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991.
Mingjun Liao Feihai Yu Minghua Song Shumin Zhang Jinzheng Zhang Ming Dong 《Acta Oecologica》2003,24(5-6):231-239
Clonal fragments of the stoloniferous herb Glechoma longituba were subjected to a complementary patchiness of light and soil nutrients including two spatially homogeneous treatments (SR–SR and IP–IP) and two spatially heterogeneous treatments (IP–SR and SR–IP). SR and IP indicate patches (shaded, rich) with low light intensity (shaded, S), high nutrient availability (rich, R) and patches (illuminated, poor) with high light intensity (illuminated, I) and low nutrient availability (poor, P), respectively. Plasticity of the species in root–shoot ratio, fitness-related traits (biomass, number of ramets and dry weight per ramet) and clonal morphological traits (length and specific length of stolon internodes, area and specific area of laminae, length and specific length of petioles) were experimentally examined. The aim is to understand adaptation of G. longituba to the environment with reciprocal patches of light and soil nutrients by plasticities both in root–shoot ratio and in (clonal) morphology. Our experiment revealed performance of the clonal fragments growing from patches with high light intensity and low soil nutrient availability into the adjacent opposite patches was increased in terms of the fitness-related characters. R/S ratio and clonal morphology were plastic. Meanwhile, the capture of light resource from the light-rich patches was enhanced while the capture of soil nutrients from either the nutrient-rich or the nutrient-poor patches was not. Analysis of cost and benefit disclosed positive effects of clonal integration on biomass production of ramets in the patches with low light intensity and high soil nutrient availability. These results suggest an existence of reciprocal translocation of assimilates and nutrients between the interconnected ramets. The reinforced performance of the clonal fragments seems to be related with specialization of clonal morphology in the species. 相似文献
992.
The promoter of the pepper pathogen-induced membrane protein gene CaPIMP1 was analyzed by an Agrobacterium-mediated transient expression assay in tobacco leaves. Several stress-related cis-acting elements (GT-1, W-box and ABRE) are located within the CaPIMP1 promoter. In tobacco leaf tissues transiently transformed with a CaPIMP1 promoter-β-glucuronidase (GUS) gene fusion, serially 5′-deleted CaPIMP1 promoters were differentially activated by Pseudomonas syringae pv. tabaci, ethylene, methyl jasmonate, abscisic acid, and nitric oxide. The −1,193 bp region of the CaPIMP1 gene promoter sequence exhibited full promoter activity. The −417- and −593 bp promoter regions were sufficient for GUS gene activation by ethylene and methyl jasmonate treatments, respectively. However, CaPIMP1 promoter sequences longer than −793 bp were required for promoter activation by abscisic acid and sodium nitroprusside treatments.
CaPIMP1 expression was activated in pepper leaves by treatment with ethylene, methyl jasmonate, abscisic acid, β-amino-n-butyric acid, NaCl, mechanical wounding, and low temperature, but not with salicylic acid. Overexpression of CaPIMP1 in Arabidopsis conferred hypersensitivity to mannitol, NaCl, and ABA during seed germination but not during seedling development. In contrast,
transgenic plants overexpressing CaPIMP1 exhibited enhanced tolerance to oxidative stress induced by methyl viologen during germination and early seedling stages.
These results suggest that CaPIMP1 expression may alter responsiveness to environmental stress, as well as to pathogen infection.
The nucleotide sequence data reported here has been deposited in the GenBank database under the accession number DQ356279. 相似文献
993.
Nitric oxide (NO) is an important molecule that acts in many tissues to regulate a diverse range of physiological processes.
It is becoming apparent that NO is a ubiquitous signal in plants. Since the discovery of NO emission by plants in the 1970s,
this gaseous compound has emerged as a major signalling molecule involved in multiple physiological functions. Research on
NO in plants has gained significant awareness in recent years and there is increasing indication on the role of this molecule
as a key-signalling molecule in plants. The investigations about NO in plants have been concentrated on three main fields:
The search of NO or any source of NO generation, effects of exogenous NO treatments, NO transduction pathways. However we
have limited information about signal transduction procedures by which NO interaction with cells results in altered cellular
activities. This article reviews recent advances in NO synthesis and its signalling functions in plants. First, different
sources and biosynthesis of NO in plants, then biological processes involving NO signalling are reviewed. NO signalling relation
with cGMP, protein kinases and programmed cell death are also discussed. Besides, NO signalling in plant defense response
is also examined. Especially NO signalling between animal and plant systems is compared. 相似文献
994.
