全文获取类型
收费全文 | 427篇 |
免费 | 21篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 22篇 |
妇产科学 | 6篇 |
基础医学 | 67篇 |
口腔科学 | 14篇 |
临床医学 | 34篇 |
内科学 | 64篇 |
皮肤病学 | 11篇 |
神经病学 | 20篇 |
特种医学 | 11篇 |
外科学 | 77篇 |
综合类 | 5篇 |
预防医学 | 22篇 |
眼科学 | 6篇 |
药学 | 56篇 |
中国医学 | 1篇 |
肿瘤学 | 29篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 11篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 10篇 |
2015年 | 12篇 |
2014年 | 13篇 |
2013年 | 23篇 |
2012年 | 38篇 |
2011年 | 47篇 |
2010年 | 18篇 |
2009年 | 13篇 |
2008年 | 25篇 |
2007年 | 17篇 |
2006年 | 30篇 |
2005年 | 19篇 |
2004年 | 20篇 |
2003年 | 21篇 |
2002年 | 16篇 |
2001年 | 3篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1992年 | 9篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1984年 | 4篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1966年 | 3篇 |
1942年 | 1篇 |
1940年 | 1篇 |
1937年 | 1篇 |
1936年 | 1篇 |
1933年 | 1篇 |
1931年 | 1篇 |
1928年 | 1篇 |
1926年 | 1篇 |
排序方式: 共有449条查询结果,搜索用时 24 毫秒
31.
Pai RR Shaktawat SS Khadilkar UN Lobo FD Rao VS Philipose R 《Indian journal of pathology & microbiology》2005,48(3):370-372
Majority of the Sclerosing stromal tumours of the ovary documented in the literature are single case reports. We report a series of 4 cases. Among the 4 cases encountered the mean age at presentation was 22.2 years. The clinical presentation varied from asymptomatic mass per abdomen (2 cases), menorrhagia (1 case) and amenorrhoea (1 case). The tumour was unilateral in all the cases with an average size of 10 cms. Grossly the appearances varied from a solid, partly cystic, edematous tumour (2 cases) to solid,firm tumour with yellow flecks (1 case) to unilocular cystic tumour (1 case). Microscopically, the tumour was characterized by cellular pseudolobules composed of a disorderly admixture of collagen-producing fibroblasts and lipid rich lutein cells with shrunken nuclei. In one case the lutein cells had a robust appearance with abundant cytoplasm and vesicular nuclei. The pseudolobules were very vascular and separated by hypocellular dense to oedematous fibrous tissue. Frozen section demonstrated fat in luteinized cells in 3 cases. 相似文献
32.
Rao AJ Ramachandra SG Ramesh V Couture L Abdennebi L Salesse R Remy JJ 《Reproductive biomedicine online》2004,8(4):385-391
Active immunization of proven fertile adult male bonnet monkeys (Macaca radiata) with phage-expressed follicle-stimulating hormone receptor (FSHR)-specific peptides from the extracellular domain resulted in a progressive drop in sperm count with all animals becoming azoospermic by day 100. However, serum testosterone concentrations were unaltered during the entire course of study and animals exhibited normal mating behaviour. Breeding studies with proven fertile female monkeys revealed that all the immunized males were infertile. Following interruption of immunization on day 225, sperm counts returned to normal with restoration of fertility. These results indicate that infertility can be induced in adult male monkeys by interfering with the action of FSH using specific peptides of the extracellular domain of FSHR as antigens, without the risk of producing cross-reacting antibodies to the other glycoprotein hormones. 相似文献
33.
Recent studies have shown enhanced antitumor efficacy with adenoviruses that either lack E1B-19K or overexpress E3-11.6K (also known as adenoviral death protein). E1B-19K is a well-characterized anti-apoptotic protein, and viruses with E1B-19K deletions show increased cytopathicity. However, the mechanism of cell killing by E3-11.6K, which plays an important role in killing infected cells and virion release, is not well characterized. To understand the mechanism of cell killing following E3-11.6K overexpression, we constructed a recombinant adenovirus, Ad-ME, by introducing viral major late promoter upstream of the E3-11.6K sequence. Similar to the E1B-19K-deleted virus, E1B/19K-, Ad-ME induced cell death to a greater extent than the wild-type virus. Cell shrinkage, membrane blebbing, activation of caspases 3 and 9, cleavage of poly(ADP-ribose)polymerase (PARP), DNA degradation, and ratio of ADP to ATP in Ad-ME-infected cells indicated that apoptosis contributes to cell death following E3-11.6K overexpression. However, the levels of activation of caspases 3 and 9 were lower in cells infected with Ad-ME compared to those infected with E1B/19K-. Furthermore, cell killing by Ad-ME was not effectively inhibited by Z-VAD-FMK, a general caspase inhibitor. Taken together, our results suggest both caspase-dependent and caspase-independent mechanisms of cell killing due to overexpression of E3-11.6K. 相似文献
34.
Naik RG Beckers C Wentwoord R Frenken A Duinkerken G Brooks-Worrell B Schloot NC Palmer JP Roep BO 《Journal of autoimmunity》2004,23(1):55-61
T-cell mediated autoimmune beta-cell destruction is an important component of type 1 diabetes (T1D) and insulin is a critical antigen recognized by autoreactive T-cells. The aim of this study was to investigate the precursor frequency of insulin reactive T-cells in type 1 diabetes. We studied 19 T1D patients, 12 age-matching non-diabetic healthy siblings and 12 non-diabetic healthy parents. Limiting dilution analysis (LDA) was performed to insulin and tetanus toxoid (TT). A progressive decrease in the number of negative cultures at increasing cell concentrations that is represented by a low goodness-of-fit (GoF, low Chi-square), was seen with the TT response in all three groups; precursor frequencies and GoF were similar in patients, siblings, and parents. Reactivity to insulin, however, showed low precursor frequencies in patients and siblings and the LDA to insulin demonstrated dramatic decreases in the number of positive cultures at higher cell concentrations leading to a high GoF in patients and siblings compared to parents. This saw-toothed pattern of reactivity to insulin is indicative of multiple hit kinetics and implies that the response is regulated. Consequently the precursor frequency of insulin autoreactive cells in patients and their siblings is probably much higher than calculated. 相似文献
35.
