全文获取类型
收费全文 | 220篇 |
免费 | 5篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 12篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 8篇 |
2014年 | 21篇 |
2013年 | 19篇 |
2012年 | 22篇 |
2011年 | 9篇 |
2010年 | 9篇 |
2009年 | 13篇 |
2008年 | 16篇 |
2007年 | 8篇 |
2006年 | 12篇 |
2005年 | 13篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有225条查询结果,搜索用时 15 毫秒
211.
Farzana PERVEEN 《Entomological Science》2008,11(1):111-121
Sublethal doses (LD10: 1.00 ng larva?1; or LD30: 3.75 ng larva?1) of chlorfluazuron were applied topically to the cuticles of newly moulted fifth instars of the common cutworm, Spodoptera litura (F.) (Lepidoptera, Noctuidae). During mating, the treated males transferred spermatophores of a significantly lower weight into females. The weight of spermatophores transferred by LD30‐treated males was significantly lower than the weight of spermatophores transferred by LD10‐treated males, which was in turn significantly lower than the weight of spermatophores transferred by untreated males. The transfer of spermatophores was delayed by 5–15 min in LD10‐ and LD30‐treated males. However, mating duration was not affected by chlorfluazuron treatment. The transfer of spermatozoa was also delayed by 5–10 min in LD10‐ and LD30‐treated females. Polygynous male adults mated an average of ten times during their lifespan of 11–13 days when paired every day with a new virgin female of the same age. The number of matings per polygynous male was not affected by chlorfluazuron treatment, but the first mating was delayed by 1 day. The number of inseminated sperm found in the spermatophore averaged 10.3 (± 2.1) × 105 over the lifespan of a male, in which the number of eupyrene sperm was 5.4 (± 1.1) × 105. The number of inseminated eupyrene sperm decreased by 66% and 88%, respectively, in LD10‐ and LD30‐treated males. No significant reduction in the number of inseminated eupyrene sperm was observed when females were treated with LD10 or LD30 doses, nor was there a significant reduction when both sexes were treated with the LD10 or LD30 doses relative to treatment of males with the same doses. The ratio of inseminated eupyrene to apyrene sperm was not affected by chlorfluazuron treatment. 相似文献
212.
Anissa Abi-Dargham Scott J. Moeller Farzana Ali Christine DeLorenzo Katharina Domschke Guillermo Horga Amandeep Jutla Roman Kotov Martin P. Paulus Jose M. Rubio Gerard Sanacora Jeremy Veenstra-VanderWeele John H. Krystal 《World psychiatry》2023,22(2):236-262
The field of psychiatry is hampered by a lack of robust, reliable and valid biomarkers that can aid in objectively diagnosing patients and providing individualized treatment recommendations. Here we review and critically evaluate the evidence for the most promising biomarkers in the psychiatric neuroscience literature for autism spectrum disorder, schizophrenia, anxiety disorders and post-traumatic stress disorder, major depression and bipolar disorder, and substance use disorders. Candidate biomarkers reviewed include various neuroimaging, genetic, molecular and peripheral assays, for the purposes of determining susceptibility or presence of illness, and predicting treatment response or safety. This review highlights a critical gap in the biomarker validation process. An enormous societal investment over the past 50 years has identified numerous candidate biomarkers. However, to date, the overwhelming majority of these measures have not been proven sufficiently reliable, valid and useful to be adopted clinically. It is time to consider whether strategic investments might break this impasse, focusing on a limited number of promising candidates to advance through a process of definitive testing for a specific indication. Some promising candidates for definitive testing include the N170 signal, an event-related brain potential measured using electroencephalography, for subgroup identification within autism spectrum disorder; striatal resting-state functional magnetic resonance imaging (fMRI) measures, such as the striatal connectivity index (SCI) and the functional striatal abnormalities (FSA) index, for prediction of treatment response in schizophrenia; error-related negativity (ERN), an electrophysiological index, for prediction of first onset of generalized anxiety disorder, and resting-state and structural brain connectomic measures for prediction of treatment response in social anxiety disorder. Alternate forms of classification may be useful for conceptualizing and testing potential biomarkers. Collaborative efforts allowing the inclusion of biosystems beyond genetics and neuroimaging are needed, and online remote acquisition of selected measures in a naturalistic setting using mobile health tools may significantly advance the field. Setting specific benchmarks for well-defined target application, along with development of appropriate funding and partnership mechanisms, would also be crucial. Finally, it should never be forgotten that, for a biomarker to be actionable, it will need to be clinically predictive at the individual level and viable in clinical settings. 相似文献
213.
214.
The Protein Journal - Phenylalanine ammonia lyase (PAL) catalyzes the deamination of phenylalanine to cinnamic acid and ammonia. It plays a crucial role in the formation of secondary metabolites... 相似文献
215.
