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161.
Maria Luiza Beçak Sylvia M. Carneiro W. Beçak 《Cellular and molecular life sciences : CMLS》1977,33(1):25-27
Summary C banded mouse pachytene chromosomes were studied with the light and electron microscopes by the whole mount technique. The X and Y chromosomes show pairing by the long, by the short or by both long and short arms. Assuming Lyon's hypothesis, the latter suggests that the Y segment transferred to the X is intercalar. With the light microscope, a negative image of the synaptonemal complex is evidenced.This work was supported by grants of the Brazilian Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundo Especial de Despesas do Instituto Butantan (FEDIB).We acknowledge Dr. N. Leon for his editorial suggestions. 相似文献
162.
Heilig R Eckenberg R Petit JL Fonknechten N Da Silva C Cattolico L Levy M Barbe V de Berardinis V Ureta-Vidal A Pelletier E Vico V Anthouard V Rowen L Madan A Qin S Sun H Du H Pepin K Artiguenave F Robert C Cruaud C Brüls T Jaillon O Friedlander L Samson G Brottier P Cure S Ségurens B Anière F Samain S Crespeau H Abbasi N Aiach N Boscus D Dickhoff R Dors M Dubois I Friedman C Gouyvenoux M James R Madan A Mairey-Estrada B Mangenot S Martins N Ménard M Oztas S Ratcliffe A Shaffer T Trask B 《Nature》2003,421(6923):601-607
Chromosome 14 is one of five acrocentric chromosomes in the human genome. These chromosomes are characterized by a heterochromatic short arm that contains essentially ribosomal RNA genes, and a euchromatic long arm in which most, if not all, of the protein-coding genes are located. The finished sequence of human chromosome 14 comprises 87,410,661 base pairs, representing 100% of its euchromatic portion, in a single continuous segment covering the entire long arm with no gaps. Two loci of crucial importance for the immune system, as well as more than 60 disease genes, have been localized so far on chromosome 14. We identified 1,050 genes and gene fragments, and 393 pseudogenes. On the basis of comparisons with other vertebrate genomes, we estimate that more than 96% of the chromosome 14 genes have been annotated. From an analysis of the CpG island occurrences, we estimate that 70% of these annotated genes are complete at their 5' end. 相似文献
163.
Mutant P450 oxidoreductase causes disordered steroidogenesis with and without Antley-Bixler syndrome
Flück CE Tajima T Pandey AV Arlt W Okuhara K Verge CF Jabs EW Mendonça BB Fujieda K Miller WL 《Nature genetics》2004,36(3):228-230
Deficient activities of multiple steroidogenic enzymes have been reported without and with Antley-Bixler syndrome (ABS), but mutations of corresponding cytochrome P450 enzymes have not been found. We identified mutations in POR, encoding P450 oxidoreductase, the obligate electron donor for these enzymes, in a woman with amenorrhea and three children with ABS, even though knock-out of POR is embryonically lethal in mice. Mutations of POR also affect drug-metabolizing P450 enzymes, explaining the association of ABS with maternal fluconazole ingestion. 相似文献
164.
In Drosophila, a 'clock' situated in the brain controls circadian rhythms of locomotor activity. This clock relies on several groups of neurons that express the Period (PER) protein, including the ventral lateral neurons (LN(v)s), which express the Pigment-dispersing factor (PDF) neuropeptide, and the PDF-negative dorsal lateral neurons (LN(d)s). In normal cycles of day and night, adult flies exhibit morning and evening peaks of activity; however, the contribution of the different clock neurons to the rest-activity pattern remains unknown. Here, we have used targeted expression of PER to restore the clock function of specific subsets of lateral neurons in arrhythmic per(0) mutant flies. We show that PER expression restricted to the LN(v)s only restores the morning activity, whereas expression of PER in both the LN(v)s and LN(d)s also restores the evening activity. This provides the first neuronal bases for 'morning' and 'evening' oscillators in the Drosophila brain. Furthermore, we show that the LN(v)s alone can generate 24 h activity rhythms in constant darkness, indicating that the morning oscillator is sufficient to drive the circadian system. 相似文献
165.
Simpson AJ Reinach FC Arruda P Abreu FA Acencio M Alvarenga R Alves LM Araya JE Baia GS Baptista CS Barros MH Bonaccorsi ED Bordin S Bové JM Briones MR Bueno MR Camargo AA Camargo LE Carraro DM Carrer H Colauto NB Colombo C Costa FF Costa MC Costa-Neto CM Coutinho LL Cristofani M Dias-Neto E Docena C El-Dorry H Facincani AP Ferreira AJ Ferreira VC Ferro JA Fraga JS França SC Franco MC Frohme M Furlan LR Garnier M Goldman GH Goldman MH Gomes SL Gruber A Ho PL Hoheisel JD Junqueira ML Kemper EL 《Nature》2000,406(6792):151-159
Xylella fastidiosa is a fastidious, xylem-limited bacterium that causes a range of economically important plant diseases. Here we report the complete genome sequence of X. fastidiosa clone 9a5c, which causes citrus variegated chlorosis--a serious disease of orange trees. The genome comprises a 52.7% GC-rich 2,679,305-base-pair (bp) circular chromosome and two plasmids of 51,158 bp and 1,285 bp. We can assign putative functions to 47% of the 2,904 predicted coding regions. Efficient metabolic functions are predicted, with sugars as the principal energy and carbon source, supporting existence in the nutrient-poor xylem sap. The mechanisms associated with pathogenicity and virulence involve toxins, antibiotics and ion sequestration systems, as well as bacterium-bacterium and bacterium-host interactions mediated by a range of proteins. Orthologues of some of these proteins have only been identified in animal and human pathogens; their presence in X. fastidiosa indicates that the molecular basis for bacterial pathogenicity is both conserved and independent of host. At least 83 genes are bacteriophage-derived and include virulence-associated genes from other bacteria, providing direct evidence of phage-mediated horizontal gene transfer. 相似文献
166.
