全文获取类型
收费全文 | 1304篇 |
免费 | 58篇 |
国内免费 | 3篇 |
出版年
2022年 | 20篇 |
2021年 | 45篇 |
2020年 | 27篇 |
2019年 | 32篇 |
2018年 | 34篇 |
2017年 | 37篇 |
2016年 | 45篇 |
2015年 | 51篇 |
2014年 | 78篇 |
2013年 | 89篇 |
2012年 | 99篇 |
2011年 | 81篇 |
2010年 | 60篇 |
2009年 | 35篇 |
2008年 | 62篇 |
2007年 | 51篇 |
2006年 | 59篇 |
2005年 | 44篇 |
2004年 | 18篇 |
2003年 | 20篇 |
2002年 | 17篇 |
2001年 | 24篇 |
2000年 | 20篇 |
1999年 | 11篇 |
1998年 | 10篇 |
1997年 | 12篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 10篇 |
1991年 | 13篇 |
1990年 | 10篇 |
1989年 | 19篇 |
1988年 | 12篇 |
1987年 | 17篇 |
1986年 | 13篇 |
1985年 | 13篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 14篇 |
1980年 | 11篇 |
1979年 | 10篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1974年 | 10篇 |
1973年 | 6篇 |
1970年 | 5篇 |
1969年 | 5篇 |
1968年 | 5篇 |
1967年 | 11篇 |
排序方式: 共有1365条查询结果,搜索用时 125 毫秒
31.
Saikia Snigdha Pal Uttariya Kalita Deep Jyoti Rai Avdhesh Kumar Sarma Anupam Kataki Amal Chandra Limaye Anil Mukund 《Molecular biology reports》2021,48(7):5399-5409
Molecular Biology Reports - RUNX1T1 is extensively studied in the context of AML1-RUNX1T1 fusion protein in acute myeloid leukemia. Little is known about the function of RUNX1T1 itself, although... 相似文献
32.
Bansal Mitaly Adamski Nikolai M. Toor Puneet Inder Kaur Satinder Sharma Achla Srivastava Puja Bansal Urmil Uauy Cristobal Chhuneja Parveen 《Molecular biology reports》2021,48(6):5209-5216
Molecular Biology Reports - Stripe rust and leaf rust are among the most devastating diseases of wheat, limiting its production globally. Wheat wild relatives harbour genetic diversity for new... 相似文献
33.
Circulating plasma microRNAs in colorectal neoplasia: A pilot study in assessing response to therapy
Stephen J O'Brien Uri Netz Jacob Hallion Campbell Bishop Vincent Stephen James Burton Mason Paas Kayla Feagins Jianmin Pan Shesh N. Rai Susan Galandiuk 《Translational oncology》2021,14(1)
IntroductionCurrent serological surveillance markers to monitor colorectal cancer (CRC) or colorectal advanced adenomas (CAA) are hampered by poor sensitivity and specificity. The aim of this study is to identify and validate a panel of plasma microRNAs which change in expression after resection of such lesions.MethodsA prospectively maintained colorectal surgery database was queried for patients in whom both pre- and post-procedural serum samples had been obtained. An initial screening analysis of CRC and CAA patients (5 each) was conducted using screening cards for 380 miRNAs. Four identified miRNAs were combined with a previously described panel of 7 miRNAs that were diagnostically predictive of CRC and CAA. Differential miRNA expression was assessed using quantitative real-time polymerase chain reaction(qRT-PCR).ResultsFifty patients were included (n = 27 CRC, n = 23 CAA). There was no difference in age, gender, or race profile of CRC patients compared to CAA patients. Six miRNA were significantly increased after CRC resection (miR-324, let7b, miR-454, miR-374a, miR-122, miR-19b, all p<0.05), while three miRNAs were significantly increased following CAA resection (miR-454, miR-374a, miR-122, all p<0.05). Three miRNA were increased in common for both (miR-454, miR-374a, miR-122).DiscussionThe expression of miRNAs associated with neoplasia (either CRC or CAA) was significantly increased following surgical resection or endoscopic removal of CRC or CAA. Future studies should focus on the evaluation of these miRNAs in CRC and CAA prognosis. 相似文献
34.
