全文获取类型
收费全文 | 103164篇 |
免费 | 7534篇 |
国内免费 | 398篇 |
专业分类
耳鼻咽喉 | 1129篇 |
儿科学 | 2569篇 |
妇产科学 | 1652篇 |
基础医学 | 14532篇 |
口腔科学 | 2201篇 |
临床医学 | 10511篇 |
内科学 | 21908篇 |
皮肤病学 | 1797篇 |
神经病学 | 10916篇 |
特种医学 | 4507篇 |
外国民族医学 | 6篇 |
外科学 | 14636篇 |
综合类 | 1263篇 |
一般理论 | 73篇 |
预防医学 | 7939篇 |
眼科学 | 1726篇 |
药学 | 6938篇 |
中国医学 | 112篇 |
肿瘤学 | 6681篇 |
出版年
2023年 | 574篇 |
2022年 | 1086篇 |
2021年 | 2149篇 |
2020年 | 1319篇 |
2019年 | 1971篇 |
2018年 | 2430篇 |
2017年 | 1786篇 |
2016年 | 2134篇 |
2015年 | 2484篇 |
2014年 | 3268篇 |
2013年 | 4301篇 |
2012年 | 6653篇 |
2011年 | 6709篇 |
2010年 | 3969篇 |
2009年 | 3623篇 |
2008年 | 5928篇 |
2007年 | 6440篇 |
2006年 | 5958篇 |
2005年 | 5904篇 |
2004年 | 5510篇 |
2003年 | 4915篇 |
2002年 | 4878篇 |
2001年 | 1872篇 |
2000年 | 1783篇 |
1999年 | 1669篇 |
1998年 | 1261篇 |
1997年 | 1035篇 |
1996年 | 864篇 |
1995年 | 858篇 |
1994年 | 728篇 |
1993年 | 673篇 |
1992年 | 1160篇 |
1991年 | 1077篇 |
1990年 | 1020篇 |
1989年 | 1001篇 |
1988年 | 898篇 |
1987年 | 838篇 |
1986年 | 856篇 |
1985年 | 865篇 |
1984年 | 689篇 |
1983年 | 600篇 |
1982年 | 578篇 |
1981年 | 477篇 |
1980年 | 405篇 |
1979年 | 517篇 |
1978年 | 411篇 |
1977年 | 393篇 |
1975年 | 341篇 |
1974年 | 355篇 |
1973年 | 343篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Workplace status and risk of hypertension among hourly and salaried aluminum manufacturing employees
Jane Ellen Clougherty Ellen A. Eisen Martin D. Slade Ichiro Kawachi Mark R. Cullen 《Social science & medicine (1982)》2009
An inverse relationship between workplace status and morbidity is well established; higher job status has been associated with reduced risks of heart disease, hypertension, and injury. Most research on job status, however, has focused on salaried populations, and it remains unclear whether job status operates similarly among hourly workers. Our objectives were to examine whether hourly status itself influences risk of hypertension after adjustment for socioeconomic confounders, and to explore the role of fine-scale job grade on hypertension incidence within hourly and salaried groups. We examined data for 14,999 aluminum manufacturing employees in 11 plants across the U.S., using logistic regression with adjustment for age, sex, race/ethnicity and other individual characteristics. Propensity score restriction was used to identify comparable groups of hourly and salaried employees, reducing confounding by sociodemographic characteristics. Job grade (coded 1 through 30, within hourly and salaried groups) was examined as a more refined measure of job status. Hourly status was associated with an increased risk of hypertension, after propensity restriction and adjustment for confounders. The observed effect of hourly status was stronger among women, although the propensity-restricted cohort was disproportionately male (96%). Among salaried workers, higher job grade was not consistently associated with decreased risk; among hourly employees, however, there was a significant trend, with higher job grades more protective against hypertension. Increasing the stringency of hypertension case criteria also increased the risk of severe or persistent hypertension for hourly employees. 相似文献
62.
63.
64.
