全文获取类型
收费全文 | 1781篇 |
免费 | 108篇 |
国内免费 | 2篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 16篇 |
2021年 | 61篇 |
2020年 | 33篇 |
2019年 | 47篇 |
2018年 | 35篇 |
2017年 | 30篇 |
2016年 | 67篇 |
2015年 | 96篇 |
2014年 | 115篇 |
2013年 | 108篇 |
2012年 | 162篇 |
2011年 | 121篇 |
2010年 | 80篇 |
2009年 | 73篇 |
2008年 | 109篇 |
2007年 | 113篇 |
2006年 | 76篇 |
2005年 | 82篇 |
2004年 | 87篇 |
2003年 | 63篇 |
2002年 | 74篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 16篇 |
1998年 | 18篇 |
1997年 | 13篇 |
1996年 | 13篇 |
1995年 | 7篇 |
1994年 | 11篇 |
1993年 | 8篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 12篇 |
1985年 | 8篇 |
1984年 | 13篇 |
1983年 | 5篇 |
1982年 | 12篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1977年 | 4篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1957年 | 2篇 |
排序方式: 共有1891条查询结果,搜索用时 139 毫秒
991.
Wing phosphorylation is a major functional determinant of the Lrs14‐type biofilm and motility regulator AbfR1 in Sulfolobus acidocaldarius 下载免费PDF全文
992.
993.
miR-203 represses 'stemness' by repressing DeltaNp63 总被引:1,自引:0,他引:1
994.
Vassura M Margara L Di Lena P Medri F Fariselli P Casadio R 《Bioinformatics (Oxford, England)》2008,24(10):1313-1315
Fault Tolerant Contact Map Reconstruction (FT-COMAR) is a heuristic algorithm for the reconstruction of the protein three-dimensional structure from (possibly) incomplete (i.e. containing unknown entries) and noisy contact maps. FT-COMAR runs within minutes, allowing its application to a large-scale number of predictions. AVAILABILITY: http://bioinformatics.cs.unibo.it/FT-COMAR 相似文献
995.
Linda Engblom Lena Eliasson-Selling Nils Lundeheim Katinka Belák Kjell Andersson Anne-Marie Dalin 《Acta veterinaria Scandinavica》2008,50(1):25
Background
The aim of this study was to get information on post mortem diagnoses of sows found dead or euthanised and to understand the diagnoses aetiology (causative background). Moreover, the study was to evaluate the association between the clinical symptoms observed on farm and post mortem findings. 相似文献996.
Transforming growth factor-beta (TGF-beta) is thought to play a role in the pathobiological progression of ovarian cancer because this peptide hormone is overexpressed in cancer tissue, plasma, and peritoneal fluid. In the current study, we investigated the role of the TGF-beta/Smad3 pathway in ovarian cancer metastasis by regulation of an epithelial-to-mesenchymal transition. When cancer cells were cultured on plastic, TGF-beta1, TGF-beta2, and TGF-beta3 induced pro-matrix metalloproteinase (MMP) secretion, loss of cell-cell junctions, down-regulation of E-cadherin, up-regulation of N-cadherin, and acquisition of a fibroblastoid phenotype, consistent with an epithelial-to-mesenchymal transition. Furthermore, Smad3 small interfering RNA transfection inhibited TGF-beta-mediated changes to a fibroblastic morphology, but not MMP secretion. When cancer cells were cultured on a three-dimensional collagen matrix, TGF-beta1, TGF-beta2, and TGF-beta3 stimulated both pro-MMP and active MMP secretion and invasion. Smad3 small interfering RNA transfection of cells cultured on a collagen matrix abrogated TGF-beta-stimulated invasion and MMP secretion. Analysis of Smad3 nuclear expression in microarrays of serous benign tumors, borderline tumors, and cystadenocarcinoma revealed that Smad3 expression could be used to distinguish benign and borderline tumors from carcinoma (P = 0.006). Higher Smad3 expression also correlated with poor survival (P = 0.031). Furthermore, a direct relationship exists between Smad3 nuclear expression and expression of the mesenchymal marker N-cadherin in cancer patients (P = 0.0057). Collectively, these results implicate an important role for the TGF-beta/Smad3 pathway in mediating ovarian oncogenesis by enhancing metastatic potential. 相似文献
997.
