全文获取类型
收费全文 | 4864篇 |
免费 | 452篇 |
出版年
2024年 | 7篇 |
2023年 | 22篇 |
2022年 | 74篇 |
2021年 | 170篇 |
2020年 | 97篇 |
2019年 | 114篇 |
2018年 | 109篇 |
2017年 | 107篇 |
2016年 | 173篇 |
2015年 | 306篇 |
2014年 | 311篇 |
2013年 | 337篇 |
2012年 | 450篇 |
2011年 | 460篇 |
2010年 | 273篇 |
2009年 | 243篇 |
2008年 | 316篇 |
2007年 | 299篇 |
2006年 | 267篇 |
2005年 | 244篇 |
2004年 | 226篇 |
2003年 | 200篇 |
2002年 | 167篇 |
2001年 | 25篇 |
2000年 | 21篇 |
1999年 | 16篇 |
1998年 | 33篇 |
1997年 | 17篇 |
1996年 | 8篇 |
1995年 | 15篇 |
1994年 | 11篇 |
1993年 | 10篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 17篇 |
1988年 | 5篇 |
1987年 | 13篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1982年 | 10篇 |
1981年 | 13篇 |
1980年 | 9篇 |
1978年 | 9篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1973年 | 9篇 |
1968年 | 6篇 |
排序方式: 共有5316条查询结果,搜索用时 328 毫秒
161.
162.
163.
164.
Jacob C. Ulirsch Jeffrey M. Verboon Shideh Kazerounian Michael H. Guo Daniel Yuan Leif S. Ludwig Robert E. Handsaker Nour J. Abdulhay Claudia Fiorini Giulio Genovese Elaine T. Lim Aaron Cheng Beryl B. Cummings Katherine R. Chao Alan H. Beggs Casie A. Genetti Colin A. Sieff Peter E. Newburger Hanna T. Gazda 《American journal of human genetics》2019,104(2):356
165.
166.
David J. Curnick Aaron B. Carlisle Matthew J. Gollock Robert J. Schallert Nigel E. Hussey 《Journal of fish biology》2019,94(4):680-685
Stable-isotope analyses (δ13C, δ15N and δ34S) of multiple tissues (fin, muscle, red blood cells and plasma), revealed ontogenetic shifts in resource use by grey reef sharks Carcharhinus amblyrhynchos and resource partitioning with silvertip sharks Carcharhinus albimarginatus within the British Indian Ocean Territory marine protected area (MPA). Resource partitioning varied temporally, with C. albimarginatus feeding on more pelagic prey during October to January, potentially attributable to an influx of pelagic prey from outside the MPA at that time. Reef sharks may therefore be affected by processes outside an MPA, even if the sharks do not leave the MPA. 相似文献
167.
Ching-Tsun Chang Wei-Chuan Chiang Yun-Chen Chang Michael K. Musyl Chi-Lu Sun Daniel J. Madigan Aaron B. Carlisle Hung-Hung Hsu Qi-Xuan Chang Nan-Jay Su Yuan-Shing Ho Chen-Te Tseng 《Journal of fish biology》2019,94(6):958-965
To gain a better understanding of the trophic ecology of Pacific blue marlin Makaira nigricans off eastern Taiwan, nitrogen and carbon stable isotopes (δ15N and δ13C) and Bayesian mixing models were used to explore trophic dynamics and potential ontogenetic feeding shifts across M. nigricans of different size classes. Makaira nigricans samples from east of Taiwan (n = 213) and Palau (n = 37), as well as their prey (n = 70), were collected during 2012 and 2013. Results indicated increases in δ15N with size, with values of larger size classes (> 200 cm eye-to-fork length; LEF) significantly higher than those < 200 cm LEF. Values of δ13C were negatively correlated with size. Makaira nigricans > 200 cm LEF had the highest estimated trophic position (4.44) and also exhibited ontogenetic changes in trophic position. Large M. nigricans fed more on dolphinfish Coryphaena hippurus and hairtail Trichiurus lepturus, while smaller M. nigricans consumed smaller forage fish (e.g., moonfish Mene maculata) and cephalopods. These changes may relate to greater swimming speeds and vertical habitat use in larger M. nigricans, allowing capture and consumption of larger prey items at higher trophic positions. The high trophic level of M. nigricans east of Taiwan confirms its important role as an apex predator in marine food webs and how ecological role changes with size. 相似文献
168.
Given the central role of light in the algal photosynthesis, respiration, cell division, growth and the accumulation of value products, the effects of light-emitting diodes (LEDs) light wavelengths (blue, white, red and green) were studied in Scenedesmus obliquus. Biomass, residual nutrient amount, soluble protein, astaxanthin and reactive oxygen species, superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity were analyzed to determine the effects of different monochromatic light wavelengths via biochemical methods. The results showed that blue light wavelength is the optimal light wavelength for phosphorus removal efficiency and the accumulation of biomass and astaxanthin in S. obliquus. Meanwhile, high reactive oxygen species content under the blue light might induce the accumulation of astaxanthin. The high activity of SOD, CAT and POD might participate in clearing the reactive oxygen species to facilitate the growth of microalgae. Furthermore, we found mixed blue/green lights treatment is the most appropriate mixture for the nitrogen removal. Under the blue light treatment, high light intensity and 18L:6D light cycle is the best condition for biomass and astaxanthin accumulation. Optimal nitrogen/phosphorus removal efficiency was observed under a 24L:0D light cycle. These results might provide a foundational data for the optimizing the productivity of high-value metabolites and treatment of wastewater. 相似文献
169.
Peres Tanara V. Horning Kyle J. Bornhorst Julia Schwerdtle Tanja Bowman Aaron B. Aschner Michael 《Biological trace element research》2019,188(1):127-134
Biological Trace Element Research - Manganese (Mn) is essential for several species and daily requirements are commonly met by an adequate diet. Mn overload may cause motor and psychiatric... 相似文献
170.
Thielen Beth K. Barnes Aaron M. T. Sabin Arick P. Huebner Becky Nelson Susan Wesenberg Elizabeth Hansen Glen T. 《Mycopathologia》2019,184(1):121-128
Mycopathologia - The Mucorales fungi—formerly classified as the zygomycetes—are environmentally ubiquitous fungi, but generally rare causes of clinical infections. In the... 相似文献