全文获取类型
收费全文 | 1164篇 |
免费 | 40篇 |
国内免费 | 1篇 |
专业分类
1205篇 |
出版年
2023年 | 17篇 |
2022年 | 40篇 |
2021年 | 50篇 |
2020年 | 26篇 |
2019年 | 35篇 |
2018年 | 53篇 |
2017年 | 40篇 |
2016年 | 51篇 |
2015年 | 61篇 |
2014年 | 68篇 |
2013年 | 91篇 |
2012年 | 101篇 |
2011年 | 71篇 |
2010年 | 34篇 |
2009年 | 38篇 |
2008年 | 37篇 |
2007年 | 32篇 |
2006年 | 24篇 |
2005年 | 20篇 |
2004年 | 15篇 |
2003年 | 21篇 |
2002年 | 18篇 |
2001年 | 20篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 14篇 |
1989年 | 10篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1960年 | 4篇 |
1953年 | 3篇 |
1938年 | 5篇 |
1936年 | 9篇 |
1935年 | 5篇 |
1933年 | 8篇 |
1932年 | 9篇 |
1931年 | 9篇 |
1929年 | 7篇 |
1923年 | 3篇 |
1918年 | 3篇 |
排序方式: 共有1205条查询结果,搜索用时 0 毫秒
51.
52.
An in vitro propagation system for Artemisia vulgaris L., a traditional medicinal plant, has been developed. The best organogenic response, including adventitious shoot number
and elongation, was obtained when hypocotyl segments were cultured onto MS medium supplemented with 4.54 μM TDZ (N-phenyl-N′-(1,2,3-thidiazol-yl) urea). Up to 28 shoots formed per explant for an optimal duration of exposure of 48 days. Regenerated
shoots formed roots when subcultured onto a medium containing 8.56 μM IAA (indole-3-acetic acid). Healthy plantlets were transferred
to a garden soil:farmyard soil:sand (2:1:1) mixture for acclimatization, which was successful, and subsequent maturity was
achieved under greenhouse conditions over a six-month period. The survival rate of the plantlets varied under acclimatization.
The regeneration protocol developed in this study provides a basis for germplasm conservation and for further investigation
of medicinally active constituents of A. vulgaris. This optimized protocol has been successfully employed for genetic transformation studies in A. vulgaris, which are currently underway in our laboratory. 相似文献
53.
54.
55.
In order to identify a high carbon-sequestering microalgal strain, the physiological effect of different concentrations of carbon sources on microalgae growth was investigated. Five indigenous strains (I-1, I-2, I-3, I-4 and I-5) and a reference strain (I-0: Coccolithus pelagicus 913/3) were subjected to CO2 concentrations of 0.03–15% and NaHCO3 of 0.05–2 g CO2 l–1. The logistic model was applied for data fitting, as well as for estimation of the maximum growth rate (μmax) and the biomass carrying capacity (Bmax). Amongst the five indigenous strains, I-3 was similar to the reference strain with regards to biomass production values. The Bmax of I-3 significantly increased from 214 to 828 mg l–1 when CO2 concentration was increased from 0.03 to 15% (r = 0.955, P = 0.012). Additionally, the Bmax of I-3 increased with increasing NaHCO3 (r = 0.885, P = 0.046) and was recorded at 153 mg l–1 (at 0.05 g CO2 l–1) and 774 mg l–1 at (2 g CO2 l–1). Relative electron transport rate (rETR) and maximum quantum yield (Fv/Fm) were also applied to assess the impact of elevated carbon sources on the microalgal cells at the physiological level. Isolate I-3 displayed the highest rETR confirming its tolerance to higher quantities of carbon. Additionally, the decline in Fv/Fm with increasing carbon was similar for strains I-3 and the reference strain. Based on partial 28s ribosomal RNA gene sequencing, strain I-3 was homologous to the ribosomal genes of Chlorella sp. 相似文献
56.
57.
Cardioprotective effect of lycopene in the experimental model of myocardial ischemia-reperfusion injury 总被引:1,自引:0,他引:1
Shervington A Cruickshanks N Wright H Atkinson-Dell R Lea R Roberts G Shervington L 《Molecular and cellular biochemistry》2006,283(1-2):1-9
The continuous advancements in cancer research have contributed to the overwhelming evidence of the presence of telomerase
in primary and secondary tumours together with hsp90 and c-Myc. This review will discuss the important role of telomerase together with hsp90 and c-Myc within the initiation and progression of gliomas. Also it will review the differential expression of these genes in the different
grades of gliomas and the possibility of new treatments targeting these specific genes. 相似文献
58.
The Natural Occurrence of Chickpea Chlorotic Dwarf Geminivirus in Chickpea and Faba Bean in the Sudan 总被引:1,自引:0,他引:1
A survey of faba bean and chickpea for virus infection, conducted during February 1994 in the Sudan, showed that bean yellow mosaic potyvirus and broad bean mottle bromovirus occurred commonly in both crops. Chickpea chlorotic dwarf geminivirus (CCDV) was detected for the first time in naturally infected chickpeas and faba beans. This is the first report of natural CCDV infection of chickpeas outside India and the first record of chickpea and faba bean infection in West Asia and North Africa (WANA). 相似文献
59.
Mesenchymal stromal cells (MSCs) show promise in cell-based transplantations and regenerative medicine applications. MSCs from Wharton’s jelly (WJ) of umbilical cord can be easily harvested and exhibit greater proliferative activity than bone marrow MSCs. It is important to develop a practical cryopreservation technique to effectively store umbilical cord for potential future applications. Successful cryopreservation would allow access to umbilical cord from the same donor for repeated WJ MSC-based transplantations. For therapeutic applications, one should be able to obtain clinically-relevant quality and quantity of MSCs from cryopreserved tissues. In this study, we optimised a serum-free formulation of 10% dimethyl sulfoxide (DMSO) and 0.2 M sucrose for cryopreservation of umbilical cord tissue. Slow freezing and rapid thawing were adopted. MSCs harvested from WJ of cryopreserved umbilical cord could undergo robust expansion, differentiate to mesodermal lineages and express MSC-characteristic surface antigens. The cumulative cell yield, however, was less compared to corresponding fresh cord tissue. 相似文献
60.
Ramdhan Yadav Dharmesh Kumar Avnesh Kumari Sudesh Kumar Yadav 《Biotechnology letters》2016,38(2):259-269