全文获取类型
收费全文 | 213篇 |
免费 | 17篇 |
专业分类
230篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 12篇 |
2015年 | 9篇 |
2014年 | 9篇 |
2013年 | 9篇 |
2012年 | 21篇 |
2011年 | 13篇 |
2010年 | 17篇 |
2009年 | 7篇 |
2008年 | 9篇 |
2007年 | 7篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 10篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1971年 | 1篇 |
1969年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有230条查询结果,搜索用时 15 毫秒
221.
222.
223.
224.
225.
Synopsis The study deals with the entrapment of fishes in the intake of Karachi Nuclear Power Plant. A total of 62 species of marine
fishes belonging to 43 genera were observed entrapped in the seawater intake. Therapon puta, Liza waigiensis, Abudefduf septemfasciatus, and Lagoceptalus inermis were the most common. Mass mortalities of the juveniles of Sardinella sindensis were recorded in September and October of 1974, 1975, and 1977. Commercially important fishes such as sardines, mullets and
anchovies, were entrapped in the intake of the power plant in considerable numbers at various times of the year. The majority
of fishes removed from the screen washes of the power plants were killed by impingement. 相似文献
226.
S1 nuclease hydrolysis and hydroxyapatite chromatography were used to study the effect of the alkylating antibiotic, streptozotocin, on the secondary structure of DNA. Native calf thymus DNA was alkylatedin vitro with increasing concentrations of streptozotocin and subjected to S 1 nuclease hydrolysis. An increasing degree of DNA degradation was seen, suggesting a destabilization of the secondary structure. Indirect evidence, deduced from alkaline hydrolysis, effect of NaCl on S1 nuclease hydrolysis, and hydroxyapatite chromatographic analysis of alkylated DNA, suggested a significant alkylation of DNA phosphates in addition to DNA bases. Nictotinamide has been reported to alter the cytotoxic and carcinogenic effects of streptozotocin. Our experiments indicate that in the presence of nicotinamide, streptozotocin causes the formation of a greater proportion of alkylated bases in relation to alkyl phosphotriesters. This may have significance in relation to the differential cytotoxicity of streptozotocin in the absence and presence of nicotinamide. 相似文献
227.
228.
Ghulam Md Ashraf Sabika Rizvi Shoa Naqvi Nida Suhail Nayeem Bilal Shirin Hasan Mohammad Tabish Naheed Banu 《Amino acids》2010,39(5):1321-1332
A soluble β-galactoside-binding lectin was purified by gel filtration chromatography from Bubalus bubalis heart. Its metal-independent nature, molecular weight of 14.5 kDa, preferential affinity for β-d-lactose, and 87–92% identity with carbohydrate recognition domain of previously reported galectin-1 confirmed its inclusion
in galectin-1 subfamily. Stokes radii determination using gel filtration under reducing and non-reducing conditions revealed
its homo-dimeric nature, further confirming its Gal-1 nomenclature. The purified lectin was found to be the most stable mammalian
heart galectin purified till date, suggesting its preferential use in various recognition studies. Treatment of the purified
lectin with oxidizing agent, thiol blocking reagents, denaturants, and detergents resulted in significant changes in UV–VIS,
fluorescence, CD and FTIR spectra, which strongly emphasized the important aspect of regular secondary structure of galectins
for the maintenance of their active conformation. Reduction of the activity of the purified lectin after oxidation by H2O2, with remarkable fluorescence quenching, may suggest potential role for galectin-1 in free radical-induced, oxidative stress-mediated
cardiovascular disorders. The predictions of bioinformatics studies were found to be in accordance with the results obtained
in wet lab. 相似文献
229.
We have earlier reported that alkylation of DNA by the chemical carcinogen dimethyl sulphate, which mainly alkylates N-7 of guanine and N-3 of adenine, causes the formation of partially denatured regions in double-stranded DNA (Rizvi RY, Alvi NK & Hadi SM, Biosci. Rep. 2, 315-322, 1982). It is known that the major site of alkylation in DNA by N-ethyl-N-nitrosourea (EtNu) are the phosphate groups. N-methyl-N-nitrosourea (MeNu), on the other hand, causes the alkylation of mainly guanine residues. We have therefore studied the effect of these two alkylating carcinogens on the secondary structure of DNA. DNA alkylated with increasing concentrations of EtNu and MeNu was subjected to alkaline and S1 nuclease hydrolysis. Thermal melting profiles of alkylated DNA were also determined using S1 nuclease. The results indicated that alkylation by the two alkylating agents had a differential effect on the secondary structure of DNA. EtNu-alkylated DNA was found to be more thermostable than native DNA at neutral pH. It was however more alkali-labile than MeNu-alkylated DNA. The greater stability of EtNu-alkylated DNA was considered to be due to abolition of negative charges on phosphate alkylation. 相似文献
230.
T A Rizvi M Mathur N C Nayak 《Virchows Archiv. B, Cell pathology including molecular pathology》1989,56(5):345-350
The effect of enhanced cell replication induced by partial hepatectomy (PH) in aflatoxin B1 (AFB1)-induced hepatocarcinogenesis has been studied in rats of the inbred As2 strain. Animals were given 0.25 mg/kg body weight of AFB1 as a single intraperitoneal dose 24 h after PH. Non-hepatectomized animals given the same dose of AFB1 served as controls. Neoplastic nodules and hepatocellular carcinoma (HCC) were detected respectively in 100% and 90% of hepatectomized animals sacrificed between 55 and 65 weeks after AFB1 administration. None of the ten non-hepatectomized rats sacrificed at this time interval showed HCC or neoplastic nodules. On histochemical staining the tumour population was found to be heterogeneous. Thus PH resulted in enhancement of AFB1-induced hepatocarcinogenesis in rats of the AS2 strain. 相似文献