全文获取类型
收费全文 | 2097篇 |
免费 | 150篇 |
国内免费 | 2篇 |
专业分类
2249篇 |
出版年
2022年 | 19篇 |
2021年 | 58篇 |
2020年 | 36篇 |
2019年 | 25篇 |
2018年 | 49篇 |
2017年 | 42篇 |
2016年 | 57篇 |
2015年 | 89篇 |
2014年 | 103篇 |
2013年 | 133篇 |
2012年 | 168篇 |
2011年 | 150篇 |
2010年 | 77篇 |
2009年 | 71篇 |
2008年 | 110篇 |
2007年 | 77篇 |
2006年 | 80篇 |
2005年 | 77篇 |
2004年 | 62篇 |
2003年 | 67篇 |
2002年 | 54篇 |
2001年 | 42篇 |
2000年 | 37篇 |
1999年 | 31篇 |
1998年 | 21篇 |
1997年 | 17篇 |
1995年 | 10篇 |
1994年 | 14篇 |
1992年 | 37篇 |
1991年 | 25篇 |
1990年 | 23篇 |
1989年 | 23篇 |
1988年 | 17篇 |
1987年 | 24篇 |
1986年 | 13篇 |
1985年 | 25篇 |
1984年 | 29篇 |
1983年 | 17篇 |
1982年 | 16篇 |
1981年 | 19篇 |
1979年 | 24篇 |
1978年 | 15篇 |
1977年 | 13篇 |
1975年 | 12篇 |
1974年 | 14篇 |
1973年 | 10篇 |
1969年 | 13篇 |
1968年 | 10篇 |
1967年 | 10篇 |
1966年 | 10篇 |
排序方式: 共有2249条查询结果,搜索用时 12 毫秒
71.
Rosenfeld JA Sarkar IN Planet PJ Figurski DH DeSalle R 《Bioinformatics (Oxford, England)》2004,20(18):3462-3465
72.
Krishnendu Chattopadhyay Amaresh Kumar Nayak Bishnu Charan Marndi Annie Poonam Koushik Chakraborty Ramani Kumar Sarkar 《Physiology and Molecular Biology of Plants》2018,24(6):1047-1058
The present study reports an unequivocal and improved protocol for efficient screening of salt tolerance at flowering stage in rice, which can aid phenotyping of population for subsequent identification of QTLs associated with salinity stress, particularly at reproductive stage. To validate the new method, the selection criteria, level and time of imposition of stress; plant growth medium were standardized using three rice genotypes. The setup was established with a piezometer placed in a perforated pot for continuous monitoring of soil EC and pH throughout the period of study. Further, fertilizer enriched soil was partially substituted by gravels for stabilization and maintaining the uniformity of soil EC in pots without hindering its buffering capacity. The protocol including modified medium (Soil:Stone, 4:1) at 8 dS m?1 salinity level was validated using seven different genotypes possessing differential salt sensitivity. Based on the important selection traits such as high stability index for plant yield, harvest index and number of grains/panicle and also high K+ concentration and low Na+– K+ ratio in flag leaf at grain filling stage were validated and employed in the evaluation of a mapping population in the modified screening medium. The method was found significantly efficient for easy maintenance of desired level of soil salinity and identification of genotypes tolerant to salinity at reproductive stage. 相似文献
73.
74.
Pandey S Chakraborti P Sharma R Bandyopadhyay S Sarkar D Adhya S 《Journal of biosciences》2004,29(1):15-22
The major surface glycoprotein gp63 of the kinetoplastid protozoal parasiteLeishmania is implicated as a ligand mediating uptake of the parasite into, and survival within, the host macrophage. By expressing
gp63 antisense RNA from an episomal vector inL. donovani promastigotes, gp63-deficient transfectants were obtained. Reduction of the gp63 level resulted in increased generation times,
altered cell morphology, accumulation of cells in the G2/M phase of the cell cycle, and increased numbers of binucleate cells
with one or two kinetoplasts. Growth was stimulated, and the number of binucleate cells reduced, by addition to the culture
of a bacterially expressed fusion protein containing the fibronectin-like SRYD motif and the zinc-binding (metalloprotease)
domain of gp63. These observations support an additional role of gp63 in promastigote multiplication; the fibronectin-like
properties of gp63 may be important in this process 相似文献
75.
