全文获取类型
收费全文 | 1149篇 |
免费 | 61篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 22篇 |
妇产科学 | 46篇 |
基础医学 | 149篇 |
口腔科学 | 10篇 |
临床医学 | 113篇 |
内科学 | 302篇 |
皮肤病学 | 32篇 |
神经病学 | 84篇 |
特种医学 | 33篇 |
外科学 | 124篇 |
综合类 | 4篇 |
预防医学 | 79篇 |
眼科学 | 90篇 |
药学 | 67篇 |
中国医学 | 1篇 |
肿瘤学 | 55篇 |
出版年
2022年 | 12篇 |
2021年 | 25篇 |
2020年 | 9篇 |
2019年 | 17篇 |
2018年 | 32篇 |
2017年 | 17篇 |
2016年 | 25篇 |
2015年 | 22篇 |
2014年 | 33篇 |
2013年 | 52篇 |
2012年 | 69篇 |
2011年 | 63篇 |
2010年 | 46篇 |
2009年 | 34篇 |
2008年 | 68篇 |
2007年 | 80篇 |
2006年 | 43篇 |
2005年 | 67篇 |
2004年 | 48篇 |
2003年 | 59篇 |
2002年 | 30篇 |
2001年 | 16篇 |
2000年 | 11篇 |
1999年 | 14篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 15篇 |
1994年 | 10篇 |
1992年 | 13篇 |
1991年 | 18篇 |
1990年 | 17篇 |
1989年 | 22篇 |
1988年 | 16篇 |
1987年 | 20篇 |
1986年 | 21篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1979年 | 6篇 |
1977年 | 5篇 |
1975年 | 7篇 |
1974年 | 9篇 |
1973年 | 11篇 |
1972年 | 7篇 |
1971年 | 6篇 |
1969年 | 7篇 |
1967年 | 9篇 |
1966年 | 5篇 |
1965年 | 5篇 |
排序方式: 共有1213条查询结果,搜索用时 15 毫秒
41.
42.
Eulogio?Pleguezuelos Lluis?Guirao Eva?Moreno Beatriz?Samitier Pilar?Ortega Xavier?Vila Manuel?V.?Garnacho-Casta?o María?Majó Laura?Ovejero Marc?MiravitllesEmail authorView authors OrcID profile 《Lung》2018,196(6):665-668
It is well known that chronic obstructive pulmonary disease (COPD) patients present with muscle dysfunction that may not correlate with the degree of severity of airflow obstruction. Historically, the strength deficit of the knee extensor musculature (quadriceps) has been described as an independent factor of mortality in COPD. We present the results of a retrospective study with longitudinal follow-up of 60 patients with severe COPD followed for 7 years. During follow-up 22 patients died, mainly of respiratory cause. We have observed that the strength of knee flexor muscles (ischiocrural) and dominant handgrip were independent predictors of mortality in severe COPD patients. However, knee extensor strength (quadriceps) was not an independent predictor of mortality. This is the first study which highlights the importance of knee flexor musculature as a prognostic factor in COPD. 相似文献
43.
44.
Patricia Balaresque Nicolas Poulet Sylvain Cussat-Blanc Patrice Gerard Lluis Quintana-Murci Evelyne Heyer Mark A Jobling 《European journal of human genetics : EJHG》2015,23(10):1413-1422
High-frequency microsatellite haplotypes of the male-specific Y-chromosome can signal past episodes of high reproductive success of particular men and their patrilineal descendants. Previously, two examples of such successful Y-lineages have been described in Asia, both associated with Altaic-speaking pastoral nomadic societies, and putatively linked to dynasties descending, respectively, from Genghis Khan and Giocangga. Here we surveyed a total of 5321 Y-chromosomes from 127 Asian populations, including novel Y-SNP and microsatellite data on 461 Central Asian males, to ask whether additional lineage expansions could be identified. Based on the most frequent eight-microsatellite haplotypes, we objectively defined 11 descent clusters (DCs), each within a specific haplogroup, that represent likely past instances of high male reproductive success, including the two previously identified cases. Analysis of the geographical patterns and ages of these DCs and their associated cultural characteristics showed that the most successful lineages are found both among sedentary agriculturalists and pastoral nomads, and expanded between 2100 BCE and 1100 CE. However, those with recent origins in the historical period are almost exclusively found in Altaic-speaking pastoral nomadic populations, which may reflect a shift in political organisation in pastoralist economies and a greater ease of transmission of Y-chromosomes through time and space facilitated by the use of horses. 相似文献
45.
