全文获取类型
收费全文 | 1626篇 |
免费 | 116篇 |
国内免费 | 4篇 |
专业分类
1746篇 |
出版年
2024年 | 8篇 |
2023年 | 22篇 |
2022年 | 72篇 |
2021年 | 91篇 |
2020年 | 55篇 |
2019年 | 93篇 |
2018年 | 110篇 |
2017年 | 61篇 |
2016年 | 77篇 |
2015年 | 71篇 |
2014年 | 73篇 |
2013年 | 137篇 |
2012年 | 104篇 |
2011年 | 106篇 |
2010年 | 68篇 |
2009年 | 53篇 |
2008年 | 61篇 |
2007年 | 60篇 |
2006年 | 45篇 |
2005年 | 49篇 |
2004年 | 54篇 |
2003年 | 44篇 |
2002年 | 34篇 |
2001年 | 12篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 6篇 |
1996年 | 13篇 |
1994年 | 5篇 |
1992年 | 7篇 |
1990年 | 10篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1969年 | 4篇 |
排序方式: 共有1746条查询结果,搜索用时 11 毫秒
51.
A validated, simple and sensitive HPLC method was developed for the simultaneous determination of lipoperoxidation relevant reactive aldehydes: glyoxal (GO), acrolein (ACR), malondialdehyde (MDA), and 4-hydroxy-2-nonenal (HNE) in human serum. The studied aldehydes were reacted with 2,2′-furil to form fluorescent difurylimidazole derivatives that were separated on a C18 column using gradient elution and fluorescence detection at excitation and emission wavelengths of 250 and 355 nm, respectively. The method showed good linearity over the concentration ranges of 0.100–5.00, 0.200–10.0, 0.200–40.0, and 0.400–10.0 nmol/mL for GO, ACR, HNE, and MDA, respectively, with detection limits ranging from 0.030 to 0.11 nmol/mL. The percentage RSD of intraday and interday precision did not exceed 5.0 and 6.2%, respectively, and the accuracy (%found) ranged from 95.5 to 103%. The proposed method was applied for monitoring the four aldehydes in sera of healthy, diabetic, and rheumatic human subjects with simple pretreatment steps and without interference from endogenous components. By virtue of its high sensitivity and accuracy, our method enabled detection of differences between analytes concentrations in sera of human subjects under different clinical conditions. 相似文献
52.
Badawi A. Abou-Awad Abdel-Sattar M. Metwally Mahmoud M. Al-Azzazy 《Archives Of Phytopathology And Plant Protection》2013,46(4):390-403
Effects on development, longevity, fecundity and predation of the predatory phytoseiid mite Typhlodromus mangiferus Zaher and El-Brolossy were studied in the laboratory at different temperatures and relative humidities using four prey mite species: the motile stages of the eriophyid mango bud mite Aceria mangiferae Sayed, the eriophyid leaf coating and webbing mite Cisaberoptus kenyae Keifer, the eriophyid mango rust mite Metaculus mangiferae (Attiah) and nymphs of the tetranychid mango red mite Oligonychus mangiferus (Rahman and Sabra). The increase of different temperatures and decrease of relative humidities from 25°C and 60% to 30°C and 55% and 35°C and 50% shortened development and increased reproduction and prey consumption. The developmental durations were almost similar when the predator was fed on eriophyids compared to that on tetranychid. The maximum reproduction (2.70, 2.08, 1.97 and 1.66 eggs/ ♀ /day) was recorded at the highest temperature and the lowest relative humidity, while the minimum reproduction (1.7, 1.54, 1.53, and 1.06 eggs/ ♀ /day) was noted at the lowest temperature and highest relative humidity with all mango prey species. Life table parameters indicated that feeding of T. mangiferus on A. mangiferae led to the highest reproduction rate (rm = 0.204 and 0.139 females/female/day), while feeding on O. mangiferus gave the lowest reproduction rate (rm = 0.137 and 0.116) at 35°C and 50% relative humidity and 25°C and 60% relative humidity, respectively. T. mangiferus seems to be a voracious predator of both mango eriophyid and tetranychid mites. The adult female daily consumed about 127 A. mangiferae, 97 C. kenyae, 86 M. mangiferae, and 18 O. mangiferus at 35°C and 50% relative humidity, while it devoured only 99.81, 86, 81, and 15 individuals, respectively at 25°C and 60% relative humidity. The present study revealed that each injurious mite is thought to be profitable prey species to T. mangiferus as a facultative predator. 相似文献
53.
