全文获取类型
收费全文 | 8811篇 |
免费 | 597篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 53篇 |
儿科学 | 140篇 |
妇产科学 | 206篇 |
基础医学 | 1185篇 |
口腔科学 | 224篇 |
临床医学 | 741篇 |
内科学 | 2260篇 |
皮肤病学 | 94篇 |
神经病学 | 1034篇 |
特种医学 | 313篇 |
外科学 | 951篇 |
综合类 | 100篇 |
一般理论 | 9篇 |
预防医学 | 788篇 |
眼科学 | 299篇 |
药学 | 620篇 |
1篇 | |
中国医学 | 8篇 |
肿瘤学 | 409篇 |
出版年
2023年 | 60篇 |
2022年 | 83篇 |
2021年 | 177篇 |
2020年 | 110篇 |
2019年 | 158篇 |
2018年 | 175篇 |
2017年 | 108篇 |
2016年 | 146篇 |
2015年 | 144篇 |
2014年 | 196篇 |
2013年 | 360篇 |
2012年 | 441篇 |
2011年 | 501篇 |
2010年 | 296篇 |
2009年 | 302篇 |
2008年 | 455篇 |
2007年 | 503篇 |
2006年 | 483篇 |
2005年 | 533篇 |
2004年 | 438篇 |
2003年 | 405篇 |
2002年 | 410篇 |
2001年 | 193篇 |
2000年 | 191篇 |
1999年 | 181篇 |
1998年 | 127篇 |
1997年 | 90篇 |
1996年 | 76篇 |
1995年 | 70篇 |
1994年 | 56篇 |
1993年 | 62篇 |
1992年 | 120篇 |
1991年 | 110篇 |
1990年 | 93篇 |
1989年 | 81篇 |
1988年 | 76篇 |
1987年 | 65篇 |
1986年 | 68篇 |
1985年 | 68篇 |
1984年 | 50篇 |
1983年 | 64篇 |
1982年 | 62篇 |
1981年 | 66篇 |
1980年 | 53篇 |
1979年 | 52篇 |
1978年 | 58篇 |
1977年 | 53篇 |
1975年 | 48篇 |
1973年 | 46篇 |
1970年 | 45篇 |
排序方式: 共有9435条查询结果,搜索用时 15 毫秒
21.
Effects of laparotomy on systemic macrophage function. 总被引:3,自引:0,他引:3
Surgical trauma induces immunosuppression that may adversely influence survival. This study examined the effect of laparotomy on two different macrophage populations, peritoneal macrophages (PM phi) and Kupffer cells. Female, 6- to 8-week old, CFW/C3H-HeN mice (n = 160) were randomly allocated to one of three study groups: control, ether anesthetic only, or ether anesthetic and laparotomy. On postoperative days 1 and 3, PM phis and Kupffer cells were harvested and assayed for superoxide anion production (O2-), percent macrophage phagocytosis of Candida albicans (CAP), percent C. albicans killed by macrophages (CAK), percent major histocompatibility complex (MHC)-class II antigen expression, and antigen presentation. Macrophages isolated on postoperative day 1 were also cocultured with 100 units/10(6) cells/ml interferon-gamma (IFN-gamma). Laparotomy significantly impaired microbicidal activity (O2-, percent CAP, and percent CAK) and antigen presentation on postoperative day 1. On postoperative day 3, O2- and antigen presentation were increased significantly (p less than 0.05) over control values, indicating a rebound phenomenon. Kupffer cell microbicidal function was unchanged on postoperative days 1 and 3. The initial immune impairment (PM phis: O2-, CAP, and CAK) was abrogated by IFN-gamma treatment. In immunosuppressed hosts after injury, administration of macrophage-activating factors such as IFN-gamma could be of therapeutic benefit. 相似文献
22.
