全文获取类型
收费全文 | 596篇 |
免费 | 52篇 |
国内免费 | 1篇 |
出版年
2023年 | 13篇 |
2022年 | 8篇 |
2021年 | 28篇 |
2020年 | 23篇 |
2019年 | 32篇 |
2018年 | 31篇 |
2017年 | 23篇 |
2016年 | 25篇 |
2015年 | 50篇 |
2014年 | 38篇 |
2013年 | 42篇 |
2012年 | 35篇 |
2011年 | 37篇 |
2010年 | 21篇 |
2009年 | 25篇 |
2008年 | 19篇 |
2007年 | 32篇 |
2006年 | 27篇 |
2005年 | 13篇 |
2004年 | 18篇 |
2003年 | 18篇 |
2002年 | 15篇 |
2001年 | 5篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1965年 | 2篇 |
1963年 | 1篇 |
排序方式: 共有649条查询结果,搜索用时 15 毫秒
601.
Ambrin Fatima Jan Hoeber Jens Schuster Eriko Koshimizu Carolina Maya-Gonzalez Boris Keren Cyril Mignot Talia Akram Zafar Ali Satoko Miyatake Junpei Tanigawa Takayoshi Koike Mitsuhiro Kato Yoshiko Murakami Uzma Abdullah Muhammad Akhtar Ali Rein Fadoul Loora Laan Casimiro Castillejo-Lpez Maarika Liik Zhe Jin Bryndis Birnir Naomichi Matsumoto Shahid M. Baig Joakim Klar Niklas Dahl 《American journal of human genetics》2022,109(3):542-546
602.
603.
604.
Stressors such as fasting or poor diet quality are thought to potentially alter the nitrogen and carbon isotopic values of animal tissues. In this study, we demonstrate an inverse correlation between growth rate and multiple tissue enrichment of δ15N, δ13C, and, to a lesser degree, δ18O in a juvenile pig. A more complex pattern is observed with respect to tissue δD and growth rate. The observed association between growth rate and tissue isotopic fractionation has important implications for paleodietary and migratory reconstructions of archaeological populations that may have been affected by famine, malnutrition, seasonal variation in food availability, and/or other factors that can affect childhood growth rates. Am J Phys Anthropol 2010. © 2010 Wiley‐Liss, Inc. 相似文献
605.
Rami Alkhatib Nour Abdo Laith AL-Eitan Rafeef Kafesha Akram Rousan 《Physiology and Molecular Biology of Plants》2020,26(5):1047-1054
Magnetism is one of the physical methods affecting water properties. It is considered as an environmental factor that plays a role in the physiological and biochemical reactions. A hydroponic experiment was conducted using four types of treated water (distilled water, magnetically treated distilled water, magnetically treated tap water, and tap water). Tobacco plants (Nicotiana tabacum var. Turkish) were placed in a growth chamber for three weeks. Plants irrigated with magnetically treated distilled water had a significant increase in the physiological parameters including shoot height and root length (P < 0.0001). The same pattern was seen in the photosynthetic rate and protein content, but no significant differences in the stomatal conductance and transpiration rate (P < 0.5601). In contrast, a significant increase of total carbohydrate content was exhibited in plant irrigated with tap water (P < 0.0064). Electron micrographs showed deformed chloroplasts with damaged thylakoid membranes associated with plastoglobules in plants irrigated with tap water and magnetically treated tap water. Lastly, this study suggests that magnetically treated water is an excellent option to improve irrigation methods and thus obtains agricultural production with high efficiency. 相似文献
606.
Macus Hao-Ran Bao Chunxue Yang Aki Pui-Wah Tse Lai Wei Derek Lee Misty Shuo Zhang Chi Ching Goh David Kung-Chun Chiu Vincent Wai-Hin Yuen Cheuk-Ting Law Wai-Ching Chin Noreen Nog-Qin Chui Bowie Po-Yee Wong Cerise Yuen-Ki Chan Irene Oi-Lin Ng Clive Yik-Sham Chung Chun-Ming Wong Carmen Chak-Lui Wong 《Cell reports》2021,34(4):108676
- Download : Download high-res image (267KB)
- Download : Download full-size image
607.