Jean Marie Jully Marie Christine Béné Gérard Martin Gilbert Faure 《Journal of clinical periodontology》1986,13(3):223-227
The cellular infiltrate present in human diseased gingiva was analyzed in biopsies from 12 patients with gingivitis or periodontitis. The samples studied had been obtained in the course of surgery at inflammatory sites remaining after institution of periodontal treatment. Histological and immunological techniques were used to identify macrophages, B-cells, plasma-cells, T-cells and T cell subsets, as well as cells expressing class II HLA membrane antigens. T-cells appeared as the predominant population, but plasma-cells were also visualized in nearly all samples. Both OKT4+ and OKT8+ cells were seen in all cases, the latter being more numerous in periodontitis patients. Interdigitating-like cells were observed, positively labelled for class II antigens, as well as macrophages which were more numerous in periodontitis patients. These results suggest the participation of all components of the immune response in gingival disease, in a way resembling chronic recurrent inflammatory diseases. 相似文献
65.
66.
The term perfusion has varied connotations in different situations. The word perfusion comes from the Latin to pour or diffuse through or over. Myocardial perfusion depends on (a) coronary artery or vessel flow, and (b) myocardial or muscle flow. The factors which determine perfusion at rest and during stress in coronary vessels and within the myocardium are clearly related but not with a predictable linear relationship. In animals there is extensive literature concerning the regulation of coronary flow and perfusion obtained by many sophisticated methods. In contrast, the techniques that are applicable to humans are relatively crude. To date, the clinical data available suggests that the normal control of coronary flow in man and in dogs is fairly similar but that models of pathology in animals bear little relation to the compensatory changes found in the coronary circulation in man. Although the data available is limited and subject to many technical inaccuracies, this article is confined to the assessment of myocardial perfusion in clinical practice. 相似文献
67.
Bergner Raoul; Hoffmann Martin; Riedel Klaus-Dieter; Mikus Gerd; Henrich Dirk M.; Haefeli Walter E.; Uppenkamp Michael; Walter-Sack Ingeborg 《Nephrology, dialysis, transplantation》2006,21(4):1019-1023
To cover intermediate sensitive Candida glabrata in ICU patients,fluconazole plasma peak levels at least in the range of 1632µg/ml appear necessary for treatment. Previous studiesdid not reach these fluconazole levels under continuous veno-venoushaemofiltration (CVVHF) with dosages of 200600 mg fluconzoledaily. In the present study, nine patients simultaneously requiringCVVHF for treatment of acute oligoanuric renal failure and antimycotictherapy of Candida septicemia received fluconazole 800 mg/day.Fluconazole plasma levels were determined to evaluate whetherthis dosage is adequate to reach the advised fluconazole levels.Patients were dialysed on two consecutive days with an ultrafiltrationrate (UF) of 1000 ml/h or 2000 ml/h, respectively, in a randomizedorder. The predilution was 800 ml/h and 1800 ml/h, respectively.The treatment was tolerated without adverse effects. All patientsreached plasma fluconazole concentrations between 16 and 32µg/ml, remaining in this range for a minimum of 1 up to24 h with a mean of 9.6 h and a UF rate of 2000 ml/h, and 15.7h with a UF rate of 1000 ml/h. So far, there are no in vivodata on the fluconazole plasma concentrations required for effectivetreatment. However, our data demonstrate, that at least thefluconazole concentrations desirable on the basis of in vitrosusceptibility testing can be reached in critically ill patientson CVVHF in an ICU setting. However, in these patients, 800mg fluconazole/day are necessary to achieve fungicidal drugconcentrations. 相似文献
68.
