全文获取类型
收费全文 | 692篇 |
免费 | 51篇 |
国内免费 | 1篇 |
专业分类
744篇 |
出版年
2023年 | 2篇 |
2022年 | 12篇 |
2021年 | 20篇 |
2020年 | 14篇 |
2019年 | 6篇 |
2018年 | 16篇 |
2017年 | 13篇 |
2016年 | 14篇 |
2015年 | 27篇 |
2014年 | 32篇 |
2013年 | 63篇 |
2012年 | 55篇 |
2011年 | 54篇 |
2010年 | 34篇 |
2009年 | 33篇 |
2008年 | 52篇 |
2007年 | 43篇 |
2006年 | 33篇 |
2005年 | 34篇 |
2004年 | 35篇 |
2003年 | 22篇 |
2002年 | 38篇 |
2001年 | 2篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1975年 | 2篇 |
1973年 | 4篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 1篇 |
1969年 | 3篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1962年 | 2篇 |
1960年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有744条查询结果,搜索用时 15 毫秒
41.
Cloning and characterization of a calcium-binding,histamine-releasing protein from Schistosoma mansoni 总被引:9,自引:0,他引:9
Rao KV Chen L Gnanasekar M Ramaswamy K 《The Journal of biological chemistry》2002,277(34):31207-31213
42.
43.
Role of macrophage-colony stimulating factor and osteoclast differentiation factor in osteoclastogenesis of bone marrow derived stem cells 总被引:3,自引:0,他引:3
Macrophage colony stimulating factor (M-CSF) and osteoclast differentiation factor (ODF) regulate osteoclastogenesis in vivo. Regulation of osteoclast development in vitro by these cytokines has been reported in the present study. Simultaneous addition of ODF and M-CSF during initiation of bone marrow culture inhibited osteoclastogenesis. However, delayed addition of ODF (three days after initiation of the culture) resulted in dramatic increase in phenotypically and functionally mature osteoclast cells. Delayed addition of ODF beyond day three decreased osteoclastogenesis. Further, removal of M-CSF as early as day three inhibited ODF-induced osteoclastogenesis. These studies provided evidence for the importance of co-ordinated regulation of osteoclastogenesis by M-CSF and ODF. 相似文献
44.
45.
Rady PL Surendran S Vu AT Hawkins JC Michals-Matalon K Tyring SK Merren J Kumar AK Matalon R 《Genetic testing》2002,6(3):211-215
Sanfilippo A syndrome is an autosomal recessive lysosomal storage disease. This disease was reported in the Cayman Islands population with carrier frequency of 1/7 to 1/10 in the West Bay district of Grand Cayman. The carrier testing of Sanfilippo A disease for families at risk was carried out using the thermal characteristics of sulfamidase activity. In the present study, a search for mutations in the sulfamidase gene in an index family was performed. In addition, 77 individuals, relatives of children with Sanfilippo A syndrome, were also studied by single-strand conformation polymorphism (SSCP), restriction fragment-length polymorphism (RFLP) analyses, and sequencing. A single mutation, G746A (R245H), was found in the family, with the patient being homozygous and both parents and 1 of the 3 siblings being carriers. Among the 77 family members of the patient with Sanfilippo syndrome, the same mutation was found among carriers of the disease. The finding of a single mutation supports the idea of a founder effect, which facilitates accurate carrier identification of Sanfilippo A syndrome in the population of Cayman Islands. 相似文献
46.
16.1% Efficient Hysteresis‐Free Mesostructured Perovskite Solar Cells Based on Synergistically Improved ZnO Nanorod Arrays
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Significant efficiency improvements are reported in mesoscopic perovskite solar cells based on the development of a low‐temperature solution‐processed ZnO nanorod (NR) array exhibiting higher NR aspect ratio, enhanced electron density, and substantially reduced work function than conventional ZnO NRs. These features synergistically result in hysteresis‐free, scan‐independent, and stabilized devices with an efficiency of 16.1%. Electron‐rich, nitrogen‐doped ZnO (N:ZnO) NR‐based electron transporting materials (ETMs) with enhanced electron mobility produced using ammonium acetate show consistently higher efficiencies by one to three power points than undoped ZnO NRs. Additionally, the preferential electrostatic interaction between the nonpolar facets of N:ZnO and the conjugated polyelectrolyte polyethylenimine (PEI) has been relied on to promote the hydrothermal growth of high aspect ratio NR arrays and substantially improve the infiltration of the perovskite light absorber into the ETM. Using the same interactions, a conformal PEI coating on the electron‐rich high aspect ratio N:ZnO NR arrays is successfully applied, resulting in a favorable work function shift and altogether leading to the significant boost in efficiency from <10% up to >16%. These results largely surpass the state‐of‐the‐art PCE of ZnO‐based perovskite solar cells and highlight the benefits of synergistically combining mesoscale control with doping and surface modification. 相似文献
47.
