全文获取类型
收费全文 | 1655篇 |
免费 | 118篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 63篇 |
妇产科学 | 62篇 |
基础医学 | 223篇 |
口腔科学 | 34篇 |
临床医学 | 144篇 |
内科学 | 445篇 |
皮肤病学 | 20篇 |
神经病学 | 142篇 |
特种医学 | 26篇 |
外科学 | 172篇 |
综合类 | 3篇 |
预防医学 | 114篇 |
眼科学 | 19篇 |
药学 | 117篇 |
中国医学 | 8篇 |
肿瘤学 | 185篇 |
出版年
2023年 | 11篇 |
2022年 | 33篇 |
2021年 | 60篇 |
2020年 | 25篇 |
2019年 | 34篇 |
2018年 | 43篇 |
2017年 | 41篇 |
2016年 | 52篇 |
2015年 | 47篇 |
2014年 | 66篇 |
2013年 | 105篇 |
2012年 | 134篇 |
2011年 | 129篇 |
2010年 | 62篇 |
2009年 | 79篇 |
2008年 | 110篇 |
2007年 | 101篇 |
2006年 | 97篇 |
2005年 | 85篇 |
2004年 | 113篇 |
2003年 | 84篇 |
2002年 | 91篇 |
2001年 | 18篇 |
2000年 | 6篇 |
1999年 | 10篇 |
1998年 | 16篇 |
1997年 | 13篇 |
1996年 | 5篇 |
1995年 | 12篇 |
1994年 | 11篇 |
1993年 | 5篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 10篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1968年 | 1篇 |
1966年 | 2篇 |
1965年 | 3篇 |
1914年 | 1篇 |
排序方式: 共有1787条查询结果,搜索用时 15 毫秒
1.
Salvatore Serra Giuliana Brunetti Giovanni Vacca Carla Lobina Mauro A M Carai Gian Luigi Gessa Giancarlo Colombo 《Alcohol》2003,29(2):101-108
Results of a recent study have demonstrated that exposure to multiple ethanol concentrations and repeated ethanol deprivation periods in Indiana ethanol-preferring (P) rats resulted in the development of an alcohol deprivation effect (ADE; the temporary increase in voluntary ethanol intake after a period of deprivation from ethanol) characterized by consumption of intoxicating amounts of ethanol. The current study was designed to possibly extend these results to Sardinian alcohol-preferring (sP) rats, generated with the same selective program previously used for P rats. To this aim, ethanol-naive sP rats were exposed initially to the home cage four-bottle choice [10%, 20%, and 30% (vol./vol.) ethanol solutions and water] for eight consecutive weeks. Subsequently, rats were divided into two groups: The first group had continuous access to the four-bottle regimen (nondeprived rats), and the second group was exposed to five cycles of 14-day periods of deprivation from ethanol and 14-day periods of reexposure to the four-bottle regimen. An ADE developed after each deprivation period. However, the extra intake of ethanol was limited to the first hour of each reaccess period. Magnitude of ADE did not change with repeated periods of deprivation. However, a shift in preference toward the two highest concentrations of ethanol solutions was evident from the first reexposure to ethanol and was maintained throughout the study. These results provide further evidence on the heterogeneity of ethanol-drinking behavior among rat lines selectively bred for high ethanol preference and consumption. 相似文献
2.
3.
Bruno Dallapiccola Giuliana Alimena Viviana Brinchi Giancarlo Isacchi Enrico Gandini 《Cancer Genetics and Cytogenetics》1980,2(4):349-360
Chromosome investigations were carried out in 7 patients with Fanconi's anemia, type Estren-Dameshek. The frequency and types of chromosome instability found in cultured lymphocytes were in accord with those detected in individuals with classical Fanconi's anemia. The break-point distribution indicates a significant excess of breaks in chromosomes No. 1, 2, and 7 and a deficit in No. 18 and X and Y chromosomes. There was a clear clustering of breaks at certain locations in chromosomes No. 1, 2, 3, 7, 9, and 14. The location of the breaks with respect to the bands demonstrated an almost exclusive involvement of the lighter bands, regardless of the banding method used. These results suggest that most breaks take place in the interbands between the G and R bands. In all patients, chromosome instability was less frequent in direct bone marrow preparations than in lymphocyte cultures. However, cultured bone marrow cells showed a significant increase of chromosome aberrations. On the whole, the chromosome data derived from this series of patients are in agreement with those obtained in individuals with classical Fanconi's anemia and give no support to the idea of cytogenetic heterogeneity between subjects affected by these two forms of childhood aplastic anemia. 相似文献
4.
Salvatore Restivo MD Riccardo Speciale MD Rosalia Gargano MD Riccardo Di Leo MD Francesco Farinella MD Salvatore Gallina MD 《Operative Techniques in Otolaryngology》2003,14(2):153-156
During the last 20 years, various conservative surgical techniques have been proposed to treat larynx cancer. On the basis of our various experiences and of the ultrastructural data on the tissues treated with radiowaves, we decided to also use radiosurgery in operations under direct microlaryngoscopy. We select 18 patients suffering from epidermoid carcinoma. These patients had been referred to our ENT clinic at the Polichnico of Palermo between 1999 and 2001. The authors describe the surgical procedures used and emphasize the advantages of radiosurgery in the treatment of larynx cancer. 相似文献
5.
