全文获取类型
收费全文 | 2048篇 |
免费 | 189篇 |
国内免费 | 1篇 |
出版年
2023年 | 7篇 |
2022年 | 4篇 |
2021年 | 27篇 |
2020年 | 35篇 |
2019年 | 58篇 |
2018年 | 58篇 |
2017年 | 30篇 |
2016年 | 41篇 |
2015年 | 90篇 |
2014年 | 94篇 |
2013年 | 110篇 |
2012年 | 109篇 |
2011年 | 92篇 |
2010年 | 79篇 |
2009年 | 76篇 |
2008年 | 113篇 |
2007年 | 117篇 |
2006年 | 127篇 |
2005年 | 119篇 |
2004年 | 97篇 |
2003年 | 97篇 |
2002年 | 98篇 |
2001年 | 93篇 |
2000年 | 75篇 |
1999年 | 69篇 |
1998年 | 32篇 |
1997年 | 21篇 |
1996年 | 32篇 |
1995年 | 27篇 |
1994年 | 17篇 |
1993年 | 20篇 |
1992年 | 30篇 |
1991年 | 17篇 |
1990年 | 18篇 |
1989年 | 23篇 |
1988年 | 9篇 |
1987年 | 10篇 |
1986年 | 10篇 |
1985年 | 3篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1972年 | 4篇 |
1969年 | 4篇 |
排序方式: 共有2238条查询结果,搜索用时 15 毫秒
51.
Qi Zou MD Chong-Jie Zhang MD Yu-Zhong Yan MD Zhi-Jun Min MD Chun-Sheng Li MD 《Journal of cellular biochemistry》2019,120(11):18650-18658
This study aims to explore the ability of magnetic resonance imaging (MRI) in mucin 1 (MUC1) modified superparamagnetic iron oxide nanoparticle (SPION) targeting human pancreatic cancer (PC). The MUC1 target-directed probe was prepared through MUC1 conjugated to SPION using the chemical method to assess its physiochemical characteristics, including hydration diameter, surface charge, and magnetic resonance signal. The cytotoxicity of MUC1-USPION was verified by MTS assay. BxPC-3 was cultured with MUC1-USPION and SPION in different concentrations. The combined condition of the targeted probes and cells were observed through Prussian blue staining. The nude mice model of pancreatic cancer was established to investigate the application of the probe. MRI was performed to determine the intensity of the signal of the transplanted tumor, while immunohistochemistry and Western blot analysis were performed to detect the expression of MUC1 after taking the transplanted tumor specimen. The particle size of the prepared molecular probe was 63.5 ± 3.2 nm, and the surface charge was 10.2 mV. Furthermore, the probe solution could significantly reduce the MRI at T2, and the magnetic resonance transverse relaxation rate (ΔR2) has a linear relationship with the concentration of iron in the solution. The cell viability of MUC1-USPION in different concentrations revealed no statistical difference, according to the MTS assay. In vitro, the MRI demonstrated decreased T2WI signal intensity in both groups, especially the targeting group. In vivo, MUC1 could selectively accumulate in the nude mice model, and significantly reduce the T2 signal strength. In subsequent experiments, the expression of MUC1 was high in pancreatic cancer tissues, but low in normal pancreatic tissues, as determined by immunohistochemistry and Western blot analysis. The prepared samples can be combined with pancreatic cancer tissue specificity by in vivo imaging, providing reliable early in vivo imaging data for disease diagnosis. 相似文献
52.
Yu Si-in Kim Hyojin Yun Dae-Jin Suh Mi Chung Lee Byeong-ha 《Plant molecular biology》2019,99(1-2):135-148
Plant Molecular Biology - A Kelch repeat F-box containing protein, SMALL AND GLOSSY LEAVES1 (SAGL1) regulates phenylpropanoid biosynthesis as a post-translational regulator for PAL1 (phenylalanine... 相似文献
53.
Ying-Chun Liang MD Yu-Peng Wu MD Xiao-Dong Li MD Shao-Hao Chen MD Xiao-Jian Ye MD Xue-Yi Xue MD Ning Xu MD 《Journal of cellular physiology》2019,234(12):23243-23255
The effective treatment of urethral stricture remains a medical problem. The use of proinflammatory cytokines as stimuli to improve the reparative efficacy of mesenchymal stem cells (MSCs) towards damaged tissues represents an evolving field of investigation. However, the therapeutic benefits of this strategy in the treatment of urethral stricture remain unknown. Here, we enriched exosomes derived from human umbilical cord-derived MSCs pretreated with or without tumor necrosis factor alpha (TNF-α) to evaluate their therapeutic effects in an in vivo model of TGFβ1-induced urethral stricture. Male Sprague-Dawley rats received sham (saline) or TGFβ1 injections to urethral tissues followed by incisions in the urethra. Animals in the TGFβ1 injection (urethral fibrosis) cohort were subsequently injected with vehicle control, or with exosomes derived from MSCs cultured with or without TNF-α. After 4 weeks, rats underwent ultrasound evaluation and, following euthanasia, urethral tissues were harvested for histological and molecular analysis. In vitro, the effects of MSC-derived exosomes on fibroblast secretion of collagen and cytokines were studied by enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), and western blot analysis. Exosomes derived from MSCs pretreated with TNF-α were more effective in suppressing urethral fibrosis and stricture than exosomes from untreated MSCs. We found that miR-146a, an anti-inflammatory miRNA, was strongly upregulated in TNF-α-stimulated MSCs and was selectively packaged into exosomes. Moreover, miR-146a-containing exosomes were taken up by fibroblasts and inhibited fibroblast activation and associated inflammatory responses, a finding that may underlie the therapeutic mechanism for suppression of urethral stricture. Inhibition of miR-146a in TNF-α-treated MSCs partially reduced antifibrotic effects and increased the release of proinflammatory factors of exosomes derived from these cells. Together these findings demonstrate that exosomes derived from TNF-α-treated MSCs are of therapeutic benefit in urethral fibrosis, suggesting that this strategy may have utility as an adjuvant therapy in the treatment of urethral stricture diseases. 相似文献
54.