Sarkar P Luchowski R Raut S Sabnis N Remaley A Lacko AG Thamake S Gryczynski Z Gryczynski I 《Biophysical chemistry》2010,153(1):61-69
The styryl group of dyes has been used in cellular studies for over 20 years because of their solvatochromic and/or electrochromic properties. Here we report characterization of solubility and solvatochromic properties of a near infra-red styryl dye, styryl 11 or LDS 798. We have extended our studies to small unilamellar vesicles and lipid based nanoparticles and found that solvatochromic properties of this dye used in tandem with fluorescence correlation spectroscopy can be used to efficiently determine the diffusion coefficient and hence the size of the submicron lipid based particles. This technique has the potential to provide essential information about liposomal and vesicular structures and their movement in vitro and in situ. 相似文献
76.
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
77.
78.
Arnab Sarkar Ashikur Rahaman Ipsita Biswas Gopeswar Mukherjee Subhrangsu Chatterjee Shamee Bhattacharjee Deba Prasad Mandal 《Journal of cellular physiology》2020,235(10):7159-7172
Transforming growth factor β (TGFβ) is a prominent cytokine that promotes tumor progression by activating epithelial-to-mesenchymal transition (EMT). This study indicated that TGFβ exerted metastasis by inducing zinc finger E-box binding homeobox 1 (ZEB1) and a long noncoding RNA, LINC00273, expressions in A549 cells. Knocking down LINC00273 diminished TGFβ induced ZEB1 expression as well as metastasis. Mechanistically, LINC00273 acted as a molecular sponge of microRNA (miR)-200a-3p which liberate ZEB1 to perform its prometastatic functions. LINC00273 knockdown and miR200a3p mimic transfection of A549 cells were used for validating the link between TGFβ and LINC00273 induced metastasis. RNA pulldown and luciferase assay were performed to establish mir200a-3p-LINC00273 interaction. High expressions of LINC00273, TGFβ, and ZEB1 with concurrent low miR200a-3p expression had been verified in vivo and in patient samples. Overall, LINC00273 promoted TGFβ-induced lung cancer EMT through miR-200a-3p/ZEB1 feedback loop and may serve as a potential target for therapeutic intervention in lung cancer metastasis. 相似文献
79.
The effect of cholesterol in neutral, positively and negatively charged liposomes on the toxicity, therapeutic efficacy, and alteration in the tissue distribution pattern of amphotericin B (Amp-B) in normal and infected mice was studied. It was observed that inclusion of cholesterol (CHOL) into egg phosphatidylcholine (EPC) liposomes increased the LD50 of Amp-B from 5.3 to 8.5 mg/kg body weight. In the case of phosphatidylserine (PS) liposomes as well as stearylamine (SA) liposomes, cholesterol incorporation had no effect in altering the toxicity of the drug. The survival pattern of animals with all types of liposomal formulation of Amp-B was similar. The tissue distribution studies indicated that in the case of normal mice, cholesterol inclusion in all types of liposomes increased the organ concentration of the drug in various tissues. In infected animals, the concentration of Amp-B in all organs was increased when cholesterol was included in EPC and EPC/PS liposomes. The organ concentration of Amp-B in lung and liver after 1 h of injection was the same in the case of EPC/SA and EPC/SA/CHOL liposomes. Considering the observations on toxicity, therapeutic efficacy, and tissue distribution, it was suggested that cholesterol had a beneficial therapeutic effect on neutral EPC liposomes. 相似文献
80.