998.
A proteomics approach to the study of absorption, distribution, metabolism, excretion, and toxicity. 总被引:1,自引:0,他引:1
Helena Nordvarg John Flensburg Ola R?nn Johan Ohman Rita Marouga Bo Lundgren Daniel Haid Eva Malmport Jan Goscinski Lena H?rnsten Michaela Scigelova Stephanie Bourin Per Garberg Gary Woffendin David Feny? Hélène Bergling Erik Forsberg 《Journal of biomolecular techniques》2004,15(4):265-275
A proteomics approach was used to identify liver proteins that displayed altered levels in mice following treatment with a candidate drug. Samples from livers of mice treated with candidate drug or untreated were prepared, quantified, labeled with CyDye DIGE Fluors, and subjected to two-dimensional electrophoresis. Following scanning and imaging of gels from three different isoelectric focusing intervals (3-10, 7-11, 6.2-7.5), automated spot handling was performed on a large number of gel spots including those found to differ more than 20% between the treated and untreated condition. Subsequently, differentially regulated proteins were subjected to a three-step approach of mass spectrometry using (a) matrix-assisted laser desorption/ionization time-of-flight mass spectrometry peptide mass fingerprinting, (b) post-source decay utilizing chemically assisted fragmentation, and (c) liquid chromatography-tandem mass spectrometry. Using this approach we have so far resolved 121 differentially regulated proteins following treatment of mice with the candidate drug and identified 110 of these using mass spectrometry. Such data can potentially give improved molecular insight into the metabolism of drugs as well as the proteins involved in potential toxicity following the treatment. The differentially regulated proteins could be used as targets for metabolic studies or as markers for toxicity. 相似文献
999.
Birgitta Adolfsson Stig Elofsson Stephan Rssner Anna‐Lena Undn 《Obesity (Silver Spring, Md.)》2004,12(10):1702-1709
Objective: To investigate whether there is any association between obesity and sexual satisfaction and sexual abuse in a normal population. Research Methods and Procedures: A representative sample of 2810 subjects from a population study was interviewed about sexual satisfaction, sexual abuse, and life satisfaction. The answers from normal weight, overweight, and obese participants were compared. Univariate and multivariate analyses were performed. Results: Data were presented separately for two age groups, 18 to 49 and 50 to 74 years, and gender. The older group of obese men reported a greater decrease of sexual desire compared with 5 years prior than normal weight men [odds ratios (OR), 2.44; 95% confidence interval (CI), 1.4 to 4.3]. The older group of overweight men reported involuntary participation in sexual activities more often than normal weight men (OR, 2.06; 95% CI, 1.1 to 3.8). Although older overweight and obese women were diagnosed with a lingering disease (defined as >1 month) more often than normal weight women (overweight: OR, 2.41; 95% CI, 1.3 to 4.4; obese: OR, 4.45; 95% CI, 1.7 to 11.5), there was no difference between BMI groups in satisfaction with physical health. Discussion: Overweight and obese groups seem to be heterogeneous with respect to sexual satisfaction and experiences of sexual abuse. No significant differences were detected between BMI groups, which does not exclude the possibility of significant differences between BMI groups among patients seeking medical attention. 相似文献
1000.
Self-assembly plays an important role in the formation of many chiral biological structures and in the preparation of chiral functional materials. Therefore the control of chirality in synthetic or biological self-assembled systems is important either for the comprehension of recognition phenomena or to obtain materials with predictable and controllable properties. Circular dichroism was developed to study molecular chirality, however, because of its outstanding sensitivity to chiral perturbations of the system under investigation; it has been extended more recently to supramolecular chemistry. In particular, self-assembly processes leading to the formation of chiral supramolecular architectures (and eventually to gels or liquid crystal phases) can be monitored by CD. Furthermore, CD spectroscopy often allows one to obtain structural information on the assembled structures. This review deals with representative contributions to the study of supramolecular chirality by means of circular dichroism. 相似文献