全文获取类型
收费全文 | 198篇 |
免费 | 17篇 |
出版年
2023年 | 2篇 |
2021年 | 5篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 13篇 |
2015年 | 17篇 |
2014年 | 10篇 |
2013年 | 10篇 |
2012年 | 17篇 |
2011年 | 16篇 |
2010年 | 6篇 |
2009年 | 4篇 |
2008年 | 9篇 |
2007年 | 17篇 |
2006年 | 8篇 |
2005年 | 9篇 |
2004年 | 2篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1985年 | 6篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1979年 | 5篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有215条查询结果,搜索用时 15 毫秒
191.
Merete Nordentoft Thomas Munk Laursen Esben Agerbo Ping Qin Eyd Hansen H?yer Preben Bo Mortensen 《BMJ (Clinical research ed.)》2004,329(7460):261
Objective To study the change in risk of suicide among patients with schizophrenia and related disorders.Design Nested case-control design with linked data.Setting 4 longitudinal Danish registers.Participants 18 744 people aged up to 75 years who committed suicide in 1981-97 individually matched with 20 controls.Results Over the time studied the reduction in suicide rate among patients with schizophrenia and schizophrenia spectrum disorder was similar to that seen in the general population (incidence rate ratio 1.00, 95% confidence interval 0.98 to 1.03). The reduction among patients with other psychosis in the schizophrenia spectrum was faster than the reduction seen in the general population. Among people admitted to hospital with schizophrenia the risk of suicide was highest in the first year after first admission, and the excess risk was largest in the younger age groups—that is, the risk decreased per year for every additional year of age.Conclusion The suicide rate among patients with a diagnosis of schizophrenia and related disorders has fallen. This may be due to better psychiatric treatment, reduced access to means of suicide, or improvements in treatment after suicide attempts. 相似文献
192.
Lund SS Tarnow L Astrup AS Hovind P Jacobsen PK Alibegovic AC Parving I Pietraszek L Frandsen M Rossing P Parving HH Vaag AA 《PloS one》2008,3(10):e3363
Background
Despite intensive insulin treatment, many patients with type-1 diabetes (T1DM) have longstanding inadequate glycaemic control. Metformin is an oral hypoglycaemic agent that improves insulin action in patients with type-2 diabetes. We investigated the effect of a one-year treatment with metformin versus placebo in patients with T1DM and persistent poor glycaemic control.Methodology/Principal Findings
One hundred patients with T1DM, preserved hypoglycaemic awareness and HaemoglobinA1c (HbA1c) ≥8.5% during the year before enrolment entered a one-month run-in on placebo treatment. Thereafter, patients were randomized (baseline) to treatment with either metformin (1 g twice daily) or placebo for 12 months (double-masked). Patients continued ongoing insulin therapy and their usual outpatient clinical care. The primary outcome measure was change in HbA1c after one year of treatment. At enrolment, mean (standard deviation) HbA1c was 9.48% (0.99) for the metformin group (n = 49) and 9.60% (0.86) for the placebo group (n = 51). Mean (95% confidence interval) baseline-adjusted differences after 12 months with metformin (n = 48) versus placebo (n = 50) were: HbA1c, 0.13% (−0.19; 0.44), p = 0.422; Total daily insulin dose, −5.7 U/day (−8.6; −2.9), p<0.001; body weight, −1.74 kg (−3.32; −0.17), p = 0.030. Minor and overall major hypoglycaemia was not significantly different between treatments. Treatments were well tolerated.Conclusions/Significance
In patients with poorly controlled T1DM, adjunct metformin therapy did not provide any improvement of glycaemic control after one year. Nevertheless, adjunct metformin treatment was associated with sustained reductions of insulin dose and body weight. Further investigations into the potential cardiovascular-protective effects of metformin therapy in patients with T1DM are warranted.Trial Registration
ClinicalTrials.gov NCT00118937相似文献193.
Magne Kaldhusdal Merete Hofshagen Atle Løvland Haakon Langstrand Keith Redhead 《FEMS immunology and medical microbiology》1999,24(3):337-343
The effect of Clostridium perfringens challenge, number of challenge days, and pre-challenge antibiotic treatment on the induction of necrotic enteritis in broiler chickens raised on litter was studied, and the relationship between bacterial counts and frequency of gut lesions was evaluated. Specific intestinal lesions in randomly selected birds were present despite a lack of disease-specific mortality. Challenge, number of challenge days and frequency of lesions were associated with median counts of C. perfringens. The effect of pre-challenge C. perfringens counts and antibiotics cannot be evaluated unless procedures for the control of pre-challenge infection and methods for the differentiation between wild-type and challenge strains are established. 相似文献
194.
195.
Simonsen HT Larsen MD Nielsen MW Adsersen A Olsen CE Strasberg D Smitt UW Jaroszewski JW 《Phytochemistry》2002,60(8):817-820
Three new natural products, 3,8-dimethoxy-5,7-dihydroxy-3′,4′-methylenedioxyflavone, 3,6,8-trimethoxy-5,7-dihydroxy-3′,4′-methylenedioxyflavone and 3,6,8,3′,4′-pentamethoxy-5,7-dihydroxyflavone were isolated from Melicope coodeana syn. Euodia simplex (Rutaceae) along with 3,6,3′-trimethoxy-5,7,4′-trihydroxyflavone and 3,3′-dimethoxy-5,7,4′-trihydroxyflavone. The structural assignments are based on 1H and 13C NMR data, including discussion of the chemical shifts of C-2 in 3,5-dihydroxy- and 3-methoxy-5-hydroxyflavones. The presence of highly methoxylated and methylenedioxyflavones is characteristic of the genus Melicope, and the present findings support the recent transfer of Euodia simplex to Melicope. 相似文献
196.
