全文获取类型
收费全文 | 182篇 |
免费 | 12篇 |
国内免费 | 11篇 |
专业分类
系统科学 | 7篇 |
现状及发展 | 85篇 |
研究方法 | 16篇 |
综合类 | 93篇 |
自然研究 | 4篇 |
出版年
2022年 | 3篇 |
2021年 | 4篇 |
2019年 | 2篇 |
2018年 | 9篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 2篇 |
2014年 | 13篇 |
2013年 | 3篇 |
2012年 | 9篇 |
2011年 | 14篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 9篇 |
2007年 | 7篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 2篇 |
2002年 | 5篇 |
1996年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 7篇 |
1982年 | 1篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 11篇 |
1978年 | 10篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1968年 | 5篇 |
1967年 | 3篇 |
1963年 | 1篇 |
1962年 | 2篇 |
1959年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有205条查询结果,搜索用时 15 毫秒
11.
Stacey SN Gudbjartsson DF Sulem P Bergthorsson JT Kumar R Thorleifsson G Sigurdsson A Jakobsdottir M Sigurgeirsson B Benediktsdottir KR Thorisdottir K Ragnarsson R Scherer D Rudnai P Gurzau E Koppova K Höiom V Botella-Estrada R Soriano V Juberías P Grasa M Carapeto FJ Tabuenca P Gilaberte Y Gudmundsson J Thorlacius S Helgason A Thorlacius T Jonasdottir A Blondal T Gudjonsson SA Jonsson GF Saemundsdottir J Kristjansson K Bjornsdottir G Sveinsdottir SG Mouy M Geller F Nagore E Mayordomo JI 《Nature genetics》2008,40(11):1313-1318
To search for new sequence variants that confer risk of cutaneous basal cell carcinoma (BCC), we conducted a genome-wide SNP association study of 930 Icelanders with BCC and 33,117 controls. After analyzing 304,083 SNPs, we observed signals from loci at 1p36 and 1q42, and replicated these associations in additional sample sets from Iceland and Eastern Europe. Overall, the most significant signals were from rs7538876 on 1p36 (OR = 1.28, P = 4.4 x 10(-12)) and rs801114 on 1q42 (OR = 1.28, P = 5.9 x 10(-12)). The 1p36 locus contains the candidate genes PADI4, PADI6, RCC2 and ARHGEF10L, and the gene nearest to the 1q42 locus is the ras-homolog RHOU. Neither locus was associated with fair pigmentation traits that are known risk factors for BCC, and no risk was observed for melanoma. Approximately 1.6% of individuals of European ancestry are homozygous for both variants, and their estimated risk of BCC is 2.68 times that of noncarriers. 相似文献
12.
Accurate business failure prediction models would be extremely valuable to many industry sectors, particularly financial investment and lending. The potential value of such models is emphasised by the extremely costly failure of high‐profile companies in the recent past. Consequently, a significant interest has been generated in business failure prediction within academia as well as in the finance industry. Statistical business failure prediction models attempt to predict the failure or success of a business. Discriminant and logit analyses have traditionally been the most popular approaches, but there are also a range of promising non‐parametric techniques that can alternatively be applied. In this paper, the relatively new technique of decision trees is applied to business failure prediction. The numerical results suggest that decision trees could be superior predictors of business failure as compared to discriminant analysis. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
13.
The amino acids L-glutamic and L-aspartic acids form the most widespread excitatory transmitter network in mammalian brain. The excitation produced by L-glutamic acid is important in the early development of the nervous system, synaptic plasticity and memory formation, seizures and neuronal degeneration. The receptors activated by L-glutamic acid are a target for therapeutic intervention in neurodegenerative diseases, brain ischaemia and epilepsy. There are two types of receptors for the excitatory amino acids, those that lead to the opening of cation-selective channels and those that activate phospholipase C (ref. 11). The receptors activating ion channels are NMDA (N-methyl-D-aspartate) and kainate/AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate)-sensitive receptors. The complementary DNAs for the kainate/AMPA receptor and for the metabotropic receptor have been cloned. We report here on the isolation and characterization of a protein complex of four major proteins that represents an intact complex of the NMDA receptor ion channel and on the cloning of the cDNA for one of the subunits of this receptor complex, the glutamate-binding protein. 相似文献
14.
