全文获取类型
收费全文 | 1019篇 |
免费 | 43篇 |
出版年
2023年 | 9篇 |
2022年 | 15篇 |
2021年 | 25篇 |
2020年 | 11篇 |
2019年 | 19篇 |
2018年 | 22篇 |
2017年 | 23篇 |
2016年 | 37篇 |
2015年 | 38篇 |
2014年 | 30篇 |
2013年 | 66篇 |
2012年 | 76篇 |
2011年 | 93篇 |
2010年 | 39篇 |
2009年 | 37篇 |
2008年 | 46篇 |
2007年 | 35篇 |
2006年 | 34篇 |
2005年 | 43篇 |
2004年 | 44篇 |
2003年 | 36篇 |
2002年 | 31篇 |
2001年 | 13篇 |
2000年 | 27篇 |
1999年 | 18篇 |
1998年 | 11篇 |
1997年 | 12篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 12篇 |
1991年 | 18篇 |
1990年 | 13篇 |
1989年 | 9篇 |
1988年 | 10篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 10篇 |
1983年 | 3篇 |
1982年 | 10篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1970年 | 3篇 |
排序方式: 共有1062条查询结果,搜索用时 156 毫秒
91.
Nishat Parveen Roberto Berni Sreeja Sudhakaran Javaid A. Bhat Suhas Shinde Naleeni Ramawat Vijay P. Singh Shivendra Sahi Rupesh Deshmukh Devendra K. Chauhan Durgesh Kumar Tripathi 《The Annals of applied biology》2022,180(1):7-25
Metalloids represent a wide range of elements with intermediate physiochemical properties between metals and non-metals. Many of the metalloids, like boron, selenium, and silicon are known to be essential or quasi-essential for plant growth. In contrast, metalloids viz. arsenic and germanium are toxic to plant growth. The toxicity of metalloids largely depends on their concentration within the living cells. Some elements, at low concentration, may be beneficial for plant growth and development; however, when present at high concentration, they often exert negative effects. In this regard, understanding the molecular mechanisms involved in the uptake of metalloids by roots, their subsequent transport to different tissues and inter/intra-cellular redistribution has great importance. The mechanisms of metalloids' uptake have been well studied in plants. Also, various transporters, as well as membrane channels involved in these processes, have been identified. In this review, we have discussed in detail the aspects concerning the positive/negative effects of different metalloids on plants. We have also provided a thorough account of the uptake, transport, and accumulation, along with the molecular mechanisms underlying the response of plants to these metalloids. Additionally, we have brought up the previous theories and debates about the role and effects of metalloids in plants with insightful discussions based on the current knowledge. 相似文献
92.
Singh Vikram Chauhan Ravishankar Kaur Inderpal Quraishi Afaque 《Plant Cell, Tissue and Organ Culture》2022,148(1):95-106
Plant Cell, Tissue and Organ Culture (PCTOC) - Ammonium nitrate (AN) is one of the major nitrogen sources of Murashige and Skoog (MS) medium. It is prohibited in various countries, including India... 相似文献
93.
Ira Vashisht Prashant Mishra Tarun Pal Sreekrishna Chanumolu Tiratha Raj Singh Rajinder Singh Chauhan 《Planta》2015,241(5):1269-1270
94.
95.
96.
The Psp system of Mycobacterium tuberculosis integrates envelope stress‐sensing and envelope‐preserving functions 下载免费PDF全文
97.
Swati Agarwal Shashi Kant Tiwari Brashket Seth Anuradha Yadav Anshuman Singh Anubha Mudawal Lalit Kumar Singh Chauhan Shailendra Kumar Gupta Vinay Choubey Anurag Tripathi Amit Kumar Ratan Singh Ray Shubha Shukla Devendra Parmar Rajnish Kumar Chaturvedi 《The Journal of biological chemistry》2015,290(34):21163-21184
The human health hazards related to persisting use of bisphenol-A (BPA) are well documented. BPA-induced neurotoxicity occurs with the generation of oxidative stress, neurodegeneration, and cognitive dysfunctions. However, the cellular and molecular mechanism(s) of the effects of BPA on autophagy and association with oxidative stress and apoptosis are still elusive. We observed that BPA exposure during the early postnatal period enhanced the expression and the levels of autophagy genes/proteins. BPA treatment in the presence of bafilomycin A1 increased the levels of LC3-II and SQSTM1 and also potentiated GFP-LC3 puncta index in GFP-LC3-transfected hippocampal neural stem cell-derived neurons. BPA-induced generation of reactive oxygen species and apoptosis were mitigated by a pharmacological activator of autophagy (rapamycin). Pharmacological (wortmannin and bafilomycin A1) and genetic (beclin siRNA) inhibition of autophagy aggravated BPA neurotoxicity. Activation of autophagy against BPA resulted in intracellular energy sensor AMP kinase (AMPK) activation, increased phosphorylation of raptor and acetyl-CoA carboxylase, and decreased phosphorylation of ULK1 (Ser-757), and silencing of AMPK exacerbated BPA neurotoxicity. Conversely, BPA exposure down-regulated the mammalian target of rapamycin (mTOR) pathway by phosphorylation of raptor as a transient cell''s compensatory mechanism to preserve cellular energy pool. Moreover, silencing of mTOR enhanced autophagy, which further alleviated BPA-induced reactive oxygen species generation and apoptosis. BPA-mediated neurotoxicity also resulted in mitochondrial loss, bioenergetic deficits, and increased PARKIN mitochondrial translocation, suggesting enhanced mitophagy. These results suggest implication of autophagy against BPA-mediated neurodegeneration through involvement of AMPK and mTOR pathways. Hence, autophagy, which arbitrates cell survival and demise during stress conditions, requires further assessment to be established as a biomarker of xenoestrogen exposure. 相似文献
98.