Awareness that some diseases are transmissible has existed forcenturies. Hippocrates in 450 BC used wine or boiled water toirrigate wounds and, in the second century, Galen was reportedto have boiled his instruments before use. In the middle ages,people suffering with leprosy and the severely ill were isolatedfrom the local population. However, modern infection controlwas only started in the 19th century as a consequence of thework of Pasteur, Lister and other pioneers. 相似文献
36.
Etoposide-incorporated tripalmitin nanoparticles with negative (ETN) and positive charge (ETP) were prepared by melt emulsification and high-pressure homogenization techniques. Spray drying of nanoparticles led to free flowing powder with excellent redispersibility. The nanoparticles were characterized by size analysis, zeta potential measurements, and scanning electron microscopy. The mean diameter of ETN and ETP nanoparticles was 391 nm and 362 nm, respectively, and the entrapment efficiency was more than 96%. Radiolabeling of etoposide and nanoparticles was performed with Technetium-99m (99mTc) with high labeling efficiency and in vitro stability. The determination of binding affinity of 99mTc-labeled complexes by diethylene triamine penta acetic acid (DTPA) and cysteine challenge test confirmed low transchelation of 99mTc-labeled complexes and high in vitro stability. Pharmacokinetic data of radiolabeled etoposide, ETN, and ETP nanoparticles in rats reveal that positively charged nanoparticles had high blood concentrations and prolonged blood residence time. Biodistribution studies of 99mTc-labeled complexes were performed after intravenous administration in mice. Both ETN and ETP nanoparticles showed significantly lower uptake by organs of the reticuloendothelial system such as liver and spleen (P < .001) compared with etoposide. The ETP nanoparticles showed a relatively high distribution to bone and brain (14-fold higher than etoposide and ETN at 4 hours postinjection) than ETN nanoparticles. The ETP nanoparticles with long circulating property could be a beneficial delivery system for targeting to tumors by Enhanced Permeability and Retention effect and to brain. 相似文献
37.
Georgakoudi I Sheets EE Müller MG Backman V Crum CP Badizadegan K Dasari RR Feld MS 《American journal of obstetrics and gynecology》2002,186(3):374-382
OBJECTIVE: The objective of this study was to assess the potential of 3 spectroscopic techniques (intrinsic fluorescence, diffuse reflectance, and light scattering) individually and in combination (trimodal spectroscopy) for the detection of cervical squamous intraepithelial lesions. STUDY DESIGN: The study was conducted with 44 patients who underwent colposcopy for the evaluation of an abnormal Papanicolaou smear. Fluorescence and reflectance spectra were collected from colposcopically normal and abnormal sites and analyzed to extract quantitative information about tissue biochemistry and morphologic condition. This information was compared with histopathologic classification, and diagnostic algorithms were developed and validated with the use of logistic regression and cross-validation. RESULTS: Diagnostically significant differences exist in the composition of fluorescing biochemicals, the scattering properties, and the epithelial cell nuclear morphology of cervical squamous intraepithelial lesions and non-squamous intraepithelial lesions. Trimodal spectroscopy is a superior tool for the detection of cervical squamous intraepithelial lesions than any 1 of the techniques alone. CONCLUSION: Trimodal spectroscopy has the potential to improve the in vivo detection of precancerous cervical changes. 相似文献
38.
39.
Madhavi Chandra Rekha Thippavuzzula V.V. Ramachandra Rao Aejaz M. Habib Chittor M. Habibullah Lakshmi Narasu Y. Prameela Mohammed N. Khaja 《Infection, genetics and evolution》2007,7(6):724-730
Hepatitis C virus shows substantial nucleotide sequence diversity distributed throughout the viral genome. In the present study genotyping for Hepatitis C virus (HCV) infected patients was based on RFLP analysis of 5' UTR and using type specific primers of NS5B regions. It was observed that 60% of the patients (30 patients with chronic hepatitis) were infected with variants of genotype 1 and 40% of the patients (4 chronic hepatitis patients, 12 patients with chronic renal failure and 4 cirrhosis) were infected with variants of type 3 of HCV. None of the cirrhotic patients and patients with chronic renal failure, in the present study, were infected with type 1 of HCV. While PCR-RFLP, typing was rapid in conjunction with the primers used for RT-PCR, NS5 typing was helpful in determining the subtype. There was good correlation between the two typing methods and this method can be used as a cost-effective method for studying large number of samples. The study shows that predominant genotypes of HCV in South India include type 1 and 3. Type 3 seems to be transmitted nosocomially as suggested by the results in patients with chronic renal failure, as these patients are exposed to multiple medical interventions. 相似文献
40.
Venkateswarlu S Ramachandra MS Rambabu M Subbaraju GV 《Journal of Asian natural products research》2000,2(2):111-120
A general and straight forward total synthesis of 1,7-bis(4-hydroxyphenyl)-3-hydroxy-1,3-heptadiene-5-one (5) starting from 4-methoxycinnamic acid (6) via ethyl 5-(4-methoxyphenyl)-3-hydroxy-2,4-pentadienoate (14) was accomplished in 19% overall yield. 相似文献