全文获取类型
收费全文 | 578篇 |
免费 | 35篇 |
出版年
2023年 | 2篇 |
2022年 | 11篇 |
2021年 | 21篇 |
2020年 | 15篇 |
2019年 | 17篇 |
2018年 | 21篇 |
2017年 | 16篇 |
2016年 | 19篇 |
2015年 | 39篇 |
2014年 | 38篇 |
2013年 | 46篇 |
2012年 | 54篇 |
2011年 | 45篇 |
2010年 | 31篇 |
2009年 | 20篇 |
2008年 | 25篇 |
2007年 | 20篇 |
2006年 | 20篇 |
2005年 | 20篇 |
2004年 | 18篇 |
2003年 | 20篇 |
2002年 | 13篇 |
2001年 | 7篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 11篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1964年 | 2篇 |
1963年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有613条查询结果,搜索用时 15 毫秒
71.
Julie Massayo Maeda Oda Karen Braj?o de Oliveira Roberta Losi Guembarovski Kalil William Alves de Lima Ana Cristina da Silva do Amaral Herrera Alda Losi Guembarovski Walter Jorge Sobrinho Daniela Rudgeri Derossi Maria Angelica Ehara Watanabe 《Molecular biology reports》2012,39(12):10131-10137
The role of chemokines and the growth factors has been extensively analyzed both in cancer risk and tumor progression. The transforming growth factor beta (TGF-β) and chemokine (C-X-C motif) receptor 4 (CXCR4) genes are implicated in several diseases, including breast cancer. Genomic DNA was obtained from 21 samples of peripheral blood or from normal tissue, previously fixed in formalin and embedded in paraffin for TGF-β T869C polymorphism analyses. Total cellular RNA was extracted from the same 21 patients, but from fresh tissue (tumor and adjacent healthy from the same breast) for expression analysis by Real Time PCR. No significant differences were observed in genotype distribution according to clinicopathological characteristics. Transforming growth factor beta (TGF-β) mRNA expression was assessed according to T869C polymorphism and CC patients presented a higher TGF-β expression but not significant when compared to other genotypes (p?=?0.064). A positive correlation was observed in relative mRNA expressions of CXCR4 and TGF-β (p?=?0.020). It is known that overexpression of TGF-β by both tumor and stromal tissue can facilitate the development of metastases, mainly by TGF-β stimulated angiogenesis and increased tumor cell motility. Our findings suggested a role of these genes as progression markers for breast carcinoma. 相似文献
72.
Gonçalo M. Rosa Franco Andreone Angelica Crottini J. Susanne Hauswaldt Jean Noël Nirhy H. Rabibisoa Miora O. Randriambahiniarime Rui Rebelo Christopher J. Raxworthy 《Biodiversity and Conservation》2012,21(6):1531-1559
The Strict Nature Reserve of Betampona protects one of the last remaining relicts (about 2,228 ha) of low elevation rainforests
in eastern Madagascar. Yet little has been previously published about the amphibian fauna of this rainforest. During 2004
and 2007, Betampona was surveyed over a total period of 102 days. Frogs were searched by opportunistic searching, pitfall
trapping and acoustic surveys. The survey work confirmed the occurrence of 76 taxa, of which 36 are currently candidate species
and about 30% were first considered as undescribed species. The identification of species included a multidimensional and
integrative approach that links morphology, bioacoustics, ecology and genetics. Of these taxa, 24 species are potentially
endemic to this low elevation eastern region. Considering the relatively small area of the Betampona forest, and its narrow
elevational range, 76 amphibian species represents an unusually high richness compared to other sites in Madagascar. Although
the eastern region is now largely deforested, our results reveal the importance of this relict forest, which is protecting
a diverse amphibian fauna that includes many potentially endemic species. 相似文献
73.
A high-density consensus map of A and B wheat genomes 总被引:1,自引:0,他引:1
Daniela Marone Giovanni Laidò Agata Gadaleta Pasqualina Colasuonno Donatella B. M. Ficco Angelica Giancaspro Stefania Giove Giosué Panio Maria A. Russo Pasquale De Vita Luigi Cattivelli Roberto Papa Antonio Blanco Anna M. Mastrangelo 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,125(8):1619-1638
A durum wheat consensus linkage map was developed by combining segregation data from six mapping populations. All of the crosses were derived from durum wheat cultivars, except for one accession of T. ssp. dicoccoides. The consensus map was composed of 1,898 loci arranged into 27 linkage groups covering all 14 chromosomes. The length of the integrated map and the average marker distance were 3,058.6 and 1.6?cM, respectively. The order of the loci was generally in agreement with respect to the individual maps and with previously published maps. When the consensus map was aligned to the deletion bin map, 493 markers were assigned to specific bins. Segregation distortion was found across many durum wheat chromosomes, with a higher frequency for the B genome. This high-density consensus map allowed the scanning of the genome for chromosomal rearrangements occurring during the wheat evolution. Translocations and inversions that were already known in literature were confirmed, and new putative rearrangements are proposed. The consensus map herein described provides a more complete coverage of the durum wheat genome compared with previously developed maps. It also represents a step forward in durum wheat genomics and an essential tool for further research and studies on evolution of the wheat genome. 相似文献
74.