Rafael Cincu Juan F Martin L��zaro Jos�� Luis Capablo Liesa Jos�� Ram��n Ara Callizo 《Indian Journal of Orthopaedics》2007,41(4):395-397
Intramedullary epidermoid cysts of the spinal cord are rare tumors, especially those not associated with spinal dysraphism. About 50 cases have been reported in the literature. Of these, only seven cases have had magnetic resonance imaging (MRI) studies. We report two cases of spinal intramedullary epidermoid cysts with MR imaging. Both were not associated with spina bifida. In one patient, the tumor was located at D4 vertebral level; while in the other, within the conus medullaris. The clinical features, MRI characteristics and surgical treatment of intramedullary epidermoid cyst are presented with relevant review of the literature. 相似文献
69.
Walter S Speidl Markus Exner Jasmin Amighi Wolfgang Mlekusch Schila Sabeti Stefan P Kastl Gerlinde Zorn Gerald Maurer Oswald Wagner Kurt Huber Erich Minar Johann Wojta Martin Schillinger 《Journal of endovascular therapy》2007,14(1):62-69
PURPOSE: To investigate whether balloon angioplasty of the superficial femoral artery (SFA) increases serum levels of C5a and whether C5a predicts risk of restenosis. METHODS: C5a antigen was measured at baseline and 8 hours after intervention in 131 consecutive patients (76 women; median age 72 years) with intermittent claudication who underwent successful primary SFA balloon angioplasty. Patients were followed for a median 10 months [interquartile range (IQR) 6 to 14] for the occurrence of >50% restenosis by duplex ultrasound. RESULTS: Median C5a levels increased significantly from 39.7 ng/mL (IQR 27.8 to 55.0) at baseline to 53.8 ng/mL (IQR 35.6 to 85.1, p<0.001) 8 hours post intervention. During the follow-up period, 70 (53%) patients developed restenosis. Increasing levels of C5a (quartiles) at baseline were significantly associated with an increased risk for restenosis (p=0.0092). Adjusted hazard ratios (95% confidence intervals) for restenosis with increasing quartiles of baseline serum C5a levels were 1.24 (0.60 to 2.58), 1.93 (0.95 to 3.93), and 2.08 (1.02 to 4.21), respectively, compared to the lowest quartile. This effect was independent of nonspecific inflammation as reflected by plasma levels of C-reactive protein. CONCLUSION: Inflammatory mechanisms play a major role in the development of restenosis after angioplasty. The complement component C5a exerts strong chemotactic and proinflammatory effects. Enhanced complement activation prior to PTA, as measured by higher levels of C5a, was significantly associated with restenosis after SFA balloon angioplasty. Pathways of complement inhibition thus may be worth investigating with respect to improving patency rates. 相似文献
70.
Sonographic evaluation of gallbladder kinetics: in vitro and in vivo comparison of different methods to assess gallbladder emptying. 总被引:3,自引:0,他引:3
Bernd Wedmann Gabriele Schmidt Martin Wegener Christoph Coenen Dieter Ricken Cornelia Drge 《Journal of clinical ultrasound : JCU》1991,19(6):341-349
In an in vitro study, 10 gallbladders of adult pigs and 6 gallbladders of lambs, all removed immediately after slaughtering, were stimulated in a water bath by electric means to induce active contraction. Gallbladder emptying was followed by ultrasonography employing five measurement procedures: (1) gallbladder width, (2) longitudinal planimetry, (3) transverse planimetry, (4) ellipsoid method, and (5) sum of cylinders method. In an in vivo investigation, gallbladder emptying of 30 volunteers (12 healthy subjects, 18 diabetics) was evaluated in the same way after ingestion of a fatty meal. Gallbladder width was found to be unsuitable to estimate the decrease in gallbladder volume due to a nonlinear relation of the parameters. Longitudinal planimetry tended to be less valid than transverse planimetry in assessing gallbladder volume reduction. The most valid estimation of gallbladder volume decreases was obtained by the two three-dimensional procedures. However, in neither in vitro nor in vivo could a significant difference between the sum of cylinders method and the ellipsoid method in determining relative volume reduction be established. We conclude that a three-dimensional measurement procedure should be used for valid assessments of gallbladder motility. However, according to our data there is no advantage in using the time-consuming sum of cylinders method compared to the simple ellipsoid method. 相似文献