全文获取类型
收费全文 | 646篇 |
免费 | 56篇 |
出版年
2022年 | 4篇 |
2021年 | 9篇 |
2020年 | 8篇 |
2019年 | 11篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 14篇 |
2015年 | 36篇 |
2014年 | 36篇 |
2013年 | 45篇 |
2012年 | 53篇 |
2011年 | 35篇 |
2010年 | 21篇 |
2009年 | 21篇 |
2008年 | 31篇 |
2007年 | 27篇 |
2006年 | 26篇 |
2005年 | 33篇 |
2004年 | 29篇 |
2003年 | 27篇 |
2002年 | 22篇 |
2001年 | 13篇 |
2000年 | 12篇 |
1999年 | 6篇 |
1998年 | 6篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1938年 | 3篇 |
1937年 | 2篇 |
1935年 | 2篇 |
1930年 | 4篇 |
排序方式: 共有702条查询结果,搜索用时 234 毫秒
91.
Asveld L 《Bioethics》2008,22(5):245-257
Respect for autonomy is problematic in relation to public health programmes such as vaccination, as the success of such programmes depends on widespread compliance. European countries have different policies for dealing with objectors to vaccination programmes. In some countries compliance is compulsory, while in others objectors are exempted or allowed to enter the programme under specific conditions.
In this paper I argue that the objectors should not be treated as a homogenous group as is done in the above-mentioned policies. Objectors have different arguments for not participating in vaccination programmes. Considering the value of respect for autonomy, some but not all of these arguments need to be accommodated by authorities.
The concept of 'narrative autonomy' provides criteria to distinguish between tenable and untenable claims to the right to refuse vaccination. Narrative autonomy understands autonomy as essentially linked to identity, as this provides the moral framework with which we assess our first-order preferences.
The above-mentioned concept of autonomy is derived from the concept of narrative identity as described by Marya Schechtman. She suggests that the application of the Articulation Constraint and the Reality Constraint enables us to establish the validity of personal narratives. Additionally, form and content features of identity, as proposed by Anthony Laden, will be used as criteria to establish the compatibility of the defectors' arguments with shared scientific and political values. Such compatibility is essential to accommodate respect for autonomy in the context of public health. 相似文献
In this paper I argue that the objectors should not be treated as a homogenous group as is done in the above-mentioned policies. Objectors have different arguments for not participating in vaccination programmes. Considering the value of respect for autonomy, some but not all of these arguments need to be accommodated by authorities.
The concept of 'narrative autonomy' provides criteria to distinguish between tenable and untenable claims to the right to refuse vaccination. Narrative autonomy understands autonomy as essentially linked to identity, as this provides the moral framework with which we assess our first-order preferences.
The above-mentioned concept of autonomy is derived from the concept of narrative identity as described by Marya Schechtman. She suggests that the application of the Articulation Constraint and the Reality Constraint enables us to establish the validity of personal narratives. Additionally, form and content features of identity, as proposed by Anthony Laden, will be used as criteria to establish the compatibility of the defectors' arguments with shared scientific and political values. Such compatibility is essential to accommodate respect for autonomy in the context of public health. 相似文献
92.
Madsen BE Ramos EM Boulard M Duda K Overgaard J Nordsmark M Wiuf C Hansen LL 《PloS one》2008,3(6):e2492
THE BACKGROUND: Ribonuclease L (RNASEL), encoding the 2'-5'-oligoadenylate (2-5A)-dependent RNase L, is a key enzyme in the interferon induced antiviral and anti-proliferate pathway. Mutations in RNASEL segregate with the disease in prostate cancer families and specific genotypes are associated with an increased risk of prostate cancer. Infection by human papillomavirus (HPV) is the major risk factor for uterine cervix cancer and for a subset of head and neck squamous cell carcinomas (HNSCC). HPV, Epstein Barr virus (EBV) and sequences from mouse mammary tumor virus (MMTV) have been detected in breast tumors, and the presence of integrated SV40 T/t antigen in breast carcinomas correlates with an aggressive phenotype and poor prognosis. A genetic predisposition could explain why some viral infections persist and induce cancer, while others disappear spontaneously. This points at RNASEL as a strong susceptibility gene. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate the implication of an abnormal activity of RNase L in the onset and development of viral induced cancers, the study was initiated by searching for germline mutations in patients diagnosed with uterine cervix cancer. The rationale behind is that close to 100% of the cervix cancer patients have a persistent HPV infection, and if a defective RNase L were responsible for the lack of ability to clear the HPV infection, we would expect to find a wide spectrum of mutations in these patients, leading to a decreased RNase L activity. The HPV genotype was established in tumor DNA from 42 patients diagnosed with carcinoma of the uterine cervix and somatic tissue from these patients was analyzed for mutations by direct sequencing of all coding and regulatory regions of RNASEL. Fifteen mutations, including still uncharacterized, were identified. The genotype frequencies of selected single nucleotide polymorphisms (SNPs) established in the cervix cancer patients were compared between 382 patients with head and neck squamous cell carcinomas (HNSCC), 199 patients with primary unilateral breast cancer and 502 healthy Danish control individuals. We found that the genotype frequencies of only one of the 15 mutations, the yet uncharacterized 5'UTR mutation rs3738579 differed significantly between cancer patients and control individuals (P-value: 4.43x10(-5)). CONCLUSION/SIGNIFICANCE: In conclusion, we have discovered an increased risk, a heterozygous advantage and thereby a protective effect linked to the RNASEL SNP rs3738579. This effect is found for patients diagnosed with carcinoma of the uterine cervix, HNSCC, and breast cancer thus pointing at RNASEL as a general marker for cancer risk and not restricted to familial prostate cancer. 相似文献
93.