K Tardiff P M Marzuk A C Leon C S Hirsch M Stajic L Portera N Hartwell 《Public health reports (Washington, D.C. : 1974)》1995,110(1):13-17
Although prior research has found that homes containing firearms and illicit drug and ethanol users are more likely to be the scene of a homicide than homes that do not contain these elements, the authors studied homicides on the streets as well as in homes so as to assess the role of firearms, cocaine, and ethanol in both settings. Using the files of the Chief Medical Examiner, the authors reviewed all 4,468 homicides occurring in New York City in 1990 and 1991. The most frequent places of occurrence were the streets and other outdoor places (49.6 percent) and the victims'' homes (19.3 percent). Firearms were the cause of death for 49.6 percent of homicides in the home and 80.3 percent of those on the streets. Use of cocaine and ethanol was found more frequently among victims killed on the streets than those killed at home. In addition, victims killed on the streets were more likely to be male, ages 15-24 years, and African American. Further research in regard to prevention and intervention strategies is needed, keeping in mind the different patterns of homicide on the streets compared with those occurring in other settings. 相似文献
23.
Leon A. Weisberg Jack Greenberg Antonio Stazio 《Computerized medical imaging and graphics》1988,12(6):379-383
The clinical and computerized tomographic (CT) findings in 10 patients with cerebral toxoplasmosis are reviewed. All patients with cerebral toxoplasmosis were homosexuals and/or intravenous drug users, and all patients had other manifestations of AIDS. Two presented with focal seizures, 4 presented with focal neurological deficit which progressively worsened, and 4 had evidence of diffuse neurological dysfunction (altered consciousness, generalized seizures). CT showed a single lesion in 3 patients and multiple lesions in 7 patients. Two patients had hypodense nonenhancing lesions(s). Eight patients had hypodense lesions with peripheral or nodular enhancement. The lesions were more commonly located in the cerebral hemispheres and subcortical gray matter nuclear masses (thalamus, basal ganglia). The finding of a hypodense lesion with a central slightly hyperdense noncalcified region that showed dense nodular homogeneous enhancement was quite characteristic of cerebral toxoplasmosis, but this pattern may also be seen in other neurological conditions including brain lymphomas. 相似文献
24.
Michiel A. M. Feldberg M.D. Ph.D. Leon P. Driessen Theo D. Witkamp Maarten S. van Leeuwen Paul F. G. M. van Waes 《Urologic radiology》1988,10(1):92-94
In a case of diffuse xanthogranulomatous pyelonephritis, computed tomography (CT) and magnetic resonance (MR) were used. The MR proved to be more precise in the preoperative evaluation of inflammatory extension to the spleen and into the abdominal wall. The CT was more accurate in excluding spread to the colon. 相似文献
25.
D W Bowden K Lohman F-C Hsu C D Langefeld J J Carr L Lenchik L E Wagenknecht B I Freedman D M Herrington 《Diabetic medicine》2006,23(7):763-767
AIMS: Increased levels of inflammatory biomarkers, especially C-reactive protein (CRP), are associated with increased risk for cardiovascular disease (CVD) events, such as myocardial infarction, stroke, peripheral vascular disease, and sudden cardiac death. Medical interventions that increase CRP levels, such as hormone replacement therapy (HRT) in post-menopausal women, are under increasing scrutiny. The effect of HRT on CRP levels in women with Type 2 diabetes (T2DM) is not well documented, and conflicting conclusions have been reported. The aim of this study was to determine the influence of HRT on women with diabetes in a large cross-sectional study. METHODS: Three hundred and twenty-seven post-menopausal women with T2DM from the Diabetes Heart Study participated. Current use of HRT was determined and serum CRP levels were measured using a high-sensitivity ELISA kit. Generalized estimating equation methods were used to assess the relationship of multiple clinical and lifestyle (e.g. smoking) measures on CRP levels including differences between women taking HRT (HRT+) and not taking HRT (HRT-). RESULTS: Overall serum CRP levels were strongly associated with body mass index (P < 0.0001) and age (P < 0.0001). Of the women, 243 were not using HRT and 84 were using HRT. HRT+ and HRT- women did not differ significantly in measures of clinical traits, with the exception of higher mean low-density lipoprotein cholesterol in HRT- women (P = 0.004). In all models tested, HRT+ women had significantly higher circulating CRP levels, with P-values ranging from 0.0045 to 0.010. CONCLUSIONS: In this study of serum CRP concentration as a function of HRT in women with Type 2 diabetes, there was consistent evidence for increased circulating CRP levels in women receiving oestrogen-containing HRT. Whether HRT-induced increases in CRP can account for the adverse cardiovascular effects of HRT remains to be established; however, based on these data, there is little reason to believe that diabetic women would be spared from such an effect. 相似文献
26.