观察人羊膜间充质干细胞(human amniotic mesenchymal stem cells,hAMSCs)成脂分化前后超微结构及其机械性能的变化,以期进一步了解hAMSCs在体外成脂分化的过程。用流式细胞仪分析细胞表面分子表达情况,油红O染色检测hAMSCs成脂分化情况,原子力显微镜观察(AFM)分化前后超微结构及机械性能的变化等。结果显示,流式细胞检测显示,CD34,CD45,HLA-DR,呈阴性表达,CD29,CD90呈阳性表达;油红O染色可见脂肪细胞胞质中有大小不等的圆性红色脂肪滴;AFM观察诱导后的hAMSCs表面有脂滴状的颗粒,粘弹力增大,硬度减小。运用AFM可以清晰观察到诱导前后形貌及机械性能变化。 相似文献
995.
Hisashi Mizutani Hideaki Sugawara Ashley M. Buckle Takeshi Sangawa Ken-ichi Miyazono Jun Ohtsuka Koji Nagata Tomoki Shojima Shohei Nosaki Yuqun Xu Delong Wang Xiao Hu Masaru Tanokura Kei Yura 《BMC structural biology》2017,17(1):4
Background
More than 7000 papers related to “protein refolding” have been published to date, with approximately 300 reports each year during the last decade. Whilst some of these papers provide experimental protocols for protein refolding, a survey in the structural life science communities showed a necessity for a comprehensive database for refolding techniques. We therefore have developed a new resource – “REFOLDdb” that collects refolding techniques into a single, searchable repository to help researchers develop refolding protocols for proteins of interest.Results
We based our resource on the existing REFOLD database, which has not been updated since 2009. We redesigned the data format to be more concise, allowing consistent representations among data entries compared with the original REFOLD database. The remodeled data architecture enhances the search efficiency and improves the sustainability of the database. After an exhaustive literature search we added experimental refolding protocols from reports published 2009 to early 2017. In addition to this new data, we fully converted and integrated existing REFOLD data into our new resource. REFOLDdb contains 1877 entries as of March 17th, 2017, and is freely available at http://p4d-info.nig.ac.jp/refolddb/.Conclusion
REFOLDdb is a unique database for the life sciences research community, providing annotated information for designing new refolding protocols and customizing existing methodologies. We envisage that this resource will find wide utility across broad disciplines that rely on the production of pure, active, recombinant proteins. Furthermore, the database also provides a useful overview of the recent trends and statistics in refolding technology development.996.
Hélène Pereira Jean-François Martin Charlotte Joly Jean-Louis Sébédio Estelle Pujos-Guillot 《Metabolomics : Official journal of the Metabolomic Society》2010,6(2):207-218
In order to study the effect of a diet on metabolites found in body fluids such as plasma, we have developed and validated
a UPLC/MS method. While methods using NMR have been well established to analyse different biological tissues, recent studies
have described robust untargeted UPLC-MS methods for plasma analysis. One major concern when profiling plasma is the presence
of an important quantity of proteins which have to be precipitated without any loss of metabolites prior to LC/MS analysis.
The utilization of untargeted approaches in nutritional metabolomics still suffers from the lack of identification of specific
biomarkers. We therefore suggest an alternative method still using a global approach but focusing at the same time on metabolites
previously described in human plasma in order to detect biomarkers of metabolic dysregulations. Thus, to fulfil our objectives,
analytical parameters were tested (i) the anticoagulant type for sample collection, (ii) the protein precipitation method
and (iii) UPLC/MS analytical conditions. Three protein precipitation methods and two anticoagulants were tested and compared.
The method utilizing blood collection on heparin and methanol precipitation was chosen for giving the most reproducible results
while keeping the complexity of the sample. Finally, a validation was proposed to evaluate the stability of this analytical
method applied to a large batch of samples for nutritional metabolomic studies. 相似文献
997.