Mahmoud El-Baz Younis Mohammed Naguib Abdel-Ghany Hasaneen Heba Mahmoud Mohammed Abdel-Aziz 《Plant signaling & behavior》2010,5(10):1197-1203
Exposure of dark- or ambient visible light-grown broad bean seedlings to low (LL) and high (HL) visible light intensities, UV-A or UV-C, either alone or in combination, induced significant increases in total phenolic compounds as well as in anthocyanins content, throughout the germination period, as compared with the respective levels in control seedlings. In general, as compared with control levels, exposure of both dark- or light-grown broad bean seedlings to LL, HL, UV-A or UV-C, induced significant increases in the contents of non-enzymatic antioxidants (total ascorbate; ASA-DASA and total glutathione; GSSG-GSH) and enzymatic antioxidant activities (superoxide dismutase; SOD, catalase; CAT, ascorbate peroxidase; APO and glutathione reductase; GR). The obtained results are discussed in relation to induced mechanisms of protection and repair from the inevitable exposure to damaging visible light and UV radiation.Key words: Vicia faba, anthocyanins, phenolic compounds, total ascorbate, total glutathione, SOD, APO, CAT, GR 相似文献
54.
Mansour MA Mostafa AM Nagi MN Khattab MM Al-Shabanah OA 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2002,132(2):123-128
The effect of aminoguanidine (AG) on nephrotoxicity induced by cisplatin (CDDP) was investigated. A single dose of CDDP (7.5 mg/kg i.p.) induced nephrotoxicity, manifested biochemically by a significant elevation in serum urea, creatinine and a severe decrease in serum albumin. Moreover, marked increases in kidney weight, urine volume and urinary excretion of albumin were observed. Nephrotoxicity was further confirmed by a significant decrease in glutathione-S-transferase (GST, E.C. 2.5.1.18), glutathione peroxidase (GSH-Px, E.C. 1.11.1.9) and catalase (E.C. 1.11.1.6) and a significant increase in lipid peroxides measured as malondialdhyde (MDA) in kidney homogenates. Administration of AG (100 mg/kg per day p.o.) in drinking water 5 days before and 5 days after CDDP injection produced a significant protection against nephrotoxicity induced by CDDP. The amelioration of nephrotoxicity was evidenced by significant reductions in serum urea and creatinine concentrations. In addition, AG tended to normalize decreased levels of serum albumin. Urine volume, urinary excretions of albumin and GST and kidney weight were significantly decreased. Moreover, AG prevented the rise of MDA and the reduction of GST and GSH-Px activities in the kidney. These results suggest that AG has a protective effect on nephrotoxicity induced by CDDP and it may therefore improve the therapeutic index of CDDP. 相似文献
55.
