全文获取类型
收费全文 | 793篇 |
免费 | 40篇 |
国内免费 | 1篇 |
专业分类
834篇 |
出版年
2024年 | 1篇 |
2023年 | 12篇 |
2022年 | 28篇 |
2021年 | 41篇 |
2020年 | 36篇 |
2019年 | 69篇 |
2018年 | 49篇 |
2017年 | 29篇 |
2016年 | 53篇 |
2015年 | 45篇 |
2014年 | 53篇 |
2013年 | 64篇 |
2012年 | 67篇 |
2011年 | 52篇 |
2010年 | 37篇 |
2009年 | 24篇 |
2008年 | 31篇 |
2007年 | 26篇 |
2006年 | 25篇 |
2005年 | 16篇 |
2004年 | 21篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1982年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1968年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有834条查询结果,搜索用时 15 毫秒
81.
Evaluation of inhibitory effect and apoptosis induction of Zyzyphus Jujube on tumor cell lines,an in vitro preliminary study 总被引:3,自引:0,他引:3
In the present study, water extract of dried fruit of Zyzyphus Jujube was tested for its possible anticancer effect and induction
of apoptosis on human tumor cell lines, HEp-2, HeLa and Jurkat cell lines. The inhibitory effect of water extract of this
fruit on cell proliferation was assessed by MTT colorimetric assay. The induction of apoptosis of this extract was analyzed
by DNA fragmentation analysis. Zyzyphus Jujube extract showed inhibitory effects on mentioned cell lines. Jurkat leukemic
line was found the most sensitive cells with IC50 of 0.1 μg mL−1. Our study also showed a typical DNA laddering in this cell line. The present study showed cytotoxic activity of Zyzyphus
Jujube on tumor cells. Although Zyzyphus Jujube has useful compounds for medical applications. 相似文献
82.
New isolates of spore-forming bacilli from larvae and pupae of 3 species of mosquitoes are recorded in central Iraq.Bacillus sphaericus Meyer and Neide was isolated fromCulex pipiens (L.) larva.Bacillus carotarum Koch andBacillus cereus Frankland & Frankland were isolated fromTheobaldia longiareolata (Macquart) pupae.Bacillus laterosporus Laubach andBacillus thuringiensis (H 18) were isolated fromAedes caspius (Pallas) larvae. In addition, unidentifiedBacillus spp. were isolated fromCx. pipiens, T. longiareolata andAe. caspius larvae. Examination of soil samples collected from mosquito natural breeding habitats revealed isolates ofB. cereus, Bacillus thuringiensis H4a 4b; H 12 and H 16 and an unidentifiedBacillus sp.
Résumé Des souches bactériennes sporogènes sont isolées de moustiques qui se trouvent dans la région centrale de l'Irak. Les résultats obtenus sont les suivants:Bacillus sphaericus Meyer & Neide [Culex pipiens (L.), larve],Bacillus carotarum Koch etBacillus cereus Frankland & Frankland [Theobaldia longiareolata (Macquart), nymphe],Bacillus laterosporus Laubach etBacillus thuringiensis (H 18) [Aedes caspius (Pallas), larvel]. L'examen des larves deCulex pipiens. T. longiareolata etAe. caspius, ainsi que l'analyse des échantillons du sol prélevés dans la région montrent la présence deBacillus cereus, Bacillus thuringiensis H4a 4b; H12 plus H16 et d'autresBacillus non identifiés.相似文献
83.
84.
Alipour M Gholami MR Jafari Anarkooli I Sohrabi D Tajki J Pourheidar M 《Cellular and molecular neurobiology》2011,31(5):765-773
The present work was designed to investigate the potential protective effects of post-ischemic treatment with aminoguanidine
(AG) on sciatic nerve ischemia/reperfusion (I/R) injury in rat. Seventy-two rats were divided into 12 groups (n = 6). We used ischemia model in these groups by occluding the right common iliac and femoral arteries for 3 h with a silk
suture 6-0 using slipknot technique. Treatment groups (2, 4, 6, 8, 10, and 12) received 150 mg/kg AG intraperitoneally 24 h
after induction of ischemia. After certain time intervals of reperfusion (2, 4, 7, 14, and 28 days), the function of the hind
limb was assessed using behavioral scores based on gait, racing reflex, toe spread, pinch sensitivity, paw position, and grasp.
