全文获取类型
收费全文 | 1547篇 |
免费 | 44篇 |
专业分类
1591篇 |
出版年
2023年 | 27篇 |
2022年 | 28篇 |
2021年 | 47篇 |
2020年 | 34篇 |
2019年 | 49篇 |
2018年 | 42篇 |
2017年 | 47篇 |
2016年 | 51篇 |
2015年 | 51篇 |
2014年 | 101篇 |
2013年 | 121篇 |
2012年 | 113篇 |
2011年 | 157篇 |
2010年 | 93篇 |
2009年 | 74篇 |
2008年 | 89篇 |
2007年 | 86篇 |
2006年 | 85篇 |
2005年 | 72篇 |
2004年 | 69篇 |
2003年 | 55篇 |
2002年 | 46篇 |
2001年 | 10篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有1591条查询结果,搜索用时 15 毫秒
11.
Protective agent, erdosteine, against cisplatin-induced hepatic oxidant injury in rats 总被引:5,自引:0,他引:5
Cisplatin, one of the most active cytotoxic agents against cancer, has several toxicities. Hepatotoxicity is one of them occurred
during high doses treatment. The aim of this study was to determine the effects of erdosteine against cisplatin-induced liver
injury through tissue oxidant/antioxidant parameters and light microscopic evaluation. The rats were randomly divided into
three groups: control (n=5), cisplatin (10 mg/kg, n=6) and cisplatin+erdosteine (50 mg/kg/day oral erdosteine, n=8) groups. The rats were sacrificed at the 5th day of cisplatin treatment. The liver tissues were examined with light microscopy
and oxidant/antioxidant biochemical parameters. The malondialdehyde (MDA) and nitric oxide (NO) levels were increased in the
cisplatin group in comparison with the control and cisplatin+erdosteine groups (p<0.05). There was no significant difference in MDA and NO levels between control and cisplatin+erdosteine groups. The activities
of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were higher in cisplatin+erdosteine group
than cisplatin group (p<0.05). However, the CAT and GSH-Px activities were significantly lower in cisplatin group than in control group (p<0.05). The light microscopic examination revealed that cytoplasmic changes especially around cells of central vein were observed
in cisplatin group. Hepatocellular vacuolization was seen in these cells. In the cisplatin plus erdosteine group, a decrease
in cytoplasmic changes with the hepatocytes and sinusoidal dilatations around cells of central vein were noticed in as compared
to cisplatin group. In the light of microscopic and biochemical results, it was concluded that cisplatin-induced liver damage
in high dose and erdosteine prevented this toxic side effect by the way of its antioxidant and radical scavenging effects.
(Mol Cell Biochem 278: 79–84, 2005) 相似文献
12.
Effects of propolis,caffeic acid phenethyl ester,and pollen on renal injury in hypertensive rat: An experimental and theoretical approach 下载免费PDF全文
Ramin Ekhteiari Salmas Mehmet Fuat Gulhan Serdar Durdagi Engin Sahna Huda I. Abdullah Zeliha Selamoglu 《Cell biochemistry and function》2017,35(6):304-314
The objective of this study was to evaluate the antioxidant effects of propolis, caffeic acid phenethyl ester (CAPE; active compound in propolis), and pollen on biochemical oxidative stress biomarkers in rat kidney tissue inhibited by Nω‐nitro‐L‐arginine methyl ester (L‐NAME). The biomarkers evaluated were paraoxonase (PON1), oxidative stress index (OSI), total antioxidant status (TAS), total oxidant status (TOS), asymmetric dimethylarginine (ADMA), and nuclear factor kappa B (NF‐κB). TAS levels and PON1 activity were significantly decreased in kidney tissue samples in the L‐NAME‐treated group (P < 0.05). The levels of TAS and PONI were higher in the L‐NAME plus propolis, CAPE, and pollen groups compared with the L‐NAME‐treated group. TOS, ADMA, and NF‐κB levels were significantly increased in the kidney tissue samples of the L‐NAME‐treated group (P < 0.05). However, these parameters were significantly lower in the L‐NAME plus propolis, CAPE, and pollen groups (P < 0.05) compared with rats administered L‐NAME alone (P < 0.05). Furthermore, the binding energy of CAPE within catalytic domain of glutathione reductase (GR) enzyme as well as its inhibitory mechanism was determined using molecular modeling approaches. In conclusion, experimental and theoretical data suggested that oxidative alterations occurring in the kidney tissue of chronic hypertensive rats may be prevented via active compound of propolis, CAPE administration. 相似文献
13.