Tahir Iqbal Farooq Rashid Perveen Akhter Wasim Yawar 《Soil & Sediment Contamination》2012,21(6):720-731
The diffusive transport of 137Cs, 90Sr, and 60Co in the clay of a radioactive waste disposal site at PINSTECH was studied to assess the safety of the underlying permeable zone against the release of these radionuclides from buried waste containers in the clay. Diffusion coefficients of these radionuclides were estimated by reservoir to sediment diffusion method via their stable counterparts in a laboratory experiment. A curve-fitting procedure was applied on the measured concentration-time profiles of the reservoir using the one-dimensional solute transport equation with a nonlinear least squares technique. Distribution coefficients were determined in laboratory batch experiments. Diffusive transport simulations were performed with the estimated values of diffusion coefficients and distribution coefficients using the one-dimensional solute transport equation describing Fickian diffusion, equilibrium adsorption, and radioactive decay. The transport simulation results showed that 137Cs, 90Sr, and 60Co will transport distances of 4.33, 3.77, and 1.51 meters, respectively, in the clay before their activity concentrations will drop to clearance levels set by the International Atomic Energy Agency (IAEA), below which the waste is treated as non-radioactive. This showed that concentrations more than clearance levels will not be able to transport to the permeable zone at a minimum depth of seven meters from the ground surface if the waste containers are disposed in a trench below which a clay layer with a thickness of 4.33 meters or more exists. 相似文献
216.
Fatimah Al-Otibi Kahkashan Perveen Noura A. Al-Saif Raedah I. Alharbi Najat A. Bokhari Gadah Albasher Rana M. Al-Otaibi Manal A. Al-Mosa 《Saudi Journal of Biological Sciences》2021,28(4):2229-2235
Cheeseweed mallow (Malva parviflora L.) was used to biosynthesize silver nanoparticles. The biosynthesized silver nanoparticles were classified by UV–vis Spectroscopy and Fourier-Transform Infrared Spectroscopy (FT-IR). The shape and size distribution were visualized by Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FE-SEM), and Zeta potential analysis. The chemical composition of M. parviflora leaf extract was identified by Gas Chromatography and Mass Spectroscopy (GC/MS). Finally, in vitro antifungal assay was done to assess the potential of biosynthesized silver nanoparticles and crude leaf extract of M. parviflora for inhibiting the mycelial growth of phytopathogenic fungi. The UV–vis analysis manifests the formation of silver nanoparticles. FTIR analysis established that chemicals of the leaf extract stabilized the biosynthesized silver nanoparticles by binding with the free silver ions. The TEM, FE-SEM and zeta potential analyzer confirmed that the biosynthesized silver nanoparticles were mostly spherical with an average diameter of 50.6 nm. The biosynthesized silver nanoparticles and leaf extract of M. parviflora effectively mitigate the mycelial growth of Helminthosporium rostratum, Fusarium solani, Fusarium oxysporum, and Alternaria alternata. The maximum reduction in mycelial growth by biosynthesized nanoparticles was observed against H. rostratum (88.6%). Whereas, the leaf extract of M. parviflora was most effective against F. solani (65.3%). Thus, the biosynthesis of nanoparticle assisted by M. parviflora is a feasible and eco-friendly method for the synthesis of silver nanoparticles. Further the silver nanoparticles and leaf extract of M. parviflora could be explored for the development of the fungicide. 相似文献
217.
218.
Bhawana Mishra Rajender S. Sangwan Smrati Mishra Jyoti S. Jadaun Farzana Sabir Neelam S. Sangwan 《Protoplasma》2014,251(5):1031-1045
Withania somnifera is one of the most important medicinal plant and is credited with various pharmacological activities. In this study, in vitro multiple shoot cultures were exposed to different concentrations (5–300 μM) of cadmium (Cd) as cadmium sulphate to explore its ability to accumulate the heavy metal ion and its impact on the metabolic status and adaptive responses. The results showed that supplemental exposure to Cd interfered with N, P, and K uptake creating N, P, and K deficiency at higher doses of Cd that also caused stunting of growth, chlorosis, and necrosis. The study showed that in vitro shoots could markedly accumulate Cd in a concentration-dependent manner. Enzymatic activities and isozymic pattern of catalase, ascorbate peroxidase, guaiacol peroxidase, peroxidase, glutathione-S-transferase, glutathione peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase were altered substantially under Cd exposure. Sugar metabolism was also markedly modulated under Cd stress. Various other parameters including contents of photosynthetic pigments, phenolics, tocopherol, flavonoids, reduced glutathione, nonprotein thiol, ascorbate, and proline displayed major inductive responses reflecting their protective role. The results showed that interplay of enzymatic as well as nonenzymatic responses constituted a system endeavor of tolerance of Cd accumulation and an efficient scavenging strategy of its stress implications. 相似文献
219.
220.
Saurabh Prabhu Zaheer Akbar Frederick Harris Katherine Karakoula Robert Lea Farzana Rowther Tracy Warr Timothy Snape 《Bioorganic & medicinal chemistry》2013,21(7):1918-1924
A series of related 2-arylindoles have been evaluated for their anticancer activity against a range of glioblastoma cell lines using a number of different cell-based assays to determine cell viability after treatment with the compounds. The best indoles, which showed comparable activity to cisplatin against a U87MG cell line in the MTS assay, were taken forward and initial studies suggest that their mechanism of action is consistent with the generation of reactive oxygen species followed by autophagic cell death. Furthermore, activity was also observed in glioblastoma short-term cell cultures for the best lead compound and in some cases gave low micromolar IC50s. 相似文献