全文获取类型
收费全文 | 654篇 |
免费 | 68篇 |
出版年
2023年 | 10篇 |
2022年 | 15篇 |
2021年 | 27篇 |
2020年 | 12篇 |
2019年 | 20篇 |
2018年 | 19篇 |
2017年 | 13篇 |
2016年 | 28篇 |
2015年 | 49篇 |
2014年 | 57篇 |
2013年 | 45篇 |
2012年 | 63篇 |
2011年 | 52篇 |
2010年 | 23篇 |
2009年 | 23篇 |
2008年 | 35篇 |
2007年 | 23篇 |
2006年 | 24篇 |
2005年 | 15篇 |
2004年 | 17篇 |
2003年 | 15篇 |
2002年 | 13篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1985年 | 8篇 |
1984年 | 9篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 4篇 |
1972年 | 5篇 |
1971年 | 5篇 |
1970年 | 4篇 |
1957年 | 1篇 |
1948年 | 1篇 |
排序方式: 共有722条查询结果,搜索用时 15 毫秒
101.
102.
103.
J. Bonaventure C. Philippe G. Plessis J. Vigneron C. Lasselin P. Maroteaux S. Gilgenkrantz 《Human genetics》1992,90(1-2):164-168
Summary A three generation family with Stickler syndrome is reported. Affected patients exhibited myopia with frequent retinal detachment or glaucoma. Most of them had characteristic facial dysmorphism, the Pierre-Robin sequence being observed in four individuals. Neonatal radiological signs of the Weissenbacher-Zweymüller syndrome were also noticed but early arthopathy was not reported in adults. Restriction fragment length polymorphism studies with the type II collagen gene (COL2A1) showed a recombination event between the disease locus and COL2A1, thus excluding collagen type II as the candidate gene. Although the calculation of the likelihood of genetic heterogeneity versus homogeneity based on 10 families was not statistically significant, we suggest that a second locus is probably involved in this highly variable syndrome. 相似文献
104.
105.
Michel Roberge Adrien R. Beaudoin 《Biochimica et Biophysica Acta (BBA)/General Subjects》1982,716(3):331-336
The pancreatic secretion of anesthetized pigs was collected by cannulation after pulse labeling with [3H]leucine. Collection at 5 min intervals started immediately post-pulse labeling up to 85 min. The volume, the protein content and the trichloroacetic acid-precipitable radioactivity of the juice were measued. The specific radioactivity of the secertory proteins was compared to that of a zymogen granule fraction isolated from the same animal. The latter was very much higher. Caerulein stimulation for 5 min at 80 min post-pulse caused a sharp drop in the specific activity of secretory proteins in the juice, to a level lower than that of the zymogen granule content. These data support the concept of more than one pool of secretory proteins in the pancreas and are incompatible with the concept that secretory proteins derive from an homogeneous granule compartment in a functionally homogeneous population of cells. To explain our results the hypothesis of a second intracellular route for the secretory proteins is proposed. 相似文献
106.
Hélène Rangé Christine Poitou Adrien Boillot Cécile Ciangura Sandrine Katsahian Jean-Marc Lacorte Sébastien Czernichow Olivier Meilhac Philippe Bouchard Catherine Chaussain 《PloS one》2013,8(3)
Epidemiological data indicate an association between periodontitis and obesity. The biological mechanisms of this relationship remain unclear. A cross-sectional study was conducted to evaluate the relationship between periodontitis and the common systemic inflammatory markers in 32 morbidly obese patients recruited in a Clinical Nutrition department. Periodontal condition was evaluated using pocket depth (PD) measurement, a classical clinical marker of ongoing periodontitis. Major periodontal risk factors were recorded (age, gender, diabetes and smoking status), as well as plasma levels of inflammatory markers (CRP, orosomucoid, IL-6) and adipokines (adiponectin, leptin). All patients included in the sample exhibited evidence of periodontitis, 16 of whom were diagnosed as having severe disease. Adjusted logistic regression analysis indicated that the severity of periodontitis was associated with the plasma level of orosomucoid (p<0.04) after adjustment for age, gender and smoking. Our study thus suggests that the severity of periodontitis, in morbidly obese patients, is associated with the increase of orosomucoid levels. 相似文献
107.
