全文获取类型
收费全文 | 1261篇 |
免费 | 83篇 |
专业分类
1344篇 |
出版年
2023年 | 8篇 |
2022年 | 14篇 |
2021年 | 20篇 |
2020年 | 12篇 |
2019年 | 19篇 |
2018年 | 27篇 |
2017年 | 18篇 |
2016年 | 51篇 |
2015年 | 53篇 |
2014年 | 52篇 |
2013年 | 83篇 |
2012年 | 113篇 |
2011年 | 98篇 |
2010年 | 66篇 |
2009年 | 50篇 |
2008年 | 74篇 |
2007年 | 88篇 |
2006年 | 79篇 |
2005年 | 55篇 |
2004年 | 50篇 |
2003年 | 54篇 |
2002年 | 53篇 |
2001年 | 21篇 |
2000年 | 9篇 |
1999年 | 17篇 |
1998年 | 12篇 |
1997年 | 17篇 |
1996年 | 11篇 |
1995年 | 11篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 6篇 |
1972年 | 2篇 |
1971年 | 5篇 |
排序方式: 共有1344条查询结果,搜索用时 15 毫秒
41.
42.
Tiziana Greggi Konstantinos Martikos Emanuela Pipitone Francesco Lolli Francesco Vommaro Elena Maredi Stefano Cervellati Mario Di Silvestre 《Scoliosis》2010,5(1):1-11
Background
The reported incidence of scoliosis in arthrogryposis varies from 30% to 67% and, in most cases, the curves progress rapidly and become stiff from early age. The authors report six cases of scoliosis in arthrogryposis to assess the role of surgical treatment.Methods
Six cases (3 males, 3 females; mean age at surgery 13.2 years) with arthrogryposis multiplex congenita associated with the characteristic amyoplasia were reviewed: they were operated on for scoliosis at the authors' Spine Surgery Department between 1987 and 2008. Surgery was performed using the Harrington-Luque instrumentation (2 cases), the Luque system (1), a hybrid segmental technique with hooks and screws (1) and spinal anchoring with pedicle screws (2).Results
The patients were clinically and radiologically reviewed at a mean follow-up of 4.2 years, ± 2.7 (range, 1 to 9 years). Three minor postoperative complications were encountered; a long-term pulmonary complication was seen in one case after reintervention and was successfully resolved after 10 days. Surgery was successful in the other 5 cases, where solid arthrodesis was achieved and no significant curve progression was observed at follow-up.Conclusions
The experience acquired with the present case series leads the authors to assert that prompt action should be taken when treating such aggressive forms of scoliosis. In case of mild spinal deformities in arthrogryposis, brace treatment should be attempted, the evolution of the curves being unpredictable; however, when the curve exceeds 40° and presents with marked hyperkyphosis, hyperlordosis or pelvic obliquity, surgery should not be delayed. 相似文献43.
44.
45.
Free l-amino acids and d-aspartate content in the nervous system of Cephalopoda. A comparative study
Antimo D'Aniello Giovanna Nardi Amedeo De Santis Amedeo Vetere Anna di Cosmo Rosangela Marchelli Arnaldo Dossena George Fisher 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》1995,112(4):661-666
We have determined the content of free l-amino acids and d-aspartate in the nervous tissue of three representative cephalopods: Sepia officinalis, Octopus vulgaris, and Loligo vulgaris, and the optic lobes of adult and embryo Sepia officinalis. Taurine is the most abundant amino acid in the cephalopod nervous tissue. Its content amounts to more than 50% of the total free amino acids. The other most concentrated amino acids are Glu, Ala, Asp, and GABA. High concentrations of d-aspartate were found in the nervous tissue of all cephalopods examined (7–12 μmol/g wet tissue) which represents 50–80% of the total aspartate (d + l), depending on the animal. Among the various regions of the brain of Octopus vulgaris, d-aspartate was found to be evenly distributed in the various regions of the brain. In nerve tissue of Sepia officinalis, there is no significant difference in the pattern of free l-amino acids, in particular of the d-aspartate concentration, between adults and embryos, except for GABA, Gly, His and Thr. This suggests that d-aspartate in nerve tissue of the Cephalopoda is of endogenous origin and not a product of accumulation from exogenous sources. From a comparative study of the content of d-aspartate in the nervous tissue of different animals, we found that protostomia contain a significantly higher amount than deuterostomia. Thus, d-aspartate could be a criterion to distinguish the protostomia phyla from the deuterostomia phyla. 相似文献
46.
