全文获取类型
收费全文 | 381篇 |
免费 | 29篇 |
专业分类
410篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 9篇 |
2021年 | 15篇 |
2020年 | 14篇 |
2019年 | 15篇 |
2018年 | 7篇 |
2017年 | 16篇 |
2016年 | 18篇 |
2015年 | 15篇 |
2014年 | 26篇 |
2013年 | 25篇 |
2012年 | 42篇 |
2011年 | 24篇 |
2010年 | 19篇 |
2009年 | 13篇 |
2008年 | 18篇 |
2007年 | 16篇 |
2006年 | 23篇 |
2005年 | 14篇 |
2004年 | 6篇 |
2003年 | 11篇 |
2002年 | 11篇 |
2001年 | 11篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1981年 | 3篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 3篇 |
排序方式: 共有410条查询结果,搜索用时 15 毫秒
1.
2.
Cadmium and cadmium compounds are water soluble, mobile in most soils, bio-available, and tend to bio-accumulate. A pot culture experiment was conducted on contaminated soil to study the influence of lime and organic matter on the mobility of cadmium in spinach and its rhizosphere soil. Application of lime (50% and 100% lime requirement) and organic matter (0.5 and 1% by weight of soil) to soil decreased the availability of Cd to the soil and plant throughout the crop growth. The highest diethylene triamine penta-acetic acid (DTPA) extractable Cd was 10.84 mg kg?1 in the treatment OM0 L0 (No application of organic matter and lime) at 20 days after sowing of spinach. Likewise, the highest Cd concentration in spinach roots and shoots were 19.80 and 17.0 mg kg?1 in the treatment OM0 L0 at 20 days after sowing. The Cd concentration in spinach roots and shoots were decreased by 63.23 and 71.88%, respectively, in the treatment OM1 L100 (application of FYM at 1.0% by weight of soil and lime at 100% lime requirement) after 60 days of growth. The lowest concentrations of Cd in the soil and plant after the harvest of the crop were 2.88 and 4.27 mg kg?1, respectively, in the treatment OM1 L100 and resulted in 65.75 and 71.55% decrease over control (OM0 L0). The highest total chlorophyll content of leaves was 2.19 mg kg?1 of fresh weight in the treatment OM1 L100 at 40 days of crop growth. 相似文献
3.
4.
Polychronis Kotoglou Alexandros Kalaitzakis Patra Vezyraki Theodore Tzavaras Lampros K. Michalis Francoise Dantzer Jae U. Jung Charalampos Angelidis 《Cell stress & chaperones》2009,14(4):391-406
For many years, there has been uncertainty concerning the reason for Hsp70 translocation to the nucleus and nucleolus. Herein,
we propose that Hsp70 translocates to the nucleus and nucleoli in order to participate in pathways related to the protection
of the nucleoplasmic DNA or ribosomal DNA from single-strand breaks. The absence of Hsp70 in HeLa cells, via Hsp70 gene silencing
(knockdown), indicated the essential role of Hsp70 in DNA integrity. Therefore, HeLa Hsp70 depleted cells were very sensitive
in heat treatment and their DNA breaks were multiple compared to that of control HeLa cells. The molecular mechanism with
which Hsp70 performs its role at the level of nucleus and nucleolus during stress was examined. Hsp70 co-localizes with PARP1
in the nucleus/nucleoli as was observed in confocal studies and binds to the BCRT domain of PARP1 as was revealed with protein–protein
interaction assays. It was also found that Hsp70 binds simultaneously to XRCC1 and PARP-1, indicating that Hsp70 function
takes place at the level of DNA repair and possibly at the base excision repair system. Making a hypothetical model, we have
suggested that Hsp70 is the molecule that binds and interrelates with PARP1 creating the repair proteins simultaneously, such
as XRCC1, at the single-strand DNA breaks. Our data partially clarify a previously unrecognized cellular response to heat
stress. Finally, we can speculate that Hsp70 plays a role in the quality and integrity of DNA.