608.
Asma Chaudhary Afia Muhammad Akram Ayesha Aihetasham Zawar Hussain Afshan Syed Abbas Rahat Abdul Rehman Qurat-ul-Ain Ahmad Anjum Tahira Ayesha Saleem Samina Qamer Youssef Alghamdi Samy F. Mahmoud Samy Sayed 《Saudi Journal of Biological Sciences》2021,28(7):3710-3719
Pomegranate peels (PPW) as municipal waste is inexpensive biomass that could be a renewable source of sugars particularly rich in hemicellulosic contents. The subsequent conversion of available sugars in PPW can provide prospective strategy for cost-effective bioenergy production. In this study, an experimental setup based on CCD was implemented with the aim of bioconversion of biomass into bioethanol. The factors considered were Hydrochloric acid concentration (X1), the hydrolysis temperature (X2) and time (X3) for optimization with dilute Hydrochloric acid (HCl) saccharification. The present study investigates the optimised level of bioethanol synthesis from acid pre-treated PPW explained by RSM. Subsequently, three yeasts viz. Saccharomyces cerevisiae K7, Metschnikowia sp. Y31 and M. cibodasensis Y34 were utilized for fermentation of acid hydrolysed and detoxified feed stocks. Optimum values of reducing sugars 48.02 ± 0.02 (gL?1) and total carbohydrates 205.88 ± 0.13 (gL?1) were found when PPW was hydrolyzed with 1% HCl concentration at 100?C of temperature for 30 min. Later on, fermentation of PPWH after detoxification with 2.5% activated charcoal. The significant ethanol (g ethanol/g of reducing sugars) yields after fermentation with Metschnikowia sp. Y31 and M. cibodasensis Y34 found to be 0.40 ± 0.03 on day 5 and 0.41 ± 0.02 on last day of experiment correspondingly. Saccharomyces cerevisiae K7 also produce maximum ethanol 0.40 ± 0.00 on last day of incubation utilizing the PPWH. The bioconversion of commonly available PPW into bioethanol as emphasize in this study could be a hopeful expectation and also cost-effective to meet today energy crisis. 相似文献
609.
Schistosomes are parasitic worms that can live in the bloodstream of their vertebrate hosts for many years. It has been proposed that the worms impinge on host purinergic signalling by degrading proinflammatory molecules like ATP as well as prothrombotic mediators like ADP. This capability may help explain the apparent refractoriness of the worms to both immune elimination and thrombus formation. Three distinct ectoenzymes, expressed at the host-exposed surface of the worm’s tegument, are proposed to be involved in the catabolism of ATP and ADP. These are alkaline phosphatase (SmAP), phosphodiesterase (SmNPP-5), and ATP diphosphohydrolase (SmATPDase1). It has recently been shown that only one of these enzymes—SmATPDase1—actually degrades exogenous ATP and ADP. However, a second ATP diphosphohydrolase homolog (SmATPDase2) is located in the tegument and has been reported to be released by the worms. It is possible that this enzyme too participates in the cleavage of exogenous nucleotide tri- and di-phosphates. To test this hypothesis, we employed RNA interference (RNAi) to suppress the expression of the schistosome SmATPDase1 and SmATPDase2 genes. We find that only SmATPDase1-suppressed parasites are significantly impaired in their ability to degrade exogenously added ATP or ADP. Suppression of SmATPDase2 does not appreciably affect the worms’ ability to catabolize ATP or ADP. Furthermore, we detect no evidence for the secretion or release of an ATP-hydrolyzing activity by cultured parasites. The results confirm the role of tegumental SmATPDase1, but not SmADTPDase2, in the degradation of the exogenous proinflammatory and prothrombotic nucleotides ATP and ADP by live intravascular stages of the parasite. 相似文献
610.