全文获取类型
收费全文 | 325篇 |
免费 | 26篇 |
国内免费 | 2篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 8篇 |
2019年 | 1篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 7篇 |
2015年 | 18篇 |
2014年 | 14篇 |
2013年 | 24篇 |
2012年 | 29篇 |
2011年 | 14篇 |
2010年 | 8篇 |
2009年 | 16篇 |
2008年 | 14篇 |
2007年 | 18篇 |
2006年 | 20篇 |
2005年 | 22篇 |
2004年 | 20篇 |
2003年 | 14篇 |
2002年 | 11篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1981年 | 1篇 |
1980年 | 5篇 |
1977年 | 2篇 |
排序方式: 共有353条查询结果,搜索用时 15 毫秒
1.
A. Verrips Gerry C. H. Steenbergen-Spanjers J. A. F. M. Luyten R. A. Wevers John H. J. Wokke Fons J. M. Gabreëls Bert G. Wolthers Lambert P. W. J. van den Heuvel 《Human genetics》1997,100(2):284-286
We report a new mutation in the sterol 27-hydroxylase (CYP 27) gene in a Dutch family with cerebrotendinous xanthomatosis:
a G→A transition in the splice donor site in intron 4. This mutation leads to skipping of exon 4, resulting in a loss of 66
amino acids in the CYP 27 enzyme molecule.
Received: 15 March 1997 / Accepted: 26 March 1997 相似文献
2.
Peter Van Bogaert Lieve Peremans Nadine Diltour Danny Van heusden Tinne Dilles Bart Van Rompaey Donna Sullivan Havens 《PloS one》2016,11(4)
The aim of the study reported in this article was to investigate staff nurses’ perceptions and experiences about structural empowerment and perceptions regarding the extent to which structural empowerment supports safe quality patient care. To address the complex needs of patients, staff nurse involvement in clinical and organizational decision-making processes within interdisciplinary care settings is crucial. A qualitative study was conducted using individual semi-structured interviews of 11 staff nurses assigned to medical or surgical units in a 600-bed university hospital in Belgium. During the study period, the hospital was going through an organizational transformation process to move from a classic hierarchical and departmental organizational structure to one that was flat and interdisciplinary. Staff nurses reported experiencing structural empowerment and they were willing to be involved in decision-making processes primarily about patient care within the context of their practice unit. However, participants were not always fully aware of the challenges and the effect of empowerment on their daily practice, the quality of care and patient safety. Ongoing hospital change initiatives supported staff nurses’ involvement in decision-making processes for certain matters but for some decisions, a classic hierarchical and departmental process still remained. Nurses perceived relatively high work demands and at times viewed empowerment as presenting additional. Staff nurses recognized the opportunities structural empowerment provided within their daily practice. Nurse managers and unit climate were seen as crucial for success while lack of time and perceived work demands were viewed as barriers to empowerment. 相似文献
3.
The measurement of the ATP content of fresh semen is as accurate as the estimation of sperm motility by conventional methods in discriminating between semen of fertile versus subfertile men. The ATP content of frozen thawed donor semen is correlated with the probability of conception per cycle of insemination. Exact quantification of cytotoxic sperm antibodies in serum is possible with the adenosine-triphosphate-release-cytotoxicity test, since measurement is free of the bias of microscopic examination. The procedure has been simplified by testing only one serum dilution and calculating the ‘sperm toxicity index’. 相似文献
4.
D Bur T Clarke J D Friesen M Gold K W Hart J J Holbrook J B Jones M A Luyten H M Wilks 《Biochemical and biophysical research communications》1989,161(1):59-63
The function of the amino acid Thr246 in L-lactate dehydrogenase from Bacillus stearothermophilus has been investigated by site-directed replacement with glycine. Kinetic experiments with a number of 2-oxo acids showed strongly reduced activity for the mutated enzyme. However, the mutant enzyme shows a relative preference for the large hydrophobic sidechains of alpha-keto acids and an even higher specific activity than the wild-type lactate dehydrogenase for the polar oxaloacetate substrate. Graphic analyses indicate that the loss of one hydrogen bond, or intrusion of water into the active site, might be responsible for the reduced activity. The kinetic results suggest that the binding modes of bulky hydrophobic or polar substrates compensate to some degree for the partially disrupted active site. 相似文献
5.
