全文获取类型
收费全文 | 6265篇 |
免费 | 373篇 |
国内免费 | 1篇 |
出版年
2023年 | 58篇 |
2022年 | 83篇 |
2021年 | 169篇 |
2020年 | 118篇 |
2019年 | 142篇 |
2018年 | 194篇 |
2017年 | 152篇 |
2016年 | 234篇 |
2015年 | 332篇 |
2014年 | 384篇 |
2013年 | 418篇 |
2012年 | 531篇 |
2011年 | 537篇 |
2010年 | 326篇 |
2009年 | 242篇 |
2008年 | 342篇 |
2007年 | 365篇 |
2006年 | 356篇 |
2005年 | 267篇 |
2004年 | 264篇 |
2003年 | 227篇 |
2002年 | 224篇 |
2001年 | 63篇 |
2000年 | 42篇 |
1999年 | 38篇 |
1998年 | 54篇 |
1997年 | 46篇 |
1996年 | 46篇 |
1995年 | 36篇 |
1994年 | 32篇 |
1993年 | 28篇 |
1992年 | 33篇 |
1991年 | 22篇 |
1990年 | 19篇 |
1989年 | 22篇 |
1988年 | 23篇 |
1987年 | 9篇 |
1986年 | 12篇 |
1985年 | 21篇 |
1984年 | 8篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1975年 | 9篇 |
1974年 | 9篇 |
1973年 | 8篇 |
排序方式: 共有6639条查询结果,搜索用时 281 毫秒
231.
Focal adhesion kinase: predictor of tumour response and risk factor for recurrence after neoadjuvant chemoradiation in rectal cancer
下载免费PDF全文
![点击此处可从《Journal of cellular and molecular medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Maria Jesús Fernández‐Aceñero Aurea Borrero‐Palacios Laura del Puerto‐Nevado Javier Martínez‐Useros Juan Pablo Marín‐Arango Cristina Caramés Ricardo Vega‐Bravo María Rodríguez‐Remírez Marlid Cruz‐Ramos Félix Manzarbeitia Jesús García‐Foncillas 《Journal of cellular and molecular medicine》2016,20(9):1729-1736
Rectal cancer represents about 30% of colorectal cancers, being around 50% locally advanced at presentation. Chemoradiation (CRT) followed by total mesorectal excision is the standard of care for these locally advanced stages. However, it is not free of adverse effects and toxicity and the complete pathologic response rate is between 10% and 30%. This makes it extremely important to define factors that can predict response to this therapy. Focal adhesion kinase (FAK) expression has been correlated with worse prognosis in several tumours and its possible involvement in cancer radio‐ and chemosensitivity has been suggested; however, its role in rectal cancer has not been analysed yet. To analyse the association of FAK expression with tumour response to CRT in locally advanced rectal cancer. This study includes 73 patients with locally advanced rectal cancer receiving standard neoadjuvant CRT followed by total mesorectal excision. Focal adhesion kinase protein levels were immunohistochemically analysed in the pre‐treatment biopsies of these patients and correlated with tumour response to CRT and patients survival. Low FAK expression was significantly correlated with local and distant recurrence (P = 0.013). Low FAK expression was found to be a predictive marker of tumour response to neoadjuvant therapy (P = 0.007) and patients whose tumours did not express FAK showed a strong association with lower disease‐free survival (P = 0.01). Focal adhesion kinase expression predicts neoadjuvant CRT response in rectal cancer patients and it is a clinically relevant risk factor for local and distant recurrence. 相似文献
232.
Leonardo da Costa Bastos Felipe Rodrigues de Souza Ana Paula Guimarães Mehdi Sirouspour Teobaldo Ricardo Cuya Guizado Pat Forgione 《Journal of biomolecular structure & dynamics》2016,34(10):2184-2198
In the present work, we propose to design drugs that target the enzyme dihydrofolate redutase (DHFR) as a means of a novel drug therapy against plague. Potential inhibitors of DHFR from Yersinia pestis (YpDHFR) were selected by virtual screening and subjected to docking, molecular dynamics (MD) simulations, and Poisson–Boltzmann surface area method, in order to evaluate their interactions in the active sites of YpDHFR and human DHFR (HssDHFR). The results suggested selectivity for three compounds that were further used to propose the structures of six new potential selective inhibitors for YpDHFR. 相似文献
233.
