全文获取类型
收费全文 | 2617篇 |
免费 | 189篇 |
出版年
2022年 | 13篇 |
2021年 | 33篇 |
2020年 | 14篇 |
2019年 | 20篇 |
2018年 | 37篇 |
2017年 | 21篇 |
2016年 | 43篇 |
2015年 | 83篇 |
2014年 | 91篇 |
2013年 | 133篇 |
2012年 | 130篇 |
2011年 | 140篇 |
2010年 | 78篇 |
2009年 | 80篇 |
2008年 | 120篇 |
2007年 | 124篇 |
2006年 | 136篇 |
2005年 | 134篇 |
2004年 | 116篇 |
2003年 | 123篇 |
2002年 | 136篇 |
2001年 | 91篇 |
2000年 | 104篇 |
1999年 | 82篇 |
1998年 | 47篇 |
1997年 | 24篇 |
1996年 | 28篇 |
1995年 | 27篇 |
1994年 | 12篇 |
1993年 | 16篇 |
1992年 | 37篇 |
1991年 | 41篇 |
1990年 | 55篇 |
1989年 | 34篇 |
1988年 | 41篇 |
1987年 | 43篇 |
1986年 | 35篇 |
1985年 | 38篇 |
1984年 | 20篇 |
1983年 | 20篇 |
1982年 | 21篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 16篇 |
1978年 | 15篇 |
1977年 | 24篇 |
1976年 | 14篇 |
1974年 | 12篇 |
1973年 | 17篇 |
1971年 | 10篇 |
排序方式: 共有2806条查询结果,搜索用时 875 毫秒
941.
942.
Takashi Takeshita Mutsuko Yamamoto-Ibusuki Yutaka Yamamoto Yoko Omoto Yumi Honda Ken-ichi Iyama Zhenhuan Zhang Hirotaka Iwase 《PloS one》2013,8(11)
Pax transactivation domain interacting protein (PTIP) associated protein 1, PA1, was a newly found protein participating in the modulation of transactivity of nuclear receptor super family members such as estrogen receptor (ER), androgen receptor (AR) and glucocorticoid receptor (GR). Breast cancer is one of the most life threatening diseases for women and has tight association with estrogen and ER. This study was performed to understand the function of PA1 in breast cancer. The expression of PA1 had been evaluated in a total of 344 primary invasive breast cancer samples and examined the relationship with clinical output, relapse free survival (RFS), breast cancer-specific survival (BCSS). PA1 expression was observed in both nucleus and cytoplasm, however, appeared mainly in nuclear. PA1 nuclear expression was correlated with postmenopausal (P = 0.0097), smaller tumor size (P = 0.0025), negative Ki67 (P = 0.02), positive AR (P = 0.049) and positive ERβ (P = 0.0020). Kaplan–Meier analysis demonstrated PA1 nuclear positive cases seemed to have a longer survival than negative ones for RFS (P = 0.023) but not for BCSS (P = 0.23). In the Cox hazards model, PA1 nuclear protein expression proved to be a significant prognostic univariate parameter for RFS (P = 0.03), but not for BCSS (P = 0.20). In addition, for those patients without lymphnode metastasis PA1 was found to be an independent prognostic factor for RFS (P = 0.025), which was verified by univariate and multivariate analyses. These investigations suggested PA1 expression could be a potential prognostic indicator for RFS in breast cancer. 相似文献
943.
Mai Wakabayashi Takayasu Mori Kiyoshi Isobe Eisei Sohara Koichiro Susa Yuya Araki Motoko Chiga Eriko Kikuchi Naohiro Nomura Yutaro Mori Hiroshi Matsuo Tomohiro Murata Shinsuke Nomura Takako Asano Hiroyuki Kawaguchi Shigeaki Nonoyama Tatemitsu Rai Sei Sasaki Shinichi Uchida 《Cell reports》2013,3(3):858-868
- Download : Download full-size image
944.
