全文获取类型
收费全文 | 2445篇 |
免费 | 180篇 |
国内免费 | 2篇 |
出版年
2024年 | 2篇 |
2023年 | 27篇 |
2022年 | 70篇 |
2021年 | 143篇 |
2020年 | 150篇 |
2019年 | 256篇 |
2018年 | 204篇 |
2017年 | 141篇 |
2016年 | 133篇 |
2015年 | 126篇 |
2014年 | 158篇 |
2013年 | 218篇 |
2012年 | 182篇 |
2011年 | 180篇 |
2010年 | 95篇 |
2009年 | 101篇 |
2008年 | 102篇 |
2007年 | 83篇 |
2006年 | 74篇 |
2005年 | 44篇 |
2004年 | 48篇 |
2003年 | 25篇 |
2002年 | 25篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1980年 | 3篇 |
1975年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有2627条查询结果,搜索用时 203 毫秒
11.
12.
A new haemoglobin variant (haemoglobin Arya), is described from an Iranian female. The substitution is at residue 47 (CD5) of the alpha chain in which aspartic acid has been substituted by asparagine. The presence of haemoglobin Arya was not associated with clinical symptoms. This variant has normal stability at 50 degrees C, but is slightly unstable when tested at 55 degrees C. 相似文献
13.
Lander-Waterman’s coverage bound establishes the total number of reads required to cover the whole genome of size G bases. In fact, their bound is a direct consequence of the well-known solution to the coupon collector’s problem which proves that for such genome, the total number of bases to be sequenced should be O(G ln G). Although the result leads to a tight bound, it is based on a tacit assumption that the set of reads are first collected through a sequencing process and then are processed through a computation process, i.e., there are two different machines: one for sequencing and one for processing. In this paper, we present a significant improvement compared to Lander-Waterman’s result and prove that by combining the sequencing and computing processes, one can re-sequence the whole genome with as low as O(G) sequenced bases in total. Our approach also dramatically reduces the required computational power for the combined process. Simulation results are performed on real genomes with different sequencing error rates. The results support our theory predicting the log G improvement on coverage bound and corresponding reduction in the total number of bases required to be sequenced. 相似文献
14.
15.
Abdolkarim Moazeni-Roodi Saeid Ghavami Hossein Ansari Mohammad Hashemi 《Journal of cellular biochemistry》2019,120(8):13583-13597
Flap endonuclease 1 (FEN1) has emerged as an important enzyme in the maintenance of genomic instability and preventing carcinogenesis. The relationship between FEN1 −69G>A (rs174538)+4150G>T (rs4246215) polymorphisms and cancer susceptibility has been reported; however, results were inconclusive. In the present study, a meta-analysis of data from eligible reports was carried out to summarize the possible relationship between FEN1 polymorphisms and cancer risk. A total of 11 articles, including 20 studies with 7366 cases and 9028 controls and 18 studies with 6649 cases and 8325 controls for FEN1 rs174538 and FEN1 rs4246215 polymorphisms, respectively, were recruited for meta-analysis. Overall, meta-analyses showed that FEN1 rs174538 and rs4246215 polymorphisms are significantly associated with the decreased risk of cancer. The stratified analysis proposed that both variants were associated with protection against gastrointestinal cancer, breast cancer, hepatocellular cancer, esophageal cancer, gastric cancer, colorectal cancer, and lung cancer. In conclusion, this meta-analysis revealed an association between FEN1 polymorphisms and cancer risk. Additional studies in a larger study population that include subjects from a variety of ethnicities are warranted to further verify our findings. 相似文献
16.
In vitro improvement of quail primordial germ cell expansion through activation of TGF‐beta signaling pathway
下载免费PDF全文
![点击此处可从《Journal of cellular biochemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
17.