Subhadeep Bhattacharjee Vinod Kumar Mithileshwari Chandrasekhar Manjari Malviya Andre Ganswindt Krishnamurthy Ramesh Kalyanasundaram Sankar Govindhaswamy Umapathy 《PloS one》2015,10(6)
Tiger (Panthera tigris), an endangered species, is under severe threat from poaching, habitat loss, prey depletion and habitat disturbance. Such factors have been reported causing local extermination of tiger populations including in one of the most important reserves in India, namely Sariska Tiger Reserve (STR) in northwestern India. Consequently, tigers were reintroduced in STR between 2008 and 2010, but inadequate breeding success was observed over the years, thus invoking an investigation to ascertain physiological correlates. In the present study, we report glucocorticoid stress responses of the reintroduced tigers in relation to anthropogenic disturbance in the STR from 2011 to 2013. We found anthropogenic disturbance such as encounter rates of livestock and humans, distance to roads and efforts to kill domestic livestock associated with an elevation in fecal glucocorticoid metabolite (fGCM) concentrations in the monitored tigers. In this regard, female tigers seem more sensitive to such disturbance than males. It was possible to discern that tiger’s fGCM levels were significantly positively related to the time spent in disturbed areas. Resulting management recommendations include relocation of villages from core areas and restriction of all anthropogenic activities in the entire STR. 相似文献
48.
Ranju Chowdhury Paulo J.C. Favas J. Pratas M. P. Jonathan P. Sankar Ganesh Santosh Kumar Sarkar 《International journal of phytoremediation》2015,17(9):885-894
The work investigates on the potential of ten mangrove species for absorption, accumulation and partitioning of trace metal(loid)s in individual plant tissues (leaves, bark and root/pneumatophore) at two study sites of Indian Sundarban Wetland. The metal(loid) concentration in host sediments and their geochemical characteristics were also considered. Mangrove sediments showed unique potential in many- fold increase for most metal(loid)s than plant tissues due to their inherent physicochemical properties. The ranges of concentration of trace metal(loid)s for As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn in plant tissue were 0.006–0.31, 0.02–2.97, 0.10–4.80, 0.13–6.49, 4.46–48.30, 9.2–938.1, 0.02–0.13, 9.8–1726, 11–5.41, 0.04–7.64, 3.81–52.20 μg g ?1respectively. The bio- concentration factor (BCF) showed its maximum value (15.5) in Excoecaria agallocha for Cd, suggesting that it can be considered as a high-efficient plant for heavy metal bioaccumulation. Among all metals, Cd and Zn were highly bioaccumulated in E. agallocha (2.97 and 52.2 μg g ?1 respectively. Our findings suggest that the species may be classified as efficient metal trap for Cd in aerial parts, as indicated by higher metal accumulation in the leaves combined with BCF and translocation factor (TF) values. 相似文献
49.
Randeep Singh Qamar Qureshi Kalyanasundaram Sankar Paul R. Krausman Surendra Prakash Goyal Kerry L. Nicholson 《Acta theriologica》2014,59(4):521-527
We used camera trapping in conjunction with a spatial explicit capture–recapture model to estimate striped hyena (Hyaena hyaena) density and occupancy models to investigate factors affecting striped hyena detection probabilities in Ranthambhore Tiger Reserve (RTR), Rajasthan, India. A sampling effort of 4,450 trap days/nights over 75 days yield 68 photo captures of 21 unique striped hyenas (based on individual markings and visual identification); the estimated striped hyena density was 5.49?±?1.27 individuals/100 km2. Results of our occupancy model suggested that a rugged terrain is an important factor that influences striped hyena detection probability. Correlation with striped hyena detection with human settlement provides evidence of social tolerance of striped hyena towards humans, and more occurrence of resources allowed coexistence of hyena in a human-dominated landscape. This elasticity (inhabited areas close to humans) demonstrated by striped hyenas is an exception among carnivore communities living in this semi-arid habitat. 相似文献
50.
Nobuhisa Ozaki Arigala Uma Ravi Sankar Mitsuji Yamashita Takashi Aoki Yasutaka Tanaka Motohiko Kimura Mitsuo Toda Michio Fujie Yasuo Takehara Harumi Sakahara 《Bioorganic & medicinal chemistry letters》2010,20(3):932-934
A new type of dendritic molecules Gd-DTPA-XDA-D1-Glc(OH), which work as a functionalized ligand coordinating gadolinium(III) ion at the center of their frameworks with two glucose moieties on the molecular surfaces, were readily synthesized with high yield. The structures were established by IR, 1H, 13C NMR, and mass spectral studies. Its bio-distribution patterns were evaluated on rats. 相似文献