967年 | 4篇 |
1966年 | 6篇 |
1965年 | 3篇 |
1948年 | 2篇 |
1914年 | 2篇 |
1911年 | 8篇 |
排序方式: 共有701条查询结果,搜索用时 0 毫秒
81.
Luiz Henrique Saes Zobiole Rubem Silvério de Oliveira Jr Don Morgan Huber Jamil Constantin César de Castro Fábio Alvares de Oliveira Adilson de Oliveira Jr. 《Plant and Soil》2010,328(1-2):57-69
Although glyphosate-resistant (GR) technology is used in most countries producing soybeans (Glycine max L.), there are no particular fertilize recommendations for use of this technology, and not much has been reported on the influence of glyphosate on GR soybean nutrient status. An evaluation of different cultivar maturity groups on different soil types, revealed a significant decrease in macro and micronutrients in leaf tissues, and in photosynthetic parameters (chlorophyll, photosynthetic rate, transpiration and stomatal conductance) with glyphosate use (single or sequential application). Irrespective of glyphosate applications, concentrations of shoot macro- and micronutrients were found lower in the near-isogenic GR-cultivars compared to their respective non-GR parental lines Shoot and root dry biomass were reduced by glyphosate with all GR cultivars evaluated in both soils. The lower biomass in GR soybeans compared to their isogenic normal lines probably represents additive effects from the decreased photosynthetic parameters as well as lower availability of nutrients in tissues of the glyphosate treated plants. 相似文献
82.
Amalia S. Afendra Efthalia E. Yiannaki Maria A. Palaiomylitou Dimitrios A. Kyriakidis Constantin Drainas 《Biotechnology letters》2002,24(7):579-583
Two recombinant plasmids, expressing ice nucleation activity, were constructed and named pCPP30inaZ and pCPP38inaZ. They were transferred to the ice-negative, xanthan-producing Xanthomonas campestris pv. campestris by electroporation. The transformants were used for co-production of xanthan gum and ice nuclei from sugar beet molasses. The highest values obtained were 20 g l–1 and 1018 ice nuclei ml–1, respectively. The above values fulfil the criteria for industrial manipulation. This is the first report on co-formation of two products by a transformed X. campestris strain. 相似文献
83.
AimThe objective was to examine the renal effects of long-term increased angiotensin II and vasopressin plasma levels in early-stage heart failure (HF). We investigated the regulations of the V2 vasopressin receptor, the type 1A angiotensin II receptor, the (pro)renin receptor, and the water channels AQP2, AQP1, AQP3, and AQP4 in the inner medulla of rat kidney.MethodsHF was induced by coronary artery ligation. Sixty-eight rats were allocated to six groups: Sham (N = 11), HF (N = 11), sodium restricted sham (N = 11), sodium restricted HF (N = 11), sodium restricted sham + DDAVP (N = 12), and sodium restricted HF + DDAVP (N = 12). 1-desamino-8-D-arginine vasopressin (0.5 ng h-1 for 7 days) or vehicle was administered. Pre- and post-treatment echocardiographic evaluation was performed. The rats were sacrificed at day 17 after surgery, before cardiac remodeling in rat is known to be completed.ResultsHF rats on standard sodium diet and sodium restriction displayed biochemical markers of HF. These rats developed hyponatremia, hypo-osmolality, and decreased fractional excretion of sodium. Increase of AQP2 and p(Ser256)-AQP2 abundance in all HF groups was blunted compared with control groups even when infused with DDAVP and despite increased vasopressin V2 receptor and Gsα abundance. This was associated with decreased protein abundance of the AT1A receptor in HF groups vs. controls.ConclusionEarly-stage HF is associated with blunted increase in AQP2 and p(Ser256)-AQP2 despite of hyponatremia, hypo-osmolality, and increased inner medullary vasopressin V2 receptor expression. Decreased type 1A angiotensin II receptor abundance likely plays a role in the transduction of these effects. 相似文献
84.