46.
Mercé Boada Carmen Antunez Jesús López-ArrietaAntonio Caruz Concha Moreno-ReyReposo Ramírez-Lorca Francisco Jesús MorónIsabel Hernández Ana MauleónMaiteé Rosende-Roca Pablo Martínez-LageJuan Marín Lluis TárragaMontserrat Alegret José Rafael PedrajasNuria Urda José Luis RoyoMaría Eugenia Saez Javier GayánAntonio González-Pérez Luis Miguel RealAgustín Ruiz José Jorge Galán 《Neurobiology of aging》2012,33(1):198
The present research is aimed at assessing the role of 3 estrogen receptor alpha (ESR1) gene variants in late onset Alzheimer's disease (AD) susceptibility. One thousand one hundred thirteen unrelated late onset sporadic AD patients, 1109 healthy controls and 121 neurologically healthy elderly controls were used to carry out case-control genetic association studies with ESR1 rs3844508, rs2234693, and ESR1 noncoding deletion 1 (ESR1-NCD1) polymorphisms. Thirty-five healthy male samples were used for molecular analyses. The rs2234693 polymorphism is associated with AD in our population (odds ratio [OR], 1.29; p = 0.008). The rs3844508 marker confers protection against AD in males (OR, 0.57; p = 0.001) and the deletion ESR1-NCD1 is a risk factor for AD in women (OR, 1.67; p < 0.001). Molecular analyses on ESR1-NCD1 indicate that this deletion confers a higher response to estradiol activity on ESR1 receptor and it is also associated with differential expression of ESR1 isoforms. Our results support the involvement of ESR1 gene in AD and point to the existence of sexual dimorphism for ESR1 markers. In addition, carriers of ESR1-NCD1 deletion could overrespond to estradiol action. 相似文献
47.
Marcos Otero-Garcia Ana Martin-Sanchez Lluis Fortes-Marco Joana Martínez-Ricós Carmen Agustin-Pavón Enrique Lanuza Fernando Martínez-García 《Brain structure & function》2014,219(3):1055-1081
Quantitative analysis of the immunoreactivity for arginine-vasopressin (AVP-ir) in the telencephalon of male (intact and castrated) and female CD1 mice allows us to precisely locate two sexually dimorphic (more abundant in intact than castrated males and females) AVP-ir cell groups in the posterior bed nucleus of the stria terminalis (BST) and the amygdala. Chemoarchitecture (NADPH diaphorase) reveals that the intraamygdaloid AVP-ir cells are located in the intra-amygdaloid BST (BSTIA) rather than the medial amygdala (Me), as previously thought. Then, we have used for the first time tract tracing (combined with AVP immunofluorescence) and fiber-sparing lesions of the BST to analyze the projections of the telencephalic AVP-ir cell groups. The results demonstrate that the posterior BST originates the sexually dimorphic innervation of the lateral septum, the posterodorsal Me and a substance P-negative area in the medioventral striato-pallidum (mvStP).The BSTIA may also contribute to some of these terminal fields. Our material also reveals non-dimorphic AVP-ir processes in two locations of the amygdala. First, the ventral Me shows dendrite-like AVP-ir processes apparently belonging supraoptic neurons, whose possible functions are discussed. Second, the Ce shows sparse, thick AVP-ir axons with high individual variability in density and distribution, whose possible influence on stress coping in relation to the affiliative or agonistic behaviors mediated by the Me are discussed. Finally, we propose that the region of the mvStP showing sexually dimorphic AVP-ir innervation is part of the brain network for socio-sexual behavior, in which it would mediate motivational aspects of chemosensory-guided social interactions. 相似文献
48.
