全文获取类型
收费全文 | 1465898篇 |
免费 | 113172篇 |
国内免费 | 13262篇 |
专业分类
耳鼻咽喉 | 17791篇 |
儿科学 | 45396篇 |
妇产科学 | 37728篇 |
基础医学 | 209767篇 |
口腔科学 | 38416篇 |
临床医学 | 147965篇 |
内科学 | 273501篇 |
皮肤病学 | 27945篇 |
神经病学 | 116415篇 |
特种医学 | 52663篇 |
外国民族医学 | 410篇 |
外科学 | 194027篇 |
综合类 | 57735篇 |
现状与发展 | 41篇 |
一般理论 | 468篇 |
预防医学 | 126929篇 |
眼科学 | 32565篇 |
药学 | 113980篇 |
239篇 | |
中国医学 | 13869篇 |
肿瘤学 | 84482篇 |
出版年
2021年 | 17334篇 |
2020年 | 12199篇 |
2019年 | 15552篇 |
2018年 | 20283篇 |
2017年 | 16745篇 |
2016年 | 16975篇 |
2015年 | 21418篇 |
2014年 | 28425篇 |
2013年 | 39875篇 |
2012年 | 55856篇 |
2011年 | 59181篇 |
2010年 | 36578篇 |
2009年 | 32803篇 |
2008年 | 51340篇 |
2007年 | 53307篇 |
2006年 | 52452篇 |
2005年 | 50070篇 |
2004年 | 45872篇 |
2003年 | 43480篇 |
2002年 | 41565篇 |
2001年 | 63342篇 |
2000年 | 64592篇 |
1999年 | 53841篇 |
1998年 | 15517篇 |
1997年 | 14242篇 |
1996年 | 13841篇 |
1995年 | 13080篇 |
1994年 | 12199篇 |
1993年 | 11254篇 |
1992年 | 41850篇 |
1991年 | 41035篇 |
1990年 | 39693篇 |
1989年 | 37533篇 |
1988年 | 34763篇 |
1987年 | 33849篇 |
1986年 | 32252篇 |
1985年 | 30713篇 |
1984年 | 23071篇 |
1983年 | 19623篇 |
1982年 | 11763篇 |
1979年 | 20815篇 |
1978年 | 14815篇 |
1977年 | 12065篇 |
1976年 | 11877篇 |
1975年 | 12114篇 |
1974年 | 14801篇 |
1973年 | 14476篇 |
1972年 | 13356篇 |
1971年 | 12418篇 |
1970年 | 11485篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
B T Hyman J E Flory S E Arnold G W Van Hoesen R L Schelper H Ghanbari H Haigler 《Journal of geriatric psychiatry and neurology》1991,4(4):231-235
A quantitative assay for ALZ-50 immunoreactivity was evaluated in samples of superior temporal gyrus taken at autopsy from 13 Alzheimer patients and 11 controls. The assayable immunoreactivity appears to be stable for at least 24 hours postmortem but was lost with formalin fixation. The mean value of the Alzheimer patients was tenfold higher than that of the controls (P less than .002). The values of four Alzheimer samples overlapped with the low levels seen in controls, but no controls had elevated levels. In this sample population, therefore, the assay had a sensitivity of 69% and specificity of 100%. 相似文献
992.
M L Chindia S W Guthua D L Mwaniki 《International journal of oral and maxillofacial surgery》1991,20(2):73-74
A case of an ameloblastoma diagnosed about 3 1/2 years after removal of an impacted mandibular 3rd molar is presented. The pre-operative radiographs, though poor in quality, showed an ill-defined radiolucency in relation to the tooth. This feature was not apparent to the examiners at the time of first presentation. Despite unfavourable working conditions in developing countries, a high level of suspicion should be maintained to avoid serious sequelae at a later stage. 相似文献
993.
994.
995.
