全文获取类型
收费全文 | 237篇 |
免费 | 12篇 |
出版年
2023年 | 1篇 |
2022年 | 8篇 |
2021年 | 14篇 |
2020年 | 12篇 |
2019年 | 20篇 |
2018年 | 27篇 |
2017年 | 12篇 |
2016年 | 10篇 |
2015年 | 9篇 |
2014年 | 11篇 |
2013年 | 14篇 |
2012年 | 14篇 |
2011年 | 12篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 12篇 |
2006年 | 3篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2002年 | 1篇 |
2001年 | 10篇 |
2000年 | 4篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1968年 | 1篇 |
1960年 | 1篇 |
1948年 | 1篇 |
排序方式: 共有249条查询结果,搜索用时 15 毫秒
21.
22.
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
23.
Brandt B Büchse T Abou-Eladab EF Tiedge M Krause E Jeschke U Walzel H 《Histochemistry and cell biology》2008,129(5):599-609
Galectin-1 (gal-1), a member of the family of β-galactoside binding proteins, participates in several biological processes
such as immunomodulation, cell adhesion, regulation of cell growth and apoptosis. The aim of this study was to investigate
whether gal-1 interferes with the Fas (Apo-1/CD95)-associated apoptosis cascade in the T-cell lines Jurkat and MOLT-4. Gal-1
and an Apo-1 monoclonal antibody (mAb) induced DNA-fragmentation in Jurkat T-cells whereas MOLT-4 cells were resistant. Gal-1
stimulated DNA-fragmentation could be efficiently inhibited by caspase-8 inhibitor II (Z-IETD-FMK) and a neutralizing Fas
mAb. Fas could be identified as a target for gal-1 recognition as demonstrated by immunofluorescence staining, binding of
the receptor glycoprotein to immobilized gal-1 and analyses by immunoblotting as well as by liquid chromatography-tandem mass
spectrometry (LC-MS/MS). Gal-1 stimulates the activation and proteolytic processing of procaspase-8 and downstream procaspase-3
in Jurkat-T cells. Inhibition of gal-1 induced procaspase-8 activation by a neutralizing Fas mAb strongly suggests that gal-1
recognition of Fas is associated with caspase-8 activation. Our data provide the first experimental evidence for targeting
of gal-1 to glycotopes on Fas and the subsequent activation of the apoptotic death-receptor pathway. 相似文献
24.
Mohammed Ramdani Roger J. Flower Najat Elkhiati with contributions from Hilary H. Birks Mohammed M. Kraïem Adel A. Fathi 《Aquatic Ecology》2001,35(3-4):389-403
Palaeolimnological studies were carried out on sediment cores from nine North African wetland lakes. The lakes represented a variety of habitats ranging from freshwater to mixohaline conditions and with and without direct connections to the sea. Sediment cores were examined for records of recent environmental change during the 20th century period. Faunal remains analysed in the sediments included those of Cladocera, Ostracoda, Chironomidae, Mollusca and, at the sites with marine connections, Foraminifera.
Cyprideis
torosa littoralis was the most common ostracod, occurring in sediments from the seven sites linked with the sea and also in brackish water Sidi Bou Rhaba. In acid Megene Chitane ostracods were scarce, being represented by a single species (Cypria ophtalmica).
Candona neglecta completely disappeared at two sites (Sidi Bou Rhaba and Bokka) during the 20th century. Of the Cladocera, Chydorus sphaericus was common in the moderately mixohaline sites and but Heterocypris salina occurred only where marine salinities were occasionally achieved (in Zerga, Ichkeul and Korba). Microinvertebrate assemblages in the Nile Delta lake cores and to a less extent in Zerga showed a clear response indicative of more fresher conditions occurring during the latter part of the 20th century. However the freshening trend began prior to construction of the Aswan High Dam (mid 1960s).With the exception of the most saline site (Korba), microinvertebrate communiuties at all the CASSARINA sites have experienced major disturbances during the 20th century. Changes in freshwater availability associated with increased human usage of water resources is perceived as a major factor regulating the abundance and occurrence of aquatic microinvertebrate species at these sites 相似文献
25.