Anil K Chauhan Chen Chen Terry L. Moore Richard J DiPaolo 《The Journal of biological chemistry》2015,290(8):5127-5140
Whether or not CD4+ T-cells express low affinity receptor FcγRIIIa (CD16a) in disease pathology has not been examined in great detail. In this study, we show that a subset of activated CD4+ T-cells in humans express FcγRIIIa. The ligation of FcγRIIIa by immune complexes (ICs) in human CD4+ T-cells produced co-stimulatory signal like CD28 that triggered IFN-γ production. The induced expression of FcγRIIIa on CD4+ helper T-cells is an important finding since these receptors via ITAM contribute to intracellular signaling. The induced expression of FcγRIIIa on CD4+ T helper cells and their ability to co-stimulate T-cell activation are important and novel findings that may reveal new pathways to regulate adaptive immune responses during inflammation and in autoimmunity. 相似文献
99.
Aher RB Wanare G Kawathekar N Kumar RR Kaushik NK Sahal D Chauhan VS 《Bioorganic & medicinal chemistry letters》2011,21(10):3034-3036
A series of dibenzylideneacetones (A1-A12) and some of their pyrazolines (B1-B4) were synthesized and evaluated in vitro for blood stage antiplasmodial properties in Plasmodium falciparum culture using SYBR-green-I fluorescence assay. The compound (1E, 4E)-1,5-bis(3,4-dimethoxyphenyl)penta-1,4-dien-3-one (A9) was found to be the most active with IC50 of 1.97 μM against chloroquine-sensitive strain (3D7) and 1.69 μM against chloroquine-resistant field isolate (RKL9). The MTT based cytotoxicity assay on HeLa cell line has confirmed that A9 is selective in its action against malaria parasite (with a therapeutic index of 166). Our results revealed that these compounds exhibited promising antiplasmodial activities which can be further explored as potential leads for the development of cheaper, safe, effective and potent drugs against chloroquine-resistant malarial parasites. 相似文献
100.
A putative epoxide hydrolase-encoding gene was identified from the genome sequence of Cupriavidus metallidurans CH34. The gene was cloned and overexpressed in Escherichia coli with His(6)-tag at its N-terminus. The epoxide hydrolase (CMEH) was purified to near homogeneity and was found to be a homodimer, with subunit molecular weight of 36 kDa. The CMEH had broad substrate specificity as it could hydrolyze 13 epoxides, out of 15 substrates tested. CMEH had high specific activity with 1,2-epoxyoctane, 1,2-epoxyhexane, styrene oxide (SO) and was also found to be active with meso-epoxides. The enzyme had optimum pH and temperature of 7.5 and 37°C respectively, with racemic SO. Biotransformation of 80 mM SO with recombinant whole E. coli cells expressing CMEH led to 56% ee(P) of (R)-diol with 77.23% conversion in 30 min. The enzyme could hydrolyze (R)-SO, ~2-fold faster than (S)-SO, though it accepted both (R)- and (S)-SO with similar affinity as K(m)(R) and K(m)(S) of CMEH were 2.05±0.42 and 2.11±0.16 mM, respectively. However, the k(cat)(R) and k(cat)(S) for the two enantiomers of SO were 4.80 and 3.34 s(-1), respectively. The wide substrate spectrum exhibited by CMEH combined with the fast conversion rate makes it a robust biocatalyst for industrial use. Regioselectivity studies with enantiopure (R)- and (S)-SO revealed that with slightly altered regioselectivity, CMEH has a high potential to synthesize an enantiopure (R)-PED, through an enantioconvergent hydrolytic process. 相似文献