Miloš R. Filipović Dragana Stanić Smiljana Raičević Mihajlo Spasić 《Free radical research》2013,47(1):62-72
The present study demonstrates that manganese superoxide dismutase (MnSOD) (Escherichia coli), binds nitric oxide (√NO) and stimulates its decay under both anaerobic and aerobic conditions. The results indicate that previously observed MnSOD-catalyzed √NO disproportionation (dismutation) into nitrosonium (NO+) and nitroxyl (NO? ) species under anaerobic conditions is also operative in the presence of molecular oxygen. Upon sustained aerobic exposure to √NO, MnSOD-derived NO? species initiate the formation of peroxynitrite (ONOO? ) leading to enzyme tyrosine nitration, oxidation and (partial) inactivation. The results suggest that both ONOO? decomposition and ONOO? -dependent tyrosine residue nitration and oxidation are enhanced by metal centre-mediated catalysis. We show that the generation of ONOO? is accompanied by the formation of substantial amounts of H2O2. MnSOD is a critical mitochondrial antioxidant enzyme, which has been found to undergo tyrosine nitration and inactivation in various pathologies associated with the overproduction of √NO. The results of the present study can account for the molecular specificity of MnSOD nitration in vivo. The interaction of √NO with MnSOD may represent a novel mechanism by which MnSOD protects the cell from deleterious effects associated with overproduction of √NO. 相似文献
35.
S. Raić M. Pongraćić J. Vorkapić-Furać D. Vikić-Topić A. Hergold-Brundić A. Nagl 《Nucleosides, nucleotides & nucleic acids》2013,32(4):937-960
Abstract Synthesis of the novel nucleoside analogues containing exocyclic pyrrolo moiety and acyclic side chains attached to the purine ring at N-9 and N-7 is described. The site of alkylation was determined by 1H and 13C NMR on the basis of chemical shifts, C-H coupling constants and connectivity in NOESY and HETCOR spectra. The N-9 substitution of 7 was proved by its X-ray crystallographic analysis. 相似文献
36.
Rai Dilip Toshiyuki Ishii Hideki Imada Yuko Wada-Kiyama Ryoiti Kiyama Eiichi Miyachi Makoto Kaneda 《Journal of molecular histology》2013,44(6):639-644
There is increasing evidence that ATP acts on purinergic receptors and mediates synaptic transmission in the retina. In a previous study, we raised the possibility that P2X-purinoceptors, presumably P2X2-purinoceptors in OFF-cholinergic amacrine cells, play a key role in the formation of OFF pathway-specific modulation. In this study, we examined whether the P2Y1-purinoceptors can function in cholinergic amacrine cells in the mouse retina since cholinergic amacrine cells in the rat retina express P2Y1-purinoceptors. P2Y1-purinoceptors were shown to be expressed in dendrites of both ON- and OFF-cholinergic amacrine cells in adults. At postnatal day 7, there was immunoreactivity for P2Y1-purinoceptors in the soma of cholinergic amacrine cells. At postnatal day 14, weak immunoreactivity for P2Y1-purinoceptors was detected in the dendrites but not in the soma of cholinergic amacrine cells. At postnatal day 21, strong immunoreactivity for P2Y1-purinoceptors was detected in dendrites of cholinergic amacrine cells. The expression pattern of P2Y1-purinoceptors was not affected by visual experience. We concluded that P2Y1-purinoceptors are not involved in the OFF-pathway-specific signal transmission in cholinergic amacrine cells of the mouse retina. 相似文献
37.
S. K. Sood B. Vijay Simha Rashmi Kumariya Anita Kumari Garsa Jitender Mehla Sunita Meena Puja Lather 《Probiotics and antimicrobial proteins》2013,5(1):37-42
A novel method based on (1) initial microbiological screening and (2) a highly specific PCR is described for selection of strains expressing YGNGV motif-containing pediocin. Initial screening is carried out using spot on the lawn assay for selection of acid-free, hydrogen peroxide (H2O2)-free and secreted heat-stable inhibitory activity producing strains. This is followed by highly specific PCR for amplification of 406-bp fragment using forward primer: 5′-tggccaatatcattggtggt-3′ targeting signal peptide sequence of pediocin structural gene and reverse primer: 5′-ctactaacgcttggctggca-3′ encoding N-terminus of immunity gene. The assay was validated with Pediococcus pentosaceus NCDC273 and Pediococcus acidilactici NCDC252 using (1) digestion of amplified 406-bp fragment with HindIII restriction enzyme-producing two restriction fragments of expected sizes (227 and 179 bp), (2) nucleotide sequencing of 406-bp fragment from both strains found these pediocins identical to pediocin PA-1/AcH and (3) identification of both pediocins as pediocin PA-1 at protein level using RP-HPLC. The assay was used for screening six strains (3 pediococci, 2 lactobacilli and an Enterococcus faecium) producing acid-free, hydrogen peroxide (H2O2)-free and secreted heat-stable inhibitory activity. This resulted in the detection of three new strains (P. pentosaceus NCDC35, E. faecium NCDC124 and Lactobacillus plantarum NCDC20) producing YGNGV motif-containing pediocins. 相似文献
38.
