全文获取类型
收费全文 | 1701篇 |
免费 | 2篇 |
国内免费 | 13篇 |
专业分类
系统科学 | 75篇 |
丛书文集 | 3篇 |
教育与普及 | 7篇 |
理论与方法论 | 26篇 |
现状及发展 | 196篇 |
研究方法 | 274篇 |
综合类 | 1006篇 |
自然研究 | 129篇 |
出版年
2021年 | 6篇 |
2020年 | 13篇 |
2019年 | 8篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 13篇 |
2015年 | 11篇 |
2014年 | 18篇 |
2013年 | 40篇 |
2012年 | 116篇 |
2011年 | 280篇 |
2010年 | 41篇 |
2009年 | 20篇 |
2008年 | 131篇 |
2007年 | 164篇 |
2006年 | 139篇 |
2005年 | 118篇 |
2004年 | 124篇 |
2003年 | 135篇 |
2002年 | 156篇 |
2001年 | 10篇 |
2000年 | 14篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 13篇 |
1989年 | 8篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1971年 | 5篇 |
1970年 | 2篇 |
1965年 | 1篇 |
1958年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有1716条查询结果,搜索用时 0 毫秒
991.
Recent studies suggest realized volatility provides forecasts that are as good as option‐implied volatilities, with improvement stemming from the use of high‐frequency data instead of a long‐memory specification. This paper examines whether volatility persistence can be captured by a longer dataset consisting of over 15 years of intra‐day data. Volatility forecasts are evaluated using four exchange rates (AUD/USD, EUR/USD, GBP/USD, USD/JPY) over horizons ranging from 1 day to 3 months, using an expanded set of short‐range and long‐range dependence models. The empirical results provide additional evidence that significant incremental information is found in historical forecasts, beyond the implied volatility information for all forecast horizons. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
992.
993.
Improper protein folding (misfolding) can lead to the formation of disordered (amorphous) or ordered (amyloid fibril) aggregates.
The major lens protein, α-crystallin, is a member of the small heat-shock protein (sHsp) family of intracellular molecular
chaperone proteins that prevent protein aggregation. Whilst the chaperone activity of sHsps against amorphously aggregating
proteins has been well studied, its action against fibril-forming proteins has received less attention despite the presence
of sHsps in deposits found in fibril-associated diseases (e.g. Alzheimer’s and Parkinson’s). In this review, the literature
on the interaction of αB-crystallin and other sHsps with fibril-forming proteins is summarized. In particular, the ability
of sHsps to prevent fibril formation, their mechanisms of action and the possible in vivo consequences of such associations are discussed. Finally, the fibril-forming propensity of the crystallin proteins and its
implications for cataract formation are described along with the potential use of fibrillar crystallin proteins as bionanomaterials.
Received 13 June 2008; received after revision 29 July 2008; accepted 05 August 2008 相似文献
994.
I summarize certain aspects of Paul Feyerabend's account of the development of Western rationalism, show the ways in which that account is supposed to run up against an alternative, that of Karl Popper, and then try to give a preliminary comparison of the two. My interest is primarily in whether what Feyerabend called his ‘story’ constitutes a possible history of our epistemic concepts and their trajectory. I express some grave reservations about that story, and about Feyerabend's framework, finding Popper's views less problematic here. However, I also suggest that one important aspect of Feyerabend's material, his treatment of religious belief, can be given an interpretation which makes it tenable, and perhaps preferable to a Popperian approach. 相似文献
995.
Taal HR St Pourcain B Thiering E Das S Mook-Kanamori DO Warrington NM Kaakinen M Kreiner-Møller E Bradfield JP Freathy RM Geller F Guxens M Cousminer DL Kerkhof M Timpson NJ Ikram MA Beilin LJ Bønnelykke K Buxton JL Charoen P Chawes BL Eriksson J Evans DM Hofman A Kemp JP Kim CE Klopp N Lahti J Lye SJ McMahon G Mentch FD Müller-Nurasyid M O'Reilly PF Prokopenko I Rivadeneira F Steegers EA Sunyer J Tiesler C Yaghootkar H;Cohorts for Heart Aging Research in Genetic Epidemiology Consortium 《Nature genetics》2012,44(5):532-538
To identify genetic variants associated with head circumference in infancy, we performed a meta-analysis of seven genome-wide association studies (GWAS) (N = 10,768 individuals of European ancestry enrolled in pregnancy and/or birth cohorts) and followed up three lead signals in six replication studies (combined N = 19,089). rs7980687 on chromosome 12q24 (P = 8.1 × 10(-9)) and rs1042725 on chromosome 12q15 (P = 2.8 × 10(-10)) were robustly associated with head circumference in infancy. Although these loci have previously been associated with adult height, their effects on infant head circumference were largely independent of height (P = 3.8 × 10(-7) for rs7980687 and P = 1.3 × 10(-7) for rs1042725 after adjustment for infant height). A third signal, rs11655470 on chromosome 17q21, showed suggestive evidence of association with head circumference (P = 3.9 × 10(-6)). SNPs correlated to the 17q21 signal have shown genome-wide association with adult intracranial volume, Parkinson's disease and other neurodegenerative diseases, indicating that a common genetic variant in this region might link early brain growth with neurological disease in later life. 相似文献
996.