Single or combined monoclonal antibodies (McAbs) Zh53, Zh820, and Zh2-1 have been used to eliminate malignant clonogenic cells from human bone marrow. The test of cytotoxicity showed that all of these McAbs could express high specific cytotoxic action against HL-60 cells and were selectively complement-dependent cytotoxic to various types of fresh leukemic cells. Clonogenic assay detected that single treatment with antibody and rabbit complement (RC) could reduce clonogenic units of HL-60 cells by more than 2 logs and two treatments reduced clonogenic units by more than 4 logs. However, combination of 2 McAbs could reduce clonogenic units by 4-5 logs. The data suggest that multiple treatments with McAbs and RC or a combination of 2 McAbs are more effective than a single treatment in eliminating clonogenic tumor cells. Treatment of normal human bone marrow with Zh53, Zh2-1 and RC did not produce a loss of normal CFU-GM, but treatment with Zh820 reduced the clonic units of normal CFU-GM by 24%.
相似文献
996.
997.
998.
C L Maini R Antonelli Incalzi M G Bonetti G Valle 《European journal of nuclear medicine》1986,12(2):60-64
A total of 131 patients with old (over 6 months) myocardial infarction (MI) and 18 normal subjects underwent equilibrium radionuclide angiocardiography at rest (rERNA). The following rERNA parameters were assessed: left ventricular ejection fraction (LVEF), peak ejection rate (PER), peak filling rate (PFR), regional wall motion and a left ventricular size index. The patients with old MI were divided into four groups (I to IV) according to increasing left ventricular (LV) size, and the behaviour of the numerical parameters (LVEF, PER, PFR) was evaluated in each group. LVEF proved to be the most sensitive numerical parameter of overall LV performance. PFR decreased significantly from group I to group III but not from group III to group IV, suggesting that for extreme degrees of left ventricular enlargement some compensatory mechanism acts to prevent a too large fall in LV compliance. The effects of the site of the previous MI on LV performance were also evaluated. Both LV size and performance were least affected by postero-inferior MI. The LVEF was, however, a better predictor of LV size than the site of the MI. 相似文献
999.
Accuracy of an anthropometric estimate of the muscle and bone area in a transversal cross-section of the arm 总被引:3,自引:0,他引:3
F L de Koning R A Binkhorst J M Kauer H O Thijssen 《International journal of sports medicine》1986,7(5):246-249
To standardize the maximal static force (Fo) of the arm flexors, the accuracy of an anthropometric method for estimating the mid-arm cross-sectional muscle and bone area (MBA) was investigated. This was done by comparing the anthropometrically determined area (MBA.A) with the area measured by means of computerized tomography (MBA.S). In the same way, the accuracy of Heymsfield's equations (Heymsfield et al., 1982) for predicting MBA (MBA.H) from anthropometric measures was tested. MBA.A was significantly larger than MBA.S, the relative difference increasing with the thickness of the subcutaneous fat layer. This difference was attributed to a 27% underestimation of the fat layer thickness as measured with the skinfold caliper. Women being fatter than men, this caused the standardized maximal static force (Fo/MBA) to be lower in women than in men. MBA.H was 12% smaller than MBA.S. This may have been due to a difference in the way of measuring the arm circumference between the present authors and Heymsfield et al. 相似文献
1000.
Localized osteolysis in stable, non-septic total hip replacement 总被引:6,自引:0,他引:6
M J Jasty W E Floyd A L Schiller S R Goldring W H Harris 《The Journal of bone and joint surgery. American volume》1986,68(6):912-919
We are reporting four cases of extensive, localized bone resorption adjacent to a rigidly anchored, cemented total hip replacement. None of these hips showed evidence of infection on clinical, bacteriological, or pathological evaluation. The tissue from the regions of osteolysis showed sheets of macrophages and foreign-body giant cells invading the femoral cortices. Abundant methylmethacrylate particulate debris was present in the tissues, but polyethylene wear debris was absent. The histological appearance of this tissue resembled that reported about loosened total hip implants with the exception of the synovial-like layer at the cement surface. The cases reported here show that aggressive bone lysis may occur around stable cemented total hip arthroplasties without the presence of sepsis or malignant disease. 相似文献