全文获取类型
收费全文 | 440篇 |
免费 | 20篇 |
专业分类
460篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 13篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 13篇 |
2018年 | 26篇 |
2017年 | 6篇 |
2016年 | 24篇 |
2015年 | 21篇 |
2014年 | 26篇 |
2013年 | 34篇 |
2012年 | 34篇 |
2011年 | 30篇 |
2010年 | 19篇 |
2009年 | 14篇 |
2008年 | 28篇 |
2007年 | 23篇 |
2006年 | 20篇 |
2005年 | 29篇 |
2004年 | 19篇 |
2003年 | 8篇 |
2002年 | 5篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 4篇 |
1971年 | 1篇 |
排序方式: 共有460条查询结果,搜索用时 0 毫秒
61.
The interaction of prostaglandin E2 (PGE2) and aspirin with the responses to peri-arterial stimulation (PS) and norepinephrine (NE) was studied in the isolated kidney of rabbit perfused through the renal artery at constant flow with Krebs' solution. NE and PS increased vascular perfusion pressure of kidney and caused a contraction on the isolated rabbit aortic strip superfused with the effluent from kidney. Addition of PGE2 to the perfusion medium decreased the PS-induced rise in perfusion pressure without changing the effect of exogenous NE. In contrast, addition of aspirin to the perfusion medium induced a potentiation of the response to PS but not to NE. These results suggest that PGE2 modulates the effect of PS probably by inhibiting the release of NE from sympathetic nerve endings. 相似文献
62.
We investigated the effect of α-melanocyte stimulating hormone (α-MSH) on endotoxin-induced intestinal inflammation and the role of nitric oxide and prostaglandins in this response. α-MSH treatment (25 μg/rat, intraperitoneally (i.p.); twice daily) reduced the severity of the lesions macroscopically and microscopically. This protective effect was found to be confined mainly to the distal ileum. These lesions were reversed by pretreatment with the non-selective COX inhibitor indomethacin (10 mg/kg, subcutaneously (s.c.)) but not by the selective COX-2 inhibitor nimesulide (3 mg/kg, s.c.), the NO donor sodium nitroprusside (4 mg/kg, i.v.) or the iNOS inhibitor dexamethasone (3 mg./kg, i.p.) at macroscopic level and reversed by Indo or Dex at microscopic level. Increased peroxidase activity -index of tissue neutrophil infiltration- in the distal ileum of LPS-treated rats was decreased by α-MSH and this effect was reversed by pretreatment with Indo. In conclusion, the neuropeptide α-MSH has a beneficial effect on endotoxin-induced distal intestinal lesions by a mechanism which probably involves nitric oxide and COX-1 derived prostaglandins. 相似文献
63.
Gunjal Garg Ali Yilmaz Praveen Kumar Onur Turkoglu David G. Mutch Matthew A. Powell Barry Rosen Ray O. Bahado-Singh Stewart F. Graham 《Metabolomics : Official journal of the Metabolomic Society》2018,14(12):154
Introduction
Epithelial ovarian cancer (EOC) remains the leading cause of death from gynecologic malignancies and has an alarming global fatality rate. Besides the differences in underlying pathogenesis, distinguishing between high grade (HG) and low grade (LG) EOC is imperative for the prediction of disease progression and responsiveness to chemotherapy.Objectives
The aim of this study was to investigate, the tissue metabolome associated with HG and LG serous epithelial ovarian cancer.Methods
A combination of one dimensional proton nuclear magnetic resonance (1D H NMR) spectroscopy and targeted mass spectrometry (MS) was employed to profile the tissue metabolome of HG, LG serous EOCs, and controls.Results
Using partial least squares-discriminant analysis, we observed significant separation between all groups (p?<?0.05) following cross validation. We identified which metabolites were significantly perturbed in each EOC grade as compared with controls and report the biochemical pathways which were perturbed due to the disease. Among these metabolic pathways, ascorbate and aldarate metabolism was identified, for the first time, as being significantly altered in both LG and HG serous cancers. Further, we have identified potential biomarkers of EOC and generated predictive algorithms with AUC (CI)?=?0.940 and 0.929 for HG and LG, respectively.Conclusion
These previously unreported biochemical changes provide a framework for future metabolomic studies for the development of EOC biomarkers. Finally, pharmacologic targeting of the key metabolic pathways identified herein could lead to novel and effective treatments of EOC.64.
