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   719篇
  免费   62篇
  国内免费   3篇
耳鼻咽喉   2篇
儿科学   14篇
妇产科学   15篇
基础医学   72篇
口腔科学   14篇
临床医学   68篇
内科学   108篇
皮肤病学   7篇
神经病学   28篇
特种医学   34篇
外科学   176篇
综合类   14篇
预防医学   74篇
眼科学   51篇
药学   67篇
肿瘤学   40篇
  2022年   4篇
  2021年   5篇
  2020年   6篇
  2019年   5篇
  2018年   12篇
  2017年   6篇
  2016年   5篇
  2015年   5篇
  2014年   6篇
  2013年   12篇
  2012年   27篇
  2011年   24篇
  2010年   22篇
  2009年   17篇
  2008年   33篇
  2007年   38篇
  2006年   31篇
  2005年   41篇
  2004年   47篇
  2003年   38篇
  2002年   26篇
  2001年   29篇
  2000年   26篇
  1999年   17篇
  1998年   12篇
  1997年   8篇
  1996年   5篇
  1995年   10篇
  1994年   12篇
  1993年   8篇
  1992年   19篇
  1991年   16篇
  1990年   16篇
  1989年   21篇
  1988年   18篇
  1987年   17篇
  1986年   15篇
  1985年   18篇
  1984年   14篇
  1983年   16篇
  1981年   6篇
  1979年   8篇
  1977年   4篇
  1975年   6篇
  1974年   4篇
  1973年   5篇
  1972年   6篇
  1969年   3篇
  1968年   4篇
  1963年   3篇
排序方式: 共有784条查询结果,搜索用时 15 毫秒
81.

Background  

Persistent whiplash associated disorders (WAD) have been associated with alterations in kinesthetic sense and motor control. The evidence is however inconclusive, particularly for differences between WAD patients and patients with chronic non-traumatic neck pain. The aim of this study was to investigate motor control deficits in WAD compared to chronic non-traumatic neck pain and healthy controls in relation to cervical range of motion (ROM), conjunct motion, joint position error and ROM-variability.  相似文献   
82.
83.
Abstract Hypercholesterolaemia is a known risk factor for coronary artery disease. This study describes a retrospective analysis of 176 patients admitted to the Coronary Care Unit (CCU) in a six month period with an admission fasting serum cholesterol of greater than 5.5 millimoles per litre (mmols/L). The patient records were examined at least six months after hospital discharge to determine what action, if any, was instituted in response to their hypercholesterolaemia. One hundred and thirty-four (76%) patients had a discharge diagnosis of myocardial ischaemia or infarction. Of the 176 patients, 73 were referred to a dietitian, 31 were given dietary advice by a medical officer, 13 were commenced on lipid-lowering drugs with nine continuing lipid-lowering drugs and only 13 patients were referred to this hospital's lipid clinic. Sixty-nine (39%) received no response to their hypercholesterolaemia. It is likely that our experience is not unique and greater attention to CCU measured lipid results and risk factor modification should be instituted by physicians. (Aust NZ J Med 1991; 21: 401–404.)  相似文献   
84.
