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   1840篇
  免费   204篇
  国内免费   3篇
耳鼻咽喉   23篇
儿科学   33篇
妇产科学   20篇
基础医学   212篇
口腔科学   45篇
临床医学   176篇
内科学   499篇
皮肤病学   19篇
神经病学   179篇
特种医学   91篇
外科学   239篇
综合类   55篇
一般理论   1篇
预防医学   211篇
眼科学   33篇
药学   155篇
肿瘤学   56篇
  2023年   16篇
  2022年   14篇
  2021年   37篇
  2020年   24篇
  2019年   45篇
  2018年   50篇
  2017年   36篇
  2016年   31篇
  2015年   46篇
  2014年   57篇
  2013年   65篇
  2012年   113篇
  2011年   110篇
  2010年   58篇
  2009年   70篇
  2008年   89篇
  2007年   96篇
  2006年   97篇
  2005年   65篇
  2004年   67篇
  2003年   63篇
  2002年   49篇
  2001年   44篇
  2000年   33篇
  1999年   34篇
  1998年   13篇
  1995年   14篇
  1993年   12篇
  1992年   43篇
  1991年   36篇
  1990年   46篇
  1989年   41篇
  1988年   30篇
  1987年   28篇
  1986年   37篇
  1985年   28篇
  1984年   17篇
  1983年   13篇
  1981年   14篇
  1980年   12篇
  1979年   21篇
  1978年   14篇
  1977年   22篇
  1974年   16篇
  1973年   16篇
  1972年   13篇
  1971年   17篇
  1970年   13篇
  1969年   14篇
  1966年   18篇
排序方式: 共有2047条查询结果,搜索用时 31 毫秒
1.
2.
Emphysematous pyelonephritis is a severe life-threatening infection which continues to carry significant morbidity and mortality. We present a case recently managed at our institution by laparoscopic nephrectomy. The patient survived, and in comparison to some of the more conventionally managed patients in the literature, made an extremely speedy recovery. We would advocate this option to be seriously considered when patients are suitable and appropriately trained surgeons are available.  相似文献   
3.
1. The effect of omega-3 fatty acid supplementation on alpha 1-adrenergic receptor-mediated phosphoinositide turnover in the hearts of 6-week streptozotocin diabetic rats was studied. 2. The diabetic state was characterized by decreased body weight gain, hypoinsulinemia and hyperglycemia. Omega-3 fatty acid treatment did not have any significant effects on the above parameters. 3. Plasma triglyceride and cholesterol levels were significantly higher in diabetic rats compared with controls. 4. Omega-3 fatty acid treatment reduced the plasma triglyceride levels in the diabetic rats, whereas plasma cholesterol levels remained unaffected. 5. Norepinephrine (10 and 100 microM) stimulated inositol monophosphate (IP1) formation was significantly decreased in the diabetic rat heart compared with controls. Omega-3 fatty acid treatment had no significant effect on the norepinephrine-mediated IP1 formation in these rats. 6. Inositol bisphosphate (IP2) formation in response to 100 microM of norepinephrine was significantly lower in the diabetic rat heart; which was also not affected by omega-3 fatty acid treatment.  相似文献   
4.

Background  

The aim of the current study is to investigate the relationship between physical anhedonia and psychopathological parameters, pharmacological parameters or motor side-effects in a sample of inpatients with schizophrenia in an acute episode of their illness.  相似文献   
5.
Deoxycorticosterone acetate (DOCA) is an agent commonly used to induce hypertension in experimental animals. This form of hypertension is dependent on altered regulation of central pressor mechanisms including the brain renin-angiotensin system. Additionally, there are characteristic changes involving the cardiovascular system and baroreflex responses. This review will discuss aspects of the pathogenesis of DOCA hypertension and the effect of various antihypertensive agents on the development of this form of hypertension.  相似文献   
6.