Chronic inflammation is a common feature of end-stage renal disease, which carries a heightened risk of atherosclerosis and other co-morbid conditions. Dialysis treatment per se can bring additional risk factors for inflammation, such as increased risk of local graft and fistula infections, impure dialysate or bio-incompatible membranes. Our study was designed to determine whether a hemodialysis session leads to an acute substantial alteration in the plasma levels of the proinflammatory cytokines interleukin (IL)-6, IL-1beta and tumor necrosis factor (TNF)-alpha, the T-lymphocyte activation factor soluble IL-2 receptor (sIL-2R), and an inflammation mediator and chemotactic granulocyte factor, IL-8, in end-stage renal disease patients receiving chronic intermittent HD. In this study, 21 (12 male/nine female) patients undergoing chronic hemodialysis were enrolled. The acute effect of a hemodialysis session on serum cytokine concentrations was assessed by comparison of pre-hemodialysis and post-hemodialysis determinations. Serum IL-1beta, sIL-2R, IL-6, IL-8 and TNF-alpha levels were determined with chemiluminescence enzyme immunometric assays. A significant difference was not observed for IL-1beta, IL-6, TNF-alpha, and sIL-2R concentrations in pre-hemodialysis and post-hemodialysis specimens (p>0.05). Serum median (25th-75th percentiles) IL-8 concentration was 69.4 (34.9-110.3) pg/ml before hemodialysis, and decreased to 31.5 (18.0-78.8) pg/ml following hemodialysis (p: 0.006). Clearance of IL-8 increased by 0.47+/-0.08 pg/ml for each unit increase in pre-dialysis IL-8 (p<0.001) and decreased by 5.63+/-2.59 pg/ml for each unit increase in pre-dialysis urea mmol/l (p<0.05). In conclusion, the results of our study demonstrate that a hemodialysis session markedly decreases IL-8 concentration, which is significantly affected by pre-dialysis concentrations, indicating that removal of IL-8 is a concentration gradient-dependent action, but does not change the serum levels of IL-1beta, sIL-2R, IL-6, and TNF-alpha, underlining importance of the structural characteristics of the molecules. 相似文献
14.
Iron overload is a major health problem for patients who have to have continuous blood transfusions. It brings some metabolic problems together. Various iron chelating agents are being used for treatment of hemochromatosis which arises from excess iron accumulation. This study was conducted with the aim of determining whether deferasirox used as an iron chelator in patients with hemochromatosis has genotoxic effects. Commercial form of deferasirox, Exjade was used as test material. Test material showed a general mutagen character in mutant strains of Salmonella typhimurium. Deferasirox has also led to an increase in mutagenity-related polymorphic band count in random amplification of polymorphic DNA test done with bone marrow cells of rats. Similarly, test material has increased micronucleus formation in cultured in vitro human peripheral lymphocytes particularly in 48 h period. Consistently with the abovementioned findings, deferasirox reduced nuclear division index (NDI) compared to controls and some part of these reductions are statistically significant. NDI reductions were found at positive control levels at high concentrations. 相似文献
15.
Effects of a GnRH agonist on oocyte number and maturation in mice superovulated with eCG and hCG 总被引:4,自引:0,他引:4
The objective was to investigate the effects of a gonadotropin-releasing hormone agonist (GnRH) on ovulation rate and the number and maturation of oocytes in mice superovulated with equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG). Thirty 3-month-old BALB/C female mice (weight: 25-30 g) were assigned to three experimental groups: control, superovulated, and superovulated with GnRH pretreatment (n=10 per group). Control mice received an i.p. injection of 0.1 ml physiological saline solution. Superovulation was induced with 5 IU eCG (i.p.) and 5 IU hCG 48 h later. Mice in the superovulated with GnRH pretreatment group were given GnRH (20 mg/kg Fertirelin, i.m.), 24 h before superovulation. Thirteen hours after hCG administration, mice were sacrificed by cervical dislocation and blood samples were collected to determine serum progesterone concentration (by radioimmunoassay). Ovaries and oviducts were also harvested to enumerate corpora lutea and cumulus-enclosed oocytes. Progesterone concentrations were not significantly different among groups. The oocyte number and the maturation, ovulation rate, and the number of corpora lutea were higher in GnRH-treated mice than both controls and superovulated mice. In conclusion, GnRH given 24 h before superovulation with eCG-hCG increased the number and maturation of oocytes and the rate of ovulation in mice. 相似文献
16.