Kevin G. Liu Millard H. Lambert Andrea H. Ayscue Brad R. Henke Lisa M. Leesnitzer William R. Oliver Jr. Kelli D. Plunket H. Eric Xu Daniel D. Sternbach Timothy M. Willson 《Bioorganic & medicinal chemistry letters》2001,11(24)
A series of PPARγ agonists were synthesized from
-tyrosine that incorporated low molecular weight N-substituents. The most potent analogue, pyrrole (Scheme 1 and Scheme 2), demonstrated a Ki of 6.9 nM and an EC50 of 4.7 nM in PPARγ binding and functional assays, respectively. Pyrrole (Scheme 1 and Scheme 2), which is readily synthesized from
-tyrosine methyl ester in four steps, also demonstrated in vivo activity in a rodent model of Type 2 diabetes. 相似文献
94.
95.
Lotte Kutscher 《Molecular & general genetics : MGG》1935,68(1):454-485
Ohne ZusammenfassungMit 9 Textfiguren 相似文献
96.
Lotte Schwinck 《Planta》1956,47(2):165-218
Ohne ZusammenfassungMit 20 Textabbildungen 相似文献
97.
Conjugative transposition of the vancomycin resistance carrying Tn1549: enzymatic requirements and target site preferences
下载免费PDF全文
![点击此处可从《Molecular microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Lotte Lambertsen Anna Rubio‐Cosials Kiran Raosaheb Patil Orsolya Barabas 《Molecular microbiology》2018,107(5):639-658
Rapid spread of resistance to vancomycin has generated difficult to treat bacterial pathogens worldwide. Though vancomycin resistance is often conferred by the conjugative transposon Tn1549, it is yet unclear whether Tn1549 moves actively between bacteria. Here we demonstrate, through development of an in vivo assay system, that a mini‐Tn1549 can transpose in E. coli away from its natural Gram‐positive host. We find the transposon‐encoded INT enzyme and its catalytic tyrosine Y380 to be essential for transposition. A second Tn1549 protein, XIS is important for efficient and accurate transposition. We further show that DNA flanking the left transposon end is critical for excision, with changes to nucleotides 7 and 9 impairing movement. These mutations could be partially compensated for by changing the final nucleotide of the right transposon end, implying concerted excision of the two ends. With changes in these essential DNA sequences, or without XIS, a large amount of flanking DNA transposes with Tn1549. This rescues mobility and allows the transposon to capture and transfer flanking genomic DNA. We further identify the transposon integration target sites as TTTT‐N6‐AAAA. Overall, our results provide molecular insights into conjugative transposition and the adaptability of Tn1549 for efficient antibiotic resistance transfer. 相似文献
98.
Molecular Genetics and Genomics - 相似文献
99.
100.
Multiple introductions,admixture and bridgehead invasion characterize the introduction history of Ambrosia artemisiifolia in Europe and Australia
下载免费PDF全文
![点击此处可从《Molecular ecology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Lotte A. van Boheemen Eric Lombaert Kristin A. Nurkowski Bertrand Gauffre Loren H. Rieseberg Kathryn A. Hodgins 《Molecular ecology》2017,26(20):5421-5434
Admixture between differentiated populations is considered to be a powerful mechanism stimulating the invasive success of some introduced species. It is generally facilitated through multiple introductions; however, the importance of admixture prior to introduction has rarely been considered. We assess the likelihood that the invasive Ambrosia artemisiifolia populations of Europe and Australia developed through multiple introductions or were sourced from a historical admixture zone within native North America. To do this, we combine large genomic and sampling data sets analysed with approximate Bayesian computation and random forest scenario evaluation to compare single and multiple invasion scenarios with pre‐ and postintroduction admixture simultaneously. We show the historical admixture zone within native North America originated before global invasion of this weed and could act as a potential source of introduced populations. We provide evidence supporting the hypothesis that the invasive populations established through multiple introductions from the native range into Europe and subsequent bridgehead invasion into Australia. We discuss the evolutionary mechanisms that could promote invasiveness and evolutionary potential of alien species from bridgehead invasions and admixed source populations. 相似文献