全文获取类型
收费全文 | 3899篇 |
免费 | 390篇 |
国内免费 | 283篇 |
出版年
2024年 | 8篇 |
2023年 | 33篇 |
2022年 | 76篇 |
2021年 | 157篇 |
2020年 | 105篇 |
2019年 | 156篇 |
2018年 | 149篇 |
2017年 | 128篇 |
2016年 | 166篇 |
2015年 | 264篇 |
2014年 | 280篇 |
2013年 | 301篇 |
2012年 | 380篇 |
2011年 | 324篇 |
2010年 | 214篇 |
2009年 | 190篇 |
2008年 | 232篇 |
2007年 | 203篇 |
2006年 | 165篇 |
2005年 | 141篇 |
2004年 | 138篇 |
2003年 | 127篇 |
2002年 | 120篇 |
2001年 | 69篇 |
2000年 | 55篇 |
1999年 | 53篇 |
1998年 | 26篇 |
1997年 | 22篇 |
1996年 | 24篇 |
1995年 | 16篇 |
1994年 | 21篇 |
1993年 | 20篇 |
1992年 | 22篇 |
1991年 | 14篇 |
1990年 | 17篇 |
1989年 | 10篇 |
1988年 | 13篇 |
1987年 | 10篇 |
1986年 | 16篇 |
1985年 | 6篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1976年 | 8篇 |
1975年 | 10篇 |
1974年 | 9篇 |
排序方式: 共有4572条查询结果,搜索用时 15 毫秒
131.
132.
Jennifer F. Doss Jude C. Jonassaint Melanie E. Garrett Allison E. Ashley-Koch Marilyn J. Telen Jen-Tsan Chi 《PloS one》2016,11(4)
Sickle cell disease (SCD) is the most common inherited hemoglobinopathy worldwide. Our previous results indicate that the reduced oxidative stress capacity of sickle erythrocytes may be caused by decreased expression of NRF2 (Nuclear factor (erythroid-derived 2)-like 2), an oxidative stress regulator. We found that activation of NRF2 with sulforaphane (SFN) in erythroid progenitors significantly increased the expression of NRF2 targets HMOX1, NQO1, and HBG1 (subunit of fetal hemoglobin) in a dose-dependent manner. Therefore, we hypothesized that NRF2 activation with SFN may offer therapeutic benefits for SCD patients by restoring oxidative capacity and increasing fetal hemoglobin concentration. To test this hypothesis, we performed a Phase 1, open-label, dose-escalation study of SFN, contained in a broccoli sprout homogenate (BSH) that naturally contains SFN, in adults with SCD. The primary and secondary study endpoints were safety and physiological response to NRF2 activation, respectively. We found that BSH was well tolerated, and the few adverse events that occurred during the trial were not likely related to BSH consumption. We observed an increase in the mean relative whole blood mRNA levels for the NRF2 target HMOX1 (p = 0.02) on the last day of BSH treatment, compared to pre-treatment. We also observed a trend toward increased mean relative mRNA levels of the NRF2 target HBG1 (p = 0.10) from baseline to end of treatment, but without significant changes in HbF protein. We conclude that BSH, in the provided doses, is safe in stable SCD patients and may induce changes in gene expression levels. We therefore propose investigation of more potent NRF2 inducers, which may elicit more robust physiological changes and offer clinical benefits to SCD patients.Trial Registration: ClinicalTrials.gov NCT01715480相似文献
133.
Prepubertal children exposed to concentrated disadvantage: An exploratory analysis of inflammation and metabolic dysfunction 下载免费PDF全文
134.
135.
Alfred Chor San Chan Qiu Qiu Siu Wai Choi Stanley Sau Ching Wong Albert Chi Yan Chan Michael G Irwin Chi Wai Cheung 《PloS one》2016,11(2)
Background
Patients receiving total intravenous anesthesia (TIVA) with propofol have been shown to experience less postoperative pain. We evaluated the post-operative analgesic effects of propofol compared with sevoflurane maintenance of anesthesia in liver surgery. This study was registered at ClinicalTrials.gov (). NCT02179437Methods
In this retrospective study, records of patients who underwent liver surgery between 2010 and 2013 were reviewed. Ninety-five patients anesthetized with propofol TIVA were matched with 95 patients anesthetized with sevoflurane. Numeric pain rating scale (NRS) pain scores, postoperative morphine consumption, side effects and patients’ satisfaction with pain relief were evaluated.Results
The TIVA group reported lower NRS pain scores during coughing on postoperative days 1 and 2 but not 3 (p = 0.0127, p = 0.0472, p = 0.4556 respectively). They also consumed significantly less daily (p = 0.001 on day 1, p = 0.0231 on day 2, p = 0.0004 on day 3), accumulative (p = 0.001 on day 1, p<0.0001 on day 2 and p = 0.0064 on day 3) and total morphine (p = 0.03) when compared with the sevoflurane group. There were no differences in total duration of intravenous patient controlled analgesia (PCA) morphine use and patient satisfaction. No difference was found in reported side effects.Conclusion
Patients anesthetized with propofol TIVA reported less pain during coughing and consumed less daily, accumulative and total morphine after liver surgery. 相似文献136.