This study examined the effects of acute and chronic ethanol on cortical somatosensory-evoked potentials (SEPs) of laboratory rats. Evoked potentials were recorded following stimulation of the left hindpaw before and after injection of either saline or ethanol. Animals were then chronically exposed to ethanol in vapor inhalation chambers for five weeks. Recordings of SEPs before and after acute ethanol injection were then obtained 24 h and again seven days after withdrawal from ethanol exposure. The results indicate that acute ethanol produced a dose-dependent reduction in SEP amplitude, but did not alter peak latencies. Chronic ethanol exposure and withdrawal resulted in a significant increase in preinjection baseline response amplitudes when measured at 24 h after withdrawal, but not at seven days, and this treatment did not alter response latency or the effects of acute ethanol administration.  相似文献   
7.
1. The present study describes the role of Ca2+ in the regulation of the hepatic vasopressin V1 receptor. With low concentrations of Ca2+, there was a small increase in [3H]-arginine vasopressin [( 3H]-AVP) binding, but above 10 mM, Ca2+ decreased the binding of this agonist. In contrast, low concentrations of Mg2+ were associated with a dramatic concentration-dependent increase in [3H]-AVP binding, reaching a maximal effect of 650% above control at concentrations ranging between 1-5 mM. At higher concentrations of Mg2+, the stimulatory effect of this cation was less pronounced, falling to 210% of control at 100 mM Mg2+. Strikingly, Ca2(+)-inhibited the stimulatory effect of Mg2+ in a concentration-dependent fashion. 2. Saturation binding data revealed that Ca2+ (2 to 10 mM) per se promotes the high affinity conformation of the V1 receptor for the agonist binding with the KD decreased from a control value of 2.3 nM to 0.5 nM in the presence of 10 mM Ca2+. This effect was attenuated with an increase in Ca2+ above 10 mM. With an increase in Ca2+ to 20 mM, however, the Bmax for [3H]-AVP binding was decreased. Ca2+ also decreased the high affinity/high capacity state (KD 100 pM) of the receptor induced by 1 mM Mg2+ for agonist interaction. 3. [3H]-V1 antagonist binding was inhibited by both Ca2+ and Mg2+. The IC50 values (mean +/- s.e. mean) for Ca2+ and Mg2+ were 32 +/- 8 and 53 +/- 9 mM respectively. Maximal inhibition achieved at 100 mM was 29% for Ca2+ and 42% for Mg2+.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
8.
9.
Independent experiments have been performed at two centers, to evaluate the dosimetric properties of their respective 109Cd K X-ray fluorescence (XRF) bone lead measurement systems. Measurements were made of the dose to several points on the skin on the lower leg, at the surface of the tibia, in the red marrow tibia cavity, at the midcalf, and in the abdominal region occupied by the conceptus. Overall agreement between the two data sets was found. Similarities and differences are discussed. The effective dose values for an in vivo measurement of tibia lead concentration in 1-, 5-, and 10-year-old and adult subjects were calculated from one data set to be 1100, 420, 190, and 34/38 (male/female) nSv, respectively, for an in vivo median precision (one standard deviation) of 4.9 micrograms Pb (g bone mineral)-1 for a 30-min adult measurement.  相似文献   
10.
Risk factors for the uptake of cigarette smoking were examined prospectively in 2159 non-smoking secondary schoolchildren aged 11-13 who participated in a survey in 1983 and were followed up 30 months later, by which time 35 per cent had taken up smoking. In a multivariate logistic model, the strongest predictors to emerge were prior experimentation with cigarettes and sex, with more girls (41%) than boys (30%) starting to smoke. Other predictors of taking up smoking were being uncertain about smoking in the future, reporting having been drunk, having a boy or girl friend, believing teachers and friends would not mind if they took up smoking, and giving lower estimates of prevalence of smoking among teachers. Parental smoking behaviour and attitudes, beliefs about the effects of smoking on health, opinions about smoking and perceived strictness of parents did not predict take up of smoking when other variables were controlled for. The odds of taking up smoking varied from 0.24 (risk = 0.19) for a child with the most favourable combination of risk factors to 3.49 (risk = 0.78) for a child with the worst prognosis. These results differ from those of many cross sectional studies and hence indicate the importance of a prospective approach to this type of research.  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