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排序方式: 共有1409条查询结果,搜索用时 109 毫秒
61.
This study was aimed to examine the risk of chronic arsenic (As) exposure for the residents living in Nui Phao, Thai Nguyen in the northern Vietnam. Groundwater, vegetables, human hair, and nail samples were collected from volunteers living in Nui Phao. The results revealed that 75% of the groundwater samples had As exceeding the World Health Organization (WHO) drinking water guideline of 10 µg L?1. The result of As concentration for most of the vegetable samples was greater than the WHO/FAO safe (0.1?mg kg?1). The result of hair and nail samples in this study showed that 3.5 and 20% of the samples had As concentration exceeding the level of As toxicity in hair and nails, respectively. The result of health risks indicated that the potential health risk of As contamination is greater for groundwater than vegetables. The total hazard quotient (HQ) value through vegetables ingestion and drinking water exceeded 1.0 suggesting potential health risk for local residents. The calculation of potential carcinogenic risk through both consumption of vegetables and drinking water was low cancer risk in adults. Other food sources and the exposure pathways are needed to exactly assess health risks in this area.  相似文献   
62.
S.B. Akben 《IRBM》2019,40(6):355-360
Breast cancer is a dangerous type of cancer that spreads into other organs over time. Therefore, medical studies are being done for the early diagnosis by means of the anthropometric data and blood analysis values besides the mammographic and histological findings. However, medical studies have identified only cancer-related values but the value ranges indicating the cancer have not been determined yet. Concurrently the automated diagnostic systems are being developed to assist medical specialists in biomedical engineering studies. The range of values or boundaries indicating the cancer are automatically determined in biomedical methods, but only the diagnostic result is presented. Because of this, biomedical studies don't provide enough opportunity for medical experts to evaluate the relationship between values and result. In this study, decision trees that is one of data mining method was applied to anthropometric data and blood analysis values to complete the mentioned deficiencies in breast cancer diagnosis aiming studies. The determined value ranges were also presented visually to medical experts understand them easily. The proposed diagnostic system has accuracy rate up to 90.52% and provides value ranges indicating the breast cancer as well as mathematically presents the relations between the values and cancer.  相似文献   
63.
Mutations in the DIIS4-S5 linker and DIIS5 have identified hotspots of pyrethroid and DDT interaction with the Drosophila para sodium channel. Wild-type and mutant channels were expressed in Xenopus oocytes and subjected to voltage-clamp analysis. Substitutions L914I, M918T, L925I, T929I and C933A decreased deltamethrin potency, M918T, L925I and T929I decreased permethrin potency and T929I, L925I and I936V decreased fenfluthrin potency. DDT potency was unaffected by M918T, but abolished by T929I and reduced by L925I, L932F and I936V, suggesting that DIIS5 contains at least part of the DDT binding domain. The data support a computer model of pyrethroid and DDT binding.  相似文献   
64.
Straede A  Heinisch JJ 《FEBS letters》2007,581(23):4495-4500
Cell wall integrity signalling in Saccharomyces cerevisiae provides a model for the regulation of fungal wall biosynthesis. Chimers of the major plasma membrane sensors Wsc1 and Mid2 fused to GFP have been employed to show that intracellular and membrane distribution is only dependent on a membrane-anchored cytoplasmic tail. Phenotypic analyses of chimeric sensors in an isogenic Deltamid2 Deltawsc1 double deletion strain indicate that this tail, provided that it is linked to an extracellular domain, also determines the cellular response to different surface stresses to a large extent.  相似文献   
65.
Routinely performed painful procedures are of increasing interest and, in 2001 (Royal Order, May 17), Belgium prohibited docking in several vertebrates including horses. In 2004, opponents to this decision submitted a Bill (Doc51 0969/001) to Parliament, intending to obtain derogation for Belgian draught horses, which were traditionally docked. The Animal Welfare Council of Belgium, an official body advising the Minister of Public Health, was asked to evaluate this complex question, including biological, ethical and socio-economic aspects, on the basis of the available peer-reviewed studies. In this context, this study reviews legal aspects (overview of the European legislation), zootechnic aspects (uses of the Belgian draught horse) and biological aspects (pain potentially related to docking; horses' welfare linked to insect harassment and hygiene, communication and reproduction) of tail docking in draught horses. We conclude that (1) there is no benefit for horses in tail docking, including Belgian draught horses, (2) potential advantages of docking are essentially in favour of humans and these advantages could be scrupulously re-evaluated, taking into account practices of other countries. Therefore, there is no need to dock any horse other than for veterinary reasons.  相似文献   
66.
关联分析在作物种质资源分子评价中的应用   总被引:8,自引:1,他引:7  
发掘优异基因资源是作物种质资源分子评价的重要部分,对作物育种尤其是分子育种具有非常重要的实践意义。基于连锁不平衡(LD)的关联分析是基因发掘也是等位基因发掘的有效途径。本文系统介绍了关联分析的基本理论、策略、特点及应用现状,并探讨了其在作物种质资源新(等位)基因发掘中的发展趋势及展望。可以预见,与传统QTL作图及功能基因组学相整合的关联分析必将大大加快我国作物种质资源的研究进程,实现我国种质资源优势向基因资源优势的转变。  相似文献   
67.