After euthanasia, sciatic nerves were removed at the end of reperfusion times and sections were cut at 5 μm, then were stained
for light microscopy studies and graded for ischemic fiber degeneration (IFD), edema, and apoptosis. Maximal behavioral deficit
occurred at 7 days of reperfusion. The comparison of behavioral score pertaining to the control and AG groups revealed significant
differences and showed also a better time course in recovery (P < 0.05). Other than 3 and 4 groups, the amount of edema in AG treatment groups showed significant differences compared with
control groups (P < 0.05). IFD was also significantly decreased in the AG treatment groups than controls. Most importantly, I/R-induced apoptosis
were improved significantly on the 4th, 7th, and 14th days of reperfusion in AG-treated groups compared to controls. In conclusion, our findings suggest that post-ischemic
administration of AG exhibits protective effect against sciatic nerve I/R injury. 相似文献
85.
Behnaz Forouhar Kalkhoran Farida Behzadian Farzaneh Sabahi Mohsen Karimi Hesam Mirshahabi 《Reports of Biochemistry & Molecular Biology》2013,2(1):28-34
Background:
Hepatitis delta virus (HDV) is a subviral human pathogen that exploits host RNA editing activity to produce two essential forms of the sole viral protein, hepatitis delta antigen (HDAg). Editing at the amber/W site of HDV antigenomic RNA leads to the production of the large form (L-HDAg), which is required for RNA packaging.Methods:
In this study, PCR-based site-directed mutagenesis by the overlap extension method was used to create the point mutation converting the small-HDAg (S-HDAg) stop codon to a tryptophan codon through three stages.Results:
Sequencing confirmed the desirable mutation and integrity of the L-HDAg open reading frame. The amplicon was ligated into pcDNA3.1 and transfected to Huh7 and HEK 293 cell lines. Western blot analysis using enhanced chemiluminescence confirmed L-HDAg expression. The recombinant L-HDAg localized within the nuclei of cells as determined by immunofluorescence and confocal microscopy.Conclusion:
Because L-HDAg requires extensive post-translational modifications, the recombinant protein expressed in a mammalian system might be fully functional and applicable as a tool in HDV molecular studies, as well as in future vaccine research.Key Words: Hepatitis Delta Virus, L-HDAg, SOEing-PCR 相似文献86.
Parvin Salehi Shanjani Mohsen Mardi Leila Pazouki Marianna Hagidimitriou Damiano Avanzato S. Mostafa Pirseyedi Mohammad Reza Ghaffari S. Mojtaba Khayam Nekoui 《Tree Genetics & Genomes》2009,5(3):447-458
Knowledge of pistachio genetic diversity is necessary for the formulation of appropriate management strategies for the conservation
of these species. We analysed amplified fragment length polymorphisms in a total of 216 pistachio accessions, which included
seven populations from three wild species (Pistacia vera, Pistacia khinjuk and Pistacia atlantica subsp. kurdica) and most of the important cultivars from Iran, together with some foreign cultivars. High levels of genetic diversity were
detected within the Iranian cultivars, and they showed a clear separation from foreign cultivars, as revealed by unweighted
pair group method with arithmetic averaging and supported by analysis of molecular variance. The lowest amount of polymorphism
was observed in P. atlantica subsp. kurdica, which showed the lowest number of total bands as compared to the other species. This revealed strong genetic erosion of
P. atlantica subsp. kurdica, which reflected a severe decline in habitat and over-exploitation. Based on these findings, strategies are proposed for
the genetic conservation and management of pistachio species and cultivars. 相似文献
87.
Bernstein PS Zhao DY Sharifzadeh M Ermakov IV Gellermann W 《Archives of biochemistry and biophysics》2004,430(2):163-169
There is growing evidence that high levels of the macular xanthophyll carotenoids lutein and zeaxanthin may be protective against visual loss from age-related macular degeneration. To study this protective effect further, it is important to measure macular carotenoid levels noninvasively in a wide variety of subjects. We have developed and validated resonance Raman spectroscopy as a sensitive and specific objective method to measure macular carotenoid levels in the living human eye. In this minireview, the principles and implementation of ocular carotenoid resonance Raman spectroscopy are reviewed, and the results of observational cross-sectional studies and of prospective supplementation studies on subjects with and without macular pathology are summarized. We have recently extended this technology to an imaging mode which will further enhance our understanding of the roles of lutein and zeaxanthin in normal macular function and in the prevention of age-related visual loss. 相似文献
88.
