全文获取类型
收费全文 | 1740篇 |
免费 | 93篇 |
国内免费 | 4篇 |
出版年
2023年 | 21篇 |
2022年 | 36篇 |
2021年 | 114篇 |
2020年 | 41篇 |
2019年 | 58篇 |
2018年 | 77篇 |
2017年 | 54篇 |
2016年 | 58篇 |
2015年 | 83篇 |
2014年 | 103篇 |
2013年 | 121篇 |
2012年 | 118篇 |
2011年 | 126篇 |
2010年 | 50篇 |
2009年 | 48篇 |
2008年 | 70篇 |
2007年 | 58篇 |
2006年 | 72篇 |
2005年 | 47篇 |
2004年 | 30篇 |
2003年 | 35篇 |
2002年 | 27篇 |
2001年 | 33篇 |
2000年 | 30篇 |
1999年 | 28篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1995年 | 4篇 |
1994年 | 19篇 |
1993年 | 10篇 |
1992年 | 17篇 |
1991年 | 16篇 |
1990年 | 20篇 |
1989年 | 18篇 |
1988年 | 12篇 |
1987年 | 17篇 |
1986年 | 15篇 |
1985年 | 21篇 |
1984年 | 12篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1979年 | 6篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1974年 | 8篇 |
1973年 | 6篇 |
1972年 | 8篇 |
1971年 | 8篇 |
1970年 | 7篇 |
排序方式: 共有1837条查询结果,搜索用时 15 毫秒
991.
Hussain MM Obunike JC Shaheen A Hussain MJ Shelness GS Goldberg IJ 《The Journal of biological chemistry》2000,275(38):29324-29330
Lipoprotein lipase (LPL) physically associates with lipoproteins and hydrolyzes triglycerides. To characterize the binding of LPL to lipoproteins, we studied the binding of low density lipoproteins (LDL), apolipoprotein (apo) B17, and various apoB-FLAG (DYKDDDDK octapeptide) chimeras to purified LPL. LDL bound to LPL with high affinity (K(d) values of 10(-12) m) similar to that observed for the binding of LDL to its receptors and 1D1, a monoclonal antibody to LDL, and was greater than its affinity for microsomal triglyceride transfer protein. LDL-LPL binding was sensitive to both salt and detergents, indicating the involvement of both hydrophobic and hydrophilic interactions. In contrast, the N-terminal 17% of apoB interacted with LPL mainly via ionic interactions. Binding of various apoB fusion peptides suggested that LPL bound to apoB at multiple sites within apoB17. Tetrahydrolipstatin, a potent enzyme activity inhibitor, had no effect on apoB-LPL binding, indicating that the enzyme activity was not required for apoB binding. LDL-LPL binding was inhibited by monoclonal antibodies that recognize amino acids 380-410 in the C-terminal region of LPL, a region also shown to interact with heparin and LDL receptor-related protein. The LDL-LPL binding was also inhibited by glycosaminoglycans (GAGs); heparin inhibited the interactions by approximately 50% and removal of trace amounts of heparin from LPL preparations increased LDL binding. Thus, we conclude that the high affinity binding between LPL and lipoproteins involves multiple ionic and hydrophobic interactions, does not require enzyme activity and is modulated by GAGs. It is proposed that LPL contains a surface exposed positively charged amino acid cluster that may be important for various physiological interactions of LPL with different biologically important molecules. Moreover, we postulate that by binding to this cluster, GAGs modulate the association between LDL and LPL and the in vivo metabolism of LPL. 相似文献
992.
Using data derived from the 1992-1993 National Family Health Survey, the sociodemographic characteristics of consanguineous marriage were determined in the Muslim population of India. In this nationally representative sample of 8436 women, consanguineous marriages accounted for 22.0% of the total. No differences between the consanguineous and non-consanguineous groups were observed in terms of mean age at marriage or mean age at cohabitation. The study confirmed the negative association between consanguineous marriage and maternal education but also indicated that women in consanguineous unions were more likely to be employed, albeit mainly in agricultural work on behalf of the family. Consanguineous couples more frequently lived in smaller towns and in an extended family environment. Somewhat conflicting results were obtained with indicators of socioeconomic status, but the overall picture suggested that consanguineous households had greater access to consumer goods because of their larger number of co-resident persons. 相似文献
993.
994.
Muhammad Ahsan Asghar Bushra Ahmad Ali Raza Bilal Adil Hafz Hassan Javed Muhammad Umer Farooq Abuzar Ghafoor Muhammad Iftikhar Hussain Iram Shafq Hassan Karim Xin Sun Wenyu Yang Gábor Kocsy Junbo Du 《Journal of Plant Ecology》2022,15(6):1107
荫蔽和微生物可在分子水平上调控植物激素以增强植物的耐旱性
植物在其生命周期内会受到一系列不利环境的影响。其中,干旱胁迫是限制农业生产力的重要因素之一。为了在逆境的环境中得以生存,植物进化出了识别环境胁迫严重性的机制。植物可通过多种方式调节激素活性,以减轻干旱带来的不良影响。受荫蔽和微生物调控,植株的抗旱性提高,产量损失减少。脱落酸、生长素和乙烯等植物激素,可调控多种代谢途径,在荫蔽和微生物介导的植株抗旱性增强过程中起着重要作用。如我们的调控模型所示,CLAVATA3/EMBRYOSURROUNDING REGION-RELATED 25多肽因其可影响ABA合成而在此过程中具有重要作用。 相似文献
995.
996.
997.
