全文获取类型
收费全文 | 6268篇 |
免费 | 422篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 27篇 |
儿科学 | 209篇 |
妇产科学 | 293篇 |
基础医学 | 824篇 |
口腔科学 | 176篇 |
临床医学 | 538篇 |
内科学 | 1575篇 |
皮肤病学 | 215篇 |
神经病学 | 485篇 |
特种医学 | 251篇 |
外科学 | 837篇 |
综合类 | 37篇 |
一般理论 | 1篇 |
预防医学 | 258篇 |
眼科学 | 44篇 |
药学 | 491篇 |
中国医学 | 7篇 |
肿瘤学 | 448篇 |
出版年
2023年 | 39篇 |
2022年 | 46篇 |
2021年 | 89篇 |
2020年 | 77篇 |
2019年 | 108篇 |
2018年 | 132篇 |
2017年 | 97篇 |
2016年 | 107篇 |
2015年 | 102篇 |
2014年 | 158篇 |
2013年 | 214篇 |
2012年 | 317篇 |
2011年 | 244篇 |
2010年 | 158篇 |
2009年 | 196篇 |
2008年 | 293篇 |
2007年 | 283篇 |
2006年 | 261篇 |
2005年 | 259篇 |
2004年 | 287篇 |
2003年 | 226篇 |
2002年 | 224篇 |
2001年 | 189篇 |
2000年 | 252篇 |
1999年 | 219篇 |
1998年 | 86篇 |
1997年 | 84篇 |
1996年 | 115篇 |
1995年 | 89篇 |
1994年 | 65篇 |
1993年 | 66篇 |
1992年 | 152篇 |
1991年 | 163篇 |
1990年 | 142篇 |
1989年 | 135篇 |
1988年 | 118篇 |
1987年 | 91篇 |
1986年 | 91篇 |
1985年 | 94篇 |
1984年 | 71篇 |
1983年 | 69篇 |
1982年 | 36篇 |
1981年 | 38篇 |
1979年 | 41篇 |
1978年 | 29篇 |
1977年 | 28篇 |
1976年 | 30篇 |
1975年 | 39篇 |
1974年 | 30篇 |
1973年 | 27篇 |
排序方式: 共有6716条查询结果,搜索用时 11 毫秒
21.
The new calcium antagonist Rec 15/2375, supposed to be selective for the vascular tissue, was compared to nifedipine, a non-selective agent that reduces blood pressure and impairs cardiac inotropism as well. Six rabbits, chronically catheterized and continuously monitored for systemic blood pressure, heart rate and the isovolumic contractility index dP/Tmax, were alternatively treated with Rec 15/2375 and nifedipine, according to a randomized cross-over design. Both drugs were given under either autonomically intact (AI) or suppressed (AS) heart function control, induced by cholinergic and beta-adrenoceptor blockade. The two agents reduced mean arterial blood pressure comparably and dose-dependently (P less than 0.01) under both experimental conditions (from 10 to 40%), thus causing heart rate to increase reflexly (P less than 0.01), similarly between drugs in AI rabbits, whereas the AS manoeuvre totally abolished such a response. Cardiac contractility, on the other hand, displayed opposing behaviour between the two drugs. Rec 15/2375 caused mild but significant (P less than 0.01) increases, which were similar at all doses (+10, +15%) and insensitive to the AS intervention, whereas nifedipine caused dose-dependent reductions (from -10 to -60%; P less than 0.01) of comparable intensity as mean blood pressure decrease in both protocols. We conclude that Rec 15/2375 effectively lowers blood pressure with no impairment, unlike nifedipine, of cardiac inotropism and we discuss the possibility that dP/dTmax may be increased as a result of the haemodynamic rearrangement following after-load reduction. 相似文献
22.