A novel ligand, [4,5-3H-Leu10]substance P ([3H]SP), with high specific activity (137 Ci/mmole) was utilized to investigate the properties of NK (neurokinin)-1 receptors on guinea pig lung membranes (GPLM) and compared them to NK-1 receptors on rat submaxillary glands (RSGM). In the presence of a neutral endopeptidase inhibitor, thiorphan (100 microM), [3H]SP bound with high specificity (greater than 95%), rapidly (k1 = 0.116 nM-1 x min-1) and in a reversible (k-1 = 0.012 min-1) manner to a single class of high-affinity (Kd = 0.16 nM) and saturable (Bmax = 256 fmol/mg protein) receptors. High specific binding with higher density (5-fold) was also detected in RSGM, albeit with a lower affinity (Kd = 1.36 nM). Guanyl-5'-yl-imidodiphosphate and guanosine-5'-O-3-thiotriphosphate inhibited binding to GPLM (and RSGM) in a concentration-related manner. In GPLM, this effect was mediated by a reduction in affinity, mainly via enhancement of ligand dissociation rates and appearance of a lower affinity state (Kd = 3.4 nM). Preincubation of GPLM with sulfhydryl modifying agents (p-chloromercuriphenyl sulfonic acid and N-ethylmaleimide) reduced receptor density and affinity in a time- and concentration-dependent manner. Competition experiments with tachykinins and analogs illustrated a rank order of potency of: SP greater than or equal to [Sar9,Met(O2)11]SP greater than SP-methyl ester greater than or equal to physalaemin greater than SP(6-11) much greater than kassinin greater than neurokinin A = eledoisin much greater than neurokinin B greater than Nle10-NKA(4-10), clearly demonstrating that these receptors are of NK-1 type. Moreover, analysis of over 30 peptide and non-peptide hormones and antagonists demonstrated exquisite selectivity (greater than 10,000-fold) towards NK-1-selective agonists (vs. other ligands. A highly significant (P less than .005) linear correlation (r = 0.924) exists between agonist affinities in GPLM and RSGM. Combined, the data suggest that [3H]SP labels a nearly homogeneous population of high-affinity, G-protein coupled NK-1 receptors on GPLM and RSGM, with very high degree of selectivity.  相似文献   
85.
Female sterilization as an interval, postabortal or postpartum procedure, is one of the most widely employed contraceptive techniques on a global basis. The short-term complications of sterilization, which include intra- and extrauterine pregnancies, are well researched and documented. The figures for long-term complications, including ectopic pregnancy, are much less reliable as the follow-up rates diminish as time passes after sterilization. Three cases of tubal pregnancy that occurred long after interval sterilization are presented as a warning against the assumption that long-term complications cannot occur.  相似文献   
86.
Home monitors of blood glucose (HMBGs) are gaining acceptance as part of the standard of care for ambulatory self-monitoring and treatment of diabetic patients. Currently there are several HMBGs marketed in the United States, each claiming reliability, accuracy, and "user friendliness," with most of these claims largely unsubstantiated. The objective of our study was to analyze and statistically compare the accuracy and precision of the HMBGs produced by the major competitors in this ever-expanding medical field. Accuracy of each monitor was studied by comparing the glucose value reported by each HMBG with that determined by a reference method (YSI 23A). Precision or reproducibility of results was performed by testing a single, known whole-blood glucose sample 20 times on each monitor. The precision of each device was tested on known low, normal, and elevated samples. Actual and absolute deviations from the reference standard demonstrate that the Accuchek bG and Glucoscan 2000 monitors provide relatively unbiased estimates of blood glucose, whereas the Glucokey, Glucochek II, Glucometer II, and Trendsmeter generally underestimate the true values. The Diascan and Accuchek II monitors, in a separate evaluation, demonstrated acceptable accuracy and precision. We conclude that the Accuchek bG and Glucoscan 2000 statistically are the most accurate and precise HMBGs.  相似文献   
87.
Gastric acid prevents bacterial colonization of the stomach and suppression of its secretion might predispose to Clostridium difficile (CD) diarrhoea. We retrospectively studied elderly patients admitted to medical wards of an acute hospital to determine whether the incidence of CD diarrhoea was greater among those previously treated with gastric acid suppressants. From records of stool CD toxin tests undertaken in 1995 and 1996, we found 126 cases with positive results, and selected 126 controls with negative results. Information about pre-morbid illness, predisposing factors for CD and medication received in the preceding 16 weeks was obtained from case-notes. A greater number of CD positive cases had received antibiotics such as Cefuroxime, ciprofloxacin or macrolides with or without metronidazole, were more severely disabled, required assistance for feeding, or had hypoalbuminaemia before the onset of diarrhoea. A greater number of controls had received lactulose, suggesting either that its laxative effect resembled CD infection prompting frequent stool tests, or that it offered protection against CD in this group. Both groups were similar for the use of proton-pump inhibitors or H2-receptor antagonists, suggesting that susceptible elderly patients are not more likely to develop CD diarrhoea after receiving gastric acid suppression therapy.  相似文献   
88.