Javier Millán Nieves Negre Elena Castellanos Lucía de Juan Ana Mateos Lluis Parpal 《Avian pathology》2010,39(1):1-6
Avian mycobacteriosis is a chronic, infectious disease caused by different species of mycobacteria, usually belonging to the Mycobacterium avium complex. From 2004 to 2007, 589 raptors brought dead or sick to a wildlife rehabilitation centre in Majorca (Balearic Islands, Spain) were necropsied. The birds belonged to 12 different species, chiefly common kestrel (Falco tinnunculus) (n=297), scops owl (Otus scops) (n=109), barn owl (Tyto alba) (n=75), long-eared owl (Asio otus) (n=58), peregrine falcon (Falco peregrinus) (n=27), and booted eagle (Hieraaetus pennatus) (n=13). Gross lesions compatible with mycobacteriosis were observed in 14 birds (2.4%) found in several locations in Majorca. They were 12 kestrels (prevalence in this species, 4.0%), one long-eared owl (1.7%) and one scops owl (0.9%), all the birds presenting white–yellowish nodules from pinpoint size to 1 cm in diameter in diverse organs, mainly in the liver, spleen and intestine. Affected organs were subjected to bacteriology and molecular identification by polymerase chain reaction and, in all cases, infection with M. avium subspecies avium was confirmed. The observed prevalences are similar to those previously observed in Holland, although the actual prevalence detected in this study is likely to be higher than reported because only birds with gross lesions were subjected to culture. Further molecular characterization with a set of six mycobacterial interspersed repetitive unit–variable number tandem repeat loci was used to sub-type the isolates in order to show the existence of possible epidemiological links. Six different genotypes were found, which points to infection from multiple foci. No temporal or geographical aggregation of the cases was observed to be associated with the presence of positive birds or with the different variable number tandem repeat allelic profiles. The most feasible origin might be water or food sources, although the reservoir of mycobacteria remains unknown. 相似文献
49.
Microsatellites are highly polymorphic markers that are distributed through all the genome being more abundant in non-coding
regions. Whether they are neutral or under selection, these markers if localized can be used as co-dominant molecular markers
to explore the dynamics of the evolutionary processes. Their cytological localization can allow identifying genes under selection,
inferring recombination from a genomic point of view, or screening for the genomic reorganizations occurring during the evolution
of a lineage, among others. In this paper, we report for the first time the localization of microsatellite loci by fluorescent
in situ hybridization on Drosophila polytene chromosomes. In Drosophila subobscura, 72 dinucleotide microsatellite loci were localized by fluorescent in situ hybridization yielding unique hybridization signals.
In the sex chromosome, microsatellite distribution was not uniform and its density was higher than in autosomes. We identified
homologous segments to the sequence flanking the microsatellite loci by browsing the genome sequence of Drosophila pseudoobscura and Drosophila melanogaster. Their localization supports the conservation of Muller’s chromosomal elements among Drosophila species and the existence of multiple intrachromosomal rearrangements within each evolutionary lineage. Finally, the lack
of microsatellite repeats in the homologous D. melanogaster sequences suggests convergent evolution for high microsatellite density in the distal part of the X chromosome. 相似文献
50.
Pregnancy in the older woman is a well-known risk factor for perinatal morbidity and mortality. OBJECTIVE: To evaluate perinatal and infant morbidity and mortality in women 50 or more years old. METHODS: A retrospective population based study (1990-2004) evaluating spontaneously pregnant Chilean women more than 50 years old (217 live or stillbirths) compared to women 20-34 years old (2,817,742 neonates, control group). The comparison was performed using Chi Square with Yates's correction or exact Fisher test as appropriate. The risk analysis was performed by odds ratio (OR) and confidence interval of 95% (CI 95%). RESULTS: Women over 50 had a significantly greater risk of fetal (OR: 3.7; CI 95%: 1.2-10.5), neonatal (OR: 10.4; CI 95%: 5.7-18.7), post-neonatal (OR: 9.5; CI 95%: 4.6-19.1) and infant death (OR: 10.5; CI 95%: 6.6-16.7). There were no differences between groups in the incidences of low and very low birth weight. CONCLUSION: Pregnancy over 50 years of age entails a very high risk of fetal, neonatal and early childhood death. Unprotected sexual life for these women should be considered only after evaluation of their potential fertility. 相似文献