全文获取类型
收费全文 | 7205篇 |
免费 | 537篇 |
国内免费 | 71篇 |
专业分类
耳鼻咽喉 | 51篇 |
儿科学 | 180篇 |
妇产科学 | 214篇 |
基础医学 | 1001篇 |
口腔科学 | 102篇 |
临床医学 | 641篇 |
内科学 | 1856篇 |
皮肤病学 | 179篇 |
神经病学 | 889篇 |
特种医学 | 274篇 |
外科学 | 612篇 |
综合类 | 11篇 |
预防医学 | 452篇 |
眼科学 | 52篇 |
药学 | 544篇 |
中国医学 | 15篇 |
肿瘤学 | 740篇 |
出版年
2024年 | 15篇 |
2023年 | 125篇 |
2022年 | 260篇 |
2021年 | 374篇 |
2020年 | 240篇 |
2019年 | 304篇 |
2018年 | 312篇 |
2017年 | 255篇 |
2016年 | 293篇 |
2015年 | 330篇 |
2014年 | 395篇 |
2013年 | 477篇 |
2012年 | 711篇 |
2011年 | 694篇 |
2010年 | 380篇 |
2009年 | 285篇 |
2008年 | 417篇 |
2007年 | 381篇 |
2006年 | 357篇 |
2005年 | 289篇 |
2004年 | 230篇 |
2003年 | 203篇 |
2002年 | 159篇 |
2001年 | 30篇 |
2000年 | 28篇 |
1999年 | 24篇 |
1998年 | 34篇 |
1997年 | 15篇 |
1996年 | 15篇 |
1995年 | 11篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 12篇 |
1991年 | 13篇 |
1990年 | 14篇 |
1989年 | 16篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 11篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1979年 | 8篇 |
1977年 | 6篇 |
1975年 | 3篇 |
1973年 | 3篇 |
1970年 | 4篇 |
1969年 | 6篇 |
1968年 | 3篇 |
1960年 | 2篇 |
排序方式: 共有7813条查询结果,搜索用时 15 毫秒
51.
Cyclooxygenase-2 activation mediates the proangiogenic effect of nitric oxide in colorectal cancer. 总被引:14,自引:0,他引:14
Fabio Cianchi Camillo Cortesini Ornella Fantappiè Luca Messerini Iacopo Sardi Nadia Lasagna Federico Perna Valentina Fabbroni Annamaria Di Felice Giuliano Perigli Roberto Mazzanti Emanuela Masini 《Clinical cancer research》2004,10(8):2694-2704
PURPOSE: Up-regulation of both inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) enzymes has been reported in colorectal cancer. We aimed at evaluating the possible interaction between the nitric oxide and COX-2 pathways, and its effect on promoting tumor angiogenesis. EXPERIMENTAL DESIGN: Expression of iNOS, COX-2, vascular endothelial growth factor (VEGF), and CD31 was analyzed in tumor samples and corresponding normal mucosa obtained from 46 surgical specimens. We also evaluated iNOS activity, prostaglandin E(2) (PGE(2)), cyclic GMP and cyclic AMP production in the same specimens. Nitrite/nitrate levels, and PGE(2) and VEGF production were assessed in HCT116 and HT29 colon cancer cell lines after induction and selective inhibition of the two enzyme pathways. RESULTS: A significant correlation was found between iNOS and COX-2 immunohistochemical expression. PGE(2) production significantly correlated with iNOS activity and cGMP levels. A significant correlation was also found among PGE(2) production, microvessel density, and VEGF expression. Coinduction of both iNOS and COX-2 activities occurred after lipopolysaccharide (LPS) and epidermal growth factor (EGF) treatment in HCT116 and HT29 cells. Inhibition of iNOS by 1400W significantly reduced both LPS- and EGF-induced PGE(2) production. Treatment with LPS, EGF, and arachidonic acid significantly increased VEGF production in the iNOS-negative/COX-2-positive HT29 cells. This effect was completely reversed by treatment with the selective COX-2 inhibitor celecoxib. CONCLUSIONS: Our data showed a prominent role of nitric oxide in stimulating COX-2 activity in colorectal cancer. This interaction is likely to produce a cooperative effect in promoting angiogenesis through PGE(2)-mediated increase in VEGF production. 相似文献
52.
