全文获取类型
收费全文 | 1166篇 |
免费 | 92篇 |
国内免费 | 1篇 |
出版年
2023年 | 16篇 |
2022年 | 19篇 |
2021年 | 60篇 |
2020年 | 43篇 |
2019年 | 53篇 |
2018年 | 53篇 |
2017年 | 58篇 |
2016年 | 60篇 |
2015年 | 94篇 |
2014年 | 104篇 |
2013年 | 103篇 |
2012年 | 108篇 |
2011年 | 98篇 |
2010年 | 63篇 |
2009年 | 50篇 |
2008年 | 56篇 |
2007年 | 49篇 |
2006年 | 29篇 |
2005年 | 35篇 |
2004年 | 31篇 |
2003年 | 24篇 |
2002年 | 15篇 |
2001年 | 6篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1259条查询结果,搜索用时 234 毫秒
101.
102.
Toxicity,behavior impairment,and repellence of essential oils from pepper‐rosmarin and patchouli to termites
下载免费PDF全文
![点击此处可从《Entomologia Experimentalis et Applicata》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Leandro Bacci Janaína K.A. Lima Ana Paula A. Araújo Arie F. Blank Indira M.A. Silva Abraão A. Santos Ane C.C. Santos Péricles B. Alves Marcelo C. Picanço 《Entomologia Experimentalis et Applicata》2015,156(1):66-76
Plant essential oils are potential sources of insecticidal compounds, but have rarely been explored for their effect on termites. In the present study, we assessed the chemical composition of essential oils of Lippia sidoides Cham. (pepper‐rosmarin; Verbenaceae) and Pogostemon cablin (Blanco) Benth. (patchouli; Lamiacaeae) and evaluated their toxicity, behavioral impairment, and repellence to termite species of the genera Amitermes and Microcerotermes (Isoptera: Termitidae: Termitinae). The main components of essential oils of L. sidoides and P. cablin were thymol (44.6%) and patchouli alcohol (36.6%), respectively. The essential oil of P. cablin was most potent against Amitermes cf. amifer Silvestri and had the lowest LD50 (0.63 μg mg?1). There was no difference in toxicity for Microcerotermes indistinctus Mathews between the essential oils of L. sidoides (LD50 = 1.49 μg mg?1) and P. cablin (LD50 = 1.67 μg mg?1). Pogostemon cablin essential oil was the most toxic to M. indistinctus (LC50 = 0.32 μl ml?1) and A. cf. amifer (LC50 = 0.29 μl ml?1). The essential oils analyzed exhibited high toxicity and repellence to the termites, in addition to reducing behavioral interactions among individuals, thus constituting potential termiticides. 相似文献
103.
104.
105.
Symptoms induced by transgenic expression of p23 from Citrus tristeza virus in phloem‐associated cells of Mexican lime mimic virus infection without the aberrations accompanying constitutive expression
下载免费PDF全文
![点击此处可从《Molecular Plant Pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Nuria Soler Carmen Fagoaga Carmelo López Pedro Moreno Luis Navarro Ricardo Flores Leandro Peña 《Molecular Plant Pathology》2015,16(4):388-399
Citrus tristeza virus (CTV) is phloem restricted in natural citrus hosts. The 23‐kDa protein (p23) encoded by the virus is an RNA silencing suppressor and a pathogenicity determinant. The expression of p23, or its N‐terminal 157‐amino‐acid fragment comprising the zinc finger and flanking basic motifs, driven by the constitutive 35S promoter of cauliflower mosaic virus, induces CTV‐like symptoms and other aberrations in transgenic citrus. To better define the role of p23 in CTV pathogenesis, we compared the phenotypes of Mexican lime transformed with p23‐derived transgenes from the severe T36 and mild T317 CTV isolates under the control of the phloem‐specific promoter from Commelina yellow mottle virus (CoYMV) or the 35S promoter. Expression of the constructs restricted to the phloem induced a phenotype resembling CTV‐specific symptoms (vein clearing and necrosis, and stem pitting), but not the non‐specific aberrations (such as mature leaf epinasty and yellow pinpoints, growth cessation and apical necrosis) observed when p23 was ectopically expressed. Furthermore, vein necrosis and stem pitting in Mexican lime appeared to be specifically associated with p23 from T36. Phloem‐specific accumulation of the p23Δ158–209(T36) fragment was sufficient to induce the same anomalies, indicating that the region comprising the N‐terminal 157 amino acids of p23 is responsible (at least in part) for the vein clearing, stem pitting and, possibly, vein corking in this host. 相似文献
106.