Formal models have linked prehistoric and historical instances of technological change (e.g., the Upper Paleolithic transition, cultural loss in Holocene Tasmania, scientific progress since the late nineteenth century) to demographic change. According to these models, cumulation of technological complexity is inhibited by decreasing— while favoured by increasing—population levels. Here we show that these findings are contingent on how complexity is defined: demography plays a much more limited role in sustaining cumulative culture in case formal models deploy Herbert Simon''s definition of complexity rather than the particular definitions of complexity hitherto assumed. Given that currently available empirical evidence doesn''t afford discriminating proper from improper definitions of complexity, our robustness analyses put into question the force of recent demographic explanations of particular episodes of cultural change. 相似文献
108.
L Lanfumey J Adrien 《Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie》1984,298(7):207-210
In Rat, neonatal lesion of the locus coeruleus induces modifications of beta-adrenergic regulations at the level of raphe dorsalis neurons. In normal conditions, the firing of serotoninergic raphe cells is not beta-adrenergic dependent. On the contrary in the lesioned animal, iontophoresis of a beta-blocking agent (DL-propranolol) produces a marked inhibition of the serotoninergic unit firing. Various mechanisms may account for this pharmacological response in the lesioned group: a classical hypersensitivity phenomenon, or the persistence of an immature regulation. 相似文献
109.
Adrien Zimmer Cécile Durand Nicolás Loira Pascal Durrens David James Sherman Philippe Marullo 《PloS one》2014,9(1)
Quantitative genetics and QTL mapping are efficient strategies for deciphering the genetic polymorphisms that explain the phenotypic differences of individuals within the same species. Since a decade, this approach has been applied to eukaryotic microbes such as Saccharomyces cerevisiae in order to find natural genetic variations conferring adaptation of individuals to their environment. In this work, a QTL responsible for lag phase duration in the alcoholic fermentation of grape juice was dissected by reciprocal hemizygosity analysis. After invalidating the effect of some candidate genes, a chromosomal translocation affecting the lag phase was brought to light using de novo assembly of parental genomes. This newly described translocation (XV-t-XVI) involves the promoter region of ADH1 and the gene SSU1 and confers an increased expression of the sulfite pump during the first hours of alcoholic fermentation. This translocation constitutes another adaptation route of wine yeast to sulfites in addition to the translocation VIII-t-XVI previously described. A population survey of both translocation forms in a panel of domesticated yeast strains suggests that the translocation XV-t-XVI has been empirically selected by human activity. 相似文献
110.
Rose Abramoff Xiaofeng Xu Melannie Hartman Sarah O’Brien Wenting Feng Eric Davidson Adrien Finzi Daryl Moorhead Josh Schimel Margaret Torn Melanie A. Mayes 《Biogeochemistry》2018,137(1-2):51-71
Soil organic carbon (SOC) can be defined by measurable chemical and physical pools, such as mineral-associated carbon, carbon physically entrapped in aggregates, dissolved carbon, and fragments of plant detritus. Yet, most soil models use conceptual rather than measurable SOC pools. What would the traditional pool-based soil model look like if it were built today, reflecting the latest understanding of biological, chemical, and physical transformations in soils? We propose a conceptual model—the Millennial model—that defines pools as measurable entities. First, we discuss relevant pool definitions conceptually and in terms of the measurements that can be used to quantify pool size, formation, and destabilization. Then, we develop a numerical model following the Millennial model conceptual framework to evaluate against the Century model, a widely-used standard for estimating SOC stocks across space and through time. The Millennial model predicts qualitatively similar changes in total SOC in response to single factor perturbations when compared to Century, but different responses to multiple factor perturbations. We review important conceptual and behavioral differences between the Millennial and Century modeling approaches, and the field and lab measurements needed to constrain parameter values. We propose the Millennial model as a simple but comprehensive framework to model SOC pools and guide measurements for further model development. 相似文献