Shuhei Nomura Stuart Gilmour Masaharu Tsubokura Daisuke Yoneoka Amina Sugimoto Tomoyoshi Oikawa Masahiro Kami Kenji Shibuya 《PloS one》2013,8(3)
Background
Safety of evacuation is of paramount importance in disaster planning for elderly people; however, little effort has been made to investigate evacuation-related mortality risks. After the Fukushima Daiichi Nuclear Plant accident we conducted a retrospective cohort survival survey of elderly evacuees.Methods
A total of 715 residents admitted to five nursing homes in Minamisoma city, Fukushima Prefecture in the five years before 11th March 2011 joined this retrospective cohort study. Demographic and clinical characteristics were drawn from facility medical records. Evacuation histories were tracked until the end of 2011. The evacuation''s impact on mortality was assessed using mortality incidence density and hazard ratios in Cox proportional hazards regression.Results
Overall relative mortality risk before and after the earthquake was 2.68 (95% CI: 2.04–3.49). There was a substantial variation in mortality risks across the facilities ranging from 0.77 (95% CI: 0.34–1.76) to 2.88 (95% CI: 1.74–4.76). No meaningful influence of evacuation distance on mortality was observed although the first evacuation from the original facility caused significantly higher mortality than subsequent evacuations, with a hazard ratio of 1.94 (95% CI: 1.07–3.49).Conclusion
High mortality, due to initial evacuation, suggests that evacuation of the elderly was not the best life-saving strategy for the Fukushima nuclear disaster. Careful consideration of the relative risks of radiation exposure and the risks and benefits of evacuation is essential. Facility-specific disaster response strategies, including in-site relief and care, may have a strong influence on survival. Where evacuation is necessary, careful planning and coordination with other nursing homes, evacuation sites and government disaster agencies is essential to reduce the risk of mortality. 相似文献945.
Hiroyuki Kida Sadahiro Nomura Mizuya Shinoyama Makoto Ideguchi Yuji Owada Michiyasu Suzuki 《PloS one》2013,8(7)
Hypothermia has been proposed as a treatment for reducing neuronal damage in the brain induced by hypoxic ischemia. In the developing brain, hypoxic ischemia-induced injury may give rise to cerebral palsy (CP). However, it is unknown whether hypothermia might affect the development of CP. The purpose of this study was to investigate whether hypothermia would have a protective effect on the brains of immature, 3-day old (P3) mice after a challenge of cerebral ischemia. Cerebral ischemia was induced in P3 mice with a right common carotid artery ligation followed by hypoxia (6% O2, 37°C) for 30 min. Immediately after hypoxic ischemia, mice were exposed to hypothermia (32°C) or normothermia (37°C) for 24 h. At 4 weeks of age, mouse motor development was tested in a behavioral test. Mice were sacrificed at P4, P7, and 5 weeks to examine brain morphology. The laminar structure of the cortex was examined with immunohistochemistry (Cux1/Ctip2); the number of neurons was counted; and the expression of myelin basic protein (MBP) was determined. The hypothermia treatment was associated with improved neurological outcomes in the behavioral test. In the normothermia group, histological analyses indicated reduced numbers of neurons, reduced cortical laminar thickness in the deep, ischemic cortical layers, and significant reduction in MBP expression in the ischemic cortex compared to the contralateral cortex. In the hypothermia group, no reductions were noted in deep cortical layer thickness and in MBP expression in the ischemic cortex compared to the contralateral cortex. At 24 h after the hypothermia treatment prevented the neuronal cell death that had predominantly occurred in the ischemic cortical deep layers with normothermia treatment. Our findings may provide a preclinical basis for testing hypothermal therapies in patients with CP induced by hypoxic ischemia in the preterm period. 相似文献
946.
Eiryu Sai Kazunori Shimada Takayuki Yokoyama Shuji Sato Tetsuro Miyazaki Makoto Hiki Yoshifumi Tamura Shigeki Aoki Hirotaka Watada Ryuzo Kawamori Hiroyuki Daida 《PloS one》2013,8(4)
Ectopic fat accumulation plays important roles in various metabolic disorders and cardiovascular diseases. Recent studies reported that myocardial triglyceride (TG) content measured by proton magnetic resonance spectroscopy (1H-MRS) is associated with aging, diabetes mellitus, and cardiac dysfunction. However, myocardial TG content in athletes has not yet been investigated. We performed 1H-MRS and cardiac magnetic resonance imaging in 10 male endurance athletes and 15 healthy male controls. Serum markers and other clinical parameters including arterial stiffness were measured. Cardiopulmonary exercise testing was also performed. There were no significant differences in clinical characteristics including age, anthropometric parameters, blood test results, or arterial stiffness between the two groups. Peak oxygen uptakes, end–diastolic volume (EDV), end–systolic volume (ESV), left ventricular (LV) mass, peak ejection rates and peak filling rates were significantly higher in the athlete group than in the control group (all P<0.02). Myocardial TG content was significantly lower in the athlete group than in the control group (0.60±0.20 vs. 0.89±0.41%, P<0.05). Myocardial TG content was negatively correlated with EDV (r = −0.47), ESV (r = −0.64), LV mass (r = −0.44), and epicardial fat volume (r = 0.47) (all P<0.05). In conclusion, lower levels of myocardial TG content were observed in endurance athletes and were associated with morphological changes related to physiological LV alteration in athletes, suggesting that metabolic imaging for measurement of myocardial TG content by 1H-MRS may be a useful technique for noninvasively assessing the “athlete’s heart”. 相似文献
947.