Frank?Gr?nlund?J?rgensenEmail author Asger?Hobolth Henrik?Hornsh?j Christian?Bendixen Merete?Fredholm Mikkel?Heide?Schierup 《BMC biology》2005,3(1):2
Background
The availability of abundant sequence data from key model organisms has made large scale studies of molecular evolution an exciting possibility. Here we use full length cDNA alignments comprising more than 700,000 nucleotides from human, mouse, pig and the Japanese pufferfish Fugu rubrices in order to investigate 1) the relationships between three major lineages of mammals: rodents, artiodactyls and primates, and 2) the rate of evolution and the occurrence of positive Darwinian selection using codon based models of sequence evolution. 相似文献197.
Aimei Wang Minna Haapalainen Satu Latvala Merete Edelenbos Anders Johansen 《Fungal biology》2018,122(10):1013-1022
Basal rot is a common onion disease and is mainly caused by Fusarium oxysporum f. sp. cepae and Fusarium proliferatum. To study the possibility of using volatile organic compounds (VOCs) as biomarkers for these fungi, pathogenic isolates of F. oxysporum and F. proliferatum from onions were cultivated in onion medium and VOCs were measured by solid phase microextraction (SPME). Forty-two compounds were detected, and thirty of these compounds were highly related to fungal metabolic activity. Allyl mercaptan was specific to F. oxysporum isolate Fox006. Analysis of the VOCs showed significant differences between the two species and among different isolates within the same species. Sixteen of the VOCs showed were highly positively correlated with the fungal biomass estimated by real-time polymerase chain reaction (PCR). Ethanol, ethyl formate, ethyl acetate, 2-methyl-1-propanol, methyl thioacetate, n-propyl acetate and 3-methyl-1-butanol are volatile metabolites that were potential indicators of Fusarium growth on onions. 相似文献
198.
Joanna E. Cobb Darren Plant Edward Flynn Meriem Tadjeddine Philippe Dieudé Fran?ois Cornélis Lisbeth ?rlestig Solbritt Rantap?? Dahlqvist George Goulielmos Dimitrios T. Boumpas Prodromos Sidiropoulos Sophine B. Krintel Lykke M. ?rnbjerg Merete L. Hetland Lars Klareskog Thomas Haeupl Andrew Filer Christopher D. Buckley Karim Raza Torsten Witte Reinhold E. Schmidt Oliver FitzGerald Douglas Veale Stephen Eyre Jane Worthington 《PloS one》2013,8(6)
Objectives
Genome-wide association studies have facilitated the identification of over 30 susceptibility loci for rheumatoid arthritis (RA). However, evidence for a number of potential susceptibility genes have not so far reached genome-wide significance in studies of Caucasian RA.Methods
A cohort of 4286 RA patients from across Europe and 5642 population matched controls were genotyped for 25 SNPs, then combined in a meta-analysis with previously published data.Results
Significant evidence of association was detected for nine SNPs within the European samples. When meta-analysed with previously published data, 21 SNPs were associated with RA susceptibility. Although SNPs in the PTPN2 gene were previously reported to be associated with RA in both Japanese and European populations, we show genome-wide evidence for a different SNP within this gene associated with RA susceptibility in an independent European population (rs7234029, P = 4.4×10−9).Conclusions
This study provides further genome-wide evidence for the association of the PTPN2 locus (encoding the T cell protein tyrosine phosphastase) with Caucasian RA susceptibility. This finding adds to the growing evidence for PTPN2 being a pan-autoimmune susceptibility gene. 相似文献199.
Proschowsky HF Flagstad A Cirera S Joergensen CB Fredholm M 《The Journal of heredity》2007,98(5):539-543
The presence of a recessive inherited muscle disease in Old Danish Pointing Dogs has been well known for years. Comparisons of this disease with myasthenic diseases of other dog breeds and humans have pointed toward a defect in the synthesis of the neurotransmitter acetylcholine possibly due to decreased activity of the enzyme choline acetyltransferase. We sequenced exons 5-18 of the gene encoding choline acetyltransferase (CHAT) in 2 affected and 2 unaffected dogs and identified a G to A missense mutation in exon 6. The mutation causes a valine to methionine substitution and segregates in agreement with the inheritance of the disease. The mutation was not detected in 50 dogs representing 25 other dog breeds. A DNA test has been developed and is now available to the breeders of Old Danish Pointing Dogs. 相似文献
200.
Alignment-Independent Comparisons of Human Gastrointestinal Tract Microbial Communities in a Multidimensional 16S rRNA Gene Evolutionary Space 总被引:1,自引:0,他引:1 下载免费PDF全文
Knut Rudi Monika Zimonja Bente Kvenshagen Jarle Rugtveit Tore Midtvedt Merete Eggesb 《Applied microbiology》2007,73(8):2727-2734
We present a novel approach for comparing 16S rRNA gene clone libraries that is independent of both DNA sequence alignment and definition of bacterial phylogroups. These steps are the major bottlenecks in current microbial comparative analyses. We used direct comparisons of taxon density distributions in an absolute evolutionary coordinate space. The coordinate space was generated by using alignment-independent bilinear multivariate modeling. Statistical analyses for clone library comparisons were based on multivariate analysis of variance, partial least-squares regression, and permutations. Clone libraries from both adult and infant gastrointestinal tract microbial communities were used as biological models. We reanalyzed a library consisting of 11,831 clones covering complete colons from three healthy adults in addition to a smaller 390-clone library from infant feces. We show that it is possible to extract detailed information about microbial community structures using our alignment-independent method. Our density distribution analysis is also very efficient with respect to computer operation time, meeting the future requirements of large-scale screenings to understand the diversity and dynamics of microbial communities. 相似文献