Zang ZJ Cutcutache I Poon SL Zhang SL McPherson JR Tao J Rajasegaran V Heng HL Deng N Gan A Lim KH Ong CK Huang D Chin SY Tan IB Ng CC Yu W Wu Y Lee M Wu J Poh D Wan WK Rha SY So J Salto-Tellez M Yeoh KG Wong WK Zhu YJ Futreal PA Pang B Ruan Y Hillmer AM Bertrand D Nagarajan N Rozen S Teh BT Tan P 《Nature genetics》2012,44(5):570-574
Gastric cancer is a major cause of global cancer mortality. We surveyed the spectrum of somatic alterations in gastric cancer by sequencing the exomes of 15 gastric adenocarcinomas and their matched normal DNAs. Frequently mutated genes in the adenocarcinomas included TP53 (11/15 tumors), PIK3CA (3/15) and ARID1A (3/15). Cell adhesion was the most enriched biological pathway among the frequently mutated genes. A prevalence screening confirmed mutations in FAT4, a cadherin family gene, in 5% of gastric cancers (6/110) and FAT4 genomic deletions in 4% (3/83) of gastric tumors. Frequent mutations in chromatin remodeling genes (ARID1A, MLL3 and MLL) also occurred in 47% of the gastric cancers. We detected ARID1A mutations in 8% of tumors (9/110), which were associated with concurrent PIK3CA mutations and microsatellite instability. In functional assays, we observed both FAT4 and ARID1A to exert tumor-suppressor activity. Somatic inactivation of FAT4 and ARID1A may thus be key tumorigenic events in a subset of gastric cancers. 相似文献
997.
Paternoster L Standl M Chen CM Ramasamy A Bønnelykke K Duijts L Ferreira MA Alves AC Thyssen JP Albrecht E Baurecht H Feenstra B Sleiman PM Hysi P Warrington NM Curjuric I Myhre R Curtin JA Groen-Blokhuis MM Kerkhof M Sääf A Franke A Ellinghaus D Fölster-Holst R Dermitzakis E Montgomery SB Prokisch H Heim K Hartikainen AL Pouta A Pekkanen J Blakemore AI Buxton JL Kaakinen M Duffy DL Madden PA Heath AC Montgomery GW Thompson PJ Matheson MC Le Souëf P;Australian Asthma Genetics Consortium 《Nature genetics》2012,44(2):187-192
Atopic dermatitis (AD) is a commonly occurring chronic skin disease with high heritability. Apart from filaggrin (FLG), the genes influencing atopic dermatitis are largely unknown. We conducted a genome-wide association meta-analysis of 5,606 affected individuals and 20,565 controls from 16 population-based cohorts and then examined the ten most strongly associated new susceptibility loci in an additional 5,419 affected individuals and 19,833 controls from 14 studies. Three SNPs reached genome-wide significance in the discovery and replication cohorts combined, including rs479844 upstream of OVOL1 (odds ratio (OR) = 0.88, P = 1.1 × 10(-13)) and rs2164983 near ACTL9 (OR = 1.16, P = 7.1 × 10(-9)), both of which are near genes that have been implicated in epidermal proliferation and differentiation, as well as rs2897442 in KIF3A within the cytokine cluster at 5q31.1 (OR = 1.11, P = 3.8 × 10(-8)). We also replicated association with the FLG locus and with two recently identified association signals at 11q13.5 (rs7927894; P = 0.008) and 20q13.33 (rs6010620; P = 0.002). Our results underline the importance of both epidermal barrier function and immune dysregulation in atopic dermatitis pathogenesis. 相似文献
998.
Germline mutations in DIS3L2 cause the Perlman syndrome of overgrowth and Wilms tumor susceptibility
Astuti D Morris MR Cooper WN Staals RH Wake NC Fews GA Gill H Gentle D Shuib S Ricketts CJ Cole T van Essen AJ van Lingen RA Neri G Opitz JM Rump P Stolte-Dijkstra I Müller F Pruijn GJ Latif F Maher ER 《Nature genetics》2012,44(3):277-284
Perlman syndrome is a congenital overgrowth syndrome inherited in an autosomal recessive manner that is associated with Wilms tumor susceptibility. We mapped a previously unknown susceptibility locus to 2q37.1 and identified germline mutations in DIS3L2, a homolog of the Schizosaccharomyces pombe dis3 gene, in individuals with Perlman syndrome. Yeast dis3 mutant strains have mitotic abnormalities. Yeast Dis3 and its human homologs, DIS3 and DIS3L1, have exoribonuclease activity and bind to the core RNA exosome complex. DIS3L2 has a different intracellular localization and lacks the PIN domain found in DIS3 and DIS3L1; nevertheless, we show that DIS3L2 has exonuclease activity. DIS3L2 inactivation was associated with mitotic abnormalities and altered expression of mitotic checkpoint proteins. DIS3L2 overexpression suppressed the growth of human cancer cell lines, and knockdown enhanced the growth of these cells. We also detected evidence of DIS3L2 mutations in sporadic Wilms tumor. These observations suggest that DIS3L2 has a critical role in RNA metabolism and is essential for the regulation of cell growth and division. 相似文献
999.
Parallel domestication of the Shattering1 genes in cereals 总被引:3,自引:0,他引:3
Lin Z Li X Shannon LM Yeh CT Wang ML Bai G Peng Z Li J Trick HN Clemente TE Doebley J Schnable PS Tuinstra MR Tesso TT White F Yu J 《Nature genetics》2012,44(6):720-724