全文获取类型
收费全文 | 1450篇 |
免费 | 146篇 |
国内免费 | 7篇 |
出版年
2023年 | 6篇 |
2022年 | 3篇 |
2021年 | 23篇 |
2020年 | 23篇 |
2019年 | 20篇 |
2018年 | 27篇 |
2017年 | 22篇 |
2016年 | 53篇 |
2015年 | 53篇 |
2014年 | 57篇 |
2013年 | 90篇 |
2012年 | 128篇 |
2011年 | 98篇 |
2010年 | 84篇 |
2009年 | 57篇 |
2008年 | 88篇 |
2007年 | 102篇 |
2006年 | 89篇 |
2005年 | 74篇 |
2004年 | 81篇 |
2003年 | 83篇 |
2002年 | 70篇 |
2001年 | 20篇 |
2000年 | 12篇 |
1999年 | 20篇 |
1998年 | 21篇 |
1997年 | 13篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 13篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 12篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 4篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1977年 | 7篇 |
1975年 | 3篇 |
1974年 | 5篇 |
1973年 | 4篇 |
1968年 | 4篇 |
排序方式: 共有1603条查询结果,搜索用时 230 毫秒
121.
Ana Carolina Luchiari Cristiane Regina do Amaral Duarte Fúlvio Aurélio de Morais Freire Kari Nissinen 《Journal of Ethology》2007,25(2):169-175
We studied the colour preference of isolated Nile tilapia (Oreochromis niloticus) and whether previous residence or body size can affect environmental colour choice. In the first phase, a cylindrical tank
was divided into five differently coloured compartments (yellow, blue, green, white and red), a single fish was introduced
into the tank and the frequency at which this fish visited each compartment was recorded over a 2-day study period. An increasingly
larger fish (approx +2 cm in length each time) was then added into the tank on each of days 3, 5 and 7 (=four fish in the
tank by day 7), and the frequency at which each fish visited the different compartments of the tank was observed twice a day
to obtain visit frequency data on the differently sized fishes. This experiment was replicated six times. In the first phase,
the solitary fish established residence inside the yellow compartment on the first and second days. Following the
introduction of a larger fish, the smaller fish was displaced from the occupied compartment. Nile tilapia possibly shows this
preference for yellow as a function of its visual spectral sensitivity and/or the spectral characteristics of its natural
environment. Moreover, body size is an important factor in determining hierarchical dominance and territorial defence, and
dominant fish chose the preferred environmental colour compartment as their territory. 相似文献
122.
Lynch AI Arnett DK Pankow JS Miller MB North KE Eckfeldt JH Hunt SC Rao DC Djoussé L 《Human genetics》2007,122(1):33-40
Evidence shows that an elevated pulse pressure (PP) may lead to an increased risk of cardiovascular morbidity and mortality.
There is also evidence that PP is a sexually dimorphic trait, and that genetic factors influence inter-individual variation
in PP. The aim of this project was to assess the genotype-by-sex interaction on PP in a sample of mostly hypertensive African
American and White participants using candidate genes involved in the renin–angiotensin–aldosterone system. Subjects were
participants in the HyperGEN Study, including men (43%) and women (57%) over the age of 55 years (mean age = 65). Candidate
gene polymorphisms used were ACE insertion/deletion (1,789 subjects genotyped) and AGT-M235T (1,800 subjects genotyped). We employed linear regression methods to assess the genotype-by-sex interaction. For ACE, genotype-by-sex interaction on PP was detected (P = 0.04): the “D/D” genotype predicted a 2.2 mmHg higher pulse pressure among women, but a 1.2 mmHg lower PP among men, compared to those with an “I” allele, after adjusting for age, weight, height, ethnicity, and antihypertension
medication use. A similar interaction was found for systolic blood pressure. The genotype-by-sex interaction was consistent
across ethnicity. The interaction was evident among those on antihypertensive medications (P = 0.05), but not among those not taking such medications (P = 0.55). In our analysis of AGT, no evidence of a genotype-by-sex interaction affecting PP, SBP, or DBP was detected. This evidence for a genotype-by-sex
interaction helps our understanding of the complex genetic underpinnings of blood pressure phenotypes. 相似文献
123.
Alanne M Kristiansson K Auro K Silander K Kuulasmaa K Peltonen L Salomaa V Perola M 《Human genetics》2007,122(3-4):355-365
Selenoprotein S (SEPS1) is a novel candidate gene involved in the regulation of inflammatory response and protection from
oxidative damage. This study explored the genetic variation in the SEPS1 locus for an association with CVD as well as with
quantitative phenotypes related to obesity and inflammation. We used the case-cohort design and time-to-event analysis in
two separate prospectively followed population-based cohorts FINRISK 92 and 97 (n = 999 and 1,223 individuals, respectively) to study the associations of five single nucleotide polymorphisms with the risk
for coronary heart disease (CHD) and ischemic stroke events. We found a significant association with increased CHD risk in
females carrying the minor allele of rs8025174 in the combined analysis of both cohorts [hazard ratio (HR) 2.95 (95% confidence interval: 1.37–6.39)]. Another variant,
rs7178239, increased the risk for ischemic stroke significantly in females [HR: 3.35 (1.66–6.76)] and in joint analysis of both sexes
and both cohorts [HR: 1.75 (1.17–2.64)]. These results indicate that variation in the SEPS1 locus may have an effect on CVD
morbidity, especially in females. This observation should stimulate further investigations of the role of this gene and protein
in the pathogenesis of CVD.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
124.