Summary. The present study examined fasting serum insulin levels in relation to body composition and dietary intake during the initial 4 weeks of a 12-week physical training programme in 26 previously sedentary men. Fasting serum insulin concentrations decreased markedly during the first 4 weeks of training and remained at these reduced levels for the rest of the study. The early fall in serum insulin concentration was significantly correlated with the concomitant decrease in body fat, the increase in lean body weight and the age of the subjects. Body weight and reported dietary intake on the other hand, did not change significantly over this period. These results indicate that the decrease in fasting serum insulin in previously sedentary men with physical training is associated with the concomitant changes in body composition. Increased muscle tissue in particular may contribute to this training-induced decrease in serum insulin.  相似文献   
89.
This study assesses the feasibility of hyperpolarized 3-Helium MRI in children with cystic fibrosis (CF) and correlates the findings with standard clinical parameters based on chest radiograph (CXR) and pulmonary function tests (PFT). An uncontrolled, observational study in eighteen children with cystic fibrosis aged 5 – 17 years (median 12.1 years), with different severity of disease was carried out. All subjects underwent routine clinical assessment including PFT and standard auxology; CXR was obtained and Shwachman and Chrispin-Norman scores calculated. Hyperpolarized 3-He magnetic resonance imaging (MRI) was carried out using a spin-exchange polarizer and a whole body 1.5 T scanner. Ventilation distribution images were obtained during a 21-second breath-hold and scored according to previously defined criteria. Spearman’s non-parametric correlations test was performed to assess for statistical significance at the p<0.05 level. The children tolerated the procedure well. No desaturation events were observed during 3-He MRI. A significant, albeit moderate, correlation was found between MRI score and FEV1% predicted (r=−0.41; p=0.047) and FVC% predicted (r=−0.42; p=0.04), while there were trends of correlations between Shwachman score and MRI score (r=−0.38; p=0.06) and Shwachman score and FEV1% predicted (r=0.39; p=0.055). The feasibility of hyperpolarized 3-He MRI in children with CF was demonstrated. MRI appears to be able to demonstrate functional lung changes, although correlations with routine clinical tests are only moderate to poor. This non-ionising radiation technique could be useful for monitoring lung disease and assessing therapy in this patient population.  相似文献   
90.
BACKGROUND: Anesthesiologists and anesthesia residents are expected to acquire and maintain skills to manage a wide range of acute intraoperative anesthetic events. The purpose of this study was to determine whether an inventory of simulated intraoperative scenarios provided a reliable and valid measure of anesthesia residents' and anesthesiologists' skill. METHODS: Twelve simulated acute intraoperative scenarios were designed to assess the performance of 64 residents and 35 anesthesiologists. The participants were divided into four groups based on their training and experience. There were 31 new CA-1, 12 advanced CA-1, and 22 CA-2/CA-3 residents as well as a group of 35 experienced anesthesiologists who participated in the assessment. Each participant managed a set of simulated events. The advanced CA-1 residents, CA-2/CA-3 residents, and 35 anesthesiologists managed 8 of 12 intraoperative simulation exercises. The 31 CA-1 residents each managed 3 intraoperative scenarios. RESULTS: The new CA-1 residents received lower scores on the simulated intraoperative events than the other groups of participants. The advanced CA-1 residents, CA-2/CA-3 residents, and anesthesiologists performed similarly on the overall assessment. There was a wide range of scores obtained by individuals in each group. A number of the exercises were difficult for the majority of participants to recognize and treat, but most events effectively discriminated among participants who achieved higher and lower overall scores. CONCLUSION: This simulation-based assessment provided a valid method to distinguish the skills of more experienced anesthesia residents and anesthesiologists from residents in early training. The overall score provided a reliable measure of a participant's ability to recognize and manage simulated acute intraoperative events. Additional studies are needed to determine whether these simulation-based assessments are valid measures of clinical performance.  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