全文获取类型
收费全文 | 680篇 |
免费 | 93篇 |
出版年
2023年 | 7篇 |
2022年 | 15篇 |
2021年 | 28篇 |
2020年 | 16篇 |
2019年 | 10篇 |
2018年 | 31篇 |
2017年 | 22篇 |
2016年 | 36篇 |
2015年 | 23篇 |
2014年 | 33篇 |
2013年 | 53篇 |
2012年 | 43篇 |
2011年 | 48篇 |
2010年 | 27篇 |
2009年 | 29篇 |
2008年 | 33篇 |
2007年 | 22篇 |
2006年 | 31篇 |
2005年 | 21篇 |
2004年 | 23篇 |
2003年 | 22篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 13篇 |
1999年 | 11篇 |
1998年 | 5篇 |
1996年 | 4篇 |
1994年 | 6篇 |
1992年 | 7篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1987年 | 3篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1971年 | 6篇 |
1970年 | 6篇 |
1969年 | 12篇 |
1968年 | 6篇 |
1967年 | 3篇 |
排序方式: 共有773条查询结果,搜索用时 281 毫秒
31.
Ole J Hamming Ewa Terczyńska‐Dyla Gabrielle Vieyres Ronald Dijkman Sanne E Jørgensen Hashaam Akhtar Piotr Siupka Thomas Pietschmann Volker Thiel Rune Hartmann 《The EMBO journal》2013,32(23):3055-3065
The IFNL4 gene is a recently discovered type III interferon, which in a significant fraction of the human population harbours a frameshift mutation abolishing the IFNλ4 ORF. The expression of IFNλ4 is correlated with both poor spontaneous clearance of hepatitis C virus (HCV) and poor response to treatment with type I interferon. Here, we show that the IFNL4 gene encodes an active type III interferon, named IFNλ4, which signals through the IFNλR1 and IL‐10R2 receptor chains. Recombinant IFNλ4 is antiviral against both HCV and coronaviruses at levels comparable to IFNλ3. However, the secretion of IFNλ4 is impaired compared to that of IFNλ3, and this impairment is not due to a weak signal peptide, which was previously believed. We found that IFNλ4 gets N‐linked glycosylated and that this glycosylation is required for secretion. Nevertheless, this glycosylation is not required for activity. Together, these findings result in the paradox that IFNλ4 is strongly antiviral but a disadvantage during HCV infection. 相似文献
32.
33.
34.
Muhammad Saqib Javaid Akhtar Ghulam Abbas Muhammad Nasim 《Acta Physiologiae Plantarum》2013,35(9):2761-2768
Salinity and drought are important agro-environmental problems occurring separately as well as together with the combined occurrence increasing with time due to climate change. Screening of bread wheat genotypes against salinity or drought alone is common; however, little information is available on the response of wheat genotypes to a combination of these stresses. This study investigates the response of a salt-resistant (SARC-1) and a salt-sensitive (7-Cerros) wheat genotype to drought at different growth stages under non-saline (ECe 2.1 dS m?1) and saline soil (ECe 15 dS m?1) conditions. Drought was applied by withholding water for 21 days at a particular growth stage viz. tillering, booting, and grain filling stages. At booting stage measurements regarding water relations, leaf ionic composition and photosynthetic attributes were made. At maturity grain yield and different yield, components were recorded. Salinity and drought significantly decreased grain yield and different yield components with a higher decrease in the case of combined stress of salinity × drought. The complete drought treatment (drought at tillering + booting + grain filling stages) was most harmful for wheat followed by drought at booting stage and grain filling–tillering stages, respectively. The salt-resistant wheat genotype SARC-1 performed better than the salt-sensitive genotype 7-Cerros in different stress treatments. A decrease in the water and turgor potentials, photosynthetic and transpiration rates, stomatal conductance, leaf K+, and increased leaf Na+ were the apparent causes of growth and yield reduction of bread wheat due to salinity, drought, and salinity × drought. 相似文献
35.
Fungal degradation of low rank coal has appeared as an alternative technique for exploitation of non-fuel options. A fungal isolate, MW1, was isolated and coal sample was subjected to fungal pretreatment. The residual coal was processed for extraction of humic acid for determining the effect of such pretreatment. Extracted humic acid was analyzed on the basis of elemental composition and spectroscopy. Fungal pretreatment caused improvement in oxygen content, E4/E6 ratio, and absorption bands related to humic materials. Conclusively, pretreatment resulted in improving chemical attributes of humic acid molecule, thus, warranting supplementary high-tech investigations for the optimization of process upscale. 相似文献
36.