Recent environmental change in North African wetland lakes: diatom and other stratigraphic evidence from nine sites in the CASSARINA Project 总被引:1,自引:0,他引:1
R.J. Flower S. Dobinson M. Ramdani M.M. Kraïem C. Ben Hamza A.A. Fathi H.M.A. Abdelzaher H.H. Birks P.G. Appleby J.A. Lees E. Shilland S.T. Patrick 《Aquatic Ecology》2001,35(3-4):369-388
All nine wetland lakes in the CASSARINA North African suite of sample sites have been disturbed strongly by human activity during the 20th century. Dated lake sediment core were used to provide evidence of the extent of recent environmental change at each site. Sedimentary diatoms at seven sites were useful for inferring salinity change trends during the last century. At two sites preservation problems severely degraded the sedimentary diatom record. Sediment core integrity was otherwise established.Lithostratigraphic measurements indicated some site specific changes in soil erosion and sediment composition but, for the Egyptian Delta lakes, no physical signal synchronous with Aswan High Dam construction was found. Sedimentary diatom assemblages were generally site characteristic and halophilous taxa were common. At two sites planktonic diatoms indicated some recent eutrophication but generally the assemblages were more indicative of salinity changes. Diatom-inferred salinity trends for the seven sites typically indicated that reductions in water salinity occurred sometime during the early or mid 20th century.Rather than climate, hydrological modification of water resources is implicated as the primary driver of salinity changes during most of the 20th century. In the western North African region these modifications were mainly local land drainage and water diversion programmes to alleviate winter flooding and/or promote summer water availability. In the Delta region, the Nile has been intensively exploited since antiquity and intensively so from the late 19th century to release more fresh water for agriculture. Here, diatom records indicate that freshening began well before the Aswan High Dam but salinity fluctuations have tended to diminish during the latter part of the 20th century. A small reversal in the water freshening trend in the 1980/90s was possibly a response to land subsidence/sea-level change or to reduced freshwater supply.Freshwater supply to the sites is generally diminishing as former freshwater surpluses switch to deficit. One site (Merja Bokka, Morocco) became completely dry in 1998 as agriculture encroached and Megene Chitane, the only acid lake in Tunisia, is currently affected by excessive inflow abstraction. At the beginning of the 21st century, eight of the nine CASSARINA sites persist as viable but modified aquatic ecosystems. They nevertheless continue to support valuable aquatic biodiversity, especially in the Delta sites and in Chitane. The modern diatom communities are clearly tolerant of considerable environmental change but the remaining sites are increasingly threatened by major hydrological disturbance. Base-line floristic data for the late 20th century are given but continuous biomonitoring combined with effective management is needed urgently to help conserve North Africa's diminishing natural wetland lake resources. 相似文献
26.
M.M. Kraïem C. Ben Hamza M. Ramdani A.A. Fathi H.M.A. Abdelzaher R.J. Flower 《Aquatic Ecology》2001,35(3-4):335-345
Age and growth characteristics of the thin-lipped Grey Mullet (Liza ramada) were investigated in three North African wetland lakes: Merja Zerga (Morocco), Garâat Ichkeul (Tunisia) and Edku Lake (Egypt). Age structure of the mullet populations was very similar in all three study lakes. Small differences in growth were indicated, especially for the Moroccan population, where growth tended to be slower than for the other two populations. The fastest growth was observed in the Edku population while the best condition was observed in the Ichkeul population. Compared with some European populations, the sampled North African populations have faster growth and better condition factors. 相似文献
27.
28.