Sandeep Rai Bidhubhusan Mahapatra Subhashish Sircar Pinnamaneni Yujwal Raj Srinivasan Venkatesh Mohammed Shaukat Bharat Bhusan Rewari 《PloS one》2013,8(6)
Introduction
Research in India has extensively examined the factors associated with non-adherence to antiretroviral therapy (ART) with limited focus on examining the relationship between adherence to ART regimen and survival status of HIV infected patients. This study examines the effect of optimal adherence to ART on survival status of HIV infected patients attending ART centers in Jharkhand, India.Materials and Methods
Data from a cohort of 239 HIV infected individuals who were initiated ART in 2007 were compiled from medical records retrospectively for 36 months. Socio-demographic characteristics, CD4 T cell count, presence of opportunistic infections at the time of ART initiation and ART regimen intake and survival status was collected periodically. Optimal adherence was assessed using pill count methods; patients who took <95% of the specified regimens were identified as non-adherent. Cox-proportional hazard model was used to determine the relative hazards of mortality.Results
More than three-fourths of the patients were male, on an average 34 year old and median CD4 T cell count was 118 cells/cmm at the time of ART registration. About 57% of the patients registered for ART were found to be adherent to ART. A total of 104 patients died in 358.5 patient-years of observation resulting in a mortality rate of 29 per 100 patient-years (95% confidence interval (CI): 23.9–35.2) and median survival time of 6.5 months (CI: 2.7–10.9). The mortality rate was higher among patients who were non-adherent to ART (64.5, CI: 50.5–82.4) than who were adherent (15.4, CI: 11.3–21.0). The risk of mortality was fourfold higher among individuals who were non-adherent to ART than who were adherent (Adjusted hazard ratio: 3.9, CI: 2.6–6.0).Conclusion
Adherence to ART is associated with a higher chance of survival of HIV infected patients, ascertaining the need for interventions to improve the ART adherence and early initiation of ART. 相似文献39.
Amit Kugler Puja Kumari Kamilya Kokabi Maxim Itkin Sergey Malitsky Inna Khozin-Goldberg 《Journal of phycology》2020,56(2):334-345
The chlorophyte microalga Lobosphaera incisa was isolated from the snowy slopes of Mt. Tateyama in Japan. This microalga stores exceptionally high amounts of the omega-6 LC-PUFA arachidonic acid in triacylglycerols, and therefore represents a potent photosynthetic source for this essential LC-PUFA. Assuming that freezing tolerance may play a role in adaptation of L. incisa to specific ecological niches, we examined the capability of L. incisa to tolerate extreme sub-zero temperatures. We report here, that the vegetative cells of L. incisa survived freezing at −20°C and −80°C (over 1 month), without cryoprotective agents or prior treatments. Cells successfully recovered upon thawing and proliferated under optimal growth conditions (25°C). However, cells frozen at −80°C showed better recovery and lower cellular ROS generation upon thawing, compared to those preserved at −20°C. Photosynthetic yield of PSII, estimated by Fv/Fm, temporarily decreased at day 1 post freezing and resumed to the original level at day 3. Interestingly, the thawed algal cultures produced a higher level of chlorophylls, exceeding the control culture. The polar metabolome of the vegetative cells comprised a range of compatible solutes, dominated by glutamate, sucrose, and proline. We posit that the presence of endogenous cryoprotectants, a rigid multilayer cell wall, the high LC-PUFA content in membrane lipids, and putative cold-responsive proteins may contribute to the retention of functionality upon recovery from the frozen state, and therefore for the survival under cryospheric conditions. From the applied perspective, this beneficial property holds promise for the cryopreservation of starter cultures for research and commercial purposes. 相似文献
40.
Ved Prakash Kanchan Vishwakarma Vijay Pratap Singh Padmaja Rai Naleeni Ramawat Durgesh Kumar Tripathi Shivesh Sharma 《Physiologia plantarum》2020,168(2):473-489
Over the past decades the role of nitric oxide (NO) and reactive oxygen species (ROS) in signaling and cellular responses to stress has witnessed an exponential trend line. Despite advances in the subject, our knowledge of the role of NO and ROS as regulators of stress and plant growth and their implication in signaling pathways is still partial. The crosstalk between NO and ROS during root formation offers new domains to be explored, as it regulates several plant functions. Previous findings indicate that plants utilize these signaling molecules for regulating physiological responses and development. Depending upon cellular concentration, NO either can stimulate or impede root system architecture (RSA) by modulating enzymes through post-translational modifications. Similarly, the ROS signaling molecule network, in association with other hormonal signaling pathways, control the RSA. The spatial regulation of ROS controls cell growth and ROS determine primary root and act in concert with NO to promote lateral root primordia. NO and ROS are two central messenger molecules which act differentially to upregulate or downregulate the expression of genes pertaining to auxin synthesis and to the configuration of root architecture. The investigation concerning the contribution of donors and inhibitors of NO and ROS can further aid in deciphering their role in root development. With this background, this review provides comprehensive details about the effect and function of NO and ROS in the development of RSA. 相似文献