Arkan Abadi Justin D. Crane Daniel Ogborn Bart Hettinga Mahmood Akhtar Andrew Stokl Lauren MacNeil Adeel Safdar Mark Tarnopolsky 《PloS one》2013,8(4)
Antioxidant supplements are widely consumed by the general public; however, their effects of on exercise performance are controversial. The aim of this study was to examine the effects of an antioxidant cocktail (α-lipoic acid, vitamin E and coenzyme Q10) on exercise performance, muscle function and training adaptations in mice. C57Bl/J6 mice were placed on antioxidant supplement or placebo-control diets (n = 36/group) and divided into trained (8 wks treadmill running) (n = 12/group) and untrained groups (n = 24/group). Antioxidant supplementation had no effect on the running performance of trained mice nor did it affect training adaptations; however, untrained female mice that received antioxidants performed significantly better than placebo-control mice (p ≤ 0.05). Furthermore, antioxidant-supplemented females (untrained) showed elevated respiratory capacity in freshly excised muscle fibers (quadriceps femoris) (p ≤ 0.05), reduced oxidative damage to muscle proteins (p ≤ 0.05), and increased expression of mitochondrial proteins (p ≤ 0.05) compared to placebo-controls. These changes were attributed to increased expression of proliferator-activated receptor gamma coactivator 1α (PGC-1α) (p ≤ 0.05) via activation of AMP-activated protein kinase (AMPK) (p ≤ 0.05) by antioxidant supplementation. Overall, these results indicate that this antioxidant supplement exerts gender specific effects; augmenting performance and mitochondrial function in untrained females, but does not attenuate training adaptations. 相似文献
37.
38.
Sanghamitra Pati Mohammad Akhtar Hussain Abhimanyu Singh Chauhan Diptimayee Mallick Sukdev Nayak 《Cancer epidemiology》2013,37(6):973-978
Cancer is a leading cause of mortality worldwide. Early diagnosis and treatment of cancer may curb the growing burden of the disease. Understanding cancer patients’ navigation pathways for seeking treatment is important in order to facilitate early diagnosis and treatment. With this background we conducted a hospital-based cross-sectional study comprising 68 randomly selected cancer inpatients in a tertiary cancer specialty hospital in Odisha, India, to explore the treatment-seeking pathways of the cancer patients and the barriers and enablers in seeking treatment. Financial constraint is one of the major reasons for the delay in accessing treatment, even when patients are suspected of or diagnosed with cancer. Low awareness of the presenting signs and symptoms of cancer and limited knowledge of the availability of cancer diagnosis and treatment facilities are major factors contributing to delay. Family and friends’ support is found to be the major enabling factor toward seeking treatment. Generation of awareness of cancer among the general population and primary-care practitioners – including those in alternative systems of medicine – is important. Information on diagnostic and treatment services appears to be a felt need. 相似文献
39.
Isadore Budnick Emily Hamburg‐Shields Demeng Chen Eduardo Torre Andrew Jarrell Batool Akhtar‐Zaidi Olivia Cordovan Rob C. Spitale Peter Scacheri Radhika P. Atit 《Genesis (New York, N.Y. : 2000)》2016,54(8):415-430
Embryonic dermal fibroblasts in the skin have the exceptional ability to initiate hair follicle morphogenesis and contribute to scarless wound healing. Activation of the Wnt signaling pathway is critical for dermal fibroblast fate selection and hair follicle induction. In humans, mutations in Wnt pathway components and target genes lead to congenital focal dermal hypoplasias with diminished hair. The gene expression signature of embryonic dermal fibroblasts during differentiation and its dependence on Wnt signaling is unknown. Here we applied Shannon entropy analysis to identify the gene expression signature of mouse embryonic dermal fibroblasts. We used available human DNase‐seq and histone modification ChiP‐seq data on various cell‐types to demonstrate that genes in the fibroblast cell identity signature can be epigenetically repressed in other cell‐types. We found a subset of the signature genes whose expression is dependent on Wnt/β‐catenin activity in vivo. With our approach, we have defined and validated a statistically derived gene expression signature that may mediate dermal fibroblast identity and function in development and disease. genesis 54:415–430, 2016. © 2016 Wiley Periodicals, Inc. 相似文献
40.
Arif Muhammad Rashid Naeem Perveen Sumera Bashir Qamar Akhtar Muhammad 《Extremophiles : life under extreme conditions》2019,23(1):69-77
Extremophiles - The gene-encoding Indole-3-glycerol phosphate synthase, a key enzyme involved in the cyclization of 1-(o-carboxyphenylamino)-1-deoxyribulose 5-phosphate, from Pyrococcus furiosus... 相似文献