Genome‐scale RNA interference screen identifies antizyme 1 (OAZ1) as a target for improvement of recombinant protein production in mammalian cells 下载免费PDF全文
137.
138.
Recent work has indicated that tropical forest and savanna can be alternative stable states under a range of climatic conditions. However, dynamical systems theory suggests that in case of strong spatial interactions between patches of forest and savanna, a boundary between both states is only possible at conditions in which forest and savanna are equally stable, called the ‘Maxwell point.’ Frequency distributions of MODIS tree-cover data at 250 m resolution were used to estimate such Maxwell points with respect to the amount and seasonality of rainfall in both South America and Africa. We tested on a 0.5° scale whether there is a larger probability of local coexistence of forests and savannas near the estimated Maxwell points. Maxwell points for South America and Africa were estimated at 1760 and 1580 mm mean annual precipitation and at Markham’s Seasonality Index values of 50 and 24 %. Although the probability of local coexistence was indeed highest around these Maxwell points, local coexistence was not limited to the Maxwell points. We conclude that critical transitions between forest and savanna may occur when climatic changes exceed a critical value. However, we also conclude that spatial interactions between patches of forest and savanna may reduce the hysteresis that can be observed in isolated patches, causing more predictable forest-savanna boundaries than continental-scale analyses of tree cover indicate. This effect could be less pronounced in Africa than in South America, where the forest-savanna boundary is substantially affected by rainfall seasonality. 相似文献
139.
Transcriptome‐wide sequencing provides insights into geocarpy in peanut (Arachis hypogaea L.) 下载免费PDF全文
Xiaoping Chen Qingli Yang Haifen Li Heying Li Yanbin Hong Lijuan Pan Na Chen Fanghe Zhu Xiaoyuan Chi Wei Zhu Mingna Chen Haiyan Liu Zhen Yang Erhua Zhang Tong Wang Ni Zhong Mian Wang Hong Liu Shijie Wen Xingyu Li Guiyuan Zhou Shaoxiong Li Hong Wu Rajeev Varshney Xuanqiang Liang Shanlin Yu 《Plant biotechnology journal》2016,14(5):1215-1224
140.
A transgenic plant cell‐suspension system for expression of epitopes on chimeric Bamboo mosaic virus particles 下载免费PDF全文
Thangarasu Muthamilselvan Chin‐Wei Lee Yu‐Hsin Cho Feng‐Chao Wu Chung‐Chi Hu Yu‐Chuan Liang Na‐Sheng Lin Yau‐Heiu Hsu 《Plant biotechnology journal》2016,14(1):231-239
We describe a novel strategy to produce vaccine antigens using a plant cell‐suspension culture system in lieu of the conventional bacterial or animal cell‐culture systems. We generated transgenic cell‐suspension cultures from Nicotiana benthamiana leaves carrying wild‐type or chimeric Bamboo mosaic virus (BaMV) expression constructs encoding the viral protein 1 (VP1) epitope of foot‐and‐mouth disease virus (FMDV). Antigens accumulated to high levels in BdT38 and BdT19 transgenic cell lines co‐expressing silencing suppressor protein P38 or P19. BaMV chimeric virus particles (CVPs) were subsequently purified from the respective cell lines (1.5 and 2.1 mg CVPs/20 g fresh weight of suspended biomass, respectively), and the resulting CVPs displayed VP1 epitope on the surfaces. Guinea pigs vaccinated with purified CVPs produced humoral antibodies. This study represents an important advance in the large‐scale production of immunopeptide vaccines in a cost‐effective manner using a plant cell‐suspension culture system. 相似文献