55.
56.
Eun-Shik Kim Dong Kyun Park Xueyong Zhao Sun Kee Hong Kang Suk Koh Min Hwan Suh Young Sun Kim 《Ecological Research》2006,21(6):907-911
Asian dusts, yellow sand, or dust and sand storms (DSS) in Asian continent are the end products of desertification, which
became a regional environmental problem being aggravated by time. It is closely related to an issue of sustainability in the
region. As the desertification is caused not only by natural factors, such as the climate change, strong wind, and low precipitation,
but also by rapidly increasing human activities, such as overgrazing, misuse of water resources, and irrational land use,
it is urgent to make efforts to combat desertification in Asian continent including China. In this regard, it is necessary
to consider socio-economic aspects as well as ecological aspects and, consequently, the project for the construction of a
Demonstration Model Village for eco-environmental rehabilitation should be paid to a special attention. The authors deal with
this regional issue in consideration of three Es, which are represented by ecology, economy, and environment in providing
the perspectives in sound approach to the issue. As an approach to the issue of Asian dusts and desertification in Asian continent,
this Eco-Village study provides one way forward. 相似文献
57.
Md Ruhul Amin Nabanita Paul Nancy Md Ramiz Uddin Miah Md Giashuddin Miah Ohseok Kwon Sang Jae Suh 《Entomological Research》2019,49(5):223-228
The study was conducted with the aim of furthering our understanding of seasonality in the population dynamics and infestation rates of the fruit fly Bactrocera spp. in sweet gourd (Cucurbita moschata) during winter and summer in 2017. We also investigated the effects of using methyl eugenol traps on fly abundance and infestation. Two fruit fly species, namely, B. cucurbitae and B. dorsalis, were present in the sweet gourd field, and we observed fluctuations in their abundance. Compared to B. dorsalis, B. cucurbitae was significantly more abundant in both winter and summer. Infestation level was found to be the highest in fields lacking methyl eugenol traps in both seasons. Fruit fly larval population per infested fruit was higher in summer than in winter. Fly abundance was significantly and positively correlated with mean temperature and rainfall but significantly and negatively correlated with light intensity. Relative humidity was insignificantly but positively correlated with fly abundance. The temperature, light intensity, relative humidity, and rainfall individually explained 48.9, 24.1, 0.8, and 1.6% of variation in fruit fly abundance, respectively. The combined effect of the weather parameters on fruit fly abundance was 75.4% and was significant predictor of fruit fly abundance. 相似文献
58.
59.
Short‐term modern life‐like stress exacerbates Aβ‐pathology and synapse loss in 3xTg‐AD mice 下载免费PDF全文
60.
Young-Jun Park Sung-Jin Yoon Hyun-Woo Suh Dong Oh Kim Jeong-Ran Park Haiyoung Jung Tae-Don Kim Suk Ran Yoon Jeong-Ki Min Hee-Jun Na Seon-Jin Lee Hee Gu Lee Young Ho Lee Hee-Bong Lee Inpyo Choi 《PLoS pathogens》2013,9(10)
Thioredoxin-interacting protein (TXNIP) has multiple functions, including tumor suppression and involvement in cell proliferation and apoptosis. However, its role in the inflammatory process remains unclear. In this report, we demonstrate that Txnip−/− mice are significantly more susceptible to lipopolysaccharide (LPS)-induced endotoxic shock. In response to LPS, Txnip−/− macrophages produced significantly higher levels of nitric oxide (NO) and inducible nitric oxide synthase (iNOS), and an iNOS inhibitor rescued Txnip−/− mice from endotoxic shock-induced death, demonstrating that NO is a major factor in TXNIP-mediated endotoxic shock. This susceptibility phenotype of Txnip−/− mice occurred despite reduced IL-1β secretion due to increased S-nitrosylation of NLRP3 compared to wild-type controls. Taken together, these data demonstrate that TXNIP is a novel molecule that links NO synthesis and NLRP3 inflammasome activation during endotoxic shock. 相似文献