全文获取类型
收费全文 | 1686233篇 |
免费 | 115969篇 |
国内免费 | 2020篇 |
专业分类
耳鼻咽喉 | 21908篇 |
儿科学 | 55019篇 |
妇产科学 | 45182篇 |
基础医学 | 260550篇 |
口腔科学 | 45083篇 |
临床医学 | 155744篇 |
内科学 | 322374篇 |
皮肤病学 | 36881篇 |
神经病学 | 129477篇 |
特种医学 | 62912篇 |
外国民族医学 | 316篇 |
外科学 | 241928篇 |
综合类 | 32256篇 |
现状与发展 | 4篇 |
一般理论 | 662篇 |
预防医学 | 136009篇 |
眼科学 | 37835篇 |
药学 | 125428篇 |
7篇 | |
中国医学 | 2965篇 |
肿瘤学 | 91682篇 |
出版年
2018年 | 17915篇 |
2017年 | 13548篇 |
2016年 | 15066篇 |
2015年 | 17265篇 |
2014年 | 23617篇 |
2013年 | 35873篇 |
2012年 | 49896篇 |
2011年 | 53751篇 |
2010年 | 31083篇 |
2009年 | 29341篇 |
2008年 | 50137篇 |
2007年 | 54223篇 |
2006年 | 53458篇 |
2005年 | 51972篇 |
2004年 | 50227篇 |
2003年 | 48197篇 |
2002年 | 46778篇 |
2001年 | 72882篇 |
2000年 | 74403篇 |
1999年 | 62513篇 |
1998年 | 17571篇 |
1997年 | 15624篇 |
1996年 | 16073篇 |
1995年 | 15168篇 |
1994年 | 13966篇 |
1992年 | 49275篇 |
1991年 | 49888篇 |
1990年 | 48785篇 |
1989年 | 47418篇 |
1988年 | 43856篇 |
1987年 | 43280篇 |
1986年 | 40951篇 |
1985年 | 38865篇 |
1984年 | 29450篇 |
1983年 | 25625篇 |
1982年 | 14725篇 |
1981年 | 13398篇 |
1979年 | 28185篇 |
1978年 | 20518篇 |
1977年 | 16994篇 |
1976年 | 16415篇 |
1975年 | 18293篇 |
1974年 | 21734篇 |
1973年 | 21349篇 |
1972年 | 19999篇 |
1971年 | 18823篇 |
1970年 | 17739篇 |
1969年 | 16588篇 |
1968年 | 15585篇 |
1967年 | 13918篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
E Griez 《L'Encéphale》1987,13(6):335-339
This paper reviews recent developments in the experimental approach to panic anxiety. Inhalation of carbon dioxide appears to trigger panic attacks in panic disorder patients and agoraphobics. The biological and psychopathological implications of this finding are discussed in the light of recent data on experimental pharmacology of anxiety. 相似文献
994.
995.
996.
G.E. ORLANDINI S. ZECCHI ORLANDINI A.F. HOLSTEIN R. EVANGELISTI and R. PONCHIETTI 《Andrologia》1987,19(3):315-321
The human prostatic urethra has been investigated by means of scanning electron microscopy. On the posterior wall of the urethra, the seminal colliculus with the orifices of the ejaculatory ducts is clearly detectable. The upper portion of the prostatic urethra shows a typical transitional epithelium with large superficial cells of a ruffled appearance. In the lower portion of the organ (underneath the openings of the ejaculatory ducts), the apical pattern of the cells varies considerably. Four main aspects are recognizable: apices provided with microvilli, dome-shaped apices with an almost smooth surface, large apices with labyrinthic microplicae and ciliated apices. Also, apices showing intermediate characteristics can be noted. The functional significance of the morphological patterns as well as the possibility of a transition among the various types of surface structures are discussed. 相似文献
997.