Thomas E. Ichim Fabio Solano Rosalia De Necochea Campion Erik J. Woods Constantin A. Dasanu Annette M. Marleau Neil H. Riordan 《Cellular immunology》2010,260(2):75-82
Duchenne muscular dystrophy (DMD) is a lethal X-linked musculodegenerative condition consisting of an underlying genetic defect whose manifestation is augmented by inflammatory mechanisms. Previous treatment approaches using gene replacement, exon-skipping or allogeneic cell therapy have been relatively unsuccessful. The only intervention to mediate improvement in survival, albeit minor, is glucocorticoid treatment. Given this modality appears to function via suppression of underlying inflammation; we focus this review on the inflammatory response as a target for mesenchymal stem cell (MSC) therapy. In contrast to other cell based therapies attempted in DMD, MSC have the advantages of (a) ability to fuse with and genetically complement dystrophic muscle; (b) possess anti-inflammatory activities; and (c) produce trophic factors that may augment activity of endogenous repair cells. We conclude by describing one practical scenario of stem cell therapy for DMD. 相似文献
85.
Pim Cuijpers Clara Miguel Mathias Harrer Constantin Yves Plessen Marketa Ciharova David Ebert Eirini Karyotaki 《World psychiatry》2023,22(1):105-115
Cognitive behavior therapy (CBT) is by far the most examined type of psychological treatment for depression and is recommended in most treatment guidelines. However, no recent meta-analysis has integrated the results of randomized trials examining its effects, and its efficacy in comparison with other psychotherapies, pharmacotherapies and combined treatment for depression remains uncertain. We searched PubMed, PsycINFO, Embase and the Cochrane Library to identify studies on CBT, and separated included trials into several subsets to conduct random-effects meta-analyses. We included 409 trials (518 comparisons) with 52,702 patients, thus conducting the largest meta-analysis ever of a specific type of psychotherapy for a mental disorder. The quality of the trials was found to have increased significantly over time (with increasing numbers of trials with low risk of bias, less waitlist control groups, and larger sample sizes). CBT had moderate to large effects compared to control conditions such as care as usual and waitlist (g=0.79; 95% CI: 0.70-0.89), which remained similar in sensitivity analyses and were still significant at 6-12 month follow-up. There was no reduction of the effect size of CBT according to the publication year (<2001 vs. 2001-2010 vs. >2011). CBT was significantly more effective than other psychotherapies, but the difference was small (g=0.06; 95% CI: 0-0.12) and became non-significant in most sensitivity analyses. The effects of CBT did not differ significantly from those of pharmacotherapies at the short term, but were significantly larger at 6-12 month follow-up (g=0.34; 95% CI: 0.09-0.58), although the number of trials was small, and the difference was not significant in all sensitivity analyses. Combined treatment was more effective than pharmacotherapies alone at the short (g=0.51; 95% CI: 0.19-0.84) and long term (g=0.32; 95% CI: 0.09-0.55), but it was not more effective than CBT alone at either time point. CBT was also effective as unguided self-help intervention (g=0.45; 95% CI: 0.31-0.60), in institutional settings (g=0.65; 95% CI: 0.21-1.08), and in children and adolescents (g=0.41; 95% CI: 0.25-0.57). We can conclude that the efficacy of CBT in depression is documented across different formats, ages, target groups, and settings. However, the superiority of CBT over other psychotherapies for depression does not emerge clearly from this meta-analysis. CBT appears to be as effective as pharmacotherapies at the short term, but more effective at the longer term. 相似文献
86.
87.