Hare NJ Soe CZ Rose B Harbour C Codd R Manos J Cordwell SJ 《Journal of proteome research》2012,11(2):776-795
75.
Stuart T. Hamilton Gillian Scott Zin Naing Jenna Iwasenko Beverley Hall Nicole Graf Susan Arbuckle Maria E. Craig William D. Rawlinson 《PloS one》2012,7(12)
Human cytomegalovirus (CMV) infection of the developing fetus can result in adverse pregnancy outcomes including death in utero. Fetal injury results from direct viral cytopathic damage to the CMV-infected fetus, although evidence suggests CMV placental infection may indirectly cause injury to the fetus, possibly via immune dysregulation with placental dysfunction. This study investigated the effects of CMV infection on expression of the chemokine MCP-1 (CCL2) and cytokine TNF-α in placentae from naturally infected stillborn babies, and compared these changes with those found in placental villous explant histocultures acutely infected with CMV ex vivo. Tissue cytokine protein levels were assessed using quantitative immunohistochemistry. CMV-infected placentae from stillborn babies had significantly elevated MCP-1 and TNF-α levels compared with uninfected placentae (p = 0.001 and p = 0.007), which was not observed in placentae infected with other microorganisms (p = 0.62 and p = 0.71) (n = 7 per group). Modelling acute clinical infection using ex vivo placental explant histocultures showed infection with CMV laboratory strain AD169 (0.2 pfu/ml) caused significantly elevated expression of MCP-1 and TNF-α compared with uninfected explants (p = 0.0003 and p<0.0001) (n = 25 per group). Explant infection with wild-type Merlin at a tenfold lower multiplicity of infection (0.02 pfu/ml), caused a significant positive correlation between increased explant infection and upregulation of MCP-1 and TNF-α expression (p = 0.0001 and p = 0.017). Cytokine dysregulation has been associated with adverse outcomes of pregnancy, and can negatively affect placental development and function. These novel findings demonstrate CMV infection modulates the placental immune environment in vivo and in a multicellular ex vivo model, suggesting CMV-induced cytokine modulation as a potential initiator and/or exacerbator of placental and fetal injury. 相似文献
76.
MC Pansani PS Azevedo BP Rafacho MF Minicucci F Chiuso-Minicucci SG Zorzella-Pezavento JS Marchini GJ Padovan AA Fernandes BB Matsubara LS Matsubara LA Zornoff SA Paiva 《PloS one》2012,7(7):e41439
Introduction
Micronutrient deficiency is observed in heart failure patients. Taurine, for example, represents 50% of total free amino acids in the heart, and in vivo studies have linked taurine deficiency with cardiomyopathy.Methods
Thirty-four male Wistar rats (body weight = 100 g) were weighed and randomly assigned to one of two groups: Control (C) or taurine-deficient (T (-)). Beta-alanine at a concentration of 3% was added to the animals’ water to induce taurine deficiency in the T (-) group. On day 30, the rats were individually submitted to echocardiography; morphometrical and histopathological evaluation and metalloproteinase activity, oxidative stress and inflammation evaluation were performed. Tissue samples were collected to determine the taurine concentration in the heart.Results
Taurine deficiency led to decreases in: ventricular wall thickness, left ventricle dry weight, myocyte sectional area, left ventricle posterior wall thickness and ventricular geometry. With regard to heart function, the velocity of the A wave, the ratio between the E and A wave, the ejection fraction, fractional shortening and cardiac output values were decreased in T (-) rats, suggesting abnormal diastolic and systolic function. Increased fibrosis, inflammation and increased activation of metalloproteinases were not observed. Oxidative stress was increased in deficient animals.Conclusions
These data suggest that taurine deficiency promotes structural and functional cardiac alterations with unique characteristics. 相似文献77.