Muallem H North KE Kakoki M Wojczynski MK Li X Grove M Boerwinkle E Wilhelmsen KC Heiss G Maeda N 《Human genetics》2007,121(3-4):421-431
The low-density lipoprotein receptor (LDLR) plays a pivotal role in cholesterol homeostasis. However, the role of genetic
variations in the 3′UTR of the LDLR in relation to plasma cholesterol has been largely understudied. Six SNPs, G44243A, G44332A, C44506G, G44695A, C44857T and
A44964G, within the 5′ region of the 3′UTR fall into three common haplotypes, GGCGCA, AGCACG, and GGCGTA, occurring at frequencies of 0.45, 0.31 and 0.17, respectively, in Caucasians (n = 29) and 0.13, 0.13 and 0.38, respectively, in African Americans (n = 32), with three other haplotypes occurring at lesser frequencies. In a tissue culture based system, expression of a reporter
gene carrying a 3′UTR that includes the 1 kb nucleotide sequences corresponding to the AGCACG or GGCGTA was 70 or 63%, respectively, of the same sequence with GGCGCA. Genotyping of two “haplotype tagging” SNPs, C44857T and A44964G, in the Atherosclerosis Risk in Communities (ARIC) study
population showed that in Caucasians, but not in African Americans, the inferred TA haplotype had a significant LDL-cholesterol lowering effect. The adjusted LDL-cholesterol levels in the TA/TA diplotypes were lower by 6.10 mg/dl in men (P < 0.001) and by 4.63 mg/dl in women (P < 0.01) than in individuals with other diplotypes. Caucasian men homozygous for CA, in contrast, showed significantly higher LDL-cholesterol (P < 0.04), lower HDL-cholesterol (P < 0.02) and higher LDL/HDL ratios (P < 0.001). Thus our data shows that 3′UTR sequences that cause higher reporter gene expression in vitro are associated in Caucasians
with plasma lipid profiles indicative of higher cardiovascular risk, suggesting that further studies of quantitative variants
in the LDLR gene will be valuable.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
An erratum to this article can be found at 相似文献
125.
The Arabidopsis transcription factor MYB77 modulates auxin signal transduction 总被引:6,自引:0,他引:6 下载免费PDF全文
Shin R Burch AY Huppert KA Tiwari SB Murphy AS Guilfoyle TJ Schachtman DP 《The Plant cell》2007,19(8):2440-2453
126.
127.
Trager EH Khanna R Marrs A Siden L Branham KE Swaroop A Richards JE 《Bioinformatics (Oxford, England)》2007,23(14):1854-1856
The Madeline 2.0 Pedigree Drawing Engine (PDE) is a pedigree drawing program for use in linkage and family-based association studies. The program is designed to handle large and complex pedigrees with an emphasis on readability and aesthetics. For complex pedigrees, we use a hybrid algorithm in which consanguinous loops are drawn as cyclic graphs whenever possible, but we resort to acyclic graphs when matings can no longer be connected without line crossings. A similar hybrid approach is used to avoid line crossings for matings between distant descendants of different founding groups. Written in object-oriented C++ and released under the GNU General Public License (GPL), Madeline 2.0 PDE reads input files specified on the command line and generates pedigree drawings without user interaction. Pedigree output in scalable vector graphics (SVG) format can be viewed in browsers with native SVG rendering support or in vector graphics editors. We provide an easy-to-use public web service, which is experimental and still under development. Availability: http://kellogg.umich.edu/madeline. 相似文献
128.
Fast and simple detection of pathogens is of utmost importance in health care and the food industry. In this article, a novel technology for the detection of pathogenic bacteria is presented. The technology uses lytic-specific bacteriophages and a nonspecific interaction of cellular components with a luminescent lanthanide chelate. As a proof of principle, Escherichia coli-specific T4 bacteriophage was used to infect the bacteria, and the cell lysis was detected. In the absence of E. coli, luminescent Eu3+–chelate complex cannot be formed and low time-resolved luminescence signal is monitored. In the presence of E. coli, increased luminescence signal is observed as the cellular contents are leached to the surrounding medium. The luminescence signal is observed as a function of the number of bacteria in the sample. The homogeneous assay can detect living E. coli in bacterial cultures and simulated urine samples within 25 min with a detection limit of 1000 or 10,000 bacterial cells/ml in buffer or urine, respectively. The detection limit is at the clinically relevant level, which indicates that the method could also be applicable to clinical settings for fast detection of urine bacteria. 相似文献
129.
130.
Matthew B. Lanktree Clara C. Elbers Yun Li Guosheng Zhang Qing Duan Konrad J. Karczewski Yiran Guo Vinicius Tragante Kari E. North Mary Cushman Folkert W. Asselbergs James G. Wilson Leslie A. Lange Fotios Drenos Alex P. Reiner Michael R. Barnes Brendan J. Keating 《Journal of lipid research》2015,56(9):1781-1786
Meta-analyses of European populations has successfully identified genetic variants in over 150 loci associated with lipid levels, but results from additional ethnicities remain limited. Previously, we reported two novel lipid loci identified in a sample of 7,657 African Americans using a gene-centric array including 50,000 SNPs in 2,100 candidate genes. Initial discovery and follow-up of signals with P < 10−5 in additional African American samples confirmed CD36 and ICAM1. Using an additional 8,244 African American female samples from the Women’s Health Initiative SNP Health Association Resource genome-wide association study dataset, we further examined the previous meta-analyses results by attempting to replicate 20 additional putative lipid signals with P < 10−4. Replication confirmed rs868213, located in a splice donor region of exocyst complex component 3-like 1 (EXOC3L1) as a novel signal for HDL (additive allelic effect β = 0.02; P = 1.4 × 10−8; meta-analyses of discovery and replication). EXOC3L1 is strongly expressed in vascular endothelium and forms part of the exocyst complex, a key facilitator of the trafficking of lipid receptors. Increasing sample sizes for genetic studies in nonEuropean populations will continue to improve our understanding of lipid metabolism. 相似文献