Hussein AA Abdel-Aziz A Gabr M Hemmaid KZ 《Canadian journal of physiology and pharmacology》2012,90(1):99-111
Diabetes mellitus (DM) is commonly associated with metabolic and cardiac dysfunctions. The aim of this study was to examine the effect of ghrelin on metabolic and cardiac dysfunctions in a type-2 diabetes mellitus (T2DM) rat model. For this, 48 male adult Sprague-Dawley rats were divided equally into 4 groups: Group I, fed normal chow, served as normal control group; Groups II-IV, were fed a high-fat diet for 2?weeks followed by injection of streptozotocin (STZ) (35?mg/kg body mass) to create a model of T2DM; Group II, were not treated; Group III, were treated with the vehicle (saline); Group IV, were treated with ghrelin (40?μg/kg body mass) twice daily for 10 days. The untreated diabetic rats showed a significant increase in serum fasting blood glucose, insulin homeostasis model assessment (HOMA) index, triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), total serum cholesterol (TC), and body mass, with a decrease in high-density lipoprotein cholesterol (HDL-C) (p?< 0.05). Hearts isolated from diabetic rats showed a significant increase in myocardial fat content, a significant decrease in GLUT4, and an increase in acyl-CoA oxidase enzyme mRNA (p?< 0.05). Ghrelin administration for 10?days caused a significant improvement in lipid profile, HOMA index, and body mass, and significantly corrected the myocardial mass, significantly reduced the fat content of the myocardium, significantly increased GLUT4, and decreased acyl CoA oxidase mRNA (p?< 0.05). Thus, ghrelin improves both the metabolic functions and the disturbed energy metabolism in the cardiac muscle of obese diabetic rats. 相似文献
56.
57.
Franz T. Fürsich Markus Wilmsen Kazem Seyed-Emami Gerhard Schairer Mahmoud R. Majidifard 《Facies》2003,48(1):171-198
Summary Following a phase of predominantly siliciclastic sedimentation in the Early and Middle Jurassic, a large-scale, low-latitude
carbonate depositional system was established in the northern part of the Tabas Block, part of the central-east Iranian microplate,
during the Callovian and persisted until the latest Oxfordian/Early Kimmeridgian. Running parallel to the present eastern
block margin, a NNW/SSE-trending carbonate platform developed in an area characterized by reduced subsidence rates (Shotori
Swell). The growth of this rimmed, flat-topped barrier platform strongly influenced the Upper Jurassic facies pattern and
sedimentary history of the Tabas Block. The platform sediments, represented by the predominantly fine-grained carbonates of
the Esfandiar Limestone Formation, pass eastward into slope to basin sediments of the Qal'eh Dokhtar Limestone Formation (platform-derived
allochthonites, microbialites, and peri-platform muds). Towards the west, they interfinger with bedded limestones and marlstones
(Kamar-e-Mehdi Formation), which were deposited in an extensive shelf lagoon. In a N−S direction, the Esfandiar Platform can
be traced for about 170 km, in an E-W direction, the platform extended for at least 35–40 km. The width of the eastern slope
of the platform is estimated at 10–15 km, the width of the western shelf lagoon varied considerably (>20–80 km). During the
Late Callovian to Middle Oxfordian, the Esfandiar Platform flourished under arid climatic conditions and supplied the slope
and basinal areas with large amounts of carbonates (suspended peri-platform muds and gravitational sediments). Export pulses
of platform material, e.g. ooids and aggregate grains, into the slope and basinal system are interpreted as highstand shedding
related to relative sealevel variations. The high-productivity phase was terminated in the Late Oxfordian when the eastern
platform areas drowned and homogeneous deep water marls of the Upper Oxfordian to Kimmeridgian Korond Formation onlapped both
the Qal'eh Dokhtar Limestone Formation and the drowned Esfandiar Limestone Formation. Tectonic instability, probably caused
by faulting at the margins of the Tabas Block in connection with rotational movements of the east-central Iranian block assemblage,
was responsible for the partial drowning of the eastern platform areas. In some areas, relicts of the platform persisted to
produce shallow-water sediments into the Kimmeridgian. 相似文献
58.