Schena M Guarrera S Buffoni L Salvadori A Voglino F Allione A Pecorari G Ruffini E Garzino-Demo P Bustreo S Consito L Bironzo P Matullo G 《DNA Repair》2012,11(4):374-380
BackgroundThe nucleotide excision repair pathway is crucial for cellular DNA integrity and the ERCC1 helicase is also potentially involved in resistance to platinum-based chemotherapy, and high levels of ERCC1 mRNA in tumours have been associated with cisplatin resistance in different human cancers. The aim of this work was to investigate the correlation between DNA repair gene expression levels in tumour tissue, normal tissue and peripheral blood samples from patients with two common human cancers, non-small cell lung cancer (NSCLC) and squamous cell carcinoma of the head and neck (HNSCC), to test if blood gene expression could be a proxy for tumour tissue gene expression to predict response to platinum-based chemotherapy.MethodsUsing RT-qPCR we determined ERCC1, ERCC2, ERCC4, XPA, XPC, XRCC1, XRCC3, APEX, OGG1, MGMT mRNA levels in fresh NSCLC, normal lung and HNSCC tissue, as well as blood, from NSCLC and HNSCC patients who were treated surgically.ResultsTarget gene expression in NSCLC and HNSCC tissue was higher than in blood. A statistically significant correlation (p < 0.05) was found between target gene mRNA expression in tumour tissue and blood, in particular ERCC1, MGMT, XPC, XRCC1 and XRCC3 in NSCLC and APEX, ERCC1, ERCC2, ERCC4, XRCC1 and XRCC3 in HNSCC.ConclusionsThe existence of a significant correlation between blood and tumour tissue expression of some genes of clinical interest, such as ERCC1 in NSCLC and HNSCC, could allow the introduction in clinical practice of a simple test that would measure mRNA levels of DNA repair genes in peripheral blood samples instead of tissue samples to determine prognostic and predictive factors in NSCLC and HNSCC patients. 相似文献
78.
Braganhol E Zanin RF Bernardi A Bergamin LS Cappellari AR Campesato LF Morrone FB Campos MM Calixto JB Edelweiss MI Wink MR Sévigny J Robson SC Battastini AM 《Purinergic signalling》2012,8(2):235-243
Gliomas are the most common and devastating type of primary brain tumor. Many non-neoplastic cells, including immune cells, comprise the tumor microenvironment where they create a milieu that appears to dictate cancer development. ATP and the phosphohydrolytic products ADP and adenosine by activating P2 and P1 receptors may participate in these interactions among malignant and immune cells. Purinergic receptor-mediated cell communication is closely regulated by ectonucleotidases, such as by members of the ectonucleoside triphosphate diphosphohydrolase (E-NTPDase) family, which hydrolyze extracellular nucleotides. We have shown that gliomas, unlike astrocytes, exhibit low NTPDase activity. Furthermore, ATP induces glioma cell proliferation and the co-administration of apyrase decreases progression of injected cells in vivo. We have previously shown that NTPDase2 reconstitution dramatically increases tumor growth in vivo. Here we evaluated whether NTPDase2 reconstitution to gliomas modulates systemic inflammatory responses. We observed that NTPDase2 overexpression modulated pro-inflammatory cytokine production and platelet reactivity. Additionally, pathological alterations in the lungs were observed in rats bearing these tumors. Our results suggest that disruption of purinergic signaling via ADP accumulation creates an inflammatory state that may promote tumor spread and dictate clinical progression. 相似文献
79.
Nicacio AC Simões R de Paula-Lopes FF de Barros FR Peres MA Assumpção ME Visintin JA 《Zygote (Cambridge, England)》2012,20(2):117-122
The aim of this work was to evaluate the effect of cryopreservation protocols on subsequent development of in vitro produced bovine embryos under different culture conditions. Expanded in vitro produced blastocysts (n = 600) harvested on days 7-9 were submitted to controlled freezing [slow freezing group: 10% ethylene glycol (EG) for 10 min and 1.2°C/min cryopreservation]; quick-freezing [rapid freezing group: 10% EG for 10 min, 20% EG + 20% glycerol (Gly) for 30 s]; or vitrification [vitrification group: 10% EG for 10 min, 25% EG + 25% Gly for 30 s] protocols. Control group embryos were not exposed to cryoprotectant or cryopreservation protocols and the hatching rate was evaluated on day 12 post-insemination. In order to evaluate development, frozen-thawed embryos were subjected to granulosa cell co-culture in TCM199 or SOFaa for 4 days. Data were analyzed by PROC MIXED model using SAS Systems for Windows?. Values were significant at p < 0.05. The hatching rate of the control group was 46.09%. In embryos cultured in TCM199, slow freezing and vitrification group hatching rates were 44.65 ± 5.94% and 9.43 ± 6.77%, respectively. In embryos cultured in SOFaa, slow freezing and vitrification groups showed hatching rates of 11.65 ± 3.37 and 8.67 ± 4.47%, respectively. In contrast, the rapid freezing group embryos did not hatch, regardless of culture medium. The slow freezing group showed higher hatching rates than other cryopreservation groups. Under such conditions, controlled freezing (1.2°C/min) can be an alternative to cryopreservation of in vitro produced bovine embryos. 相似文献