Masatoshi Nomura Hiroyuki Kamogawa Eko Susanto Chikara Kawagoe Hajime Yasui Naotsune Saga Masashi Hosokawa Kazuo Miyashita 《Journal of applied phycology》2013,25(4):1159-1169
The present study describes the seasonal changes in lipid components of two brown algae, Sargassum horneri (Turner) and Cystoseira hakodatensis (Yendo), with specific reference to fucoxanthin (Fx) and n-3 (omega-3) polyunsaturated fatty acids (PUFAs). Young thalli of S. horneri were collected from different places, Nesaki and Matsushima, and cultivated in the same place. Total lipids (TL) and Fx contents of S. horneri increased from October or November and reached a maximum in January and then decreased thereafter. TL and Fx of S. horneri originated from Matsushima were always higher than those originated from Nesaki, suggesting that genetic variation might be a reason for the different TL and Fx contents found in both S. horneri seeds from different origin. Similar seasonal variation in the TL and Fx content has been more clearly observed in C. hakodatensis. Maximum TL content of S. horneri and C. hakodatensis reached to more than 14 and 15 % in winter season. These values were much higher than those found in previous studies showing TL content range from 1 to 5 %. Fatty acid composition of lipids from S. horneri and C. hakodatensis also changed seasonally. Total monounsaturated fatty acids showed the lower values from January to April, while there were no big variations in total saturated fatty acids and total n-6 PUFAs. On the other hand, total n-3 PUFAs became highest in winter. Overall, S. horneri and C. hakodatensis harvested from winter to spring will be used as good n-3 PUFA source with high levels of TL and Fx. 相似文献
948.
A new flavanone and other flavonoids from green perilla leaf extract inhibit nitric oxide production in interleukin 1β-treated hepatocytes 总被引:1,自引:0,他引:1
Ayaka Nakajima Yuka Yamamoto Nao Yoshinaka Mayuri Namba Hirotaka Matsuo Tetsuya Okuyama 《Bioscience, biotechnology, and biochemistry》2013,77(1):138-146
A new flavanone, shisoflavanone A (1), and several flavonoids were purified from the ethyl acetate-soluble fraction of green perilla leaves (Perilla frutescens Britton var. crispa form viridis), and their structures were identified. Shisoflavanone A was elucidated as 8-hydroxy-6,7-dimethoxyflavanone based on its spectral data. Other constituents of the ethyl acetate-soluble fraction, i.e. 5,8-dihydroxy-7-methoxyflavanone (2), negletein (5,6-dihydroxy-7-methoxyflavone) (3), luteolin (4), apigenin (5), esculetin (6), and protocatechuic acid (7), were identified. This is the first time that constituents 2, 3, and 6 have been found in green perilla. Shisoflavanone A and the other constituents (except 7) significantly inhibited nitric oxide production in interleukin 1β-stimulated rat hepatocytes, which have been used to monitor the anti-inflammatory effects of herbal constituents. The present findings suggest that these constituents, including shisoflavanone A, may be involved in the anti-inflammatory effects of green perilla leaves. 相似文献
949.
Naofumi Kitabatake Hirotaka Sasaki Etsushiro Doi 《Bioscience, biotechnology, and biochemistry》2013,77(11):2881-2883
Two proteins of low molecular weight, which bind cadmium and are rich in cysteine were isolated from kidneys of the striped dolphin, Stenella coeruleoalba, and identified as metallo-thioneins I and II. The two isoforms closely resembled horse renal isometallothioneins both in chromatographic behaviors and chemical compositions. The molecular weights of performic acid-oxidized proteins were estimated to be 6,800. Twenty to 21 cysteine residues and about 6 g-atoms of heavy metals (Zn, Cd, Cu, and Hg) were present per mole of each isomer. 相似文献
950.
Yasuo Yamamoto Eiji Kawanishi Yuichi Koga Shigeki Sakamaki Toshiaki Sakamoto Kiichiro Ueta Yasuaki Matsushita Chiaki Kuriyama Minoru Tsuda-Tsukimoto Sumihiro Nomura 《Bioorganic & medicinal chemistry letters》2013,23(20):5641-5645
Inhibition of renal sodium-dependent glucose cotransporter 2 (SGLT2) increases urinary glucose excretion (UGE), and thus reduces blood glucose levels in hyperglycemia. A series of N-glucosides was synthesized for biological evaluation as human SGLT2 (hSGLT2) inhibitors. Among these compounds, N-glucoside 9d possessing an indole core structure showed good in vitro activity (IC50 = 7.1 nM against hSGLT2). Furthermore, 9d exhibited favorable in vivo potency with regard to UGE in rats based on good pharmacokinetic profiles. 相似文献