Parisa Ahmadpour Mohsen Soleimani Fatemeh Ahmadpour Arifin Abdu 《International journal of phytoremediation》2014,16(5):454-468
Contamination of soils with copper (Cu) has become a serious problem in the environment. Phytoremediation is an emerging green technology that uses green plants to remediate heavy metal contaminated areas. This study was conducted to evaluate the potential of Jatropha curcas for remediation of soils contaminated with Cu. Seedlings were planted in soils spiked with Cu in amount of 0, 50, 100, 200, 300, and 400 mg kg–1 (Cu0, Cu50,Cu100,Cu200,Cu300, and Cu400) for a period of five months. The maximum height and number of leaves were recorded in control (Cu0) whereas the highest basal stem diameter was found in seedlings exposed to Cu50. Copper concentrations among plant parts were in the following trend: roots > stems > leaves. The highest total Cu concentration (665 ± 1 mg kg?1) and total Cu removal (1.2 ± 0.2%) based on total plant dry biomass were found in Cu400 and Cu50 treatments, respectively. J. curcas exhibited high root concentration factor (RCF > 1) and low translocation factor (TF < 1). Although Cu accumulation by the plant didn't reach the criteria of Cu hyperaccumulators, this species showed a potential to be used in phytostabilization of mildly Cu contaminated areas. However, the plant cannot be used for phytoextraction of Cu-contaminated soils. 相似文献
89.
In Vitro Insulin Release from Thermosensitive Chitosan Hydrogel 总被引:1,自引:0,他引:1
Recently, great attention has been paid to in situ gel-forming chitosan/glycerol-phosphate (chitosan/Gp) solution due to their good biodegradability and thermosensitivity. This in situ gel-forming system is injectable fluid that can be introduced into the body in a minimally invasive manner prior to solidifying within the desired tissue. At the present study, insulin release from chitosan/Gp solution has been investigated. Insulin in different concentrations was loaded in two formulations of chitosan/Gp solution and in vitro drug release was studied over a period of 3 weeks. Results indicated that the release of insulin from chitosan/Gp gel decreases by increasing in Gp salt and initial insulin concentration. Stability of released insulin was investigated by 8-anilino-1-naphthalenesulfonate probe. Results proved that insulin have been released in its native form. Because of simple preparation and administration, prolonged release of insulin and stability of released insulin, this in situ gel-forming system could be used as a controlled release delivery system for insulin.KEY WORDS: biodegradable, chitosan, controlled release, in situ forming, insulin 相似文献
90.
Mohammad Ali Assarehzadegan Mojtaba Sankian Farahzad Jabbari Mohsen Tehrani Reza Falak AbdolReza Varasteh 《Molecular biology reports》2011,38(1):65-73
Salsola kali pollen is a common cause of pollinosis during summer and early fall in desert and semi-desert regions. The aim of this study
was the identification and characterization of Sal k 3, a new allergen from S. kali pollen. S. kali pollen extract was fractionated by SDS-PAGE and the allergenic profile was determined by IgE-immunoblotting using twelve
S. kali allergic patients. Protein identification was carried out by the means of mass spectrometry. Using degenerated primers, two
DNA fragments encoding N- and C-terminal domain of Sal k 3 were amplified by PCR, then cloned into the PTZ57R/T vector and
sequenced. The open reading frame of Sal k 3 fragments were subcloned in the pET-32b(+) vector, expressed in E. coli, and purified by Ni2+ affinity chromatography. The IgE-binding capacity of rSal k 3 fragments was then studied by IgE-immunoblotting, inhibition
assays, and skin prick tests. A 45-kDa allergen was identified as a fragment of the cobalamin-independent methionine synthase
(MetE) by mass spectrometry and was detected in the sera of 8/12 (66.6%) of S. kali allergic patients. Moreover, inhibition assays demonstrated that the purified rSal k 3 fragments were similar to their counterparts
in the crude extract. Sal k 3 represents a new allergen of S. kali pollen and seems to be an important allergenic compound in S. kali pollen. 相似文献