Sebastian Ocklenburg Wanda M. Gerding Maximilian Raane Larissa Arning Erhan Genç Jörg T. Epplen Onur Güntürkün Christian Beste 《Molecular neurobiology》2018,55(10):7691-7700
Molecular neurobiological factors determining corpus callosum physiology and anatomy have been suggested to be one of the major factors determining functional hemispheric asymmetries. Recently, it was shown that allelic variations in two myelin-related genes, the proteolipid protein 1 gene PLP1 and the contactin 1 gene CNTN1, are associated with differences in interhemispheric integration. Here, we investigated whether three single nucleotide polymorphisms that were associated with interhemispheric integration via the corpus callosum in a previous study also are relevant for functional hemispheric asymmetries. To this end, we tested more than 900 healthy adults with the forced attention dichotic listening task, a paradigm to assess language lateralization and its modulation by cognitive control processes. Moreover, we used the line bisection task, a paradigm to assess functional hemispheric asymmetries in spatial attention. We found that a polymorphism in PLP1, but not CNTN1, was associated with performance differences in both tasks. Both functional hemispheric asymmetries and their modulation by cognitive control processes were affected. These findings suggest that both left and right hemisphere dominant cognitive functions can be modulated by allelic variation in genes affecting corpus callosum structure. Moreover, higher order cognitive processes may be relevant parameters when investigating the molecular basis of hemispheric asymmetries. 相似文献
65.
66.
Abdullah Karaer Gorkem Tuncay Emrullah Tanrikut Onur Ozgul 《Biological trace element research》2018,184(1):42-46
The purpose of this study is to investigate the relationship between the blood level of cadmium and the occurrence of ectopic pregnancy. Forty-one (41) case patients with ectopic pregnancy and 41 uncomplicated intrauterine pregnant patients as controls were recruited. The concentrations of cadmium (Cd) were measured from blood samples using atomic absorption spectrometry. The cases and controls were similar in age, body mass index, and smoking habits. The median blood level of Cd was 0.32 μg/l (interquartile range [IQR] 0.00–0.71) in the women with ectopic pregnancies and 0.34 μg/l (IQR 0.09–0.59) in the controls. There was no significant association between blood cadmium levels and ectopic pregnancy. 相似文献
67.
Mehtap Yıldız Ercan Ekbiç Eftal Düzyaman Sedat Serçe Kazım Abak 《Journal of plant biochemistry and biotechnology.》2016,25(3):234-244
Okra is an important vegetable crop that provides a significant portion of vitamins and minerals for populations in several countries. Okra has been cultivated in Turkey for centuries, and was likely introduced by the Arabs from Africa in ancient times. In this study, we aimed to clarify the genetic variation within 35 Turkish okra germplasm, by comparing it against 25 different genotypes from India, Africa, and the United States, using 30 morphological characters and 19 sequence-related amplified polymorphism (SRAP) primer combinations. Fruit, leaf, and stem color were the primary characteristics to distinguish the okra accessions. Those features, among 30 individual phenotypic traits, explained 42 % of phenotypic variation in the first three axes of the principal component analysis (PCA) with leaf shape, flower size, cotyledon length, fruit-surface angularity, cotyledon width, and petal color. Phenotypic observation results showed that while 1051 Togo (10.76), Red Wonder (7.99), TR-05-1 (7.2), 1159 Togo (7.17), and Red Balady (7.15) were found to be more divergent accessions, Cajun Queen (5.06), Perkins Spineless (5.09), Jade (5.18), TR-01-1 (5.2), and DLGG (5.32) were the closest okra accessions. According to phenotypic data, Turkish okra accessions were located adjacent to the Indian, American, and African okra accessions in clusters three and four. However, marker data showed that African okra possessed a more distinct form compared to the other okra germplasms. Nineteen SRAP primer combinations produced 92 bands and 29 (31.5 %) of them were found to be polymorphic among okra accessions. 1051 Togo was found to be the most divergent accession in phenotypic observation. 相似文献
68.