Marzieh Taghipour Shamsollah Ayoubi Hossein Khademi 《Soil & Sediment Contamination》2011,20(8):921-937
Heavy metals’ origin, accumulation, and distribution in soil have been the focus of much attention by many researchers. The objective of this study was to recognize the sources of heavy metals in surface soils in Hamadan Province in western Iran using multivariate geostatistical techniques. A total of 263 surface (0–10 cm) soil samples and 18 rock samples from major parent materials were collected. Cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) contents of the samples were determined. Selected soil physical and chemical characteristics were also measured. A multivariate geostatistical analysis was performed to identify the common source of heavy metals. The quantities of Co, Cr, and Ni were found to be associated with parent rocks, corresponding to the first factor termed the “lithologic component.” The second factor was mainly attributed to Cu, which also comprised the first and third factors, indicating a mixed source both from lithologic and anthropogenic inputs. Zn and Pb contents were related to the anthropogenic activities and comprised the third factor. A significant correlation was found between metals from the lithogenic sources and selected soil properties such as soil organic matter, clay, CEC, and carbonate, indicating an interaction among them. Generally, Zn and Pb showed a less significant correlation with soil properties. 相似文献
18.
Omid Haghighi Soheila Davaeifar Hossein Shahbani Zahiri Hadi Maleki Kambiz Akbari Noghabi 《International journal of peptide research and therapeutics》2020,26(2):783-793
Glutamate dehydrogenase (GDH), which is present in most bacteria and eukaryotes’ mitochondria, plays an important role in amino acid metabolism. In g 相似文献
19.
Effect of Drought Stress on Certain Morphological and Physiological Characteristics of a Resistant and a Sensitive Canola Cultivar 总被引:1,自引:0,他引:1
Ghorban Khodabin Zeinolabedin Tahmasebi‐Sarvestani Amir Hossein Shirani Rad Seyed Ali Mohammad Modarres‐Sanavy 《化学与生物多样性》2020,17(2)
Water stress is one of the main abiotic factors that reduces plant growth, mainly due to high evaporative demand and low water availability. In order to evaluate the effects of drought stress on certain morphological and physiological characteristics of two canola cultivars, we conducted a factorial experiment based on a completely randomized design. The findings show that drought stress exacerbations result in the plant's response to stress due to increased canola resistance caused by changes in plant pigments, proline, catalase, ascorbate peroxidase, peroxidase, superoxide dismutase and malondialdehyde, glucose, galactose, rhamnose and xylose. These in turn ultimately influence the morphological characteristics of canola. Drought stress reduces the concentration of carotenoids, chlorophyll a, chlorophyll b, total chlorophylls; however, glucose, galactose, rhamnose, xylose, proline, catalase, ascorbate peroxidase, peroxidase, superoxide dismutase, malondialdehyde (in leaves and roots) and the chlorophyll a and b ratios were increased. Reduction of plant height, stem height, root length, fresh and dry weight of canola treated with 300 g/l PEG compared to non‐treatment were 0.264, 0.236, 0.394, 0.183 and 0.395, respectively. From the two canola cultivars, the morphological characteristics of the NIMA increased compared to the Ks7 cultivar. Interaction effects of cultivar and drought stress showed that NIMA cultivar without treatment had the highest number of morphological characteristics such as carotenoid concentration, chlorophyll a, chlorophyll b, total chlorophylls a and b, whereas the cultivar with 300 g/l PEG (drought stress) had the highest amount of proline, malondialdehyde, soluble sugars and enzymes in leaves and roots. Increasing activity of oxidative enzymes and soluble sugars in canola under drought stress could be a sign of their relative tolerance to drought stress. 相似文献
20.
Foroughi Kobra Jahanbani Sarvin Nazarnezhad Simin Khastar Hossein Jafarisani Moslem Tashakori Mersedeh Kazemi Seyedeh Sareh 《International journal of peptide research and therapeutics》2020,26(2):1115-1126
International Journal of Peptide Research and Therapeutics - Survivin is a unique member of the inhibitor of apoptosis protein family. Research has approved Survivin’s ability to interact... 相似文献