全文获取类型
收费全文 | 1195篇 |
免费 | 115篇 |
国内免费 | 1篇 |
出版年
2024年 | 3篇 |
2023年 | 14篇 |
2022年 | 34篇 |
2021年 | 85篇 |
2020年 | 77篇 |
2019年 | 145篇 |
2018年 | 119篇 |
2017年 | 76篇 |
2016年 | 61篇 |
2015年 | 56篇 |
2014年 | 68篇 |
2013年 | 96篇 |
2012年 | 97篇 |
2011年 | 90篇 |
2010年 | 43篇 |
2009年 | 41篇 |
2008年 | 39篇 |
2007年 | 34篇 |
2006年 | 24篇 |
2005年 | 19篇 |
2004年 | 23篇 |
2003年 | 13篇 |
2002年 | 8篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1967年 | 2篇 |
排序方式: 共有1311条查询结果,搜索用时 390 毫秒
991.
Seyed Elyas Meshkani Narges Kooshan Arezoo Baradaran Moghadam Farahnaz Falanji Abolfazl Adli Fahimeh Baghbani-Arani Alireza Ghasemi Arian Abolfazl Rad 《Journal of cellular physiology》2019,234(10):18146-18155
Pterygium as a complex disease shares common features with other malignant cells in its onset recurrence and especially epithelial–mesenchymal transition (EMT) transition. Although using different approaches including conjunctival autografts, amniotic membrane, radiotherapy, mitomycin C (MMC) has shown promising insights in the inhibition of pterygium recurrence, it needs to be investigated in more details in molecular pathways to present adjuvant target therapy. In this study, we aimed to evaluate the expression of and then illustrate the role of signaling pathways on EMT in pterygium. Using real-time polymerase chain reaction, the twist-related protein 1 (TWIST1) expression was compared in primary pterygium and normal conjunctiva. This study assessed the mRNA expression, as well as the association between the clinicopathological indices and the gene expression level. The expression level of TWIST1 was overexpressed in 36% of our cohort ( n = 76). There was a significant positive correlation between recurrence with grade T, grade V and a significant negative correlation with growth activity. Our vast literature review on different signaling pathways in pterygium showed that EMT has centralization role in recurrence of this disease. Our data confirmed that EMT is important in the recurrence of pterygium samples and different signaling pathways end up activating the EMT markers. It is suggested to evaluate the environmental factors and their correlation with molecular markers to select favorable treatment for this kind of diseases. 相似文献
992.
Atena Soleimani Mostafa Amirinejad Sara Rahsepar Fatemeh Vazirian Afsane Bahrami Gordon A. Ferns Majid Khazaei Amir Avan Seyed Mahdi Hassanian 《Journal of cellular biochemistry》2019,120(5):6860-6867
Breast cancer is one of the most prevalent malignancies among women around the world. RAS proteins require posttranslational modifications, including protein prenylation for proper membrane localization and signaling. Regulation of RAS signaling via specific and novel pharmacological inhibitors is a potentially novel therapeutic approach in breast cancer therapy. This review summarizes the recent knowledge about the clinical value of RAS prenylation pharmacological inhibitors in breast cancer treatment. 相似文献
993.
Bolhassani A Gholami E Zahedifard F Moradin N Parsi P Doustdari F Seyed N Papadopoulou B Rafati S 《Experimental parasitology》2011,(1):9-17
An intercellular spreading strategy using herpes simplex virus type 1 (HSV-1) VP22 protein is employed to enhance DNA vaccine potency of Leishmania major amastin antigen in BALB/c mice model. We evaluated the immunogenicity and protective efficacy of plasmid DNA vaccines encoding amastin-enhanced green fluorescent protein (EGFP) and VP22-amastin-EGFP. Optimal cell-mediated immune responses were observed in BALB/c mice immunized with VP22-amastin-EGFP as assessed by cytokine gene expression analysis using real time RT-PCR. Vaccination with the VP22-amastin-EGFP fusion construct elicited significantly higher IFN-gamma response upon antigen stimulation of splenocytes from immunized mice compared to amastin as a sole antigen. Mice immunized by VP22-amastin-EGFP showed partial protection following infectious challenge with L. major, as measured by parasite load in spleens. These results suggest that the development of DNA vaccines encoding VP22 fused to a target Leishmania antigen would be a promising strategy to improve immunogenicity and DNA vaccine potency. 相似文献
994.