Imanishi L Vayssières A Franche C Bogusz D Wall L Svistoonoff S 《Molecular plant-microbe interactions : MPMI》2011,24(11):1317-1324
Among infection mechanisms leading to root nodule symbiosis, the intercellular infection pathway is probably the most ancestral but also one of the least characterized. Intercellular infection has been described in Discaria trinervis, an actinorhizal plant belonging to the Rosales order. To decipher the molecular mechanisms underlying intercellular infection with Frankia bacteria, we set up an efficient genetic transformation protocol for D. trinervis based on Agrobacterium rhizogenes. We showed that composite plants with transgenic roots expressing green fluorescent protein can be specifically and efficiently nodulated by Frankia strain BCU110501. Nitrogen fixation rates and feedback inhibition of nodule formation by nitrogen were similar in control and composite plants. In order to challenge the transformation system, the MtEnod11 promoter, a gene from Medicago truncatula widely used as a marker for early infection-related symbiotic events in model legumes, was introduced in D. trinervis. MtEnod11::GUS expression was related to infection zones in root cortex and in the parenchyma of the developing nodule. The ability to study intercellular infection with molecular tools opens new avenues for understanding the evolution of the infection process in nitrogen-fixing root nodule symbioses. 相似文献
107.
Diana?Negr?o?Cavalcanti Meire-Anne?Rezende?de?Oliveira Joel?Campos?De-Paula Leandro?Silva?Barbosa Tamara?Fogel Marcelo?Alves?Pinto Izabel?Christina?Nunes?de?Palmer Paix?o Valéria?Laneuville?TeixeiraEmail author 《Journal of applied phycology》2011,23(5):873-876
This study evaluated the variability in the production of an HIV-1 antiviral diterpene in individuals of Dictyota menstrualis throughout reproductive stages. The brown alga Dictyota has an isomorphic biphasic life cycle. The quantification of the active principle by GC–FID indicated a greater production
of the diterpene in the female gametophytic phase (42.11 ppm). However, these individuals had the highest variation between
individuals (standard deviation of 68.20 ppm in the range from 0.39 to 227 ppm). Sporophytic individuals showed less variability.
This variability in the production of the antiviral diterpene is important to the development of future antiviral drugs. 相似文献
108.
Kudryashev M Cyrklaff M Alex B Lemgruber L Baumeister W Wallich R Frischknecht F 《Cellular microbiology》2011,13(5):731-741
Some Borrelia species are the causative agents of tick-borne Lyme disease responsible for different disabilities depending on species and hosts. Borrelia are highly motile bacterial cells, and light microscopy shows that these spirochetes can associate with each other during movement. Using cryo-electron tomography, we observed closely associated Borrelia cells. Some of these showed a single outer membrane surrounding two longitudinally arranged cytoplasmic cylinders. We also observed fusion of two cytoplasmic cylinders and differences in the surface layer density of fused spirochetes. These processes could play a role in the interaction of Borrelia species with the host's immune system. 相似文献
109.
Kaiser M Grünspan LD Costa TD Tasso L 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(30):3639-3644
A simple, accurate and precise high-performance liquid chromatographic method with fluorescence detection was developed and validated for the determination of gemifloxacin (GEM) in rat plasma using furosemide as internal standard (I.S.). Plasma samples were pretreated by direct deproteinization and all samples and standard solutions were chromatographed at 45°C using triethylamine solution (0.5%, v/v, pH 3.0±0.1), methanol and acetonitrile (63:30:7, v/v/v) as the mobile phase. Chromatographic resolution was achieved using a RP-C(18) column (Atlantis, Waters, 150 mm × 4.6 mm, 5 μm) at a flow rate of 1.0 mL min(-1) and an injection volume of 30 μL. The analytes were measured by fluorescence detection with excitation and emission wavelengths of 344 nm and 399 nm, respectively. The retention times for GEM and I.S. were approximately 7.5 and 12.6 min, respectively. The lower limit of quantitation (LLOQ) was 20 ng mL(-1) and the calibration curves were linear over a concentration range of 20-5000 ng mL(-1). The intra- and inter-day precisions, expressed by relative standard deviation (R.S.D.) were lower than 6.24% and 4.49%, respectively. The accuracy ranged from 91.3% to 112% and from 98.8% to 106% for the lower and upper limit of quantitation of the calibration curve, respectively. Ratio of peak area of analyte to I.S. was used for quantification of plasma samples. No interferences from endogenous substances were found. The recovery of GEM and I.S. from plasma was greater than 90%. Drug stability in plasma was shown at room temperature for 4h, after three freeze-thaw cycles for 24h, in freezer at -80°C for 60 days, and in the autosampler after processing for 12h. The utility of the assay was confirmed by the successful analysis of plasma samples from GEM pharmacokinetics studies in the rats after intravenous administration. 相似文献
110.
Several Gram-negative bacterial pathogens have developed type III secretion systems (T3SSs) to deliver virulence proteins
directly into eukaryotic cells in a process essential for many diseases. The type III secretion processes require customized
chaperones with high specificity for binding partners, thus providing the secretion to occur. Due to the very low sequence
similarities among secretion chaperones, annotation and discrimination of a great majority of them is extremely difficult
and a task with low scores even if genes are encountered that codify for small (<20 kDa) proteins with low pI and a tendency
to dimerise. Concerning about this, herein, we present structural features on two hypothetical T3SSs chaperones belonging
to plant pathogen Xanthomonas axonopodis pv. citri and suggest how low resolution models based on Small Angle X-ray Scattering patterns can provide new structural insights
that could be very helpful in their analysis and posterior classification. 相似文献