Understanding the mechanism of the protein stability change is one of the most challenging tasks. Recently, the prediction of protein stability change affected by single point mutations has become an interesting topic in molecular biology. However, it is desirable to further acquire knowledge from large databases to provide new insights into the nature of them. This paper presents an interpretable prediction tree method (named iPTREE-2) that can accurately predict changes of protein stability upon mutations from sequence based information and analyze sequence characteristics from the viewpoint of composition and order. Therefore, iPTREE-2 based on a regression tree algorithm exhibits the ability of finding important factors and developing rules for the purpose of data mining. On a dataset of 1859 different single point mutations from thermodynamic database, ProTherm, iPTREE-2 yields a correlation coefficient of 0.70 between predicted and experimental values. In the task of data mining, detailed analysis of sequences reveals the possibility of the compositional specificity of residues in different ranges of stability change and implies the existence of certain patterns. As building rules, we found that the mutation residues in wild type and in mutant protein play an important role. The present study demonstrates that iPTREE-2 can serve the purpose of predicting protein stability change, especially when one requires more understandable knowledge.  相似文献   
68.
Actinomycetes are one of the most valuable sources of natural products with industrial and medicinal importance. After more than half a century of exploitation, it has become increasingly challenging to find novel natural products with useful properties as the same known compounds are often repeatedly re-discovered when using traditional approaches. Modern genome mining approaches have led to the discovery of new biosynthetic gene clusters, thus indicating that actinomycetes still harbor a huge unexploited potential to produce novel natural products. In recent years, innovative synthetic biology and metabolic engineering tools have greatly accelerated the discovery of new natural products and the engineering of actinomycetes. In the first part of this review, we outline the successful application of metabolic engineering to optimize natural product production, focusing on the use of multi-omics data, genome-scale metabolic models, rational approaches to balance precursor pools, and the engineering of regulatory genes and regulatory elements. In the second part, we summarize the recent advances of synthetic biology for actinomycetal metabolic engineering including cluster assembly, cloning and expression, CRISPR/Cas9 technologies, and chassis strain development for natural product overproduction and discovery. Finally, we describe new advances in reprogramming biosynthetic pathways through polyketide synthase and non-ribosomal peptide synthetase engineering. These new developments are expected to revitalize discovery and development of new natural products with medicinal and other industrial applications.  相似文献   
69.
We showed previously that large domain exchanges between the bradykinin B2 (BKB2) and angiotensin II type 1a (AT1a) receptors can result in functional hybrids. However, when we proceeded to exchange the entire bradykinin B2 receptor (BKB2R) C-terminal tail with the AT1aR C-terminus, the hybrid, while continuing to bind BK and be endocytosed as wild type (WT) BKB2R, lost much of its ability to activate phosphatidylinositol (PI) turnover or the release of arachidonic acid (ARA). In this study, we constructed chimeric receptors within the proximal C-terminus between the BKB2R and AT1aR or bradykinin B1 receptor (BKB1R). The mutant and WT receptor cDNAs were stably transfected into Rat-1 cells. Also, point mutations were generated to evaluate the role of the individual residues within this region. These chimeric studies revealed that the proximal portion of the BKB2R C-tail is crucial for G protein-linked BKB2R functions. This region could not be swapped with the AT1aR to obtain a BK activated PI turnover or ARA release. Further studies demonstrated that the distal portion (325-330) of this region is exchangeable; however, the middle portion (317-324) is not. Small motif exchanges within this section identified the KSR and EVY motifs as crucial for G(alphaq), G(alphai) related signaling of the BKB2R. Point mutations then showed that the charged amino acids K317, R319, and E320 are the residues critical for linking to PI turnover and ARA release. However, these proximal chimeras showed normal receptor uptake. Interestingly, while apparently not activating G protein-linked signaling, the proximal tail AT1aR exchange mutant and the entire C-terminus exchange hybrid continued to cause a substantial bradykinin effected increase in connective tissue growth factor (CTGF) mRNA level, as WT BKB2R.  相似文献   
70.
A vast number of lakes developed in the abandoned opencast lignite mines of Lusatia (East Germany) contain acidic waters (mmolSm–2a). Potential Fe(III) reduction measured by the accumulation of Fe(II) during anoxic incubation yielded similar rates in both types of sediments, however, the responses towards the supplementation of Fe(III) and organic carbon were different. Sulfate reduction rates estimated with 35S-radiotracer were much lower in the slightly acidic sediment than in the pH-neutral sediment (156 v.s. 738mmolSO4 2–m–2a–1). However, sulfate reduction rates were increased by the addition of organic carbon. Severe limitation of sulfate-reducing bacteria under acidic conditions was also reflected by low most probable numbers (MPN). High MPN of acidophilic iron- and sulfur-oxidizing bacteria in acidic sediments indicated a high reoxidation potential. The results show that potentials for reductive processes are present in acidic sediments and that these are determined mainly by the availability of oxidants and organic matter.  相似文献   
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