Leon Ardekian Efrat Oved-Peleg Eli E Mactei Micha Peled 《Journal of oral and maxillofacial surgery》2006,64(2):277-282
PURPOSE: Augmentation of the maxillary sinus floor is a well-documented technique and is generally accepted as a pure implantology procedure to facilitate placement of dental implants in the posterior atrophic maxilla. The objective of this report was to evaluate the significance of the sinus membrane perforations on the incidence, complications, and success rate of this procedure. PATIENTS AND METHODS: Patients who received sinus floor augmentation and simultaneous placement of dental implant were included in this study. Subgroup I consisted of patients who had their sinus membrane perforated and repaired during the procedure with resorbable membrane. Subgroup II consisted of patients whose Schneiderian membrane was not perforated during the procedure. The patients were followed between 1 to 4 years after augmentation. RESULTS: All perforations were classified as class II or III. The success rate of the implants in the perforation group was 94.4%, and that for the nonperforation group was 93.9%. The difference between the 2 study groups was statistically not significant. A significant statistical correlation was found between the residual ridge height and the membrane perforation (P < .01). CONCLUSIONS: Mainly due to technical difficulties, maxillary sinus membrane perforation occurs more frequently with a small height of residual alveolar bone. In this study, no statistical difference was observed in the success rate of the immediate implants placed with sinus bone grafting in patients whose membrane was perforated versus those patients in whom an intact membrane was maintained. 相似文献
27.
The Stiles-Crawford effect of the first kind (SCE-I) was measured on both emmetropic and myopic subjects at six different retinal locations. The results revealed a number of significant discrepancies in receptor alignment between the groups of different refractive errors. In myopic subjects, the receptors in the nasal retina (i.e. between the fovea and the optic nerve head) were found to be aligned nasally towards the optic nerve head, whereas the receptors in the temporal retina were aligned towards the centre of the exit pupil. In emmetropic subjects, the receptors across the retina were finely tuned towards the centre of the exit pupil. The magnitude of the receptor displacement in myopic subjects was found to be directly associated with the length of the eyeball. 相似文献
28.
30.
Olfactory stimulation evokes a column of activity within the olfactory bulb extending from the glomerular layer to the granule cell layer that can be visualized with 2-deoxyglucose autoradiography, optical imaging, Fos protein immunohistochemistry and c-fos mRNA in situ hybridization. The Fos response to odors is typified by the activity of relatively few juxtaglomerular cells, which often occur in foci, and a large number of granule cells extending through much of the bulb. In this study, we characterized the granule cell response to an odor for which young rats had acquired a preference. Fos-like immunoreactive granule cells were quantified by image analysis, and densely stained cells were counted in a region previously shown to be responsive to peppermint odor. We found that odor-trained pups have about half the number of Fos-immunopositive superficial granule cells which respond to a learned odor than do control pups. We then determined whether there was a correlation between the juxtaglomerular cell response and the response of the superficial granule cells deep to those glomerular layer cells. We found a positive correlation between the number of juxtaglomerular cells and the number of granule cells demonstrating Fos immunoreactivity in both control and trained pups, a relationship that changed with early olfactory training. 相似文献