Predicting failure in polytetrafluoroethylene vascular access grafts for hemodialysis: a pilot study
C R Shackleton D C Taylor A R Buckley V A Rowley P L Cooperberg P D Fry 《Canadian journal of surgery》1987,30(6):442-444
In order to determine if serial, noninvasive evaluation of polytetrafluoroethylene (PTFE) vascular access grafts could identify a subgroup of patients at risk for thrombosis, the authors studied flow characteristics, using duplex ultrasonic scanning, in 18 hemodialysis patients with forearm loop grafts. On average, five examinations were performed per patient over the 10-month study period. Seven episodes of thrombosis occurred in six patients. The mean Doppler flow in grafts that subsequently thrombosed was significantly lower than in those that did not (544 +/- 218 ml/min versus 843 +/- 391 ml/min, p less than 0.001). The interval from last examination to thrombosis ranged from 13 to 58 days. At a defined cut-off flow of 450 ml/min, this test yielded a sensitivity of 83% and a specificity of 75% for episodes of thrombosis occurring within 2 to 6 weeks. The authors conclude that episodes of thrombosis in PTFE arm loop grafts are usually preceded by significantly lower Doppler-measured flow than grafts that do not thrombose and that it may be possible, by this means, to identify grafts at risk. 相似文献
998.
F Mandelli G De Rossi P Mancini A Alberti A Cajozzo F Grignani P Leoni V Liso M Martelli A Neri 《Journal of clinical oncology》1987,5(3):398-406
Clinical and biological data were evaluated using Desu univariate analyses or Cox multivariate analyses in a series of 1,777 chronic lymphocytic leukemia (CLL) patients from an Italian Cooperative Group. In univariate analyses, age and sex of patients, presence of bone marrow (BM; greater than or equal to 50%), and peripheral blood (PB; greater than or equal to 60,000/microL) lymphocytosis, anemia (hemoglobin [Hb] less than 11 g/dL), thrombocytopenia (less than 100,000/microL), direct Coombs' test positivity, hepatomegaly, splenomegaly, and extent of lymph node involvement were shown to be of significant prognostic value. Multivariate analyses, through a stepwise procedure, showed that the most important prognostic variables are Hb, hepatomegaly, lymph node involvement, PB lymphocytosis, and age and sex of patients. Further covariates would produce an improvement having a nonsignificant P value. Based on the results of multivariate analyses, a four-step staging using the significant variables of the Cox model is proposed. 相似文献
999.
The present paper deals with a Finnish long-term prospective study, the objective of which is to shed light on adjustment to retirement and old age. In this phase, only the preliminary findings of the initial survey carried out in 1982 are available. For the purposes of the study, a random sample of 200 individuals was drawn from among Turku inhabitants born in 1920. Another sample, consisting of 189 persons of the same age, was drawn from rural municipalities in the neighborhood of Turku. An extensive structured psychosocial interview could be conducted with a total of 339 subjects. The research methods used included e.g. the 36-item version of Goldberg's General Health Questionnaire (GHQ). Relatively little mental disturbance was revealed in the interview, and no major differences occurred between the urban and the rural sample. Somewhat over one-third of both samples were probable psychiatric cases as defined according to the GHQ. 相似文献
1000.
We isolated hybridoma cells, which secreted monoclonal antibody (MAb) 121 SLE, an IgM showing the following reactivities: (1) by immunodiffusion, MAb 121 SLE and MAb NS 19-9 (a monoclonal antibody directed against a sialylated Lewis(a) antigen called CA 19-9) showed an identical precipitin line with mucin preparation containing this CA 19-9; (2) by immunoradiometric assay, MAb 121 SLE totally inhibited fixation of radiolabelled MAb NS 19-9; (3) by immunoperoxidase, MAb 121 SLE stained the normal gastrointestinal mucosa of Le-positive individuals exclusively, and this staining disappeared after neuraminidase treatment, as observed using MAb NS 19-9. However, the pattern of the staining obtained with MAb 121 SLE differed slightly from that given by MAb 19-9 on the different positive areas of the gastrointestinal mucosae. These differences principally concerned the number of positive epithelial cells and the intensity of their staining; (4) moreover, antibodies against idiotype determinant of NS 19-9 antibody did not react with the antibody 121 SLE. We concluded that MAb 121 SLE is different from the MAb NS 19-9. However, both these antibodies were associated with the same molecular sialylated Lewis(a) structure. 相似文献