全文获取类型
收费全文 | 1350934篇 |
免费 | 101402篇 |
国内免费 | 4313篇 |
专业分类
耳鼻咽喉 | 16939篇 |
儿科学 | 44088篇 |
妇产科学 | 36758篇 |
基础医学 | 199851篇 |
口腔科学 | 36112篇 |
临床医学 | 131416篇 |
内科学 | 261291篇 |
皮肤病学 | 26613篇 |
神经病学 | 113530篇 |
特种医学 | 48589篇 |
外国民族医学 | 366篇 |
外科学 | 185739篇 |
综合类 | 28900篇 |
现状与发展 | 1篇 |
一般理论 | 480篇 |
预防医学 | 116541篇 |
眼科学 | 29217篇 |
药学 | 99764篇 |
6篇 | |
中国医学 | 3175篇 |
肿瘤学 | 77273篇 |
出版年
2021年 | 11840篇 |
2019年 | 12411篇 |
2018年 | 17137篇 |
2017年 | 12836篇 |
2016年 | 13806篇 |
2015年 | 15772篇 |
2014年 | 21617篇 |
2013年 | 33060篇 |
2012年 | 45711篇 |
2011年 | 48317篇 |
2010年 | 27736篇 |
2009年 | 25446篇 |
2008年 | 43573篇 |
2007年 | 45863篇 |
2006年 | 45852篇 |
2005年 | 44141篇 |
2004年 | 42021篇 |
2003年 | 39901篇 |
2002年 | 38665篇 |
2001年 | 60941篇 |
2000年 | 62622篇 |
1999年 | 52360篇 |
1998年 | 14639篇 |
1997年 | 13311篇 |
1996年 | 13146篇 |
1995年 | 12486篇 |
1994年 | 11646篇 |
1993年 | 10940篇 |
1992年 | 41621篇 |
1991年 | 40812篇 |
1990年 | 39496篇 |
1989年 | 37409篇 |
1988年 | 34657篇 |
1987年 | 33742篇 |
1986年 | 32197篇 |
1985年 | 30680篇 |
1984年 | 23074篇 |
1983年 | 19622篇 |
1982年 | 11779篇 |
1979年 | 20858篇 |
1978年 | 14846篇 |
1977年 | 12087篇 |
1976年 | 11894篇 |
1975年 | 12120篇 |
1974年 | 14831篇 |
1973年 | 14500篇 |
1972年 | 13379篇 |
1971年 | 12443篇 |
1970年 | 11501篇 |
1969年 | 10421篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
Juvenile hypocalcemia provokes persistent electroencephalographic change in renally compromised rats
J J Lipman D L White P L Lawrence P E Teschan 《Journal of the American College of Nutrition》1988,7(6):453-460
In view of the putative involvement of calcium in uremic encephalopathy and the critical importance of this element in juvenile development, we examined the effect of temporary restriction of dietary calcium intake on serum chemistry and the quantitative electroencephalogram (Q.EEG) in unilaterally 3/4 nephrectomized juvenile male Sprague-Dawley rats. Animals were renally infarcted at 22-26 days of age (50-74 g) and placed on one of two isocaloric dietary regimens: powdered normal rat diet (ND, n = 25) or low calcium diet (LCD, n = 8) for 30 days. At this time, ND animals showed normal serum chemistries, whereas LCD rats were hypocalcemic and azotemic with significantly elevated blood urea nitrogen (BUN) and serum creatinine concentrations and reduced renal creatinine clearance values. All animals thereafter received ND for 25-34 further days, during which time chronic Q.EEG electrodes were implanted. At the end of the common ND feeding period, serum chemistry values were equal and normal in both groups. The average theta/alpha ratio (TAR) of the overnight Q.EEG was assessed for 3 days. We found that the TAR of previously LCD animals was significantly elevated compared with ND rats. This indicates an encephalopathic slowing of the background rhythm of these animals. We conclude that, following restoration of a transient uremic and hypocalcemic episode induced by LCD feeding, the Q.EEG background frequency of juvenile renally impaired rats was abnormally slow after 30 days of ND feeding. 相似文献
142.
143.
144.
145.
146.