234.
Felix Krengel Quentin Chevalier Jonathan Dickinson Josefina Herrera Santoyo Ricardo Reyes Chilpa 《化学与生物多样性》2019,16(4)
Ibogaine and other ibogan type alkaloids present anti‐addictive effects against several drugs of abuse and occur in different species of the Apocynaceae family. In this work, we used gas chromatography‐mass spectrometry (GC/MS) and principal component analysis (PCA) in order to compare the alkaloid profiles of the root and stem barks of four Mexican Tabernaemontana species with the root bark of the entheogenic African shrub Tabernanthe iboga. PCA demonstrated that separation between species could be attributed to quantitative differences of the major alkaloids, coronaridine, ibogamine, voacangine, and ibogaine. While T. iboga mainly presented high concentrations of ibogaine, Tabernaemontana samples either showed a predominance of voacangine and ibogaine, or coronaridine and ibogamine, respectively. The results illustrate the phytochemical proximity between both genera and confirm previous suggestions that Mexican Tabernaemontana species are viable sources of anti‐addictive compounds. 相似文献
235.
Oliveira Sílvia Ardais Ana Paula Bastos Clarissa Ribeiro Gazal Marta Jansen Karen de Mattos Souza Luciano da Silva Ricardo Azevedo Kaster Manuella Pinto Lara Diogo Rizzato Ghisleni Gabriele 《Purinergic signalling》2019,15(1):37-44
Purinergic Signalling - Genetic variants involved in adenosine metabolism and its receptors were associated with increased risk for psychiatric disorders, including anxiety, depression, and... 相似文献
236.
Guilherme Rocha Melo Gondim Fabiana Baroni Alves Makdissi Ricardo Cesar Fogaroli Juan Bautista Donoso Collins Hirofumi Iyeyasu Douglas Guedes de Castro Maria Letícia Gobo Silva Michael Jenwei Chen Tharcisio Machado Coelho Henderson Ramos Antônio Cássio Assis Pellizzon 《Reports of Practical Oncology and Radiotherapy》2019,24(6):551-555
BackgroundWhole breast irradiation reduces loco-regional recurrence and risk of death in patients submitted to breast-conserving treatment. Data show that radiation to the index quadrant alone may be enough in selected patients.AimTo report the experience with intra-operative radiotherapy (IORT) with Electron-beam Cone in Linear Accelerator (ELIOT) and the results in overall survival, local control and late toxicity of patients submitted to this treatment.Materials and Methods147 patients treated with a median follow up of 6.9 years (0.1?11.5 years). The actuarial local control and overall survival probabilities were estimated using the Kaplan Meier method. All tests were two-sided and p ? 0.05 was considered statistically significant.ResultsOverall survival of the cohort in 5 years, in the median follow up and in 10 years was of 98.3%, 95.1% and 95.1%, respectively, whereas local control in 5 years, in the median follow up and in 10 years was of 96%, 94.9% and 89.5%, respectively. Two risk groups were identified for local recurrence depending on the estrogen or progesterone receptors, axillary or margin status and lymphovascular invasion (LVI) (p = 0.016).ConclusionsIORT is a safe and effective treatment. Rigorous selection is important to achieve excellent local control results. 相似文献
237.
Thiago Doria Barral Ricardo Barros Mariutti Raghuvir Krishnaswamy Arni Anderson Jesus Santos Dan Loureiro Ana Rita Sokolonski Vasco Azevedo Sibele Borsuk Roberto Meyer Ricardo Dias Portela 《Microbial biotechnology》2019,12(6):1313-1323
Caseous lymphadenitis (CLA) is a small ruminant disease characterized by the development of granulomatous lesions in superficial and internal lymph nodes, as well as in some organs, and causes significant economic losses worldwide. The aetiological agent of CLA is the bacterium Corynebacterium pseudotuberculosis; however, the commercially available diagnostic tools present problems with regard to specificity, which can lead to false-negative results. This study aimed to develop an indirect enzyme-linked immunosorbent assay (ELISA) for the detection of specific immunoglobulins in goats and sheep using recombinant C. pseudotuberculosis PLD, CP40, PknG, DtxR and Grx proteins. For validation of the ELISAs, 130 goat serum samples and 160 sheep serum samples were used. The best ELISA for goats was developed using a combination of PLD and CP40 as antigens at a 1:1 ratio, which presented 96.9% sensitivity and 98.4% specificity. The most effective ELISA for sheep presented 91% sensitivity and 98.7% specificity when recombinant PLD alone was used as the antigen. These ELISAs can be used as highly accurate tools in epidemiological surveys and for the serodiagnosis of C. pseudotuberculosis infection in goats and sheep. 相似文献
238.