Behnaz Ahmadi Abdolrahim Nikzamir Seid Mohamadali Ghafari Ghorban Mohamadzadeh Mahmod Latifi Ahmad Bafandeh Mohammad Fathi Mir Saeed Yekaninejad Mahfam Nikzamir 《Molecular biology reports》2014,41(2):997-1001
Cyclooxygenases are key enzymes in conversion of arachidonic acid into prostaglandin H2. Cyclooxygenase-2 (COX-2) increases prostaglandins in neoplastic tissue. COX-2 has important roles in cell proliferation cancers, angiogenesis, and alzheimer. COX-2 is up-regulated in several types of cancer, and it is hypothesized that COX-2 expression may be genetically influenced. Our main objective was to evaluated the association of polymorphism COX-2 with risk of breast cancer in khouzestan province, and the second objective of the study was to evaluate the association with biochemistry parameters. This study consisting of 150 patients with breast cancer and 120 normal DNA was extracted from the white blood cells. Polymorphism cox2 gene was detected by polymerase chain reaction according to the standard methods. The profile lipids and estrogen were measured in two groups by standard methods. Chi square analysis showed that there was no association between breast cancer risk and COX-2 ?765G>C genotype and alleles. Also, no association were observed between ?765G>C polymorphism and biochemistry parameters. A multiple logistic regression model with cox2 genotypes and LDL and HDL as covariates revealed that there is no significant association between cox2 genotypes and risk of breast cancer, but higher values of LDL and HDL significantly increase risk of breast cancer. 相似文献
29.
Mohammad Hashim Baby Tabassum Elsayed Fathi Abd_Allah Abeer Hashem Priya Bajaj 《Saudi Journal of Biological Sciences》2018,25(8):1739-1742
Cadmium is the second most hazardous metals with bio-concentration factor (BCF)?>?100 Although WHO permitted cadmium concentration in drinking water is 0.005?mg/L, yet the reality is far above to this limit because of industrial utility of this metal. Oral exposure of cadmium to human results in dreadful symptoms of metabolic disorders especially in liver and kidneys. Endogenous protection could be supported by some exogenous herbal supplement (viz., Catharanthus roseus in this case) to overcome the toxic effects. Present Study has been designed to find out the functional renal changes under the effect of cadmium and Catharanthus roseus in the model organism albino rats. Cadmium significantly (p?>?0.01) increases the level of nitrogenous waste (Urea, BUN, Uric Acid and Creatinin), while decreases the serum protein profile in acute and sub-acute sets. Urea concentration of control ranged from 16.56 to 17.72?mg/dl while that of Group-B and D were 19.84 to 20.87?mg/dl and 17.56 to 17.59?mg/dl respectively. Similarly uric acid concentration ranged in control form 6.98 to 8.01?mg/dl in group-B from 7.58 to 10.25?mg/dl, in Group-D 8.02 to 8.59?mg/dl respectively. Creatinin concentration ranged in control 0.57 to 0.65?mg/dl, in group-B 0.97 to 1.02?mg/dl, in group-D – 0.95 to 0.98?mg/dl respectively.These results might be due to altered filtration rate of kidney because of protein disruption. The studies conclude the efficient nephro-protection offered by Catharanthus roseus extract against Cadmium toxicity. 相似文献
30.
Saira Bano Shujaul Mulk Khan Jan Alam Abdulaziz A. Alqarawi Elsayed Fathi Abd_Allah Zeeshan Ahmad Inayat Ur Rahman Habib Ahmad Abdullah Aldubise Abeer Hashem 《Saudi Journal of Biological Sciences》2018,25(4):801-810
The present study was conducted to elaborate vegetation composition structure to analyze role of edaphic and topographic factors on plant species distribution and community formation during 2013–14. A mixture of quadrat and transect methods were used. The size of quadrat for trees shrubs and herbs were 10 × 5, 5 × 2, 1 × 1 meter square respectively. Different phytosociological attribute were measured at each station. Primary results reported 123 plant species belong to 46 families. Asteraceae and Lamiaceae were dominant families with 8 species each. PCORD version 5 were used for Cluster and Two Way Cluster Analyses that initiated 4 plant communities within elevation range of 529–700 m from sea level. Indicator species analyses (ISA) were used to identify indicator species of each community. CANOCO Software (version 4.5) was used to measure the influence of edaphic and topographic variables on species composition, diversity and community formation. Whereas Canonical Correspondence Analysis (CCA) was used to measure the effect of environmental variables which showed elevation and aspect were the stronger environmental variable among topographic and CaCO3 contents, electric conductivity, soil pH were the stronger edaphic factors in determination of vegetation and communities of the Bheer Hills. Grazing pressure was one of the main anthropogenic factors in this regard. 相似文献