全文获取类型
收费全文 | 1754篇 |
免费 | 132篇 |
出版年
2023年 | 5篇 |
2022年 | 12篇 |
2021年 | 27篇 |
2020年 | 22篇 |
2019年 | 24篇 |
2018年 | 23篇 |
2017年 | 29篇 |
2016年 | 36篇 |
2015年 | 86篇 |
2014年 | 72篇 |
2013年 | 140篇 |
2012年 | 178篇 |
2011年 | 147篇 |
2010年 | 98篇 |
2009年 | 81篇 |
2008年 | 105篇 |
2007年 | 114篇 |
2006年 | 106篇 |
2005年 | 101篇 |
2004年 | 89篇 |
2003年 | 81篇 |
2002年 | 78篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1999年 | 18篇 |
1998年 | 24篇 |
1997年 | 19篇 |
1996年 | 14篇 |
1995年 | 17篇 |
1994年 | 12篇 |
1993年 | 15篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 9篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1971年 | 1篇 |
排序方式: 共有1886条查询结果,搜索用时 15 毫秒
231.
Schroeder GM Wei D Banfi P Cai ZW Lippy J Menichincheri M Modugno M Naglich J Penhallow B Perez HL Sack J Schmidt RJ Tebben A Yan C Zhang L Galvani A Lombardo LJ Borzilleri RM 《Bioorganic & medicinal chemistry letters》2012,22(12):3951-3956
5-Butyl-1,4-diphenyl pyrazole and 2-amino-5-chloro pyrimidine acylsulfonamides were developed as potent dual antagonists of Bcl-2 and Bcl-xL. Compounds were optimized for binding to the I88, L92, I95, and F99 pockets normally occupied by pro-apoptotic protein Bim. An X-ray crystal structure confirmed the proposed binding mode. Observation of cytochrome c release from isolated mitochondria in MV-411 cells provides further evidence of target inhibition. Compounds demonstrated submicromolar antiproliferative activity in Bcl-2/Bcl-xL dependent cell lines. 相似文献
232.
Lombardi R Donini M Villani ME Brunetti P Fujiyama K Kajiura H Paul M Ma JK Benvenuto E 《Transgenic research》2012,21(5):1005-1021
We previously described the expression of a tumour-targeting antibody (mAb H10) in Nicotiana benthamiana by vacuum-agro-infiltration and the remarkable yields of highly pure protein achieved. The objective of the present work was to investigate different strategies for transient overexpression of the mAb H10 in which glycan configuration was modulated and assess how these strategies affect the accumulation yield and stability of the antibody. To this aim, three procedures have been assayed: (1) Site-directed mutagenesis to abolish the glycosylation site; (2) endoplasmic reticulum retention (C-terminal SEKDEL fusion) to ensure predominantly high-mannose type glycans; and (3) expression in a N. benthamiana RNAi down-regulated line in which β1,2-xylosyltransferase and α1,3-fucosyltransferase gene expression is silenced. The three antibody variants (H10-Mut) (H10-SEKDEL) (H10(XylT/FucT)) were transiently expressed, purified and characterised for their glycosylation profile, expression/purification yield and antibody degradation pattern. Glycosylation analysis of H10(XylT/FucT) demonstrated the absence of plant complex-type sugars, while H10-SEKDEL, although substantially retained in the ER, revealed the presence of β1,2-xylose and α1,3-fucose residues, indicating a partial escape from the ER retrieval system. Antibody accumulation and purification yields were not enhanced by ER retention. All H10 antibody glyco-forms revealed greater degradation compared to the original, resulting mostly in the formation of Fab fragments. In the case of aglycosylated H10-Mut, more than 95% of the heavy chain was cleaved, confirming the pivotal role of the sugar moiety in protein stability. Identification of possible 'fragile' sites in the H10 antibody hinge region could be of general interest for the development of new strategies to reduce antibody degradation and increase the yield of intact IgGs in plants. 相似文献
233.
Tumbarello M Fiori B Trecarichi EM Posteraro P Losito AR De Luca A Sanguinetti M Fadda G Cauda R Posteraro B 《PloS one》2012,7(3):e33705
Background
Very few data exist on risk factors for developing biofilm-forming Candida bloodstream infection (CBSI) or on variables associated with the outcome of patients treated for this infection.Methods and Findings
We identified 207 patients with CBSI, from whom 84 biofilm-forming and 123 non biofilm-forming Candida isolates were recovered. A case-case-control study to identify risk factors and a cohort study to analyze outcomes were conducted. In addition, two sub-groups of case patients were analyzed after matching for age, sex, APACHE III score, and receipt of adequate antifungal therapy. Independent predictors of biofilm-forming CBSI were presence of central venous catheter (odds ratio [OR], 6.44; 95% confidence interval [95% CI], 3.21–12.92) or urinary catheter (OR, 2.40; 95% CI, 1.18–4.91), use of total parenteral nutrition (OR, 5.21; 95% CI, 2.59–10.48), and diabetes mellitus (OR, 4.47; 95% CI, 2.03–9.83). Hospital mortality, post-CBSI hospital length of stay (LOS) (calculated only among survivors), and costs of antifungal therapy were significantly greater among patients infected by biofilm-forming isolates than those infected by non-biofilm-forming isolates. Among biofilm-forming CBSI patients receiving adequate antifungal therapy, those treated with highly active anti-biofilm (HAAB) agents (e.g., caspofungin) had significantly shorter post-CBSI hospital LOS than those treated with non-HAAB antifungal agents (e.g., fluconazole); this difference was confirmed when this analysis was conducted only among survivors. After matching, all the outcomes were still favorable for patients with non-biofilm-forming CBSI. Furthermore, the biofilm-forming CBSI was significantly associated with a matched excess risk for hospital death of 1.77 compared to non-biofilm-forming CBSI.Conclusions
Our data show that biofilm growth by Candida has an adverse impact on clinical and economic outcomes of CBSI. Of note, better outcomes were seen for those CBSI patients who received HAAB antifungal therapy. 相似文献234.
