全文获取类型
收费全文 | 2259篇 |
免费 | 178篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 66篇 |
妇产科学 | 37篇 |
基础医学 | 300篇 |
口腔科学 | 90篇 |
临床医学 | 262篇 |
内科学 | 599篇 |
皮肤病学 | 33篇 |
神经病学 | 134篇 |
特种医学 | 128篇 |
外科学 | 193篇 |
综合类 | 47篇 |
一般理论 | 1篇 |
预防医学 | 154篇 |
眼科学 | 31篇 |
药学 | 200篇 |
肿瘤学 | 168篇 |
出版年
2022年 | 16篇 |
2021年 | 25篇 |
2020年 | 23篇 |
2019年 | 33篇 |
2018年 | 42篇 |
2017年 | 16篇 |
2016年 | 27篇 |
2015年 | 29篇 |
2014年 | 55篇 |
2013年 | 77篇 |
2012年 | 95篇 |
2011年 | 85篇 |
2010年 | 57篇 |
2009年 | 61篇 |
2008年 | 82篇 |
2007年 | 100篇 |
2006年 | 98篇 |
2005年 | 81篇 |
2004年 | 76篇 |
2003年 | 87篇 |
2002年 | 80篇 |
2001年 | 86篇 |
2000年 | 78篇 |
1999年 | 62篇 |
1998年 | 37篇 |
1997年 | 40篇 |
1996年 | 42篇 |
1995年 | 25篇 |
1994年 | 32篇 |
1993年 | 20篇 |
1992年 | 54篇 |
1991年 | 38篇 |
1990年 | 43篇 |
1989年 | 61篇 |
1988年 | 39篇 |
1987年 | 57篇 |
1986年 | 80篇 |
1985年 | 56篇 |
1984年 | 38篇 |
1983年 | 34篇 |
1982年 | 25篇 |
1981年 | 31篇 |
1980年 | 25篇 |
1979年 | 31篇 |
1977年 | 18篇 |
1975年 | 15篇 |
1974年 | 20篇 |
1973年 | 22篇 |
1972年 | 12篇 |
1970年 | 19篇 |
排序方式: 共有2459条查询结果,搜索用时 15 毫秒
1.
2.
3.
T W Mattox R O Brown B A Boucher E A Buonpane T C Fabian R W Luther 《JPEN. Journal of parenteral and enteral nutrition》1988,12(6):592-596
The purpose of this study was to evaluate the use of serum fibronectin and serum somatomedin-C as nutritional markers during enteral nutrition support (ENS) of critically ill, traumatized patients using an enteral product containing high concentrations of branched-chain amino acids. Twelve critically injured patients received a standard enteral formula with 30 g of a 44% branched-chain amino acid supplement added to each liter of formula. Fibronectin concentration, somatomedin-C concentration, and nitrogen balance were measured on study days 1, 4, 7, 14, 21, 28 or until adequate oral intake began. Both fibronectin and somatomedin-C concentrations increased significantly from baseline by day 7 of ENS. Nitrogen balance increased significantly from baseline by day 4. On days 14 and 21, only somatomedin-C and nitrogen balance increased significantly from baseline. Nitrogen balance was significantly correlated with somatomedin-C concentration (r = 0.53, p less than 0.01), cumulative caloric intake (r = 0.68, p less than 0.01), and cumulative nitrogen intake (r = 0.72, p less than 0.01). The results of this study suggest that serum somatomedin-C is useful and serum fibronectin has potential in monitoring nutrition support response in critically ill, traumatized patients. 相似文献
4.
Chris Jarrold Peter Smith Jill Boucher Paul Harris 《Journal of autism and developmental disorders》1994,24(4):433-455
In an attempt to tap underlying competencies, the ability of children with autism to comprehend pretend acts carried out by an experimenter was compared with that shown by controls. These acts consisted of the pouring of a pretend substance from an appropriate container onto a target figure. There was no significant difference in the groups' ability to identify the pretend substance involved, to predict the pretend outcome of the actions, or to reflect on the pretend nature of the episodes. However, the performance of controls on these latter two tasks was surprisingly poor, limiting the implications that might be drawn from the observed absence of group differences in comprehension abilities.We are very grateful to the teachers and headteachers of the following schools for their cooperation and assistance throughout the period of this research: John Worrall School, Sheffield; Doucecroft School, Kelvedon; East Hill First and Middle School, Sheffield; East Hill Second School, Sheffield; Mossbrook School, Sheffield; Priory School, Doncaster; The Rowan School, Dore; St. Mary's School, Sheffield. We also thank James Russell for his helpful comments of earlier drafts of this paper. 相似文献
5.
Bipolar affective disorder. II. EEG, neuropsychological, and clinical correlates of CT abnormality 总被引:1,自引:0,他引:1
M J Dewan C V Haldipur M F Boucher T Ramachandran L F Major 《Acta psychiatrica Scandinavica》1988,77(6):677-682
Since the clinical significance of CT abnormalities found in bipolar patients remains obscure, we studied 26 DSM-III bipolar patients who had specific CT abnormalities (third ventricle enlargement, and hyperdensity of the caudate, thalamus, anterior frontal white matter, and right temporal lobe) on numerous parameters such as EEG, the Halstead-Reitan Neuropsychological Battery, premorbid personality adjustment, family history of affective disorder, positive and negative symptoms, employment history, and response to lithium carbonate treatment. None of these measures could differentiate between the CT abnormal and CT normal subgroups. The implications of these findings are discussed. 相似文献
6.
