全文获取类型
收费全文 | 684篇 |
免费 | 32篇 |
国内免费 | 1篇 |
专业分类
717篇 |
出版年
2023年 | 6篇 |
2022年 | 8篇 |
2021年 | 22篇 |
2020年 | 8篇 |
2019年 | 17篇 |
2018年 | 25篇 |
2017年 | 17篇 |
2016年 | 27篇 |
2015年 | 42篇 |
2014年 | 47篇 |
2013年 | 50篇 |
2012年 | 61篇 |
2011年 | 48篇 |
2010年 | 35篇 |
2009年 | 29篇 |
2008年 | 44篇 |
2007年 | 49篇 |
2006年 | 39篇 |
2005年 | 29篇 |
2004年 | 23篇 |
2003年 | 28篇 |
2002年 | 21篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有717条查询结果,搜索用时 15 毫秒
91.
Eleni A. Charmpila Maximilian Wagner Bettina Reichenbacher 《Journal of fish biology》2021,98(5):1450-1455
Otolith morphology is a widely accepted tool for species identification in teleost fish, but whether this holds true for very small species remains to be explored. Here, the saccular otoliths of the cryptobenthic Mediterranean clingfish Gouania (Gobiesocidae) are described for the first time. The new data, although preliminary, indicate that otolith morphology and morphometry support the recognition of the recently differentiated five species of Gouania in the Mediterranean Sea. Furthermore, otoliths of phylogenetically closely related Gouania species resemble each other more than do those of the more distantly related species. 相似文献
92.
George Pentheroudakis Georgia Raptou Vassiliki Kotoula Ralph M. Wirtz Eleni Vrettou Vasilios Karavasilis Georgia Gourgioti Chryssa Gakou Konstantinos N. Syrigos Evangelos Bournakis Grigorios Rallis Ioannis Varthalitis Eleni Galani Georgios Lazaridis George Papaxoinis Dimitrios Pectasides Gerasimos Aravantinos Thomas Makatsoris Konstantine T. Kalogeras George Fountzilas 《PloS one》2015,10(5)
Background
Although host immune response is an emerging prognostic factor for colorectal cancer, there is no consensus on the optimal methodology, surrogate markers or tissue for study.Patients and Methods
Tumour blocks were prospectively collected from 344 patients with stage II/III colorectal cancer (CRC) treated with adjuvant chemotherapy. Whole section lymphocytic infiltration was studied along with mRNA expression of CD3Z, CD8, CD4, CXCL9, CXCL13, IGHM, FOXP3, SNAI2 and ESR1 by qRT-qPCR in tissue microarray (TMA) cores from the centre of tumour, invasive margin and adjacent normal mucosa.Results
Lymphocytic infiltration, deficient MMR (10.9%), KRAS (40.7%) and BRAF (4.9%) mutations or single mRNA gene expression were not prognostic. Tumour ESR1 gene expression (Hazard Ratio [HR] for relapse 2.33, 95% CI 1.35-4.02; HR for death 1.74, 95% CI 1.02-2.97) and absence of necrosis (HR for relapse 1.71, 95% CI 1.05-2.71; HR for death 1.98, 95% CI 1.14-3.43) were adverse prognostic features. We used CD3Z and CD8 expression in order to devise the mRNA-based Immune Score (mIS) and proceeded to partitioning analysis in 267 patients, with age, stage, tumour site (Right vs Left CRC), KRAS mutation and tumour mIS as input factors. Only in patients with stage III right-sided colon cancer, a low immune response was associated with inferior disease-free survival (mIS-low, HR for relapse 2.28, 95% CI 1.05-8.02). No prognostic significance was seen for tumour mIS in any other stage or site of CRC, or for a similar mIS score derived from adjacent normal mucosa. Independent adverse prognostic significance was retained in multivariable analysis for absence of necrosis, tumour ESR1 expression in all patients and low tumour mIS in stage III right-sided CRC.Conclusions
In localised CRC, mRNA-based CD3Z/CD8 profiling of tumour immune response may have stage, site and tissue-specific prognostic significance, along with ESR1 expression.Trial Registration
ANZCTR.org.au ACTRN12610000509066 相似文献93.
Ntountaniotis D Mali G Grdadolnik SG Maria H Skaltsounis AL Potamitis C Siapi E Chatzigeorgiou P Rappolt M Mavromoustakos T 《Biochimica et biophysica acta》2011,1808(12):2995-3006
It is proposed that AT1 antagonists (ARBs) exert their biological action by inserting into the lipid membrane and then diffuse to the active site of AT1 receptor. Thus, lipid bilayers are expected to be actively involved and play a critical role in drug action. For this reason, the thermal, dynamic and structural effects of olmesartan alone and together with cholesterol were studied using differential scanning calorimetry (DSC), 13C magic-angle spinning (MAS) nuclear magnetic resonance (NMR), cross-polarization (CP) MAS NMR, and Raman spectroscopy as well as small- and wide angle X-ray scattering (SAXS and WAXS) on dipalmitoyl-phosphatidylcholine (DPPC) multilamellar vesicles. 13C CP/MAS spectra provided direct evidence for the incorporation of olmesartan and cholesterol in lipid bilayers. Raman and X-ray data revealed how both molecules modify the bilayer's properties. Olmesartan locates itself at the head-group region and upper segment of the lipid bilayers as 13C CP/MAS spectra show that its presence causes significant chemical shift changes mainly in the A ring of the steroidal part of cholesterol. The influence of olmesartan on DPPC/cholesterol bilayers is less pronounced. Although, olmesartan and cholesterol are residing at the same region of the lipid bilayers, due to their different sizes, display distinct impacts on the bilayer's properties. Cholesterol broadens significantly the main transition, abolishes the pre-transition, and decreases the membrane fluidity above the main transition. Olmesartan is the only so far studied ARB that increases the gauche:trans ratio in the liquid crystalline phase. These significant differences of olmesartan may in part explain its distinct pharmacological profile. 相似文献
94.