G M Nardi R Felippi S DalBó J M Siqueira-Junior D C Arruda F Delle Monache A K Timbola M G Pizzolatti K Ckless R M Ribeiro-do-valle 《Phytomedicine》2003,10(2-3):176-184
Croton celtidifolius Baill commonly known as "sangue-de-adave" is a tree found in the Atlantic Forest of south of Brazil, mainly in Santa Catarina. The bark and leaf infusions of this medicinal plant have been popularly used for the treatment of inflammatory diseases. In this study we evaluated the anti-inflammatory and antioxidant properties of crude extract (CE), aqueous fraction (AqF), ethyl acetate fraction (EAF), butanolic fraction (BuF) and catechin, gallocatechin and sub-fractions, 19SF, 35SF and 63SF that contained a mixture of proanthocyanidins and were derived from the EAF fraction. The CE, AqF, EAF, BuF, catechin and sub-fractions 35SF and 63SF reduced paw edema induced by carrageenan. The CE, fractions, sub-fractions and isolated compounds showed antioxidant properties in vitro, all were able to scavenge superoxide anions at a concentration of 100 microg ml(-1). The EAF, catechin and gallocatechin were most effective in the deoxyribose assay, IC50 0.69 (0.44-1.06), 0.20 (0.11-0.39), 0.55 (0.28-1.08) microg x ml(-1) respectively. The CE and other fractions and sub-fractions inhibited deoxyribose degradation up to 1 microg x ml(-1). In the hydrophobic system only AqF did not show lipid peroxidation inhibition. The CE, other fractions, sub-fractions and isolated compounds inhibited lipidid peroxidation only at a concentration of 100 microg x ml(-1). In summary, this study demonstrates that Croton celtidifolius bark has significant anti-inflammatory and antioxidant activity. 相似文献
47.
Melania Melis Maria Carla Aragoni Massimiliano Arca Tiziana Cabras Claudia Caltagirone Massimo Castagnola Roberto Crnjar Irene Messana Beverly J. Tepper Iole Tomassini Barbarossa 《PloS one》2013,8(3)
The genetic predisposition to taste 6-n-propylthiouracil (PROP) varies among individuals and is associated with salivary levels of Ps-1 and II-2 peptides, belonging to the basic proline-rich protein family (bPRP). We evaluated the role of these proteins and free amino acids that selectively interact with the PROP molecule, in modulating bitter taste responsiveness. Subjects were classified by their PROP taster status based on ratings of perceived taste intensity for PROP and NaCl solutions. Quantitative and qualitative determinations of Ps-1 and II-2 proteins in unstimulated saliva were performed by HPLC-ESI-MS analysis. Subjects rated PROP bitterness after supplementation with Ps-1 and II-2, and two amino acids (L-Arg and L-Lys) whose interaction with PROP was demonstrated by 1H-NMR spectroscopy. ANOVA showed that salivary levels of II-2 and Ps-1 proteins were higher in unstimulated saliva of PROP super-tasters and medium tasters than in non-tasters. Supplementation of Ps-1 protein in individuals lacking it in saliva enhanced their PROP bitter taste responsiveness, and this effect was specific to the non-taster group.1H-NMR results showed that the interaction between PROP and L-Arg is stronger than that involving L-Lys, and taste experiments confirmed that oral supplementation with these two amino acids increased PROP bitterness intensity, more for L-Arg than for L-Lys. These data suggest that Ps-1 protein facilitates PROP bitter taste perception and identifies a role for free L-Arg and L-Lys in PROP tasting. 相似文献
48.
