全文获取类型
收费全文 | 372篇 |
免费 | 33篇 |
专业分类
405篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 5篇 |
2017年 | 14篇 |
2016年 | 11篇 |
2015年 | 19篇 |
2014年 | 20篇 |
2013年 | 26篇 |
2012年 | 27篇 |
2011年 | 22篇 |
2010年 | 24篇 |
2009年 | 15篇 |
2008年 | 26篇 |
2007年 | 19篇 |
2006年 | 19篇 |
2005年 | 21篇 |
2004年 | 9篇 |
2003年 | 13篇 |
2002年 | 6篇 |
2001年 | 12篇 |
2000年 | 14篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有405条查询结果,搜索用时 0 毫秒
41.
JH Lee JM Lee EM Ramos T Gillis JS Mysore S Kishikawa T Hadzi AE Hendricks MR Hayden PJ Morrison M Nance CA Ross RL Margolis F Squitieri C Gellera E Gomez-Tortosa C Ayuso O Suchowersky RJ Trent E McCusker A Novelletto M Frontali R Jones T Ashizawa S Frank MH Saint-Hilaire SM Hersch HD Rosas D Lucente MB Harrison A Zanko RK Abramson K Marder J Sequeiros G Bernhard Landwehrmeyer;On behalf of the Registry Study of the European Huntington’s Disease Network 《Biochemical and biophysical research communications》2012,426(3):404-408
42.
Vallejos-Almirall Alejandro Riquelme Margarita Uribe Elena Agurto-Muñoz Cristian Rosas Anali Vergara Carola 《Journal of applied phycology》2022,34(5):2371-2382
Journal of Applied Phycology - Ultraviolet (UV) radiation generates cyclobutane pyrimidine dimer (CPD) photoproducts in the DNA of skin cells, causing photoaging and non-melanoma skin cancer.... 相似文献
43.
Marina Lozano Almudena Estalrrich Luca Bondioli Ivana Fiore José‐Maria Bermúdez de Castro Juan Luis Arsuaga Eudald Carbonell Antonio Rosas David W. Frayer 《Evolutionary anthropology》2017,26(6):313-324
Fossil hominids often processed material held between their upper and lower teeth. Pulling with one hand and cutting with the other, they occasionally left impact cut marks on the lip (labial) surface of their incisors and canines. From these actions, it possible to determine the dominant hand used. The frequency of these oblique striations in an array of fossil hominins documents the typically modern pattern of 9 right‐ to 1 left‐hander. This ratio among living Homo sapiens differs from that among chimpanzees and bonobos and more distant primate relatives. Together, all studies of living people affirm that dominant right‐handedness is a uniquely modern human trait. The same pattern extends deep into our past. Thus far, the majority of inferred right‐handed fossils come from Europe, but a single maxilla from a Homo habilis, OH‐65, shows a predominance of right oblique scratches, thus extending right‐handedness into the early Pleistocene of Africa. Other studies show right‐handedness in more recent African, Chinese, and Levantine fossils, but the sample compiled for non‐European fossil specimens remains small. Fossil specimens from Sima del los Huesos and a variety of European Neandertal sites are predominately right‐handed. We argue the 9:1 handedness ratio in Neandertals and the earlier inhabitants of Europe constitutes evidence for a modern pattern of handedness well before the appearance of modern Homo sapiens. 相似文献
44.
Effects of pesticides on the fatty acid and phospholipid composition of Escherichia coli. 总被引:3,自引:0,他引:3 下载免费PDF全文
Cells of Escherichia coli contained an altered phospholipid and fatty acid composition when grown in the presence of some pesticides. Whereas parathion increased the concentration of all phospholipid species without changes in their polar head groups. DDT (dichlorodiphenyltrichloroethane) decreased the proportion of neutral serine-derived phosphatides and dieldrin decreased the proportion of negatively charged phospholipids. The saturated/unsaturated plus cyclopropane fatty acid ratio was increased in all cases. The changes suggested that cells adapted their membrane lipids to compensate for the presence of pesticides in the environment. 相似文献
45.
Alejandro Velasco Victor Manuel Velasco Fernando Rosas Cihan Cevik Carlos A Morillo 《Indian pacing and electrophysiology journal》2013,13(1):34-37
Chagas disease is a highly prevalent zoonosis in Mexico, Central, and South America. Early cardiac involvement is one of the most serious complications of this disease, and conduction disturbances may occur at an early age. We describe a young pregnant woman with Chagas disease and a high degree atrioventricular block, who required implantation of a permanent dual chamber pacemaker. Using an electroanatomic navigation EnSite NavX® system the pacemaker was successfully implanted with minimal fluoroscopic exposure. This case demonstrates the safety and feasibility of using an electroanatomic navigation system to guide permanent pacemaker implantation minimizing x-ray exposure in pregnant patients. 相似文献
46.