Richard Gashururu S. Ndichu Maingi Samuel M. Githigia Methode N. Gasana Peter O. Odhiambo Dennis O. Getange Richard Habimana Giuliano Cecchi Weining Zhao James Gashumba Joel L. Bargul Daniel K. Masiga 《PLoS neglected tropical diseases》2021,15(12)
BackgroundAfrican Trypanosomiases threaten the life of both humans and animals. Trypanosomes are transmitted by tsetse and other biting flies. In Rwanda, the African Animal Trypanosomiasis (AAT) endemic area is mainly around the tsetse-infested Akagera National Park (NP). The study aimed to identify Trypanosoma species circulating in cattle, their genetic diversity and distribution around the Akagera NP.MethodologyA cross-sectional study was carried out in four districts, where 1,037 cattle blood samples were collected. The presence of trypanosomes was determined by microscopy, immunological rapid test VerY Diag and PCR coupled with High-Resolution Melt (HRM) analysis. A parametric test (ANOVA) was used to compare the mean Packed cell Volume (PCV) and trypanosomes occurrence. The Cohen Kappa test was used to compare the level of agreement between the diagnostic methods.FindingsThe overall prevalence of trypanosome infections was 5.6%, 7.1% and 18.7% by thin smear, Buffy coat technique and PCR/HRM respectively. Microscopy showed a low sensitivity while a low specificity was shown by the rapid test (VerY Diag). Trypanosoma (T.) congolense was found at a prevalence of 10.7%, T. vivax 5.2%, T. brucei brucei 2% and T. evansi 0.7% by PCR/HRM. This is the first report of T.evansi in cattle in Rwanda. The non-pathogenic T. theileri was also detected. Lower trypanosome infections were observed in Ankole x Friesian breeds than indigenous Ankole. No human-infective T. brucei rhodesiense was detected. There was no significant difference between the mean PCV of infected and non-infected animals (p>0.162).ConclusionsOur study sheds light on the species of animal infective trypanosomes around the Akagera NP, including both pathogenic and non-pathogenic trypanosomes. The PCV estimation is not always an indication of trypanosome infection and the mechanical transmission should not be overlooked. The study confirms that the area around the Akagera NP is affected by AAT, and should, therefore, be targeted by the control activities. AAT impact assessment on cattle production and information on the use of trypanocides are needed to help policymakers prioritise target areas and optimize intervention strategies. Ultimately, these studies will allow Rwanda to advance in the Progressive Control Pathway (PCP) to reduce or eliminate the burden of AAT. 相似文献
88.
Emmanuelle Génin Baptiste Coustet Yannick Allanore Ikue Ito Maria Teruel Arnaud Constantin Thierry Schaeverbeke Adeline Ruyssen-Witrand Shigeto Tohma Alain Cantagrel Olivier Vittecoq Thomas Barnetche Xavier Le Lo?t Patrice Fardellone Hiroshi Furukawa Olivier Meyer Benjamin Fernández-Gutiérrez Alejandro Balsa Miguel A. González-Gay Gilles Chiocchia Naoyuki Tsuchiya Javier Martin Philippe Dieudé 《PloS one》2013,8(4)
Background
BANK1 and BLK belong to the pleiotropic autoimmune genes; recently, epistasis between BANK1 and BLK was detected in systemic lupus erythematosus. Although BLK has been reproducibly identified as a risk factor in rheumatoid arthritis (RA), reports are conflicting about the contribution of BANK1 to RA susceptibility. To ascertain the real impact of BANK1 on RA genetic susceptibility, we performed a large meta-analysis including our original data and tested for an epistatic interaction between BANK1 and BLK in RA susceptibility.Patients and Methods
We investigated data for 1,915 RA patients and 1,915 ethnically matched healthy controls genotyped for BANK1 rs10516487 and rs3733197 and BLK rs13277113. The association of each SNP and RA was tested by logistic regression. Multivariate analysis was then used with an interaction term to test for an epistatic interaction between the SNPs in the 2 genes.Results
None of the SNPs tested individually was significantly associated with RA in the genotyped samples. However, we detected an epistatic interaction between BANK1 rs3733197 and BLK rs13277113 (Pinteraction = 0.037). In individuals carrying the BLK rs13277113 GG genotype, presence of the BANK1 rs3733197 G allele increased the risk of RA (odds ratio 1.21 [95% confidence interval 1.04–1.41], P = 0.015. Combining our results with those of all other studies in a large trans-ethnic meta-analysis revealed an association of the BANK1 rs3733197 G allele and RA (1.11 [1.02–1.21], P = 0.012).Conclusion
This study confirms BANK1 as an RA susceptibility gene and for the first time provides evidence for epistasis between BANK1 and BLK in RA. Our results illustrate the concept of pleiotropic epistatic interaction, suggesting that BANK1 and BLK might play a role in RA pathogenesis. 相似文献89.