Picchiassi E Coata G Fanetti A Centra M Pennacchi L Di Renzo GC 《Prenatal diagnosis》2008,28(6):525-530
OBJECTIVES: Detection of free fetal DNA (ffDNA) in maternal blood during pregnancy has given rise to the possibility of developing new noninvasive approaches for early prenatal diagnosis.On a large-scale study, two protocols of real-time polymerase chain reaction (PCR) were compared in order to establish which Y-specific locus, either multicopy DYS14 or single copy SRY sequence, was the most suitable for developing a test with high diagnostic efficiency for early fetal gender assessment. The second aim was to assess whether the combination of the two detection systems could increase the performance of the prenatal test. METHODS: We analyzed 145 plasma samples from healthy pregnant women between 11 and 12 weeks of singleton gestation. For each sample, fetal gender was determined by using both protocols (DYS14 and SRY) during the same real-time PCR run. RESULTS: The data obtained by the DYS14 and SRY assays showed an efficiency in fetal gender prediction of 97.9 and 80%, respectively. It is not advisable to combine the two protocols because this association does not help in further improvements in fetal gender prediction. CONCLUSIONS: DYS14 assay is the best approach for early fetal gender assessment because it is more sensitive, accurate, and efficient than the SRY assay. 相似文献
6.
D'Amelio P Grimaldi A Di Bella S Brianza SZ Cristofaro MA Tamone C Giribaldi G Ulliers D Pescarmona GP Isaia G 《BONE》2008,43(1):92-100
Compelling evidences suggest that increased production of osteoclastogenic cytokines by activated T cells plays a relevant role in the bone loss induced by estrogen deficiency in the mouse. However, little information is available on the role of T cells in post-menopausal bone loss in humans. To investigate this issue we have assessed the production of cytokines involved in osteoclastogenesis (RANKL, TNFalpha and OPG), in vitro osteoclast (OC) formation in pre and post-menopausal women, the latter with or without osteoporosis. We evaluated also OC precursors in peripheral blood and the ability of peripheral blood mononuclear cells to produce TNFalpha in both basal and stimulated condition by flow cytometry in these subjects. Our data demonstrate that estrogen deficiency enhances the production of the pro-osteoclastogenetic cytokines TNFalpha and RANKL and increases the number of circulating OC precursors. Furthermore, we show that T cells and monocytes from women with osteoporosis exhibit a higher production of TNFalpha than those from the other two groups. Our findings suggest that estrogen deficiency stimulates OC formation both by increasing the production of TNFalpha and RANKL and increasing the number of OC precursors. Women with post-menopausal osteoporosis have a higher T cell activity than healthy post-menopausal subjects; T cells thus contribute to the bone loss induced by estrogen deficiency in humans as they do in the mouse. 相似文献
7.
Napolitano L Francomano F Gargano E Francione T Angelucci D Napolitano AM 《Annali italiani di chirurgia》2001,72(1):61-4; discussion 65
The Authors present 9 cases of gastro-enteropancreatic neuro-endocrine biologically inactive tumors. In 5 cases the tumor site was appendicular. In 4 patients an appendectomy was performed, in one patient a right hemicolectomy and the patients after a period of 3-9 years are well and disease free. In a patient with a gastric carcinoid and a single hepatic metastasis a total gastrectomy with an hepatic metastasectomy were performed but the patient died 16 months thereafter. In a case localized to the right colon with a single hepatic metastasis a right hemicolectomy was performed with a metastasectomy but the patient died after 12 months. In a case localized to an ileal loop a segmental resection was performed followed by a medical therapy with octreotide and the patient is well and disease free after 3 years. In a case localized to the pancreas with widespread lymphatic metastasis it was performed a simple biliary diversion (coledocho-duodenostomy) followed by medical therapy with octreotide. Surprisingly after 4 years the patient is alive and a TC control shows a decrease of the pancreatic tumor and of the lympho glandular tumefactions. 相似文献
8.
9.
10.
Melioli G Semino C Margarino G Mereu P Scala M Cangemi G Crocetti E Machì AM Ferlazzo G 《Head & neck》2003,25(4):297-305
BACKGROUND: In a group of patients with head and neck cancers (H&NC), the expansion of the population of CD3-,CD16+ natural killer (NK) cells in the peripheral blood was studied. METHODS: Cytofluorimetric analysis of the expression of killer Ig-like receptors (KIR, namely p58.1, p58.2, p58.3, p70, and p140) and CD94-NKG2a was performed. Cytolytic activities were studied using 51Cr release assay. T and NK cell cloning was performed using limiting dilution culture conditions. Cytokine production was analyzed using commercial enzyme immunoassays. RESULTS: Phenotypic analysis showed that the expanded populations were heterogeneous. Even in the presence of a large number of circulating NK cells, "nonspecific" cytolytic capacities were heavily reduced, whereas cytolytic capacity related to T cells was virtually normal. Unlike NK cell clones derived from healthy donors, most NK cells derived from H&NC patients expressed surface "activating" NK cell receptors (KAR) for HLA, detected by use of a redirected cytolytic assay. Analysis of the CD4+ subpopulation at the clonal level demonstrated that they had a severe proliferative defect. CONCLUSION: These experimental data indicated that H&NC patients have a polyclonal expansion of functionally deficient NK cells expressing KAR. In addition, the proliferative capacity of patients' "helper" cells was strongly inhibited, thus accounting for a severe impairment of cytolytic activity of the expanded NK cells. 相似文献