Hashemnia M Khodakaram-Tafti A Razavi SM Nazifi S 《The Korean journal of parasitology》2011,49(3):213-219
This experiment was conducted to assess the changing patterns and relative values of acute phase proteins and inflammatory cytokines in experimental caprine coccidiosis. Eighteen newborn kids were allocated to 3 equal groups. Two groups, A and B, were inoculated with a single dose of 1×10(3) and1×10(5) sporulated oocysts of Eimeria arloingi, respectively. The third group, C, received distilled water as the control. Blood samples were collected from the jugular vein of each kid in both groups before inoculation and at days 7, 14, 21, 28, 35, and 42 post-inoculation (PI), and the levels of haptoglobin (Hp), serum amyloid A (SAA), TNF-α, and IFN-γ were measured. For histopathological examinations, 2 kids were selected from each group, euthanized, and necropsied on day 42 PI. Mean Hp concentrations in groups A and B (0.34 and 0.68 g/L) at day 7 PI were 3.2 and 6.3 times higher than the levels before inoculation. The mean SAA concentrations in groups A and B (25.6 and 83.5 μg/ml) at day 7 PI were 4.2 and 13.7 times higher than the levels before inoculation. The magnitude and duration of the Hp and SAA responses correlated well with the inoculation doses and the severity of the clinical signs and diarrhea in kids. These results were consistent with the histopathological features, which showed advanced widespread lesions in group B. In both groups, significant correlations were observed for TNF-α and IFN-γ with SAA and Hp, respectively. In conclusion, Hp and SAA can be useful non-specific diagnostic indicators in caprine coccidiosis. 相似文献
995.
Sabri A Ziaee AA Ostad SN Alimoghadam K Ghahremani MH 《Cell biochemistry and function》2011,29(1):64-70
Epidermal growth factor (EGF) promotes proliferation in human mesenchymal stem cells (hMSCs) during in vitro propagation. In this study, we investigated the effects of PI3K/AKT, ERK1/2, P38 and JNK on EGF signalling in hMSCs. The effects of EGF on MAPKs and PI3K/AKT crosstalk were investigated by immunoblotting; cyclooxygenase-2 (COX-2) expression was studied by real-time RT-PCR; and cell proliferation was evaluated by methylthiazolyl tetrazolium bromide assay. Our results showed that EGF immediately activated all four pathways, induced proliferation and increased COX-2 expression. Interestingly, inhibition of PI3K/AKT-enhanced EGF-stimulated ERK1/2 activity, and inhibition of ERK1/2 and JNK reduced AKT phosphorylation. Furthermore, EGF-induced proliferation as well as EGF-augmented COX2 expression was hindered by ERK1/2 and p38 inhibitors. The results of this study provide evidences to be used in extended proliferation of hMSCs for cell therapy. 相似文献
996.
Dastgheib SM Amoozegar MA Khajeh K Ventosa A 《Applied microbiology and biotechnology》2011,90(1):305-312
Biodegradation of petroleum compounds in saline environments seems intricate and needs more attention. In this study, tetracosane
was used to enrich alkane-degrading bacteria from oil-contaminated saline soils. Among the isolates, strain Qtet3, with the
highest 16s rRNA gene sequence similarity to Alcanivorax dieselolei B-5T, was able to grow at a wide range of NaCl concentrations and was shown by GC analysis to degrade more than 90% of tetracosane
in 10 days. This strain has at least two alkB genes and could grow on crude oil and diesel fuel, and utilize various pure aliphatic hydrocarbon substrates (from C12 to C34). Highly hydrophobic cell surfaces and lack of significant surface tension reduction in the media suggest that the main mechanism
of the cells for accessing substrate is to attach directly to hydrocarbon particles. Application of this strain for remediating
crude oil-contaminated soils irrigated with defined saline water demonstrated that this halotolerant bacterium could survive
and grow in saline soils irrigated with NaCl solutions up to 5% w/v, with the highest hydrocarbon degradation of 26.1% observed
at 2.5% NaCl. This strain is promising for future industrial applications especially in bioremediation of saline soils and
wastes. 相似文献
997.