M. Wensing A. H. Penninks† S. L. Hefle‡ J. H. Akkerdaas§ R. van Ree§ S. J. Koppelman† C. A. F. M. Bruijnzeel-Koomen A. C. Knulst 《Clinical and experimental allergy》2002,32(12):1757-1762
BACKGROUND: The risk for allergic reactions depends on the sensitivity of individuals and the quantities of offending food ingested. The sensitivity varies among allergic individuals, as does the threshold dose of a food allergen capable of inducing an allergic reaction. OBJECTIVE: This study aimed at determining the distribution of minimum provoking doses of hazelnut in a hazelnut-allergic population. METHODS: Thirty-one patients with a history of hazelnut-related allergic symptoms, a positive skin prick test to hazelnut and/or an elevated specific IgE level, were included. Double-blind, placebo-controlled food challenges (DBPCFC) were performed with seven increasing doses of dried hazelnut (1 mg to 1 g hazelnut protein) randomly interspersed with seven placebo doses. RESULTS: Twenty-nine patients had a positive challenge. Itching of the oral cavity and/or lips was the first symptom in all cases. Additional gastrointestinal symptoms were reported in five patients and difficulty in swallowing in one patient. Lip swelling was observed in two patients, followed by generalized urticaria in one of these. Threshold doses for eliciting subjective reactions varied from a dose of 1 mg up to 100 mg hazelnut protein (equivalent to 6.4-640 mg hazelnut meal). Extrapolation of the dose-response curve showed that 50% of our hazelnut-allergic population will suffer from an allergic reaction after ingestion of 6 mg (95% CI, 2-11 mg) of hazelnut protein. Objective symptoms were observed in two patients after 1 and 1,000 mg, respectively. CONCLUSION: DBPCFCs demonstrated threshold doses in half of the hazelnut-allergic patients similar to doses previously described to be hidden in consumer products. This stresses the need for careful labelling and strategies to prevent and detect contamination of food products with hazelnut residues. 相似文献
147.
Kay Kathryn L Roberts Beverley J Turnbull 《The Australian journal of advanced nursing》2002,20(2):8-14
The aim of this study was to document the amount of recent change in Australian nurse academics' scholarly productivity and to investigate the influence of demographic factors such as gender, academic rank, qualifications, increase in qualifications, state of residence, university and university size. Scholarly productivity was calculated from an audit of journal articles. The findings of this study indicate that, while there has been a slight increase in scholarly productivity in the last five years, nursing still lags behind other disciplines. Scholarly productivity was found to be positively associated with highest academic qualification, academic rank and promotion. The study indicates the continuing need for senior nurse academics to provide mentoring to colleagues and foster the development of skills associated with scholarly productivity. 相似文献
148.
Current trend in the treatment of Hodgkin's disease 总被引:1,自引:0,他引:1
M Tubiana J L Amiel M Hayat M Henry-Amar J M Cosset J P Droz P Carde 《Radiation Medicine》1983,1(3):221-229
The analysis of three subsequent randomized trials carried out within the frame of the European Organization for Research on Cancer (E.O.R.T.C.) enables to define a strategy for the staging and the treatment of early stages of Hodgkin's disease. Several prognostic factors were identified by multivariate analyses: 1) erythrocyte sedimentation rate, which has a greater impact on relapse-free survival than systemic symptoms but which can be combined with them; the combination of the two is a more powerful prognostic indicator than ESR alone; 2) the number of involved lymphatic areas: patients with one or two lymphatic areas involved (CS I and II2) have a better outcome than stage II patients with 3 or more areas involved (CS II3). Patients with favorable prognostic indicators are submitted to staging laparotomy because for them spleen involvement has a pejorative impact. For patients with unfavorable indicators, the spleen involvement has little prognostic significance and therefore those patients who need, anyway, an aggressive treatment do not undergo staging laparotomy. Patients with favorable prognostic indicators and negative staging laparotomy can be treated by radiotherapy alone, patients with positive laparotomy or patients with unfavorable prognostic indicators are treated by combination of multiple chemotherapy and radiotherapy. 相似文献
149.
150.
W L Sanvito 《Arquivos de neuro-psiquiatria》1991,49(3):243-250
It is stressed that the brain/mind complex constitutes a monolithic system that functions with emergent properties at several levels of hierarchical organization. These hierarchical levels are non-reducible to one another; they are at least three (neuronal, functional, and semantic), and they function within an interactional plan. From the epistemological view-point, the brain/mind complex uses logical and non-logical mechanisms to deal with day-to-day problems. Logic is necessary for the thinking process, but it is not sufficient. Emphasis is given to non-logical mechanisms; fuzzy logic and heuristics, which allow the mind to develop strategies to find solutions, are analysed. 相似文献