Tiziana Cabras Elisabetta Pisano Caterina Montaldo Maria Rita Giuca Federica Iavarone Giuseppe Zampino Massimo Castagnola Irene Messana 《Molecular & cellular proteomics : MCP》2013,12(7):1844-1852
People with Down syndrome, a frequent genetic disorder in humans, have increased risk of health problems associated with this condition. One clinical feature of Down syndrome is the increased prevalence and severity of periodontal disease in comparison with the general population. Because saliva plays an important role in maintaining oral health, in the present study the salivary proteome of Down syndrome subjects was investigated to explore modifications with respect to healthy subjects. Whole saliva of 36 Down syndrome subjects, divided in the age groups 10–17 yr and 18–50 yr, was analyzed by a top-down proteomic approach, based on the high performance liquid chromatography-electrospray ionization–MS analysis of the intact proteins and peptides, and the qualitative and quantitative profiles were compared with sex- and age-matched control groups. The results showed the following interesting features: 1) as opposed to controls, in Down syndrome subjects the concentration of the major salivary proteins of gland origin did not increase with age; as a consequence concentration of acidic proline rich proteins and S cystatins were found significantly reduced in older Down syndrome subjects with respect to matched controls; 2) levels of the antimicrobial α-defensins 1 and 2 and histatins 3 and 5 were significantly increased in whole saliva of older Down syndrome subjects with respect to controls; 3) S100A7, S100A8, and S100A12 levels were significantly increased in whole saliva of Down syndrome subjects in comparison with controls. The increased level of S100A7 and S100A12 may be of particular interest as a biomarker of early onset Alzheimer''s disease, which is frequently associated with Down syndrome.Down syndrome (DS)1 is a frequent genetic disorder in humans characterized by premature aging (1). A clinical feature of people with DS is the increased prevalence and severity of periodontal disease compared with age-matched subjects of similar levels of intellectual impairment and compared with the general population (2). Common conditions observed in DS are marginal gingivitis, acute and subacute necrotizing gingivitis, advanced periodontitis, gingival recession, and pocket formation (3, 4). It is known that saliva plays an important role in maintaining oral and dental health, because of the presence of a variety of antimicrobial peptides mainly derived from gland secretion, oral epithelial cells, and neutrophils (5). Several papers reported that neutrophils and T-lymphocyte function is impaired in people with DS (6–9). However, the salivary secretion of the antimicrobial LL-37 in young individuals with DS was found normal (10). A review of the literature (11, 12) reveals only sporadic and contradictory reports that attempt to explain the role of saliva in the oral health of subjects with DS, and on the whole, information on the biochemical composition of their saliva is scarce. On the basis of the above information, in the present study, we proposed to investigate the salivary proteome of DS subjects by an intact protein-based “top-down” approach. The spectrum of salivary peptides of DS subjects was compared with that of sex and age-matched healthy control groups to determine qualitative and quantitative differences. Interestingly, the results showed that several members of the S100A family, which possess different biological functions, and also described as potential markers of the Alzheimer Disease, were significantly increased in saliva of Down syndrome subjects with respect to controls. 相似文献
49.
Kathrin Loosli Alicia Davis Adrian Muwonge Tiziana Lembo 《PLoS neglected tropical diseases》2021,15(7)
Universal access to healthcare, including quality medicines, is a fundamental human right but is still out of reach for many in low- and middle-income countries (LMICs). An existing framework capturing variability of access to healthcare in low-resource settings includes the 5 dimensions: availability, accessibility, affordability, adequacy, and acceptability. This framework encompasses key components, including health infrastructure and means to access it as well as service organisation, costs, and factors that influence users’ satisfaction. However, in reality, the effectiveness of accessed healthcare is measured by the likelihood of a positive outcome. We therefore propose an expansion of this framework to include an additional dimension, “aspects of quality,” incorporating quality, which critically influences the ability of the accessed services to generate optimal health outcomes. Within this framework, we explore literature from East Africa likely relevant to a range of LMIC contexts, mainly focusing on the provision of widely used antimicrobials such as antimalarials and antibiotics. We argue that major inadequacies exist across all 6 dimensions of access and quality of drugs and their provision. While the global focus is on curbing excessive antimicrobial use to tackle the antimicrobial resistance (AMR) crisis, major constraints around access shape patients’ health-seeking decisions leading to potentially problematic practices that might exacerbate the AMR problem. We advocate for a holistic approach to tackling these inadequacies, encompassing all dimensions of access and quality of healthcare in order to improve health outcomes while simultaneously counteracting the AMR crisis. 相似文献
50.
Riccardo Ronzoni Tiziana Anelli Martina Brunati Margherita Cortini Claudio Fagioli Roberto Sitia 《Traffic (Copenhagen, Denmark)》2010,11(7):947-957
In many protein storage diseases, detergent‐insoluble proteins accumulate in the early secretory compartment (ESC). Protein condensation reflects imbalances between entry into (synthesis/translocation) and exit from (secretion/degradation) ESC, and can be also a consequence of altered quality control (QC) mechanisms. Here we exploit the inducible formation of Russell bodies (RB), dilated ESC cisternae containing mutant Ig‐µ chains, as a model to mechanistically dissect protein condensation. Depending on the presence or absence of Ig‐L chains, mutant Ig‐µ chains lacking their first constant domain (Ch 1) accumulate in rough or smooth RB (rRB and sRB), dilations of the endoplasmic reticulum (ER) and ER‐Golgi intermediate compartment (ERGIC), respectively, reflecting the proximal and distal QC stations in the stepwise biogenesis of polymeric IgM. Either weakening ERp44‐dependent distal QC or facilitating ER‐associated degradation (ERAD) inhibits RB formation. Overexpression of PDI or ERp44 inhibits µΔCh 1 secretion. However, PDI inhibits while ERp44 promotes µΔCh 1 condensation. Both Ero1α silencing and overexpression prevent RB formation, demonstrating a strict redox dependency of the phenomenon. Altogether, our findings identify key controllers of protein condensation along the ESC as potential targets to handle certain storage disorders. 相似文献