Elisa Giovannetti Valentina Mey Romano Danesi Irene Mosca Mario Del Tacca 《Clinical cancer research》2004,10(9):2936-2943
PURPOSE: Gemcitabine is an inhibitor of ribonucleotide reductase (RR) and DNA synthesis and is an effective agent in the treatment of pancreas cancer. The present study investigates whether the multitargeted antifolate pemetrexed would be synergistic with gemcitabine against MIA PaCa-2, PANC-1, and Capan-1 pancreatic cancer cell lines. EXPERIMENTAL DESIGN: Cells were treated with gemcitabine and pemetrexed, and the type of drug interaction was assessed using the combination index. Cytotoxicity of gemcitabine was examined with inhibitors of (a) deoxycytidine kinase (dCK), which activates gemcitabine by phosphorylation, and (b) 5'-nucleotidase (drug dephosphorylation) and cytidine deaminase (drug deamination), the main inactivating enzymes. The effects of gemcitabine and pemetrexed on cell cycle were analyzed by flow cytometry, and apoptosis was examined by fluorescence microscopy. Finally, quantitative, real-time PCR was used to study the pharmacogenetics of the drug combination. RESULTS: Synergistic cytotoxicity and enhancement of apoptosis was demonstrated, mostly with the sequence pemetrexed-->gemcitabine. Pemetrexed increased cells in S phase, the most sensitive to gemcitabine, and a positive correlation was found between the expression ratio of dCK:RR and gemcitabine sensitivity. Indeed, pemetrexed significantly enhanced dCK gene expression (+227.9, +86.0, and +135.5% in MIA PaCa-2, PANC-1, and Capan-1 cells, respectively), and the crucial role of this enzyme was confirmed by impairment of gemcitabine cytotoxicity after dCK saturation with 2'-deoxycytidine. CONCLUSIONS: These data demonstrate that the gemcitabine and pemetrexed combination displays schedule-dependent synergistic cytotoxic activity, favorably modulates cell cycle, induces apoptosis, and enhances dCK expression in pancreatic cancer cells. 相似文献
53.
Franca Formelli Tiziana Camerini Elena Cavadini Valentina Appierto Maria Grazia Villani Alberto Costa Giuseppe De Palo Maria Gaetana Di Mauro Umberto Veronesi 《Cancer epidemiology, biomarkers & prevention》2003,12(1):34-41
OBJECTIVES: To assess, in women participating in a breast cancer prevention trialon fenretinide (4-HPR), the relationship of drug and retinol levels with the risk of second breast malignancy, taking into account age and menopausal status. METHODS: In a multicenter prevention trial, women with early breast cancer were randomly assigned to receive no treatment or 200 mg of 4-HPR/day for 5 years. Blood was collected at baseline and on a yearly basis during intervention from women recruited at the Istituto Tumori (Milan, Italy; 818 and 756 in the 4-HPR and control arm, respectively, who accounted for 53% of the participants in the trial). The plasma concentrations of 4-HPR, its main metabolite N-(4-methoxyphenyl) retinamide, and retinol were assayed by high-performance liquid chromatography. Three age ranges (or=56 years), menopausal status at baseline, and disease outcome at a median follow-up of 97 months were taken into account in the analysis. RESULTS: Baseline retinol levels were significantly lower (P or=46 years versus or= 0.71; P 相似文献
54.
Takashi Murata Kiyoshi Akagi Valentina V. Ostapenko Hiroyoshi Isoda Kenji Nagata Reiko Nasu Toshiko Shiga Yoshimasa Tanaka Itsuo Yamamoto 《Acta oncologica (Stockholm, Sweden)》1998,37(5):485-488
Capacitive heating is widely used in hyperthermic treatment of human malignancies. However, the pain on the body surface or thermoesthesia in the subcutaneous fatty layer may prevent an elevation of temperature in the tumors. Impedance matching is improved by a subtrap method entailing the application of two copper plates (10×850×0.06 mm) as a subtrap circuit to each of two capacitive electrodes. In a clinical trial the Tmax, Tave, Tmin for the subtrap method were all higher in comparison with those for the conventional technique (42.5±0.7°C, 41.9±1.0°C, 41.3±1.1°C vs. 41.1±1.5°C, 40.6±1.3°C, 40.0±1.3°C). Although the maximal radiofrequency (RF) power applied to patients was higher with the subtrap method (875±189 W vs. 763±200 W), the incidence of surface pain was reduced dramatically. It is concluded that the subtrap method substantially improves the RF capacitive heating of deep-seated tumors. 相似文献
55.
Eman Abu-Gharbieh Valentina Vasina Elisabetta Poluzzi Fabrizio De Ponti 《Pharmacological research》2004,50(3):211-222
Macrolides are widely used antibacterial agents. Although generally well tolerated, they have a number of important additional pharmacological effects, which can sometimes result in significant adverse reactions. This review focuses on three of these side effects: the prokinetic action associated with stimulation of motilin receptors, the proarrhythmic effect due to prolongation of the QT interval of the electrocardiogram and the potential for drug interactions due to inhibition of drug metabolising enzymes. For macrolides that have obtained marketing authorisation in Italy, United Kingdom or United States of America, we also considered whether these actions are properly reported in the approved summaries of the product characteristics and tried to provide strategies to identify patients at risk of significant side effects when macrolides are administered. 相似文献
56.
57.