A clinical, microbiologic, and radiographic study of deep caries lesions after incomplete caries removal. 总被引:3,自引:0,他引:3
Marisa Maltz Elenara F de Oliveira Vania Fontanella Rafael Bianchi 《Quintessence international, dental digest》2002,33(2):151-159
OBJECTIVE: Clinical, radiographic, and microbiologic changes in deep caries lesions were assessed after incomplete carious dentin removal and tooth sealing. METHOD AND MATERIALS: Thirty-two teeth with deep caries lesions were studied. Treatment consisted of incomplete excavation of the demineralized dentin, application of calcium hydroxide, and sealing for a 6- to 7-month period. The color and consistency of the dentin were clinically assessed. Differences in radiographic density were assessed by digital image subtraction. Microbiologic samples were obtained from the demineralized dentin before the temporary sealing and after the experimental period. The samples were cultivated on blood agar under aerobic and anaerobic conditions, in Mitis Salivarius agar, and Rogosa selective Lactobacillus agar. RESULTS: Two cases were lost during the study; one presented pulpal necrosis. In the other case, there was pulpal exposure during removal of provisional sealing. In all teeth, the initial demineralized dentin was soft and wet; one lesion was yellow, 21 were light brown, and eight were dark brown. After treatment, the dentin was dry, and 80.00% of specimens were hard, 16.67% were leathery, and 3.33% remained soft. The dentin was light brown in five teeth and dark brown in 25. There was a statistically significant mean difference in radiographic density (pixel intensity), 88.77 +/- 7.02 in the control areas and 94.66 +/- 6.75 in the test areas. The counts of anaerobic and aerobic bacteria, lactobacilli, and Streptococci mutans had decreased significantly by the end of treatment. CONCLUSION: Incomplete removal of carious dentin and subsequent tooth sealing resulted in the arrest of the lesions, suggesting that complete dentinal caries lesion removal is not essential to the control of caries lesions. 相似文献
23.
Annalisa Volpi Francesco Bacci Angelo Paradiso Luca Saragoni Emanuela Scarpi Monica Ricci Mirella Aldi Simonetta Bianchi Pietro Muretto Fiorella Nuzzo Gianni Simone Anita Mangia Francesco Schittulli Dino Amadori 《Modern pathology》2004,17(9):1038-1044
Available results highlight the lack of good level of evidence studies on the pure prognostic value of histological grade. In the present study, the prognostic relevance of histological grade and of its three components, tubule formation, nuclear pleomorphism and mitotic count, was analyzed in a series of 372 patients with node-negative breast cancer treated with locoregional therapy alone until early relapse. Histological grade was determined blindly by two observers and discordance between evaluations was resolved after joint review using a multihead microscope. No relation was observed between histological grade and any of its three components and disease-free survival. Conversely, a significant relation was observed between histological grade and distant metastasis-free survival (at 6 years, 94, 86 and 76% for grades 1, 2 and 3, respectively, P=0.013) as well as overall survival (98, 90 and 86%, P=0.001). A breakdown analysis as a function of the three components showed that neither tubule formation nor nuclear pleomorphism was associated with prognosis, and only mitotic count strongly influenced both distant metastasis-free survival (91, 82 and 74%, P=0.014) and overall survival (97, 87 and 85%, P=0.011). Histological grade suffers from a much higher subjectivity than any other microscopic evaluation of biomarkers as it is the sum of three different morphological features. Within the Italian Network for Quality Assessment of Tumor Biomarkers program we observed that histological grade is an independent prognostic variable, but also that this role is ascribable only to the number of mitotic figures. In conclusion, due to the ever smaller size of diagnosed breast cancers, resulting in less cancer tissue for biofunctional and molecular analysis, mitotic count evaluated under strict quality control conditions seems to be an accurate and feasible prognostic variable. 相似文献
24.