D. Kumar 《Cellular and molecular life sciences : CMLS》1981,37(1):37-38
Summary Autoradiographic studies using3H-uridine in the salivary gland of adultLygaeus sp. were carried out. The gland cell nuclei, particularly the multiple nucleoli, are the sites of incorporation of the label exhibiting RNA synthesis. The labelled molecules (RNA) are transported to the cell cytoplasm and then into the gland lumen in which no turnover of the radioactivity is observed.I am grateful to my teacher, Prof. P. S. Ramamurty, School of Life Sciences, University of Hyderabad, for his constant inspiration. Grateful acknowledgement is made to Prof. J. P. Thapliyal, Dept of Zoology, B. H. U. for encouragement and to Dr Om Prakash, Dept of Biochemistry, B. H. U. for his valuable criticism. 相似文献
15.
16.
Summary Cyclical variations in acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) levels in foot muscle (FM) and AChE activity in central nervous system (CNS) ofLaevicaulis, during 24-h-day, were maximal at 04.00 h and minimal at 12.00 h. But BuChE activity was 180°C out of phase with AChE in CNS. The rhythmic trend of AChE in CNS might be due to true cholinesterase activity.Acknowledgements. The Senior Fellowship (CSIR) awarded to TPK is thankfully acknowledged. 相似文献
17.
Zusammenfassung Bei Kontrolle der Speicheldrüsen ergibt sich, dass die Acridinbehandlung beiDrosophila Komplexinversionen erzeugt. 相似文献
18.
A naturally occurring MTA1 variant sequesters oestrogen receptor-alpha in the cytoplasm 总被引:13,自引:0,他引:13
Kumar R Wang RA Mazumdar A Talukder AH Mandal M Yang Z Bagheri-Yarmand R Sahin A Hortobagyi G Adam L Barnes CJ Vadlamudi RK 《Nature》2002,418(6898):654-657
Oestrogen receptor (ER) is a good prognostic marker for the treatment of breast cancers. Upregulation of metastatic tumour antigen 1 (MTA1) is associated with the invasiveness and metastatic potential of several human cancers and acts as a co-repressor of nuclear ER-alpha. Here we identify a naturally occurring short form of MTA1 (MTA1s) that contains a previously unknown sequence of 33 amino acids with an ER-binding motif, Leu-Arg-Ile-Leu-Leu (LRILL). MTA1s localizes in the cytoplasm, sequesters ER in the cytoplasm, and enhances non-genomic responses of ER. Deleting the LRILL motif in MTA1s abolishes its co-repressor function and its interaction with ER, and restores nuclear localization of ER. Dysregulation of human epidermal growth factor receptor-2 in breast cancer cells enhances the expression of MTA1s and the cytoplasmic sequestration of ER. Expression of MTA1s in breast cancer cells prevents ligand-induced nuclear translocation of ER and stimulates malignant phenotypes. MTA1s expression is increased in human breast tumours with no or low nuclear ER. The regulation of the cellular localization of ER by MTA1s represents a mechanism for redirecting nuclear receptor signalling by nuclear exclusion. 相似文献
19.
20.
D. S. Kumar 《Cellular and molecular life sciences : CMLS》1981,37(9):962-963
Summary Ovariectomy reduced the respiratory rates of liver and skeletal muscle homogenates of the Indian garden lizard,Calotes versicolor. Administration of oestradiol dipropionate elevated the rate of tissue respiration of ovariectomized animals. This finding lends support to the view that oestradiol, like testosterone, is able to stimulate the oxidative metabolism of this animal.Part of a thesis qualified for the award of Ph.D. degree of Banaras Hindu University, Varanasi, India. The author expresses his deep sense of gratitude to Professor J. P. Thapliyal of the Department of Zoology, Banaras Hindu University for valuable guidance and constant inspiration. Financial assistance was provided by a Council of Scientific and Industrial Research (New Delhi) Junior Research Fellowship. 相似文献