The purported alpha 2-adrenergic agonist clonidine was found to inhibit rest tremor at doses of 0.023-0.1 mg/kg in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine monkey model of parkinsonism. The effect was dose dependent, but sedation and reduced mobility were observed. Atropine at doses of 0.1-1 mg/kg also reduced tremor in a dose-dependent fashion, but side-effects in the form of agitation, dilated pupils, and dry mouth were seen. When the two drugs were combined, however, we saw a significant potentiation of the antitremor effect. We could even abolish tremor with doses of atropine and clonidine that by themselves were without effect. The side-effects were almost eliminated by the combination. 相似文献
7.
8.
J B Richardson A De Notariis C C Ferguson R C Boucher 《Laboratory investigation; a journal of technical methods and pathology》1981,44(2):144-150
The effects of a virus infection on the barrier function of tracheal epithelium were compared to the effects of a chemical agent (methacholine) which selectively increases membrane permeability, and both were compared to controls. The disruption of the airway epithelium induced by the virus infection caused an increased permeation of horseradish peroxidase (HRP) through this barrier. Methacholine enhanced HRP uptake from the airway lumen to the blood as compared to controls. Visualization of HRP in the tracheal epithelium by transmission electron microscopy correlated with the radioimmunoassay measurements in the blood. Serial anti-HRP antibody titers were measured by a competitive binding technique. The antigen permeation induced by methacholine was associated with an enhanced anti-HRP antibody production. The larger increase in antigen permeation seen with the viral infection was associated with depressed anti-HRP titers. It was concluded that viral disruption of the airway epithelial barrier may contribute to an increased uptake of orally inhaled antigens. The relationship, however, between the increased antigen penetration consequent to the viral infection and the development of allergy remains unclear. 相似文献
9.
Sperm analysis by FISH in a case of t(17; 22) (q11; q12) balanced translocation: case report 总被引:2,自引:0,他引:2
Geneix A Schubert B Force A Rodet K Briançon G Boucher D 《Human reproduction (Oxford, England)》2002,17(2):325-331
Individual sperm from men with balanced translocations have different chromosomal contents. Thus, an estimation of the overall sperm chromosomal imbalance of such patients could help to give the couple an adapted genetic counselling. We report here the study of a balanced translocation carrier, t(17;22) (q11;q12) whose reproductive history reported four miscarriages. Moreover, he had an abnormal semen analysis with oligoteratozoospermia. The meiotic segregation pattern was examined in 700 sperm, using fluorescence in-situ hybridization (FISH). Nineteen percent of the sperm had balanced translocations or were normal. All other sperm were unbalanced (81%) and their distribution was observed as follows: the frequencies of adjacent 1, adjacent 2 and 3:1 segregations were 12.9, 5.8 and 46.8% respectively. Among the segregations scored, 13.7% were related to second meiotic division abnormalities. Less than 2% of the total sperm scored were not explained. The 3:1 segregation was present at a very high rate, which is very unusual. In cases of balanced translocations, we believe that no general features can be drawn. Thus, the FISH technique may be very helpful for genetic counselling, which remains an important step and must be done with care. 相似文献
10.
Michel Boucher Claude Dubray Pierre Duchêne-Marullaz 《Naunyn-Schmiedeberg's archives of pharmacology》1984,326(2):148-154
Summary The chronotropic effects of dopamine were studied in the conscious dog with chronic A-V block. Dopamine at 12.5–200 g/kg and 12.5–50 g/kg/min lowered atrial rate independently of dose. After blockade of muscarine receptors or alpha-adrenoceptors, it raised atrial rate. After blockade of dopamine receptors, dopamine still lowered atrial rate, and did so dose-relatedly after blockade of beta-adrenoceptors. It raised ventricular rate, and at high doses also induced ventricular rhythm disorders. Blockade of muscarine receptors enhanced the ventricular cardioaccelerator effect of dopamine (P<0.025) at 100 g/kg, while blockade of alpha-adrenoceptors reduced it (P<0.05). Blockade of dopamine receptors did not modify this effect, but blockade of beta-adrenoceptors reversed it. Dopamine at 25–200 g/kg raised mean blood pressure. This effect was enhanced by blockade of muscarine receptors, reversed by blockade of alpha-adrenoceptors, and was unaffected by blockade of beta-adrenoceptors or dopamine receptors. These results show that the atrial cardiomoderator effect of dopamine is a vagal reflex response to its hypertensive action, and that it is limited by its direct beta-adrenergic stimulating action. They also show that the ventricular cardioaccelerator effect of dopamine is attenuated by a reflex vagal depressor effect consequent to the induced hypertension. No evidence was found for the existence of positive chronotropic dopamine receptors in either atria or ventricles.A preliminary report of these findings was presented at the Symposium on Peripheral Dopaminergic Receptors, July 1978, in Strasbourg, France (Boucher et al. 1979b) 相似文献