Computational prediction of RNA‐binding residues is helpful in uncovering the mechanisms underlying protein‐RNA interactions. Traditional algorithms individually applied feature‐ or template‐based prediction strategy to recognize these crucial residues, which could restrict their predictive power. To improve RNA‐binding residue prediction, herein we propose the first integrative algorithm termed RBRDetector (RNA‐Binding Residue Detector) by combining these two strategies. We developed a feature‐based approach that is an ensemble learning predictor comprising multiple structure‐based classifiers, in which well‐defined evolutionary and structural features in conjunction with sequential or structural microenvironment were used as the inputs of support vector machines. Meanwhile, we constructed a template‐based predictor to recognize the putative RNA‐binding regions by structurally aligning the query protein to the RNA‐binding proteins with known structures. The final RBRDetector algorithm is an ingenious fusion of our feature‐ and template‐based approaches based on a piecewise function. By validating our predictors with diverse types of structural data, including bound and unbound structures, native and simulated structures, and protein structures binding to different RNA functional groups, we consistently demonstrated that RBRDetector not only had clear advantages over its component methods, but also significantly outperformed the current state‐of‐the‐art algorithms. Nevertheless, the major limitation of our algorithm is that it performed relatively well on DNA‐binding proteins and thus incorrectly predicted the DNA‐binding regions as RNA‐binding interfaces. Finally, we implemented the RBRDetector algorithm as a user‐friendly web server, which is freely accessible at http://ibi.hzau.edu.cn/rbrdetector . Proteins 2014; 82:2455–2471. © 2014 Wiley Periodicals, Inc. 相似文献
998.
Yan Liu Zheng-lian Xue Shao-peng Chen Zhou Wang Yong Zhang Wei-liang Gong Zhi-ming Zheng 《Journal of industrial microbiology & biotechnology》2016,43(6):751-760
To enhance the screening efficiency and accuracy of a high-yield menaquinone (vitamin K2, MK) bacterial strain, a novel, quantitative method by fluorescence-activated cell sorting (FACS) was developed. The staining technique was optimized to maximize the differences in fluorescence signals between spontaneous and MK-accumulating cells. The fluorescence carrier rhodamine 123 (Rh123), with its ability to reflect membrane potential, proved to be an appropriate fluorescent dye to connect the MK content with fluorescence signal quantitatively. To promote adequate access of the fluorescent molecule to the target and maintain higher cell survival rates, staining and incubation conditions were optimized. The results showed that 10 % sucrose facilitated uptake of Rh123, while maintaining a certain level of cell viability. The pre-treatment of cells with MgCl2 before staining with Rh123 also improved cell viability. Using FACS, 50 thousands cells can easily be assayed in less than 1 h. The optimized staining protocol yielded a linear response for the mean fluorescence against high performance liquid chromatography-measured MK content. We have developed a novel and useful staining protocol in the high-throughput evaluation of Flavobacterium sp. mutant libraries, using FACS to identify mutants with increased MK-accumulating properties. This study also provides reference for the screening of other industrial microbial strains. 相似文献
999.
The Effect of Sterilization Methods on the Physical Properties of Silk Sericin Scaffolds 总被引:1,自引:0,他引:1
Protein-based biomaterials respond differently to sterilization methods. Since protein is a complex structure, heat, or irradiation
may result in the loss of its physical or biological properties. Recent investigations have shown that sericin, a degumming
silk protein, can be successfully formed into a 3-D scaffolds after mixing with other polymers which can be applied in skin
tissue engineering. The objective of this study was to investigate the effectiveness of ethanol, ethylene oxide (EtO) and
gamma irradiation on the sterilization of sericin scaffolds. The influence of these sterilization methods on the physical
properties such as pore size, scaffold dimensions, swelling and mechanical properties, as well as the amount of sericin released
from sericin/polyvinyl alcohol/glycerin scaffolds, were also investigated. Ethanol treatment was ineffective for sericin scaffold
sterilization whereas gamma irradiation was the most effective technique for scaffold sterilization. Moreover, ethanol also
caused significant changes in pore size resulting from shrinkage of the scaffold. Gamma-irradiated samples exhibited the highest
swelling property, but they also lost the greatest amount of weight after immersion for 24 h compared with scaffolds obtained
from other sterilization methods. The results of the maximum stress test and Young’s modulus showed that gamma-irradiated
and ethanol-treated scaffolds are more flexible than the EtO-treated and untreated scaffolds. The amount of sericin released,
which was related to its collagen promoting effect, was highest from the gamma-irradiated scaffold. The results of this study
indicate that gamma irradiation should have the greatest potential for sterilizing sericin scaffolds for skin tissue engineering. 相似文献
1000.