Predicting the impact of mutations on the specific activity of Bacillus thermocatenulatus lipase using a combined approach of docking and molecular dynamics 下载免费PDF全文
Onur Yukselen Emel Timucin Ugur Sezerman 《Journal of molecular recognition : JMR》2016,29(10):466-475
Lipases are important biocatalysts owing to their ability to catalyze diverse reactions with exceptional substrate specificities. A combined docking and molecular dynamics (MD) approach was applied to study the chain‐length selectivity of Bacillus thermocatenulatus lipase (BTL2) towards its natural substrates (triacylglycerols). A scoring function including electrostatic, van der Waals (vdW) and desolvation energies along with conformational entropy was developed to predict the impact of mutation. The native BTL2 and its 6 mutants (F17A, V175A, V175F, D176F, T178V and I320F) were experimentally analyzed to determine their specific activities towards tributyrin (C4) or tricaprylin (C8), which were used to test our approach. Our scoring methodology predicted the chain‐length selectivity of BTL2 with 85.7% (6/7) accuracy with a positive correlation between the calculated scores and the experimental activity values (r = 0.82, p = 0.0004). Additionally, the impact of mutation on activity was predicted with 75% (9/12) accuracy. The described study represents a fast and reliable approach to accurately predict the effect of mutations on the activity and selectivity of lipases and also of other enzymes. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
69.
Ibrahim Celik Mehmet Ali Sogut Ercan Ozkaynak Sami Doganlar Anne Frary 《Molecular breeding : new strategies in plant improvement》2016,36(10):137
Natural root-knot nematode resistance genes are unique resources to control this major pest in pepper (Capsicum annuum). Although four genes (Me1, Me3, Me7 and N) conferring broad-spectrum resistance were mapped to a cluster in a 28-cm interval on chromosome P9, limited markers targeting this region were available. In the present study, the Me-gene cluster was structurally annotated for resistance genes to develop markers targeting the N gene. As a result, the Me-gene cluster (4.07 Mb in size) was found to contain three resistance gene hotspots. In addition, a SSR maker tightly linked to the N gene (0.8 cM away) was developed for marker-assisted selection in pepper. 相似文献
70.
Effects of brassinosteroids on barley root growth,antioxidant system and cell division 总被引:1,自引:0,他引:1
Gonul Kartal Aslihan Temel Ercan Arican Nermin Gozukirmizi 《Plant Growth Regulation》2009,58(3):261-267
Homobrassinolide (HBR), which is one of the most biologically active forms of Brassinosteroids (BRs), was used to examine
the potential effects of hormone on root germination, antioxidant system enzymes and cell division of barley (Hordeum vulgare L.). Seeds were germinated between filter papers in 0.1, 0.5 and 1.0 μM HBR-supplemented distilled water for 48 h at dark
with their controls. HBR application increased especially the primary root growth significantly with increasing concentrations
when compared with the control materials and reached two fold increase in 1.0 μM HBR treated material. Treated and untreated
control group roots were fixed in 1:3 aceto-alcohol and aceto-orcein preparations were made. Roots treated with HBR showed
more mitotic activity, mitotic abnormalities and significant enlargements at the root tips when compared with control material.
HBR application decreased total soluble protein content, superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6) and peroxidase
(EC 1.11.1.11) activities significantly at 1.0 μM HBR concentration. Data presented here is one of the first detailed analyses
of HBR effect on barley root development. 相似文献