Capriotti AL Caracciolo G Cavaliere C Foglia P Pozzi D Samperi R Laganà A 《Journal of Proteomics》2012,75(6):1924-1932
Cationic liposomes (CLs) are one of the most employed nonviral nanovector systems in gene therapy. However, their transfection efficiency is strongly affected by interactions with plasma components, that lead to the formation of a “protein corona” onto CL surface. The interactions between nanoparticles entering the body and biomolecules have an essential role for their biodistribution. Because the knowledge of proteins adsorbed onto vector surface could be useful in the screening of new, more efficient and more biocompatible liposomal formulations, the behavior of three CLs with different membrane charge densities was investigated. The proteins of the three coronas were identified by nano-liquid chromatography-tandem mass spectrometry, and quantified with label-free spectral counting strategy. Fibrinogen displayed higher association with CLs with high membrane charge density, while apolipoproteins and C4b-binding protein with CLs with low membrane charge density. These results are discussed in terms of the different lipid compositions of CLs and may have a deep biological impact for in vivo applications. Surface charge of nanoparticles is emerging as a relevant factor determining the corona composition after interaction with plasma proteins. Remarkably, it is also shown that the charge of the protein corona formed around CLs is strongly related to their membrane charge density. 相似文献
235.
P Giovanni Artini G Simi M Ruggiero S Pinelli OM Di Berardino F Papini S Papini P Monteleone V Cela 《Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology》2012,28(9):669-673
Objective: To analyze the effect of dehydroepiandrosterone (DHEA) supplementation on follicular microenvironment and on in vitro fertilization (IVF) outcomes among poor responder patients. Study design: We enrolled 24 patients diagnosed as poor responders based on ESHRE consensus criteria. One group received 25?mg/die three times daily of DHEA supplementation for 3 months previous to IVF cycle, while the other did not receive any treatment. COH was performed with rFSH and hMG, and a GnRH antagonist was administered according to a flexible protocol. We evaluated perifollicular vascularization of recruited follicles through power Doppler blood flow analysis and follicles were graded as described by Chui et al. Follicular fluids (FF) from F3-F4 follicles were collected, and FF levels of vascular endothelial growth factor (VEGF) and hypoxic inducible factor1 (HIF1) were measured. Results: FF levels of HIF1 were statistically significant lower in women treated with DHEA (14.76 ± 51.13 vs. 270.03 ± 262.18 pg/ml; p = 0.002). On the contrary, VEGF levels did not differ between the two groups. Concerning COH, in the DHEA-group the mean duration of treatment was significantly shorter (9.83 ± 1.85 vs. 12.09?±?2.81; p = 0.023). Total numbers of oocytes retrieved, fertilized oocytes, good quality embryos, number of transferred embryos and clinical pregnancies tended to be higher in study group, but the results were not significant. On the other hand, considering the oocytes retrieved in selected F3-F4 follicles, there was a relation between HIF1 levels and oocytes quality. In fact, mature oocytes retrieved in selected follicles were significantly more numerous in DHEA-group (0.50 ± 0.52 vs. 0.08?±?0.29; p = 0.018). Conclusions: The improvement of reproductive parameters after DHEA supplementation in poor responders may be explained through the effect that this pro-hormone exerts on follicular microenvironment. 相似文献
236.
Background
The findings of the few studies that have to date investigated the way in which individuals with Anorexia Nervosa (AN) navigate their social environment are somewhat contradictory. We undertook this study to shed new light on the social-cognitive profile of patients with AN, analysing Theory of Mind and emotional functioning. Starting from previous evidence on the role of the amygdala in the neurobiology of AN and in the social cognition, we hypothesise preserved Theory of Mind and impaired emotional functioning in patients with AN.Methodology
Thirty women diagnosed with AN and thirty-two women matched for education and age were involved in the study. Theory of Mind and emotional functioning were assessed with a set of validated experimental tasks. A measure of perceived social support was also used to test the correlations between this dimension and the social-cognitive profile of AN patients.Principal Findings
The performance of patients with AN is significantly worse than that of healthy controls on tasks assessing emotional functioning, whereas patients’ performance is comparable to that of healthy controls on the Theory of Mind task. Correlation analyses showed no relationship between scores on any of the social-cognition tasks and either age of onset or duration of illness. A correlation between social support and emotional functioning was found. This latter result seems to suggest a potential role of social support in the treatment and recovery of AN.Conclusions
The pattern of results followed the experimental hypothesis. They may be useful to help us better understand the social-cognitive profile of patients with AN and to contribute to the development of effective interventions based on the ways in which patients with AN actually perceive their social environment. 相似文献237.
238.
239.