Valentina Gizzonio Pietro Avanzini Maddalena Fabbri-Destro Cristina Campi Giacomo Rizzolatti 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2014,232(7):2381-2390
The aim of the present study was to assess the cognitive profiles of children with autistic spectrum disorder and of their healthy siblings (Siblings). With the term cognitive profile, we indicate the relationship extant among the values of verbal and performance subtests of the Wechsler Intelligence Scale. The conducted statistical analyses indicated that, although siblings showed a normal intelligent quotient and did not differ in this aspect from typically developing group, their cognitive profile was amazingly similar to that of their relatives affected by autism. A k-means clustering analysis on the values of single subtests further confirmed this result, showing a clear separation between typically developing children on the one side, and autistics and their siblings on the other. We suggest that the common cognitive profile observed in autistic children and their siblings could represent a marker of liability to autism and, thus, a possible intermediate phenotype of this syndrome. 相似文献
58.
Gitana Scozzari Renza Trapani Mauro Toppino Mario Morino 《Surgery for obesity and related diseases》2013,9(1):133-142
BackgroundBecause the number of patients with a previous bariatric procedure continues to rise, it is advisable for bariatric surgeons to know how to manage the rare event of the development of an esophagogastric cancer. The aim of the study was to perform a systematic review of all reported cases of esophagogastric cancers after bariatric surgery.MethodsSystematic review of English and French written literature in MEDLINE and EMBASE database.ResultsGlobally, 28 articles describing 33 patients were retrieved. Neoplasms were diagnosed at a mean of 8.5 years after bariatric surgery (range 2 months–29 years). There were 11 esophageal and 22 gastric cancers; although adenocarcinoma represented most cases (90.6%), a tubulovillous adenoma with high-grade atypia, an intramural gastrointestinal stromal tumor, and a diffuse large B-cell lymphoma of the gastric fundus were also reported. Node involvement was reported in 14 cases, and distal metastases in 5. The most frequently reported symptoms were dysphagia and food intolerance, vomiting, epigastric pain, and weight loss. Surgery was performed in 28 patients, although 4 underwent only chemotherapy and/or radiotherapy and 1 received palliative care. Reported mortality rate was 48.1%.ConclusionsTo date, it is not possible to quantify the incidence of esophagogastric cancer after bariatric surgery because of the paucity of reported data. Nevertheless, because the main concern is the delay in diagnosis, it is of critical importance to carefully evaluate any new or modified upper digestive tract symptom occurring during bariatric surgery follow-up. 相似文献
59.
Gian Piero Siliquini MD Valentina Elisabetta Bounous MD PhD Lorenzo Novara MD Margherita Giorgi MD Fabrizio Bert MD Nicoletta Biglia MD PhD 《The breast journal》2021,27(5):448-455
Adjuvant chemotherapy and endocrine therapy can induce early iatrogenic menopause or worsen pre-existing menopausal symptoms in breast cancer survivors (BCS). The second most frequent menopausal symptom after hot flushes is the genitourinary syndrome (GSM). Since hormone replacement therapy is contraindicated in BCS, vaginal laser might represent a new nonhormonal option for GSM. This study aims at evaluating the effectiveness of the fractional CO₂ vaginal laser for GSM in BCS compared with healthy women. This is a retrospective study on 135 postmenopausal women (45 BCS and 90 healthy women) who underwent fractional CO2 laser for GSM. Objective (VHI and VVHI) and subjective outcomes (VAS for dyspareunia and vaginal dryness and a pain questionnaire) were evaluated at baseline visit and at every follow-up visit. Subjective and objective parameters improved significantly in both groups after laser therapy. The improvement was progressive and long-lasting up to 12 months after the end of the treatment. No severe adverse events were observed during the treatment. Fractional CO₂ vaginal laser induces a significant and long-lasting improvement on GSM symptoms in BCS. However, this improvement is slower than in healthy women undergoing the same treatment. Laser therapy turns out to be safe and well-tolerated. 相似文献
60.
Roberta Cocchiara Giovanna Di Trapani Antonina Azzolina Domenico Geraci 《Journal of immunoassay & immunochemistry》2013,34(4):337-352
Abstract An ELISA assay is described for the measurement of the smIgG. The method is based on the detection of cell-smIgG directly on the same microplate used for the culture. The cells, preincubated at 37°C for one hour, were cultured in the presence of S-ConA and serum-free medium for two days. Using this strategy, the background noise due to non specific adsorbtion of IgG to plastic wells and cytophilic antibodies was eliminated. The cells in the presence of S-ConA and serum-free medium adhered to the plastic wells, and the cell-smIgG were detected using an anti-human IgG covalently linked to alkaline phosphatase or its F(ab')2 fragment. The possibility of measuring the modulation of the expression of the cell-smIgG without any additional manipulation is stressed. 相似文献