全文获取类型
收费全文 | 6860篇 |
免费 | 326篇 |
国内免费 | 160篇 |
出版年
2023年 | 60篇 |
2022年 | 68篇 |
2021年 | 97篇 |
2020年 | 109篇 |
2019年 | 171篇 |
2018年 | 184篇 |
2017年 | 126篇 |
2016年 | 128篇 |
2015年 | 160篇 |
2014年 | 363篇 |
2013年 | 453篇 |
2012年 | 246篇 |
2011年 | 356篇 |
2010年 | 282篇 |
2009年 | 400篇 |
2008年 | 370篇 |
2007年 | 394篇 |
2006年 | 311篇 |
2005年 | 360篇 |
2004年 | 252篇 |
2003年 | 249篇 |
2002年 | 222篇 |
2001年 | 123篇 |
2000年 | 120篇 |
1999年 | 125篇 |
1998年 | 135篇 |
1997年 | 101篇 |
1996年 | 78篇 |
1995年 | 104篇 |
1994年 | 91篇 |
1993年 | 76篇 |
1992年 | 91篇 |
1991年 | 55篇 |
1990年 | 52篇 |
1989年 | 51篇 |
1988年 | 51篇 |
1987年 | 46篇 |
1986年 | 29篇 |
1985年 | 55篇 |
1984年 | 116篇 |
1983年 | 78篇 |
1982年 | 61篇 |
1981年 | 65篇 |
1980年 | 67篇 |
1979年 | 62篇 |
1978年 | 34篇 |
1977年 | 29篇 |
1976年 | 26篇 |
1975年 | 19篇 |
1974年 | 20篇 |
排序方式: 共有7346条查询结果,搜索用时 31 毫秒
991.
992.
《Saudi Journal of Biological Sciences》2020,27(11):2869-2875
Background; findings from the meta-analysis have shown that patients present improvements in glycaemic control, and in the prevention and control of the acute and chronic complications, when they receive effective treatment, self-management support and regular monitoring. The present study aimed to evaluate the effect of implementing a health education program on outcomes of type I diabetic patients. Quasi-experimental study design was used to fulfill the aim of the study. The study was conducted in the outpatient diabetic clinic at Asyut University Hospital; 60 adult male and female patients who attended the outpatient diabetic clinic were included. Two tools were used in this study; structured interviewing questionnaire with three parts; part one: demographic patient variables, part two: patient's medical data and part three: patient's knowledge regarding diabetes, the second tool is evaluation of type I diabetic patients' outcomes (pre/post). Results revealed that the highest percentage of the studied samples were in the age group 18 to less than 30 years, 90.0% of the study group and 83.4% of the control group were having a family history of diabetes, a statistically significant difference was found in the study group patients pre and post application of the program regarding insulin injection and glycemic control. Conclusion: this study demonstrated the effectiveness of health education program implementation on the outcomes of type I diabetic patients in terms of improved knowledge and practicing exercise, teeth care, feet care and on glycemic control. 相似文献
993.
Summary. Serology, isoelectric focusing (IEF) of expressed antigens, and restriction fragment length polymorphisms (RFLP) were compared for the identification of BoLA class I haplotypes. Expressed antigens identified as bands by IEF correlated well with serological definition confirming and extending our earlier findings (Joosten et al. 1988). Comparison of serology and isoelectric focusing bands with restriction fragments was more complicated; fragments were found which correlated both with broadly reacting and antigen specific sera. We also found correlation of fragments with two or more sera which showed no cross-reactivity. Fragments unique to particular haplotypes were also observed.
Serology remains the simplest method of typing BoLA class I antigens. Isoelectric focusing generally agrees with serological definition of antigens and detects antigens not yet defined by serology. It may also be useful in defining the products of other expressed BoLA class I loci. In order to identify RFLPs which could be used for typing, comparison with serology or IEF is essential. Haplotype specific RFLPs could be useful in identifying genes linked to the MHC. 相似文献
Serology remains the simplest method of typing BoLA class I antigens. Isoelectric focusing generally agrees with serological definition of antigens and detects antigens not yet defined by serology. It may also be useful in defining the products of other expressed BoLA class I loci. In order to identify RFLPs which could be used for typing, comparison with serology or IEF is essential. Haplotype specific RFLPs could be useful in identifying genes linked to the MHC. 相似文献
994.
