全文获取类型
收费全文 | 862篇 |
免费 | 47篇 |
出版年
2023年 | 14篇 |
2022年 | 20篇 |
2021年 | 34篇 |
2020年 | 23篇 |
2019年 | 20篇 |
2018年 | 26篇 |
2017年 | 31篇 |
2016年 | 40篇 |
2015年 | 53篇 |
2014年 | 37篇 |
2013年 | 67篇 |
2012年 | 73篇 |
2011年 | 68篇 |
2010年 | 48篇 |
2009年 | 30篇 |
2008年 | 41篇 |
2007年 | 28篇 |
2006年 | 30篇 |
2005年 | 25篇 |
2004年 | 36篇 |
2003年 | 7篇 |
2002年 | 27篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1977年 | 7篇 |
1976年 | 3篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 4篇 |
1966年 | 2篇 |
排序方式: 共有909条查询结果,搜索用时 15 毫秒
101.
P. A. Vikas N. K. Sajeshkumar P. C. Thomas Kajal Chakraborty K. K. Vijayan 《Hydrobiologia》2012,684(1):129-142
Autochthonous parthenogentic Artemia populations have been reported from Indian hypersaline habitats since 1950s. Exotic Artemia franciscana was imported and introduced into India as live food for aquaculture since the early eighties. To assess the present status
of the Artemia populations and the possibility of invasion by the introduced A. franciscana in Indian Salinas, an extensive study was conducted using conventional and molecular approaches. Morphological and biometric
observations, crossbreeding experiments and molecular and phylogenetic analysis using Internally Transcribed Spacer-1 sequence
revealed the extensive presence of alien, sexual A. franciscana populations in various hypersaline areas. Individual culture experiments and crossbreeding studies further confirmed the
absence of autochthonous parthenogentic Artemia populations. Lack of regional endemism in populations of distant origins was evident, indicating that the invaded populations
have naturalized and are in the process of evolution. This forms the first report of invasion by A.
franciscana in hypersaline habitats of Indian subcontinent and further studies are required to assess the biological implications of
this invasion. 相似文献
102.
Anticonvulsant property of Acorus calamus is known. Since combination therapy can lower the dose of individual drug and dose related toxicities, in this study, the effect of co-administration of hydroalcoholic extract of A. calamus (HAEAC) on conventional antiepileptic drugs (AEDs), sodium valproate and carbamazepine was determined using pentylenetetrazole-induced seizures model in rats. On combining the subanticonvulsant doses of HAEAC with sodium valproate and carbamazepine, greater protection as compared to either drug alone was observed. This was not related to change in levels of the AEDs. Thus, the results further substantiate anticonvulsant effect of HAEAC and suggest a potential for add on therapy with AEDs. 相似文献
103.
Kumar V Fahey PG Jong YJ Ramanan N O'Malley KL 《The Journal of biological chemistry》2012,287(8):5412-5425
104.
105.
Ahsan MJ Samy JG Jain CB Dutt KR Khalilullah H Nomani MS 《Bioorganic & medicinal chemistry letters》2012,22(2):969-972
In search of potential therapeutics for tuberculosis, we describe herewith the synthesis, characterization and antimycobacterial activity of 1,5-dimethyl-2-phenyl-4-([5-(arylamino)-1,3,4-oxadiazol-2-yl]methylamino)-1,2-dihydro-3H-pyrazol-3-one analogues. Among the synthesized compounds, 4-[(5-[(4-fluorophenylamino]-1,3,4-oxadiazol-2-yl)methylamino]-1,2-dihydro-1,5-dimethyl-2-phenylpyrazol-3-one (4a) was found to be the most promising compound active against Mycobacterium tuberculosis H(37)Rv and isoniazid resistant M. tuberculosis with minimum inhibitory concentrations, 0.78 and 3.12μg/mL, respectively, free from any cytotoxicity (>62.5μg/mL). 相似文献
106.
Background
Immune activation is a strong predictor of disease progression in HIV infection. Combinatorial plasma biomarker signatures that represent surrogate markers of immune activation in both viremic and aviremic HIV patients on combination antiretroviral therapy (cART) have not been defined. Here, we identify a plasma inflammatory biomarker signature that distinguishes between both viremic and aviremic HIV patients on cART and healthy controls and examine relationships of this signature to markers of disease progression.Methods
Multiplex profiling and ELISA were used to detect 15 cytokines/chemokines, soluble IL-2R (sIL-2R), and soluble CD14 (sCD14) in plasma from 57 HIV patients with CD4 nadir <300 cells/µl and 29 healthy controls. Supervised and unsupervised analyses were used to identify biomarkers explaining variance between groups defined by HIV status or drug abuse. Relationships between biomarkers and disease markers were examined by Spearman correlation.Results
The majority (91%) of HIV subjects were on cART, with 38% having undetectable viral loads (VL). Hierarchical clustering identified a biomarker cluster in plasma consisting of two interferon-stimulated gene products (CXCL9 and CXCL10), T cell activation marker (sIL-2R), and monocyte activation marker (sCD14) that distinguished both viremic and aviremic HIV patients on cART from controls (p<0.0001) and were top-ranked in variables important in projection plots. IL-12 and CCL4 were also elevated in viremic and aviremic patients compared to controls (p<0.05). IL-12 correlated with IFNα, IFNγ, CXCL9, and sIL-2R (p<0.05). CXCL10 correlated positively with plasma VL and percentage of CD16+ monocytes, and inversely with CD4 count (p = 0.001, <0.0001, and 0.04, respectively).Conclusion
A plasma inflammatory biomarker signature consisting of CXCL9, CXCL10, sIL-2R, and sCD14 may be useful as a surrogate marker to monitor immune activation in both viremic and aviremic HIV patients on cART during disease progression and therapeutic responses. 相似文献107.
