首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1971篇
  免费   165篇
  国内免费   4篇
耳鼻咽喉   15篇
儿科学   38篇
妇产科学   33篇
基础医学   272篇
口腔科学   86篇
临床医学   227篇
内科学   524篇
皮肤病学   22篇
神经病学   128篇
特种医学   70篇
外科学   177篇
综合类   30篇
一般理论   1篇
预防医学   142篇
眼科学   27篇
药学   191篇
肿瘤学   157篇
  2022年   12篇
  2021年   24篇
  2020年   21篇
  2019年   31篇
  2018年   38篇
  2017年   15篇
  2016年   26篇
  2015年   24篇
  2014年   49篇
  2013年   66篇
  2012年   92篇
  2011年   81篇
  2010年   48篇
  2009年   46篇
  2008年   77篇
  2007年   80篇
  2006年   96篇
  2005年   77篇
  2004年   73篇
  2003年   83篇
  2002年   76篇
  2001年   76篇
  2000年   73篇
  1999年   56篇
  1998年   26篇
  1997年   27篇
  1996年   23篇
  1995年   17篇
  1994年   14篇
  1992年   51篇
  1991年   36篇
  1990年   42篇
  1989年   48篇
  1988年   34篇
  1987年   47篇
  1986年   66篇
  1985年   46篇
  1984年   31篇
  1983年   28篇
  1982年   18篇
  1981年   22篇
  1980年   18篇
  1979年   30篇
  1977年   12篇
  1975年   12篇
  1974年   20篇
  1973年   21篇
  1972年   12篇
  1971年   11篇
  1970年   19篇
排序方式: 共有2140条查询结果,搜索用时 437 毫秒
1.
2.
3.
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.
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.
6.
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   
7.
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   
8.
9.
10.
A phenytoin prodrug, 3-phosphoryloxymethyl phenytoin (ACC-9653; 1), has been developed with more favorable physicochemical properties than phenytoin for parenteral administration. The purpose of this study was to evaluate the pharmacokinetic profile of 1 following iv and im administration in adult patients receiving chronic oral phenytoin monotherapy. Each patient (9 males, 1 female) received a single iv dose of undiluted 1 equivalent to their twice daily phenytoin dose (100-200 mg). An equivalent dose of im 1 was administered in the gluteus maximus muscle one week later. Serial blood samples were obtained after each dose. Phenytoin and 1 concentrations were measured using HPLC. Compartmental analysis using weighted nonlinear least squares, and noncompartmental pharmacokinetic analysis were performed on each patient's concentration-time data. Data following iv 1 in eight of ten patients were best described using a two-compartment model. Mean pharmacokinetic parameter estimates for iv 1 in these patients were central volume of distribution (Vdc) of 0.040 +/- 0.0084 L/kg and plasma disappearance half-life (t1/2 alpha) of 8.0 +/- 2.9 min ("conversion" t1/2). Overall mean clearance (CL) was 0.24 +/- 0.080 L/kg/h in the 10 patients. Mean pharmacokinetic parameter estimates for im 1 were a rate constant (ka) of 2.47 +/- 1.41 h-1 and an absolute bioavailability (F) of 100.5 +/- 20.3%. Mean observed tmax values for phenytoin were 0.57 +/- 0.26 and 1.46 +/- 0.76 h following iv and im 1, respectively. Model-independent estimates of clearance agreed well with the compartmental analyses. Steady-state predose phenytoin concentrations did not significantly vary from the comparable concentrations following iv 1 administration (p = 0.22).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号