Ann Depicker Lieve Herman Anni Jacobs Jozef Schell Marc Van Montagu 《Molecular & general genetics : MGG》1985,201(3):477-484
Summary We investigated whether the efficiency of transformation of plant cells by Agrobacterium tumefaciens during cocultivation is limited by the properties of the plant cells or by the infecting bacteria.Therefore, tobacco protoplasts were infected by cocultivation with two different agrobacteria strains carrying Ti plasmids with distinguishable T-DNAs. These T-DNAs cotransform plant cells at a frequency equal to the product of their independent transformation frequencies, which indicates that all plant cells are equally competent. On the other hand, when these T-DNAs are located on the same Ti plasmid vector within one bacterial strain, the cotransformation frequency is significantly higher than the product of the single transformation frequencies. We interpret these results to indicate that transformation is limited more by the establishment of effective bacteria/plant cell interaction than by (i) the process of DNA integration and (ii) by the number of plant cells capable of being transformed by Agrobacterium. We found that most plant cells are transformed by only one or a few agrobacteria. Analysis of the number of T-DNA copies in these clonally transformed lines indicates amplification of the original, infecting T-region copy. 相似文献
6.
Differentiation of canalicular cell processes in bone cells by basement membrane matrix components: regulation by discrete domains of laminin 总被引:11,自引:0,他引:11
We have investigated the interaction of rat primary calvarial bone cells and a mouse osteoblast-like cell line MC3T3-E1 with basement membrane components. On a reconstituted gel of basement membrane, both cell types attached and formed isolated clusters that developed long interconnecting cell processes similar to the canalicular network observed in bone. The differentiation of the osteoblastic phenotype was stimulated as determined by increased alkaline phosphatase production and the deposition of mineral. Antibodies to laminin and to a 32/67 kd laminin receptor blocked this differentiation. Cell morphology was altered by the addition of active laminin-derived synthetic peptides, YIGSR-NH2 and CSRARKQAASIKVAVSADR-NH2, but not by an active RGD-containing peptide. When coated directly on plastic, all three peptides promoted cell adhesion, demonstrating that bone cells interact with specific molecular domains of laminin. These data demonstrate that basement membrane plays a key role in formation of a network of cytoplasmic processes resembling the osteocyte canalicular network in bone. 相似文献
7.
Lieve Vits Kristel De Boulle Edwin Reyniers Ingrid Handig John K. Darby Ben Oostra Patrick J. Willems 《Human genetics》1994,94(5):523-526
The fragile X syndrome is the result of amplification of a CGG trinucleotide repeat in the FMR1 gene and anticipation in this disease is caused by an intergenerational expansion of this repeat. Although regression of a CGG repeat in the premutation range is not uncommon, regression from a full premutation (>200 repeats) or premutation range (50–200 repeats) to a repeat of normal size (<50 repeats) has not yet been documented. We present here a family in which the number of repeats apparently regressed from approximately 110 in the mother to 44 in her daughter. Although the CGG repeat of the daughter is in the normal range, she is a carrier of the fragile X mutation based upon the segregation pattern of Xq27 markers flanking FMR1. It is unclear, however, whether this allele of 44 repeats will be stably transmitted, as the daughter has as yet no progeny. Nevertheless, the size range between normal alleles and premutation alleles overlap, a factor that complicates genetic counseling. 相似文献
8.
Sonja Buyle Edwin Reyniers Lieve Vits Kristel De Boulle Ingrid Handig Floris L. E. Wuyts Wout Deelen Dicky J. J. Halley Ben A. Oostra Patrick J. Willems 《Human genetics》1993,92(3):269-272
For many years, the high prevalence of the fragile X syndrome was thought to be caused by a high mutation frequency. The recent isolation of the FMR1 gene and identification of the most prevalent mutation enable a more precise study of the fragile X mutation. As the vast majority of fragile X patients show amplification of an unstable trinucleotide repeat, DNA studies can now trace back the origin of the fragile X mutation. To date, de novo mutations leading to amplification of the CGG repeat have not yet been detected. Recently, linkage disequilibrium was found in the Australian and US populations between the fragile X mutation and adjacent polymorphic markers, suggesting a founder effect of the fragile X mutation. We present here a molecular study of Belgian and Dutch fragile X families. No de novo mutations could be found in 54 of these families. Moreover, we found significant (P < 0.0001) linkage disequilibrium in 68 unrelated fragile X patients between the fragile X mutation and an adjacent polymorphic microsatellite at DXS548. This suggests that a founder effect of the fragile X mutation also exists in the Belgian and Dutch populations. Both the absence of new mutations and the presence of linkage disequilibrium suggest that a few ancestral mutations are responsible for most of the patients with fragile X syndrome. 相似文献
9.
Molecular cloning of a gene involved in glucose sensing in the yeast Saccharomyces cerevisiae 总被引:6,自引:1,他引:5
Linda Van Aelst Stefan Hohmann Botchaka Bulaya Wim de Koning Laurens Sierkstra Maria José Neves Kattie Luyten Rafael Alijo José Ramos Paola Coccetti Enzo Martegani Neuza Maria de Magalhães-Rocha Rogelio Lopes Brandão Patrick Van Dijck Mieke Vanhalewyn Peter Durnez Arnold W. H. Jans Johan M. Thevelein 《Molecular microbiology》1993,8(5):927-943
10.