食品包装材料的迁移及安全壁垒研究
3 总被引:4,自引:0,他引:4
食品包装安全是食品安全的重要组成部分,分析研究了欧美食品包装材料安全性法规的整体框架,尤其是关于食品接触包装材料迁移的安全法规,并重点对欧美制定迁移安全法规的依据-食品聚合物包装材料成分迁移的数学模型和实验测试方法进行了探讨. 相似文献
167.
Defective planar cell polarity in polycystic kidney disease 总被引:15,自引:0,他引:15
Fischer E Legue E Doyen A Nato F Nicolas JF Torres V Yaniv M Pontoglio M 《Nature genetics》2006,38(1):21-23
Morphogenesis involves coordinated proliferation, differentiation and spatial distribution of cells. We show that lengthening of renal tubules is associated with mitotic orientation of cells along the tubule axis, demonstrating intrinsic planar cell polarization, and we demonstrate that mitotic orientations are significantly distorted in rodent polycystic kidney models. These results suggest that oriented cell division dictates the maintenance of constant tubule diameter during tubular lengthening and that defects in this process trigger renal tubular enlargement and cyst formation. 相似文献
168.
Crow YJ Hayward BE Parmar R Robins P Leitch A Ali M Black DN van Bokhoven H Brunner HG Hamel BC Corry PC Cowan FM Frints SG Klepper J Livingston JH Lynch SA Massey RF Meritet JF Michaud JL Ponsot G Voit T Lebon P Bonthron DT Jackson AP Barnes DE Lindahl T 《Nature genetics》2006,38(8):917-920
Aicardi-Goutières syndrome (AGS) presents as a severe neurological brain disease and is a genetic mimic of the sequelae of transplacentally acquired viral infection. Evidence exists for a perturbation of innate immunity as a primary pathogenic event in the disease phenotype. Here, we show that TREX1, encoding the major mammalian 3' --> 5' DNA exonuclease, is the AGS1 gene, and AGS-causing mutations result in abrogation of TREX1 enzyme activity. Similar loss of function in the Trex1(-/-) mouse leads to an inflammatory phenotype. Our findings suggest an unanticipated role for TREX1 in processing or clearing anomalous DNA structures, failure of which results in the triggering of an abnormal innate immune response. 相似文献
169.
François Bernier 《Cellular and molecular life sciences : CMLS》2013,70(17):3045-3056
DING proteins, named after their conserved N-terminus, form an overlooked protein family whose members were generally discovered through serendipity. It is characterized by an unusually high sequence conservation, even between distantly related species, and by an outstanding diversity of activities and ligands. They all share a demonstrated capacity to bind phosphate with high affinity or at least a predicted phosphate-binding site. However, DING protein genes are conspicuously absent from databases. The many novel family members identified in recent years have confirmed that DING proteins are ubiquitous not only in animals and plants but probably also in prokaryotes. At the functional level, there is increasing evidence that they participate in many health-related processes such as cancers as well as bacterial (Pseudomonas) and viral (HIV) infections, by mechanisms that are now beginning to be understood. They thus represent potent targets for the development of novel therapeutic approaches, especially against HIV. The few genomic sequences that are now available are starting to give some clues on why DING protein genes and mRNAs are well conserved and difficult to clone. This could open a new era of research, of both fundamental and applied importance. 相似文献
170.
New models of collaboration in genome-wide association studies: the Genetic Association Information Network 总被引:7,自引:0,他引:7
GAIN Collaborative Research Group Manolio TA Rodriguez LL Brooks L Abecasis G;Collaborative Association Study of Psoriasis Ballinger D Daly M Donnelly P Faraone SV;International Multi-Center ADHD Genetics Project Frazer K Gabriel S Gejman P;Molecular Genetics of Schizophrenia Collaboration Guttmacher A Harris EL Insel T Kelsoe JR;Bipolar Genome Study Lander E McCowin N Mailman MD Nabel E Ostell J Pugh E Sherry S 《Nature genetics》2007,39(9):1045-1051
The Genetic Association Information Network (GAIN) is a public-private partnership established to investigate the genetic basis of common diseases through a series of collaborative genome-wide association studies. GAIN has used new approaches for project selection, data deposition and distribution, collaborative analysis, publication and protection from premature intellectual property claims. These demonstrate a new commitment to shared scientific knowledge that should facilitate rapid advances in understanding the genetics of complex diseases. 相似文献