95.
Burguete A Pontiki E Hadjipavlou-Litina D Villar R Vicente E Solano B Ancizu S Pérez-Silanes S Aldana I Monge A 《Bioorganic & medicinal chemistry letters》2007,17(23):6439-6443
We report the synthesis, anti-inflammatory and antioxidant activities of novel ring substituted 3-phenyl-1-(1,4-di-N-oxide quinoxalin-2-yl)-2-propen-1-one derivatives and of their 4,5-dihydro-(1H)-pyrazole analogues. The tested compounds inhibit the carrageenin-induced rat paw edema (4.5-56.1%) and present important scavenging activities. Compound 2a is the most potent (56.1%) in the in vivo experiment and exhibits promising in vitro inhibition of soybean lipoxygenase (IC(50)<1microM). 相似文献
96.
Ellen Silva Lago-Vanzela Fabiana Carina Pavezzi Natália Martin Eleni Gomes Roberto Da Silva 《Plant Physiology and Biochemistry》2011,49(11):1251-1258
The seedless grapes BRS Clara and BRS Morena, developed in Brazil, are currently growing in popularity due to their premium texture and taste. However, there are no reports on the polyphenoloxidase (PPO) from these cultivars. In this paper, active and latent PPO from BRS Clara and BRS Morena seedless grapes were extracted using the non-ionic detergents Triton-X-100 (active) and Triton-X-114 (latent), and their catecholase activities were characterized. The PPO extracted using Triton-X-110 exhibited maximum activities at pH 6.0 and at 25 °C. Above 30 °C, a gradual decline in activities was noted, with complete inactivation at 60 °C. The PPO from grapes extracted with Triton-X-114 was activated with 0.2% of the ionic detergent sodium dodecyl sulfate (SDS), and exhibited maximum activities at pH 5.5 and at 30 °C. It was stable until the temperature reached 60 °C. 相似文献
97.
Wills AK Lawlor DA Matthews FE Sayer AA Bakra E Ben-Shlomo Y Benzeval M Brunner E Cooper R Kivimaki M Kuh D Muniz-Terrera G Hardy R 《PLoS medicine》2011,8(6):e1000440
Background
Much of our understanding of the age-related progression of systolic blood pressure (SBP) comes from cross-sectional data, which do not directly capture within-individual change. We estimated life course trajectories of SBP using longitudinal data from seven population-based cohorts and one predominantly white collar occupational cohort, each from the United Kingdom and with data covering different but overlapping age periods.Methods and Findings
Data are from 30,372 individuals and comprise 102,583 SBP observations spanning from age 7 to 80+y. Multilevel models were fitted to each cohort. Four life course phases were evident in both sexes: a rapid increase in SBP coinciding with peak adolescent growth, a more gentle increase in early adulthood, a midlife acceleration beginning in the fourth decade, and a period of deceleration in late adulthood where increases in SBP slowed and SBP eventually declined. These phases were still present, although at lower levels, after adjusting for increases in body mass index though adulthood. The deceleration and decline in old age was less evident after excluding individuals who had taken antihypertensive medication. Compared to the population-based cohorts, the occupational cohort had a lower mean SBP, a shallower annual increase in midlife, and a later midlife acceleration. The maximum sex difference was found at age 26 (+8.2 mm Hg higher in men, 95% CI: 6.7, 9.8); women then experienced steeper rises and caught up by the seventh decade.Conclusions
Our investigation shows a general pattern of SBP progression from childhood in the UK, and suggests possible differences in this pattern during adulthood between a general population and an occupational population. Please see later in the article for the Editors'' Summary 相似文献98.
Morgane Sonia Thion Donovan Low Aymeric Silvin Jinmiao Chen Pauline Grisel Jonas Schulte-Schrepping Ronnie Blecher Thomas Ulas Paola Squarzoni Guillaume Hoeffel Fanny Coulpier Eleni Siopi Friederike Sophie David Claus Scholz Foo Shihui Josephine Lum Arlaine Anne Amoyo Anis Larbi Sonia Garel 《Cell》2018,172(3):500-516.e16
99.
The occurrence of functional chloroplasts in internal stem tissues and their distribution profiles in 20 woody species have been investigated. Chloroplasts were identified from the red chlorophyll auto-fluorescence using epi-fluorescence microscopy. Chloroplasts were detected in the cortex of all species examined, in the xylem rays of 19 and in the perimedullar and the pith cells of 16 out of the 20 investigated species. Chloroplast containing cell clusters in the pith were identified in some species. In addition, we report on the semi-quantitative distribution of chlorophylls in various internal stem tissues. Chlorophyll level was estimated by reflectance measurements at specific wave bands. Although decreasing chlorophyll gradients from cortex to pith were observed in half of the species, chlorophyll distribution in the remaining species was irregular with occasionally high levels in the pith. According to our data, chlorophyll occurrence in stem internal tissues is quite widespread, even in the light remote, deeply shaded central compartments like pith, provided that corresponding cells are viable. The species-specific tissue distribution of chlorophyll levels may be used to select suitable plants to investigate further this neglected area of photosynthesis research. 相似文献
100.