Collagenous and non-collagenous proteins (NCPs) in the extracellular matrix, as well as the coupling mechanisms between osteoclasts and osteoblasts, work together to ensure normal bone metabolism. Each protein plays one or more critical roles in bone metabolism, sometimes even contradictory, thus affecting the final mechanical, physical and chemical properties of bone tissue. Anomalies in the amount and structure of one or more of these proteins can cause abnormalities in bone formation and resorption, which consequently leads to malformations and defects, such as osteoporosis (OP). The connections between key proteins involved in matrix formation and resorption are far from being elucidated. In this review, we resume knowledge on the crosstalk between collagen type I and selected NCPs (Transforming Growth Factor-β, Insulin-like Growth Factor-1, Decorin, Osteonectin, Osteopontin, Bone Sialoprotein and Osteocalcin) of bone matrix, focusing on their possible involvement and role in OP. The different elements of this network can be pharmacologically targeted or used for the design/development of innovative regenerative strategies to modulate a feedback loop in bone remodelling. 相似文献
995.
996.
997.
Angelina García Maia Pauro Rodrigo Nores Claudio M. Bravi Darío A. Demarchi 《American journal of physical anthropology》2012,149(4):583-590
We analyzed the patterns of variation of haplogroup D1 in central Argentina, including new data and published information from other populations of South America. Almost 28% (107/388) of the individuals sampled in the region belong to haplogroup D1, whereas more than 52% of them correspond to the recently described subhaplogroup D1j (Bodner et al.: Genome Res 22 (2012) 811–820), defined by the presence of additional transitions at np T152C–C16242T–T16311C to the nodal D1 motif. This lineage was found at high frequencies across a wide territory with marked geographical–ecological differences. Additionally, 12 individuals present the mutation C16187T that defines the recently named subhaplogroup D1g (Bodner et al.: Genome Res 22 (2012) 811–820), previously described in populations of Patagonia and Tierra del Fuego. Based on our results and additional data already published, we postulate that the most likely origin of subhaplogroup D1j is the region of Sierras Pampeanas, which occupies the center and part of the northwestern portion of Argentina. The extensive yet restricted geographical distribution, the relatively large internal diversity, and the absence or low incidence of D1j in other regions of South America suggest the existence of an ancient metapopulation covering the Sierras Pampeanas, being this lineage its genetic signature. Further support for a scenario of local origin for D1j in the Sierras Pampeanas stems from the fact that early derivatives from a putative ancestral lineage carrying the transitions T16311C–T152C have only been found in this region, supporting the hypothesis that it might represent an ancestral motif previous to the appearance of D1j‐specific change C16242T. © 2012 Wiley Periodicals, Inc. 相似文献
998.
999.
Julia E. Maxson Samuel B. Luty Jason D. MacManiman Melissa L. Abel Brian J. Druker Jeffrey W. Tyner 《The Journal of biological chemistry》2014,289(9):5820-5827
Mutations in the CSF3 granulocyte colony-stimulating factor receptor CSF3R have recently been found in a large percentage of patients with chronic neutrophilic leukemia and, more rarely, in other types of leukemia. These CSF3R mutations fall into two distinct categories: membrane-proximal mutations and truncation mutations. Although both classes of mutation have exhibited the capacity for cellular transformation, several aspects of this transformation, including the kinetics, the requirement for ligand, and the dysregulation of downstream signaling pathways, have all been shown to be discrepant between the mutation types, suggesting distinct mechanisms of activation. CSF3R truncation mutations induce overexpression and ligand hypersensitivity of the receptor, likely because of the removal of motifs necessary for endocytosis and degradation. In contrast, little is known about the mechanism of activation of membrane-proximal mutations, which are much more commonly observed in chronic neutrophilic leukemia. In contrast with CSF3R truncation mutations, membrane-proximal mutations do not exhibit overexpression and are capable of signaling in the absence of ligand. We show that the Thr-615 and Thr-618 sites of membrane-proximal mutations are part of an O-linked glycosylation cluster. Mutation at these sites prevents O-glycosylation of CSF3R and increases receptor dimerization. This increased dimerization explains the ligand-independent activation of CSF3R membrane-proximal mutations. Cytokine receptor activation through loss of O-glycosylation represents a novel avenue of aberrant signaling. Finally, the combination of the CSF3R membrane proximal and truncation mutations, as has been reported in some patients, leads to enhanced cellular transformation when compared with either mutation alone, underscoring their distinct mechanisms of action. 相似文献
1000.
《Bioscience, biotechnology, and biochemistry》2013,77(2):410-413
A previous report described the presence of a self-splicing group I intron in a flagellin gene from a thermophilic Bacillus species. Here, we present evidence that the splicing reaction of the flagellin introns is dependent on temperature. Furthermore, a complementation analysis using a Bacillus subtilis flagellin-deficient mutant indicated that the intron-containing flagellin gene significantly restored the motility of the mutant at higher temperatures. 相似文献