Outlining prior scientific knowledge on the subject and novel information: The role of Hsp70 translocation to the nucleus
and nucleolus during heat stress has been nearly unknown. It has been proposed that this biological phenomenon is correlated
to Hsp70-chaperoning activity. Furthermore, some previous observations in yeast have revealed that Rad9 complexes—Rad9 being
the prototype DNA-damage checkpoint gene—contain Ssa1 and or Ssa2 chaperone proteins, both reconstituting the functions of
the corresponding Hsp70 in mammalian cells. Here, we propose that Hsp70 translocates to the nuclei/nucleoli during heat stress,
binds to PARP-1 and/or XRCC1, and protects HeLa cells from increased single-strand DNA breaks. 相似文献
5.
HS‐SPME‐GC‐FID method for detection and quantification of Bacillus cereus ATCC 10702 mediated 2‐acetyl‐1‐pyrroline 下载免费PDF全文
Yogita Deshmukh Puja Khare D. D. Patra Altafhusain B. Nadaf 《Biotechnology progress》2014,30(6):1356-1363
A rapid micro‐scale solid‐phase micro‐extraction (SPME) procedure coupled with gas‐chromatography with flame ionized detector (GC‐FID) was used to extract parts per billion levels of a principle basmati aroma compound “2‐acetyl‐1‐pyrroline” (2‐AP) from bacterial samples. In present investigation, optimization parameters of bacterial incubation period, sample weight, pre‐incubation time, adsorption time, and temperature, precursors and their concentrations has been studied. In the optimized conditions, detection of 2‐AP produced by Bacillus cereus ATCC10702 using only 0.5 g of sample volume was 85 μg/kg. Along with 2‐AP, 15 other compounds produced by B. cereus were also reported out of which 14 were reported for the first time consisting mainly of (E)?2‐hexenal, pentadecanal, 4‐hydroxy‐2‐butanone, n‐hexanal, 2–6‐nonadienal, 3‐methoxy‐2(5H) furanone and 2‐acetyl‐1‐pyridine and octanal. High recovery of 2‐AP (87 %) from very less amount of B. cereus samples was observed. The method is reproducible fast and can be used for detection of 2‐AP production by B. cereus. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1356–1363, 2014 相似文献
6.
Yeetong P Tongkobpetch S Kingwatanakul P Deekajorndech T Bernardini IM Suphapeetiporn K Gahl WA Shotelersuk V 《Gene》2012,499(2):323-325
Cystinosis is an autosomal recessive disorder characterized by defective transport of cystine across the lysosomal membrane and resulting in renal, ophthalmic, and other organ abnormalities. Mutations in the CTNS gene cause a deficiency of the transport protein, cystinosin. We performed mutation analysis of CTNS in six cystinosis patients from four families in Thailand. Using PCR sequencing of the entire coding regions, we identified all eight mutant alleles, including two mutations, p.G309D and p.Q284X, that have not been previously reported. This study expands the mutational and population spectrum of nephropathic cystinosis. 相似文献
7.
Bidhan Chandra De Mahesh Chandra Patra Sushil Kumar Biswajit Brahma Devika Goutam Latika Jaiswal 《Animal biotechnology》2013,24(3):211-216
A novel noninvasive genomic DNA isolation protocol from fecal tissue, by the proteinase K digestion and guanidine hydrochloride extraction method, was assessed for the genotyping of cattle and buffalo. The epithelial tissues present on the surface of the feces were used as source for isolation of genomic DNA. The DNA isolated from fecal tissue was found to be similar as those obtained from other body tissues such as skin, brain, liver, kidney, and muscle. The quality of DNA was checked by agarose gel electrophoresis and polymerase chain reaction (PCR). We successfully amplified a 320 bp MHC class II DRB gene and a 125 bp mt-DNA D-loop region from isolated genomic DNA of cattle. Thus, the DNA isolated using this method was suitable for common molecular biology methods, such as restriction enzyme digestion and genotyping of dairy animals through PCR. 相似文献
8.
