全文获取类型
收费全文 | 149篇 |
免费 | 5篇 |
专业分类
154篇 |
出版年
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 8篇 |
2013年 | 9篇 |
2012年 | 13篇 |
2011年 | 12篇 |
2010年 | 7篇 |
2009年 | 6篇 |
2008年 | 12篇 |
2007年 | 13篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 4篇 |
2002年 | 5篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
排序方式: 共有154条查询结果,搜索用时 15 毫秒
71.
Umit Baris Kutman Bahar Yildiz Kutman Yasemin Ceylan Emir Ali Ova Ismail Cakmak 《Plant and Soil》2012,361(1-2):177-187
Background and aims
Whether root Zn uptake during grain filling or remobilization from pre-anthesis Zn stores contributes more to grain Zn in wheat is subject to an on-going debate. This study investigated the effects of N nutrition and post-anthesis Zn availability on the relative importance of these sources.Methods
Durum wheat plants were grown in nutrient solution containing adequate Zn (0.5?μM) and three different N levels (0.5; 1.5; 4.5?mM). One third of the plants were harvested when they reached anthesis. One half of the remaining plants were grown to maturity with adequate Zn, whereas the Zn supply to the other half was discontinued at anthesis. Roots, straw and grains were harvested separately and analyzed for Zn and N.Results
Depending on the N supply, Zn remobilization from pre-anthesis sources provided almost all of grain Zn when the Zn supply was withheld at anthesis; otherwise up to 100?% of grain Zn could be accounted for by Zn taken up post-anthesis. By promoting tillering and grain yield and extending the grain filling, higher N supply favored the contribution of Zn uptake to grain Zn accumulation.Conclusion
Remobilization is critical for grain Zn accumulation when Zn availability is restricted during grain filling. However, where root uptake can continue, concurrent Zn uptake during grain development, favored by higher N supply, overshadows net remobilization. 相似文献72.
Expression of high zinc efficiency of Aegilops tauschii and Triticum monococcum in synthetic hexaploid wheats 总被引:4,自引:0,他引:4
The effect of varied zinc (Zn) supply on shoot and root dry matter production, severity of Zn deficiency symptoms and Zn tissue
concentrations was studied in two Triticum turgidum (BBAA) genotypes and three synthetic hexaploid wheat genotypes by growing
plants in a Zn-deficient calcareous soil under greenhouse conditions with (+Zn=5 mg kg-1 soil) and without (−Zn) Zn supply. Two synthetic wheats (BBAADD) were derived from two different Aegilops tauschii (DD) accessions
using same Triticum turgidum (BBAA), while one synthetic wheat (BBAAAA) was derived from Triticum turgidum (BBAA) and Triticum
monococcum (AA). Visible symptoms of Zn deficiency, such as occurrence of necrotic patches on leaves and reduction in shoot
elongation developed more rapidly and severely in tetraploid wheats than in synthetic hexaploid wheats. Correspondingly, decreases
in shoot and root dry matter production due to Zn deficiency were higher in tetraploid wheats than in synthetic hexaploid
wheats. Transfer of the DD genome from Aegilops tauschii or the AA genome from Triticum monococcum to tetraploid wheat greatly
improved root and particularly shoot growth under Zn-deficient, but not under Zn-sufficient conditions. Better growth and
lesser Zn deficiency symptoms in synthetic hexaploid wheats than in tetraploid wheats were not accompanied by increases in
Zn concentration per unit dry weight, but related more to the total amount of Zn per shoot, especially in the case of synthetic
wheats derived from Aegilops tauschii. This result indicates higher Zn uptake capacity of synthetic wheats. The results demonstrated
that the genes for high Zn efficiency from Aegilops tauschii (DD) and Triticum monococcum (AA) are expressed in the synthetic
hexaploid wheats. These wheat relatives can be used as valuable sources of genes for improvement of Zn efficiency in wheat.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
73.
Magnesium in crop production, food quality and human health 总被引:3,自引:0,他引:3
Ismail Cakmak 《Plant and Soil》2013,368(1-2):1-4
74.
Genotypic variation in common bean in response to zinc deficiency in calcareous soil 总被引:2,自引:0,他引:2
Hacisalihoglu Gökhan Ozturk Levent Cakmak Ismail Welch Ross M. Kochian Leon 《Plant and Soil》2004,259(1-2):71-83
Plant and Soil - Greenhouse experiments have been carried out to study the genotypic variation among 35 bean (Phaseolus vulgaris&;nbsp;L.) genotypes with regards to tolerance to zinc (Zn)... 相似文献
75.
Koç A Kaymak AO Karaer K Ergün MA Aksu T Perçin EF 《Genetic counseling (Geneva, Switzerland)》2008,19(2):193-198
Congenital radio-ulnar synostosis may be an isolated abnormality or additional abnormalities may accompany it. It may also be found as a part of well-known syndromes. We present a case with bilateral congenital radio-ulnar synostosis, speech delay, dimple on shoulders, café au lait spot and characteristic facial appearance. The proband has a brother with similar clinical findings with the exception of congenital radio-ulnar synostosis. We discuss the possible relationship between our case and previously described syndromes with congenital radio-ulnar synostosis, and distinct phenotypic features of the presented case. 相似文献
76.