Reinout Raijmakers Joyce JBC van Beers Mahmoud El-Azzouny Natasja FC Visser Borut Bo?i? Ger JM Pruijn Albert JR Heck 《Arthritis research & therapy》2012,14(3):R114-10
Introduction
Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation of the joints and the presence of autoantibodies directed against proteins containing the non-standard arginine-derived amino acid citrulline. The protein fibrinogen, which has an essential role in blood clotting, is one of the most prominent citrullinated autoantigens in RA, particularly because it can be found in the inflamed tissue of affected joints. Here, we set out to analyze the presence of citrullinated endogenous peptides in the synovial fluid of RA and arthritic control patients.Methods
Endogenous peptides were isolated from the synovial fluid of RA patients and controls by filtration and solid phase extraction. The peptides were identified and quantified using high-resolution liquid chromatography-mass spectrometry.Results
Our data reveal that the synovial fluid of RA patients contains soluble endogenous peptides, derived from fibrinogen, containing significant amounts of citrulline residues and, in some cases, also phosphorylated serine. Several citrullinated peptides are found to be more abundantly present in the synovial fluid of RA patients compared to patients suffering from other inflammatory diseases affecting the joints.Conclusions
The increased presence of citrullinated peptides in RA patients points toward a possible specific role of these peptides in the immune response at the basis of the recognition of citrullinated peptides and proteins by RA patient autoantibodies. 相似文献47.
Almudena Estalrrich Antonio Rosas Samuel García‐Vargas Antonio García‐Tabernero David Santamaría Marco de la Rasilla 《American journal of physical anthropology》2011,144(1):154-161
The distribution of subvertical grooves on interproximal wear dental facets from the El Sidrón (Asturias, Spain) Neandertals is described and analyzed. Out of 93 teeth, 64.5% present subvertical grooves, including a high frequency (50%) on the anterior dentition. Contrary to some studies, subvertical grooves from adjacent facets perfectly overlap each other and do not interdigitate, probably forming small channels. Both the facet and the groove surface share the same polished appearance, suggesting a common origin. Statistical analyses reveal that the number of grooves is neither dependent on the degree of occlusal wear, nor on the position on the tooth or the individual's age. However, facet width is an important factor determining the number of subvertical grooves. The etiology of subvertical grooves formation on Neandertal teeth remains unclear. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
48.
BACKGROUND: Biochemical testing for pheochromocytoma by measurement of fractionated plasma metanephrines is limited by false positive rates of up to 18% in people without known genetic predisposition to the disease. The plasma normetanephrine fraction is responsible for most false positives and plasma normetanephrine increases with age. The objective of this study was to determine if we could improve the specificity of fractionated plasma measurements, by statistically adjusting for age. METHODS: An age-adjusted metanephrine score was derived using logistic regression from 343 subjects (including 33 people with pheochromocytoma) who underwent fractionated plasma metanephrine measurements as part of investigations for suspected pheochromocytoma at Mayo Clinic Rochester (derivation set). The performance of the age-adjusted score was validated in a dataset of 158 subjects (including patients 23 with pheochromocytoma) that underwent measurements of fractionated plasma metanephrines at Mayo Clinic the following year (validation dataset). None of the participants in the validation dataset had known genetic predisposition to pheochromocytoma. RESULTS: The sensitivity of the age-adjusted metanephrine score was the same as that of traditional interpretation of fractionated plasma metanephrine measurements, yielding a sensitivity of 100% (23/23, 95% confidence interval [CI] 85.7%, 100%). However, the false positive rate with traditional interpretation of fractionated plasma metanephrine measurements was 16.3% (22/135, 95% CI, 11.0%, 23.4%) and that of the age-adjusted score was significantly lower at 3.0% (4/135, 95% CI, 1.2%, 7.4%) (p < 0.001 using McNemar's test). CONCLUSION: An adjustment for age in the interpretation of results of fractionated plasma metanephrines may significantly decrease false positives when using this test to exclude sporadic pheochromocytoma. Such improvements in false positive rate may result in savings of expenditures related to confirmatory imaging. 相似文献
49.
Sciutto E Rosas G Cruz-Revilla C Toledo A Cervantes J Hernández M Hernándezt B Goldbaum FA de Aluja AS Fragoso G Larralde C 《The Journal of parasitology》2007,93(4):824-831
Review of experimental and observational evidence about various cestode infections of mammalian hosts revives hope for the development of an effective vaccine against adult intestinal tapeworms, the central protagonists in their transmission dynamics. As for Taenia solium, there are abundant immunological data regarding cysticercosis in humans and pigs, but information about human taeniasis is scarce. A single publication reporting protection against T. solium taeniasis by experimental primo infection and by vaccination of an experimental foster host, the immunocompetent female hamster, kindles the hope of a vaccine against the tapeworm to be used in humans, its only natural definitive host. 相似文献
50.
Koen Peeters Grietens Joan Muela Ribera Veronica Soto Alex Tenorio Sarah Hoibak Angel Rosas Aguirre Elizabeth Toomer Hugo Rodriguez Alejandro Llanos Cuentas Umberto D'Alessandro Dionicia Gamboa Annette Erhart 《PloS one》2013,8(1)