Vikas Duhan Neha Joshi P. Nagarajan Pramod Upadhyay 《Journal of visualized experiments : JoVE》2012,(66)
Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body temperature that is observed during fever. The use of hyperthermia as an adjuvant has emerged as a promising procedure for tumor regression in the field of cancer biology. For this purpose, the most important requirement is to have reliable and uniform heating protocols. We have developed a protocol for hyperthermia (whole body) in mice. In this protocol, animals are exposed to cycles of hyperthermia for 90 min followed by a rest period of 15 min. During this period mice have easy access to food and water. High body temperature spikes in the mice during first few hyperthermia exposure cycles are prevented by immobilizing the animal. Additionally, normal saline is administered in first few cycles to minimize the effects of dehydration. This protocol can simulate fever like conditions in mice up to 12-24 hr. We have used 8-12 weeks old BALB/Cj female mice to demonstrate the protocol. 相似文献
108.
Hoffman SM Tully JE Lahue KG Anathy V Nolin JD Guala AS van der Velden JL Ho YS Aliyeva M Daphtary N Lundblad LK Irvin CG Janssen-Heininger YM 《American journal of physiology. Lung cellular and molecular physiology》2012,303(6):L528-L538
Protein-S-glutathionylation (PSSG) is an oxidative modification of reactive cysteines that has emerged as an important player in pathophysiological processes. Under physiological conditions, the thiol transferase, glutaredoxin-1 (Glrx1) catalyses deglutathionylation. Although we previously demonstrated that Glrx1 expression is increased in mice with allergic inflammation, the impact of Glrx1/PSSG in the development of allergic airways disease remains unknown. In the present study we examined the impact of genetic ablation of Glrx1 in the pathogenesis of allergic inflammation and airway hyperresponsiveness (AHR) in mice. Glrx1(-/-) or WT mice were subjected to the antigen, ovalbumin (OVA), and parameters of allergic airways disease were evaluated 48 h after three challenges, and 48 h or 7 days after six challenges with aerosolized antigen. Although no clear increases in PSSG were observed in WT mice in response to OVA, marked increases were detected in lung tissue of mice lacking Glrx1 48 h following six antigen challenges. Inflammation and expression of proinflammatory mediators were decreased in Glrx1(-/-) mice, dependent on the time of analysis. WT and Glrx1(-/-) mice demonstrated comparable increases in AHR 48 h after three or six challenges with OVA. However, 7 days postcessation of six challenges, parameters of AHR in Glrx1(-/-) mice were resolved to control levels, accompanied by marked decreases in mucus metaplasia and expression of Muc5AC and GOB5. These results demonstrate that the Glrx1/S-glutathionylation redox status in mice is a critical regulator of AHR, suggesting that avenues to increase S-glutathionylation of specific target proteins may be beneficial to attenuate AHR. 相似文献
109.
Satiander Rana Niha Dhar Wajid W. Bhat Sumeer Razdan Shabnam Khan Rekha S. Dhar Prabhu Dutt Surrinder K. Lattoo 《In vitro cellular & developmental biology. Plant》2012,48(5):546-554
Withania somnifera, commonly known as ashwagandha or Indian ginseng, is a valuable medicinal plant, synthesizing a wide array of pharmacologically active secondary metabolites known as withanolides. In this study, we investigated variation among 54 regenerated plants attained through indirect organogenesis from leaf explants. Organogenic calli were induced on Murashige and Skoog medium containing 2?mg?l?1 kinetin and 1?mg?l?1 indole-3-butyric acid. High-performance liquid chromatography was used for quantitative determination of the major withanolides in the somaclones. One somaclone (WS-R-1) showed significantly higher accumulation of 12-deoxywithastramonolide (WS-12D; 0.516%) compared to the explant donor mother plant (0.002%). The incidence of somaclonal variation at the cytological level was investigated by studying mitosis and meiosis in relation to chromosome number and structural organization. There were no alterations in chromosome phenotypes, somatic chromosome count, or meiotic behavior. Fidelity at genomic level was evaluated by random amplification of polymorphic DNA (RAPD) analyses, which revealed multiple genetic polymorphisms between the WS-12D over-producing somaclone and the explant donor mother plant. This study demonstrates the capability of inducing chemotypic variability for the development of high-yielding clones due to molecular instability in W. somnifera using an in vitro approach. 相似文献
110.
VG Rao J Bhat R Yadav GP Gopalan S Nagamiah MK Bhondeley SM Anjinappa J Ramchandra VK Chadha F Wares 《PloS one》2012,7(8):e43225