Iron (Fe) deficiency is increasingly being observed in cropping systems with frequent glyphosate applications. A likely reason for this is that glyphosate interferes with root uptake of Fe by inhibiting ferric reductase in roots required for Fe acquisition by dicot and nongrass species. This study investigated the role of drift rates of glyphosate (0.32, 0.95 or 1.89 mm glyphosate corresponding to 1, 3 and 6% of the recommended herbicidal dose, respectively) on ferric reductase activity of sunflower (Helianthus annuus) roots grown under Fe deficiency conditions. Application of 1.89 mm glyphosate resulted in almost 50% inhibition of ferric reductase within 6 h and complete inhibition 24 h after the treatment. Even at lower rates of glyphosate (e.g. 0.32 mm and 0.95 mm), ferric reductase was inhibited. Soluble sugar concentration and the NAD(P)H oxidizing capacity of apical roots were not decreased by the glyphosate applications. To our knowledge, this is the first study reporting the effects of glyphosate on ferric reductase activity. The nature of the inhibitory effect of glyphosate on ferric reductase could not be identified. Impaired ferric reductase could be a major reason for the increasingly observed Fe deficiency in cropping systems associated with widespread glyphosate usage. 相似文献
77.
An adaptive neuro-fuzzy inference technique has been adopted to estimate light levels in a reservoir. The data were collected
randomly from Doğanci Dam Reservoir over a number of years. The input data set is a matrix with vectors of time, depth, sampling
location, and incident solar radiation. The output data set is a vector representing light measured at various depths. Randomization
and logarithmic transformations have been applied as preprocessing. One-half of the data have been utilized for training;
testing and validation steps utilized one-fourth each. An adaptive neuro-fuzzy inference system (ANFIS) has been built as
a prediction model for light penetration. Very high correlation values between predictions and real values on light measurements
with relatively low root mean square error values have been obtained for training, test, and validation data sets. Elimination
of the overtraining problem was ensured by satisfying close root mean square error values for all sets. 相似文献
78.
Ibrahim Cakmak Daniel S. Song T. Andrew Mixson Eduardo Serrano Meredith L. Clement Amy Savitski Ge’Andra Johnson Tugrul Giray Charles I. Abramson John F. Barthell Harrington Wells 《Journal of Insect Behavior》2010,23(2):100-116
Foraging behavior of Apis mellifera caucasica, A.m. carnica and A.m. syriaca in Turkey was studied for intrinsic subspecies-based differences. Models of forager flower-color fidelity, risk sensitive behavior and maximizing net gain were tested. Foragers were presented artificial flower patches containing blue, white and yellow flowers. Some bees of each subspecies showed high fidelity to yellow flowers, while others favored blue and white flowers. The degree of fidelity, however, differed among subspecies and was dependent upon which color was favored. Bees of all subspecies demonstrated risk indifferent behavior regardless of whether they favored yellow flowers or blue and white flowers. Flower handling time differed among subspecies and increased with reward quantity, and when a reward was present. Flight time between consecutive flowers also differed among honey bee subspecies. Foragers of all subspecies had a higher net gain when visiting flowers with consistent rewards. 相似文献
79.
Effect of zinc nutritional status on activities of superoxide radical and hydrogen peroxide scavenging enzymes in bean leaves 总被引:5,自引:0,他引:5
The effect of varied zinc (Zn) supply on the activities of superoxide dismutase (SOD), ascorbate (AsA) peroxidase, glutathione (GSSG) reductase, catalase and guaiacol peroxidase was studied in leaves of bean (Phaseolus vulgaris) plants grown for 15 days in nutrient solution. Zinc deficiency severely decreased plant growth and the leaf concentrations of soluble protein and chlorophyll. Resupply of Zn to deficient plants for up to 72h restored protein concentrations more rapidly than chlorophyll and plant growth. With the exception of guaiacol peroxidase, the activities of all enzymes were significantly decreased by Zn deficiency, in particular GSSG reductase and SOD. Within 72h of resupplying Zn to deficient plants, the enzyme activities reached the level of the Zn sufficient plants. The results indicate severe impairment in the ability of Zn-deficient leaves to enzymically scavenge O2
- and H2O2. Consequences and reasons of this impairment are discussed in terms of photooxidation of chloroplast pigments and inhibition of the biosynthesis of the related scavenger enzyme proteins. 相似文献
80.
Burcu Bayoglu Huseyin Altug Cakmak Husniye Yuksel Gunay Can Bilgehan Karadag Turgut Ulutin Vural Ali Vural Mujgan Cengiz 《Molecular and cellular biochemistry》2013,379(1-2):77-85
Metabolic syndrome (MetS) is a common multifactorial disorder that involves abdominal obesity, dyslipidemia, hypertension, and hyperglycemia. Genome-wide association studies have identified a major risk locus for coronary artery disease and myocardial infarction on chromosome 9p21. Here, we examined the frequency of single nucleotide polymorphisms (SNPs) on chromosome 9p21 in a sample of Turkish patients with MetS and further investigated the correlation between regional SNPs, haplotypes, and MetS. The real-time polymerase chain reaction (RT-PCR) was used to analyze 4 SNPs (rs10757274 A/G, rs2383207 A/G, rs10757278 A/G, rs1333049 C/G) in 291 MetS patients and 247 controls. Analysis of 4 SNPs revealed a significant difference in the genotype distribution for rs2383207, rs10757278, and rs1333049 between MetS patients and controls (p = 0.041, p = 0.005, p = 0.023, respectively) but not for rs10757274 (p = 0.211). MetS and control allelic frequencies for rs2383207, rs10757278, and rs1333049 were statistically different (p < 0.05). The rs2383207 AG variant, was identified as a MetS risk factor (p = 0.012, OR = 33.271; 95 % CI: 2.193–504.805) and the AA haplotype in block 1 and the GC, AG haplotypes in block 2 were associated with MetS (χ 2 = 3.875, p = 0.049; χ 2 = 9.334, p = 0.0022; χ 2 = 9.134, p = 0.0025, respectively). In this study, we found that chromosome 9p21 SNP rs10757278 and related haplotypes correlate with MetS risk. This is the first report showing an association between a 9p21 variant and MetS and suggests that rs10757278 polymorphism may confer increased risk for disease. 相似文献