Abdel‐Maaboud I. Mohamed Osama H. Abdelmageed Hesham Salem Dalia M. Nagy Mahmoud A. Omar 《Luminescence》2013,28(3):345-354
A validated simple and sensitive spectrofluorimetric method was developed for the determination of chlorpromazine hydrochloride, promethazine hydrochloride, trifluperazine hydrochloride, thioridazine hydrochloride, perazine maleate and oxomemazine. The method was based on condensation of malonic acid/acetic anhydride (MAA) under the catalytic effect of the tertiary amine moiety of the studied phenothiazines to provide a deep yellow to brown colour with green florescence. Relative fluorescence intensity of the products was measured at λexc 398 nm and λem 432 nm. Different variables affecting the reaction were studied and optimized. The method was successfully applied for the determination of the studied drugs in commercial dosage forms. The lower detection limits allowed the application of this method for the determination of the compounds in plasma as an example of a biological fluid. In addition, the method was considered specific for the determination of tertiary amines in the presence of primary and secondary amines; as a result, it was deemed suitable for the determination of the cited drugs in the presence of their degradation products resulting from N‐dealkylation or oxidation of the corresponding sulphoxides or sulphones. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
59.
Seyed Mahmoud Hashemi Zuhair Mohammad Hassan Ali Akbar Pourfathollah Sara Soudi Abbas Shafiee Masoud Soleimani 《Journal of cellular biochemistry》2013,114(4):955-965
Adipose tissue‐derived mesenchymal stem cells (AD‐MSCs) have been shown to be capable of differentiating into multiple cell type and exert immunomodulatory effects. Since the selection of ideal stem cell is apparently crucial for the outcome of experimental stem cell therapies, therefore, in this study we compared AD‐MSCs conditioned media (CM) from BALB/c, C57BL/6, and DBA mouse strains. No significant difference was found in the morphology, cell surface markers, in vitro differentiation and proliferation potentials of AD‐MSCs isolated from C57BL/6, BALB/c, and DBA mice. The immunological assays showed some variation among the strains in the cytokines, nitric oxide (NO), and indoleamine 2,3‐dioxygenase (IDO) production and immunomodulatory effects on splenocytes functions. Our results indicated a suppression of splenocytes proliferation in the presence of AD‐MSC CM from the three inbred mouse strains. However, BALB/c CM exerted a higher suppression of splenocytes proliferation. AD‐MSCs isolated from C57BL/6 and BALB/c mice produced higher levels of TGF‐β than those from DBA mice. Furthermore, IL‐17 and IDO production was higher in AD‐MSCs isolated from BALB/c mice. Our results indicated an increased production of TGF‐β, IL‐4, IL‐10, NO, and IDO by splenocytes in response to CM from BALB/c AD‐MSCs. In conclusion, our results showed that the immunomodulatory properties of mouse AD‐MSCs is strain‐dependent and this variation should be considered during selection of appropriate stem cell source for in vivo experiments and stem cell therapy strategies. J. Cell. Biochem. 114: 955–965, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
60.
Said I. Ismail Ismail S. Mahmoud Mahmoud Al-Ardah Amid Abdelnour Nidal A. Younes 《Journal of genetics》2009,88(2):233-238
Five patients, four brothers and their paternal aunt, presented with a history of overt hyperthyroidism and goiter. Hyperthyroidism
in this family was remarkable for its poor response to carbimazole (30–50 mg/d). The thyroid ultrasound showed a diffusely
enlarged gland in all the affected members, and thyroid stimulating antibodies (TSAB) were negative. Screening for germline
mutations in thyroid stimulating hormone (TSH) receptor (TSHR) gene was performed by direct sequencing of genomic DNA extracted from peripheral blood leukocytes of all family members.
The sequence analysis of all TSHR gene exons and intron borders revealed two genomic variants. The first was a single nucleotide polymorphism (SNP) within
exon seven (Asn187Asn), whereas the other was located in intron seven (IVS7+68T>G). All affected members, two asymptomatic
brothers with sub-clinical hyperthyroidism, and their father were heterozygous for those two genomic variants. Anti-thyroid
drug treatment for several months successfully relieved symptoms in one subject, whereas the remaining patients required total
thyroidectomy to control their disease. This is the first Jordanian family with familial non-autoimmune hyperthyroidism, with
mutations affecting the TSHR gene. 相似文献