James R. Probert Catherine L. Parr Ricardo M. Holdo T. Michael Anderson Sally Archibald Colin J. Courtney Mustaphi Andrew P. Dobson Jason E. Donaldson Grant C. Hopcraft Gareth P. Hempson Thomas A. Morrison Colin M. Beale 《Global Change Biology》2019,25(10):3406-3423
Fire is a key driver in savannah systems and widely used as a land management tool. Intensifying human land uses are leading to rapid changes in the fire regimes, with consequences for ecosystem functioning and composition. We undertake a novel analysis describing spatial patterns in the fire regime of the Serengeti‐Mara ecosystem, document multidecadal temporal changes and investigate the factors underlying these patterns. We used MODIS active fire and burned area products from 2001 to 2014 to identify individual fires; summarizing four characteristics for each detected fire: size, ignition date, time since last fire and radiative power. Using satellite imagery, we estimated the rate of change in the density of livestock bomas as a proxy for livestock density. We used these metrics to model drivers of variation in the four fire characteristics, as well as total number of fires and total area burned. Fires in the Serengeti‐Mara show high spatial variability—with number of fires and ignition date mirroring mean annual precipitation. The short‐term effect of rainfall decreases fire size and intensity but cumulative rainfall over several years leads to increased standing grass biomass and fuel loads, and, therefore, in larger and hotter fires. Our study reveals dramatic changes over time, with a reduction in total number of fires and total area burned, to the point where some areas now experience virtually no fire. We suggest that increasing livestock numbers are driving this decline, presumably by inhibiting fire spread. These temporal patterns are part of a global decline in total area burned, especially in savannahs, and we caution that ecosystem functioning may have been compromised. Land managers and policy formulators need to factor in rapid fire regime modifications to achieve management objectives and maintain the ecological function of savannah ecosystems. 相似文献
239.
Roger T. Chetelat Xiaoqiong Qin Meilian Tan Diana Burkart‐Waco Yosuke Moritama Xiuwen Huo Tim Wills Ricardo Pertuz 《The Plant journal : for cell and molecular biology》2019,100(4):836-850
The wild tomato relative Solanum sitiens is a xerophyte endemic to the Atacama Desert of Chile and a potential source of genes for tolerance to drought, salinity and low‐temperature stresses. However, until recently, strong breeding barriers prevented its hybridization and introgression with cultivated tomato, Solanum lycopersicum L. We overcame these barriers using embryo rescue, bridging lines and allopolyploid hybrids, and synthesized a library of introgression lines (ILs) that captures the genome of S. sitiens in the background of cultivated tomato. The IL library consists of 56 overlapping introgressions that together represent about 93% of the S. sitiens genome: 65% in homozygous and 28% in heterozygous (segregating) ILs. The breakpoints of each segment and the gaps in genome coverage were mapped by single nucleotide polymorphism (SNP) genotyping using the SolCAP SNP array. Marker‐assisted selection was used to backcross selected introgressions into tomato, to recover a uniform genetic background, to isolate recombinant sub‐lines with shorter introgressions and to select homozygous genotypes. Each IL contains a single S. sitiens chromosome segment, defined by markers, in the genetic background of cv. NC 84173, a fresh market inbred line. Large differences were observed between the lines for both qualitative and quantitative morphological traits, suggesting that the ILs contain highly divergent allelic variation. Several loci contributing to unilateral incompatibility or hybrid necrosis were mapped with the lines. This IL population will facilitate studies of the S. sitiens genome and expands the range of genetic variation available for tomato breeding and research. 相似文献
240.
Pereira Felipe Walter Vitule Jean Ricardo Simões 《Reviews in Fish Biology and Fisheries》2019,29(3):639-652
Reviews in Fish Biology and Fisheries - Biological invasions via anthropogenic vectors, intentional or not, are one of the main causes of ecological change in aquatic ecosystems. Micropterus... 相似文献