The main objective of this study was to investigate the potential of peanut husk (Arachis hypogaea L.) as a fiber–peanut mixture to produce fiberboards for general purposes. For panel production, the addition of peanut husk at various percentages to the wood fiber was the only variable. Panels produced utilizing peanut husk were compared to panels produced using 100% wood fiber. The chemical properties of peanut husk; holocellulose and lignin content, alcohol–benzene, hot and cold water, and dilute alkali (1% NaOH) solubility, were also determined. Results indicated that panels could be produced utilizing up to 30% peanut husk without affecting the usability of the panels. It was not possible to meet the minimum IB strength standards when peanut husk was added to the mixture. Higher additions resulted in panels having lower elastic and rupture moduli than the minimum requirements according to TS-EN standards. 相似文献
17.
Our overall objectives were to prepare commercially acceptable formulations of the postharvest biological control yeasts, Metschnikowia pulcherrima and Pichia guilliermondii, which have a long storage life and to determine the effectiveness of these formulations to control postharvest green and blue moulds on citrus fruit. Yeasts, grown on a cane molasses-based medium, were combined with talc or kaolin carriers and various adjuvants and the viability of yeast in 12 formulations was determined over a 6 month period. Formulation no. 11, containing talc, sodium alginate, sucrose, and yeast extract, for both yeasts had a significantly higher viable yeast cell content over a 6 month storage period. Among the formulations, three formulations (formulations no. 5, 6, and 11) were selected for additional in vivo testing because they had higher levels of viability amongst yeast cell populations during storage and were easier to resuspend remained in suspension more easily. These formulations were tested on Satsuma mandarin and grapefruit to control green and blue moulds. Formulations no. 5, 6, and 11 for both yeasts effectively controlled green mould, while only formulation no. 11 with either yeast isolate M. pulcherrima (isolate M1/1) or P. guilliermondii (isolate P1/3) effectively controlled both blue and green moulds. 相似文献
18.
Sinha J Inan M Fanders S Taoka S Gouthro M Swanson T Barent R Barthuli A Loveless BM Smith LA Smith T Henderson I Ross J Meagher MM 《Journal of biotechnology》2007,127(3):462-474
A process was developed for production of a candidate vaccine antigen, recombinant C-terminal heavy chain fragment of the botulinum neurotoxin serotype E, rBoNTE(H(c)) in Pichia pastoris. P. pastoris strain GS115 was transformed with the rBoNTE(H(c)) gene inserted into pHILD4 Escherichia coli-P. pastoris shuttle plasmid. The clone was characterized for genetic stability, copy number, and BoNTE(H(c)) sequence. Expression of rBoNTE(H(c)) from the Mut(+) HIS4 clone was confirmed in the shake-flask, prior to developing a fed-batch fermentation process at 5 and 19 L scale. The fermentation process consists of a glycerol growth phase in batch and fed-batch mode using a defined medium followed by a glycerol/methanol transition phase for adaptation to growth on methanol and a methanol induction phase resulting in the production of rBoNTE(H(c)). Specific growth rate, ratio of growth to induction phase, and time of induction were critical for optimal rBoNTE(H(c)) production and minimal proteolytic degradation. A computer-controlled exponential growth model was used for process automation and off-gas analysis was used for process monitoring. The optimized process had an induction time of 9 h on methanol and produced up to 3 mg of rBoNTE(H(c)) per gram wet cell mass as determined by HPLC and Western blot analysis. 相似文献
19.
Many studies require collection of metabolic wastes from laboratory animals, and oftentimes it is important that feces and urine be collected separately. The authors describe an easily assembled and inexpensive device that can be used to collect urine samples from rats without any invasive operations. The device affords reasonable separation of feces and urine. 相似文献
20.
Genome-wide fungal stress responsive miRNA expression in wheat 总被引:2,自引:0,他引:2
Behçet Inal Mine Türktaş Hakan Eren Emre Ilhan Sezer Okay Mehmet Atak Mustafa Erayman Turgay Unver 《Planta》2014,240(6):1287-1298