Sharadamma N Khan K Kumar S Patil KN Hasnain SE Muniyappa K 《The FEBS journal》2011,278(18):3447-3462
The occurrence of DNA architectural proteins containing two functional domains derived from two different architectural proteins is an interesting emerging research theme in the field of nucleoid structure and function. Mycobacterium tuberculosis HupB, unlike Escherichia coli HU, is a two-domain protein that, in the N-terminal region, shows broad sequence homology with bacterial HU. The long C-terminal extension, on the other hand, contains seven PAKK/KAAK motifs, which are characteristic of the histone H1/H5 family of proteins. In this article, we describe several aspects of HupB function, in comparison with its truncated derivatives lacking either the C-terminus or N-terminus. We found that HupB binds a variety of DNA repair and replication intermediates with K(d) values in the nanomolar range. By contrast, the N-terminal fragment of M. tuberculosis HupB (HupB(MtbN)) showed diminished DNA-binding activity, with K(d) values in the micromolar range, and the C-terminal domain was completely devoid of DNA-binding activity. Unlike HupB(MtbN) , HupB was able to constrain DNA in negative supercoils and introduce negative superhelical turns into relaxed DNA. Similarly, HupB exerted a robust inhibitory effect on DNA strand exchange promoted by cognate and noncognate RecA proteins, whereas HupB(MtbN), even at a 50-fold molar excess, had no inhibitory effect. Considered together, these results suggest that synergy between the N-terminal and C-terminal domains of HupB is essential for its DNA-binding ability, and to modulate the topological features of DNA, which has implications for processes such as DNA compaction, gene regulation, homologous recombination, and DNA repair. 相似文献
998.
999.
Metanorms is a mechanism proposed to promote cooperation in social dilemmas. Recent experimental results show that network structures that underlie social interactions influence the emergence of norms that promote cooperation. We generalize Axelrod's analysis of metanorms dynamics to interactions unfolding on networks through simulation and mathematical modeling. Network topology strongly influences the effectiveness of the metanorms mechanism in establishing cooperation. In particular, we find that average degree, clustering coefficient and the average number of triplets per node play key roles in sustaining or collapsing cooperation. 相似文献
1000.
Comprehensive study of mtDNA among Southwest Asian dogs contradicts independent domestication of wolf, but implies dog-wolf hybridization 总被引:1,自引:0,他引:1
Ardalan A Kluetsch CF Zhang AB Erdogan M Uhlén M Houshmand M Tepeli C Ashtiani SR Savolainen P 《Ecology and evolution》2011,1(3):373-385
Studies of mitochondrial DNA (mtDNA) diversity indicate explicitly that dogs were domesticated, probably exclusively, in southern East Asia. However, Southwest Asia (SwAsia) has had poor representation and geographical coverage in these studies. Other studies based on archaeological and genome-wide SNP data have suggested an origin of dogs in SwAsia. Hence, it has been suspected that mtDNA evidence for this scenario may have remained undetected. In the first comprehensive investigation of genetic diversity among SwAsian dogs, we analyzed 582 bp of mtDNA for 345 indigenous dogs from across SwAsia, and compared with 1556 dogs across the Old World. We show that 97.4% of SwAsian dogs carry haplotypes belonging to a universal mtDNA gene pool, but that only a subset of this pool, five of the 10 principal haplogroups, is represented in SwAsia. A high frequency of haplogroup B, potentially signifying a local origin, was not paralleled with the high genetic diversity expected for a center of origin. Meanwhile, 2.6% of the SwAsian dogs carried the rare non-universal haplogroup d2. Thus, mtDNA data give no indication that dogs originated in SwAsia through independent domestication of wolf, but dog-wolf hybridization may have formed the local haplogroup d2 within this region. Southern East Asia remains the only region with virtually full extent of genetic variation, strongly indicating it to be the primary and probably sole center of wolf domestication. An origin of dogs in southern East Asia may have been overlooked by other studies due to a substantial lack of samples from this region. 相似文献