Aditya Nath Jha Vipin Kumar Singh Namrata Kumari Ashish Singh Justin Antony Hoang van Tong Sakshi Singh Sudhanshu S. Pati Pradeep K. Patra Rajender Singh Nguyen L. Toan Le H. Song Amal Assaf Iara J. T. Messias–Reason Thirumalaisamy P. Velavan Lalji Singh Kumarasamy Thangaraj 《PloS one》2012,7(10)
Background
Interleukin 4 (IL-4) is an anti-inflammatory cytokine, which regulates balance between TH1 and TH2 immune response, immunoglobulin class switching and humoral immunity. Polymorphisms in this gene have been reported to affect the risk of infectious and autoimmune diseases.Methods
We have analyzed three regulatory IL-4 polymorphisms; -590C>T, -34C>T and 70 bp intron-3 VNTR, in 4216 individuals; including: (1) 430 ethnically matched case-control groups (173 severe malaria, 101 mild malaria and 156 asymptomatic); (2) 3452 individuals from 76 linguistically and geographically distinct endogamous populations of India, and (3) 334 individuals with different ancestry from outside India (84 Brazilian, 104 Syrian, and 146 Vietnamese).Results
The -590T, -34T and intron-3 VNTR R2 alleles were found to be associated with reduced malaria risk (P<0.001 for -590C>T and -34C>T, and P = 0.003 for VNTR). These three alleles were in strong LD (r2>0.75) and the TTR2 (-590T, -34T and intron-3 VNTR R2) haplotype appeared to be a susceptibility factor for malaria (P = 0.009, OR = 0.552, 95% CI = 0.356 –0.854). Allele and genotype frequencies differ significantly between caste, nomadic, tribe and ancestral tribal populations (ATP). The distribution of protective haplotype TTR2 was found to be significant (χ2 3 = 182.95, p-value <0.001), which is highest in ATP (40.5%); intermediate in tribes (33%); and lowest in caste (17.8%) and nomadic (21.6%).Conclusions
Our study suggests that the IL-4 polymorphisms regulate host susceptibility to malaria and disease progression. TTR2 haplotype, which gives protection against malaria, is high among ATPs. Since they inhabited in isolation and mainly practice hunter-gatherer lifestyles and exposed to various parasites, IL-4 TTR2 haplotype might be under positive selection. 相似文献9.
10.
One monomeric neutral Cu(II) complex [(pmtpm)CuCl2] (1) is reported by Lindoy and Livingstone [8]. Two new complexes namely, μ-Cl bridged binuclear Cu(II) complex [{(pmtpm)Cu(Cl)}2 μ-Cl](ClO4) (2) and a bis μ-Cl bridged binuclear Cu(II) complex [{(pmtpm)Cu}2(μ-Cl)2](ClO4)2 (3) derived from a tridentate Schiff base ligand, 2-pyridyl-N-(2′-methylthiophenyl)methyleneimine (pmtpm) were synthesized and characterized by various spectroscopic methods and by X-ray crystallography. (N2S)CuCl2 chromophore(s) of distorted square pyramidal coordination geometries around Cu(II) ion(s) have been observed for all the complexes 1-3. The equatorial sites of the square plane comprise two N and a thioether S donor atoms of the pmtpm ligand as well as one Cl− ion (terminal in 1 and 2, and bridging in 3) while the remaining axial site is occupied by a terminal Cl− ion (for 1) or a bridging Cl− ion (for 2 and 3). The equatorial Cu-Cl distances are much shorter [1: 2.2511(4) Å, 2: 2.2307(12) Å, 3: 2.2513(12) Å] than the axial Cu-Cl distances [1: 2.4394(4) Å, 2: 2.5597(9) Å, 3: 2.7037(12) Å]. The correlation of an axial Cu-Cl bond elongation with a lower g|| value in the solid state EPR spectrum and a blue shifted ligand field transition in the solid and solution phase absorption spectrum has been observed. 相似文献