M. Bocakova R. Constantin L. Bocak 《Cladistics : the international journal of the Willi Hennig Society》2012,28(2):117-129
The melyrid lineage of beetles form a distinct group of the superfamily Cleroidea with a high level of soft‐bodiedness. Here we present the first molecular phylogenetic analysis of this group. The data matrix included partial sequences of the small and large subunits of rRNA, the mitochondrial large subunit rRNA, and cytochrome oxidase subunit I of 67 melyrid and eight outgroup taxa. The concatenated sequences were analysed using maximum‐parsimony (MP), maximum‐likelihood (ML) and Bayesian analysis (BA) approach. The results strongly supported the monophyly of the melyrid lineage splitting into six major clades: Rhadalidae, Mauroniscidae, Prionoceridae, Melyridae sensu stricto, Dasytidae and Malachiidae. The rhadalids were placed in the most basal position, followed by mauroniscids and prionocerids. Three terminal lineages—the true melyrids, dasytids, and malachiids—are well supported by all analyses, but their mutual relationships remain uncertain as MP analysis proposed alternative topologies to that of the ML and BA trees, with often low node support in the latter two methods. The monophyly of the subfamily Danacaeinae (Dasytidae) with respect to the danacaeine genera of the southern hemisphere (Hylodanacaea, Listrocerus, Amecocerus) was challenged as they were found to be polyphyletic. Similarly, the monophyly of Attalus was rejected by our analyses and shown to be polyphyletic. Based on the preferred phylogenetic hypothesis, the subfamilies Rhadalinae, Dasytinae and Malachiinae are elevated to family rank. © The Willi Hennig Society 2011. 相似文献
90.
Marita Bosticardo Silvia Musio Elena Fontana Stefano Angiari Elena Draghici Gabriela Constantin Pietro L. Poliani Rosetta Pedotti Anna Villa 《PloS one》2014,9(1)
Wiskott-Aldrich Syndrome protein (WASP) is a key regulator of the actin cytoskeleton in hematopoietic cells. Defective expression of WASP leads to multiple abnormalities in different hematopoietic cells. Despite severe impairment of T cell function, WAS patients exhibit a high prevalence of autoimmune disorders. We attempted to induce EAE, an animal model of organ-specific autoimmunity affecting the CNS that mimics human MS, in Was−/− mice. We describe here that Was−/− mice are markedly resistant against EAE, showing lower incidence and milder score, reduced CNS inflammation and demyelination as compared to WT mice. Microglia was only poorly activated in Was−/− mice. Antigen-induced T-cell proliferation, Th-1 and -17 cytokine production and integrin-dependent adhesion were increased in Was−/− mice. However, adoptive transfer of MOG-activated T cells from Was−/− mice in WT mice failed to induce EAE. Was−/− mice were resistant against EAE also when induced by adoptive transfer of MOG-activated T cells from WT mice. Was+/− heterozygous mice developed an intermediate clinical phenotype between WT and Was−/− mice, and they displayed a mixed population of WASP-positive and -negative T cells in the periphery but not in their CNS parenchyma, where the large majority of inflammatory cells expressed WASP. In conclusion, in absence of WASP, T-cell responses against a CNS autoantigen are increased, but the ability of autoreactive T cells to induce CNS autoimmunity is impaired, most probably because of an inefficient T-cell transmigration into the CNS and defective CNS resident microglial function. 相似文献