Hussain I Hawkins J Harrison D Hille C Wayne G Cutler L Buck T Walter D Demont E Howes C Naylor A Jeffrey P Gonzalez MI Dingwall C Michel A Redshaw S Davis JB 《Journal of neurochemistry》2007,100(3):802-809
Generation and deposition of the amyloid beta (Abeta) peptide following proteolytic processing of the amyloid precursor protein (APP) by BACE-1 and gamma-secretase is central to the aetiology of Alzheimer's disease. Consequently, inhibition of BACE-1, a rate-limiting enzyme in the production of Abeta, is an attractive therapeutic approach for the treatment of Alzheimer's disease. We have designed a selective non-peptidic BACE-1 inhibitor, GSK188909, that potently inhibits beta-cleavage of APP and reduces levels of secreted and intracellular Abeta in SHSY5Y cells expressing APP. In addition, we demonstrate that this compound can effectively lower brain Abeta in vivo. In APP transgenic mice, acute oral administration of GSK188909 in the presence of a p-glycoprotein inhibitor to markedly enhance the exposure of GSK188909 in the brain decreases beta-cleavage of APP and results in a significant reduction in the level of Abeta40 and Abeta42 in the brain. Encouragingly, subchronic dosing of GSK188909 in the absence of a p-glycoprotein inhibitor also lowers brain Abeta. This pivotal first report of central Abeta lowering, following oral administration of a BACE-1 inhibitor, supports the development of BACE-1 inhibitors for the treatment of Alzheimer's disease. 相似文献
998.
Muhammad Shuaib Sajjad Ahmed Kashif Ali Muhammad Ilyas Firasat Hussain Zara Urooj Syed Sadaqat Shah Tanweer Kumar Muzammil Shah Ikramullah Khan Fida Hussain 《农业工程》2019,39(1):109-115
Background
Ethnobotanical and ecological study of plants is very important in understanding the culture of a society and it provides a base for further study on scientific lines. This paper, the use of medicinal plants and their role in the treatment of different diseases have been duly observed and noted in Tehsil Timergara.Methods
The survey was carried out from September 2014 to October 2016. During this survey, a total of 16 trips with 4 in each season were carried out to collect data. A total of 115 respondents were interviewed through questionnaires regarding the available medicinal plants; most of the respondents were 65 to 80?years old. The obtained ethnobotanical data was then analyzed by Frequency Citation (FC), Relative Frequency Citation index (RFC), and Use Value index (UV) to find the most common plants species used for various diseases.Results
The local community of the study area, 59 plant species belonging to 39 genera, 28 families for different medicinal purposes. During the survey 38 species were herbs, 6 shrubs, and 15 trees. Leaf and whole plants were most frequently used parts in making of medicine while 30% of the whole plant was used in the ethnobotanical uses. A total of 46 plants showed important value in the ethnomedicinal purpose, in which the highest number of species (11) were used for chest problem particularly in a cough, as laxatives (4) and in asthma (5 species), 14 species were used as fuel which is also an important feature of the plants. Soil analysis of five collection area is studied.Conclusion
The current result of RFC and UV shows that medicinal flora needs to be pharmacologically and phytochemically investigated to prove their efficacy. The documentation of medicinal knowledge is important to preserve this precious old knowledge before it is lost forever, due to technological and environmental changes in the world. 相似文献999.
Molecular and Morphometric Characteristics of Ceratomyxa hamour n. sp. (Myxosporea: Bivalvulida) Infecting the Gallbladder of the Orange‐spotted Grouper Epinephelus coioides from the Arabian Gulf,Saudi Arabia 下载免费PDF全文
Lamjed Mansour Hussain A. Al‐Qahtani Saleh Al‐Quraishy Abdel‐Azeem S. Abdel‐Baki 《The Journal of eukaryotic microbiology》2015,62(1):95-101
Ceratomyxa hamour n. sp. was found to infect the gallbladder of the orange‐spotted grouper, Epinephelus coioides located off the Saudi Arabian coast of the Arabian Gulf. The infection was reported as a free‐floating spore in the bile, and pseudoplasmodia were not observed. Mature spores were crescent‐shaped and measured on average 7 μm in length and 16 μm in thickness. The polar capsule, meanwhile, had length to width measurements of 4 μm and 3 μm on average. A periodical survey was conducted throughout a sampling period between December 2012 and December 2013, with the results showing that the parasite was present throughout the year with a mean prevalence of 32.6%. The objective of this study was to characterize this new species based on its morphological and molecular differences from previously described species. Molecular analysis based on the partial sequence of the SSU rDNA gene, showed the highest similarity (97.8%) to Ceratomyxa buri, reported in the cultured yellow tail Seriola quinqueradiata in Japan. Indeed, C. buri and the new species described here formed an individual cluster with a high degree of bootstrap support. This is the first reported species of genus Ceratomyxa from the Arabian Gulf fishes off Saudi Arabia. 相似文献
1000.
Muhammad Ramzan Manwar Hussain Mukhtiar Baig Hussein Sheik Ali Mohamoud Zaheer Ulhaq Daniel C. Hoessli Ghaidaa Siraj Khogeer Ranem Radwan Al-Sayed Jumana Yousuf Al-Aama 《Saudi Journal of Biological Sciences》2015,22(4):359-373
The BRAF gene encodes for a serine/threonine protein kinase that participates in the MAPK/ERK signalling pathway and plays a vital role in cancers and developmental syndromes (RASopathies). The current review discusses the clinical significance of the BRAF gene and other members of RAS/RAF cascade in human cancers and RAS/MAPK syndromes, and focuses the molecular basis and clinical genetics of BRAF to better understand its parallel involvement in both tumourigenesis and RAS/MAPK syndromes—Noonan syndrome, cardio-facio-cutaneous syndrome and LEOPARD syndrome. 相似文献