B Huser G Thiel M Oberholzer T Beveridge L Bianchi M J Mihatsch J Landmann 《Transplantation》1992,54(1):65-69
Twelve consecutive first cadaveric kidney transplant recipients received cyclosporine G (CsG)(initial dose 12 mg/kg per day) as basic immunosuppressive treatment along with prednisone (initial dose 0.5 mg/kg per day) for the first three months after transplantation. Thereafter CsG was replaced by Sandimmun (cyclosporine, CsA). Evaluation of the immunosuppressive efficacy and assessment of possible side effects of CsG was made and compared with the results in 38 historical control patients starting with the same dose of CsA as part of the same immunosuppressive dosage schedule. Statistically, there was no difference in patient survival at three (91% in CsG group versus 95% in CsA group) and twelve months (91% in CsG group versus 92% in CsA group), or in graft survival at three (75% in CsG group versus 89% in CsA group) and twelve months (75% in CsG group versus 84% in the CsA group). At equivalent oral doses of CsG and CsA significantly higher blood levels of CsG were observed (2P less than 0.05). Nephrotoxicity assessed by graft biopsy could be demonstrated to a similar extent in both groups, whereas hepatotoxicity was more pronounced during CsG treatment. Sequential measurements of bilirubin revealed a significant increase in all patients but median values were significantly higher in the CsG patients. A pronounced and concordant elevation of liver enzymes occurred during CsG treatment in three out of 12 patients. Liver biopsies performed in these patients revealed histological alterations consistent with toxic liver injury. Thus, in human kidney transplant recipients CsG and CsA appeared to be equally immunosuppressive and nephrotoxic but more hepatotoxic. On the basis of this limited experience we conclude that in human kidney transplant recipients CsG has no advantage over CsA. 相似文献
25.
26.
27.
G Pinotti R Novario F Berrino P Bianchi M A Comi M C Gamba A Venco 《Haematologica》1992,77(5):405-412
BACKGROUND. The incidence of primary gastric non-Hodgkin's lymphoma (NHL) appears to have increased worldwide in recent years, and this seems to be confirmed by large-sample population studies. METHODS AND RESULTS. We derived our data from the Lombardy Cancer Registry, which provides the incidence of cancer in the province of Varese, Northern Italy. From 1978 to 1987 we identified 3261 cases of gastric neoplasms, 119 of which were gastric NHL: 32 (1.87%) from 1978 to 1982, and 87 (5.32%) from 1983 to 1987. The difference in the age and sex standardized incidence trend between these two time periods was statistically significant (p < 0.001). The overall survival rate of the 112 evaluable patients was 54% at 5 years and 45% at 10 years. A multivariate analysis was performed. Age (p < 0.0005), clinical stage (p < 0.04) and therapy (p < 0.0005) were found to be significant prognostic factors for survival. CONCLUSIONS. This study stresses the utility of prospective randomized clinical trials that could indicate the optimal management of patients with primary gastric lymphoma. 相似文献
28.
29.
30.
L. Pantoni C. Sarti F. Pescini S. Bianchi L. Bartolini P. Nencini A. M. Basile M. Lamassa R. N. Kalaria M. T. Dotti A. Federico D. Inzitari 《European journal of neurology》2004,11(11):782-787
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetically transmitted cerebrovascular disease. Typically, the first clinical manifestation is migraine and the full clinical spectrum of the disease with recurrent strokes of the subcortical type, cognitive, and mood disorders is seen during the fourth and fifth decades of life. Vascular risk factors are usually absent in CADASIL patients and the diagnosis of the disease is particularly suspected in young adults with cerebrovascular events of unknown cause, diffuse leukoencephalopathy on computed tomography or magnetic resonance imaging, and a history of cerebrovascular diseases or dementia in many family members. We describe three Italian CADASIL patients who presented to medical attention for cerebrovascular events occurred after the age of 55 and had, in addition to hypertension and hyperlipidemia, thrombophilic risk factors such as hyperhomocysteinemia, elevated levels of lipoprotein(a), and antiphospholipid antibodies. Symptoms possibly related to cortical involvement, such as dysphasia and visual field deficits, were reported by two of these patients. We conclude that a diagnosis of CADASIL should not be disregarded in patients with vascular risk factors and presenting with symptoms not immediately referable to subcortical damage at ages more advanced than commonly reported. 相似文献