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   515篇
  免费   11篇
耳鼻咽喉   5篇
儿科学   10篇
妇产科学   19篇
基础医学   57篇
口腔科学   4篇
临床医学   117篇
内科学   132篇
皮肤病学   27篇
神经病学   18篇
特种医学   2篇
外科学   54篇
一般理论   2篇
预防医学   32篇
眼科学   4篇
药学   37篇
肿瘤学   6篇
  2016年   3篇
  2015年   4篇
  2014年   4篇
  2013年   12篇
  2012年   3篇
  2011年   4篇
  2010年   12篇
  2009年   19篇
  2008年   8篇
  2007年   5篇
  2006年   8篇
  2003年   8篇
  2001年   5篇
  2000年   4篇
  1999年   14篇
  1998年   19篇
  1997年   37篇
  1996年   33篇
  1995年   24篇
  1994年   20篇
  1993年   17篇
  1992年   17篇
  1991年   19篇
  1990年   11篇
  1989年   14篇
  1988年   6篇
  1987年   19篇
  1986年   15篇
  1985年   7篇
  1984年   15篇
  1983年   12篇
  1982年   12篇
  1981年   8篇
  1980年   7篇
  1979年   10篇
  1978年   7篇
  1977年   6篇
  1976年   7篇
  1975年   5篇
  1974年   3篇
  1971年   5篇
  1970年   3篇
  1969年   7篇
  1965年   3篇
  1959年   2篇
  1957年   2篇
  1956年   3篇
  1955年   4篇
  1954年   5篇
  1949年   2篇
排序方式: 共有526条查询结果,搜索用时 15 毫秒
1.
We describe a case of 1:1 atrial flutter in a patient with coronary disease taking propafenone. In atrial flutter, the atrial rate is usually about 300 beciis/min with 2:1 AV conduction and a ventricular rate of 150 beats/min. Class IA antiarrhythmic drugs, especially quinidine and disopyramide, may cause 1:1 AV response because they reduce atrial rate and are vagolytic. However, propafenone is a Class IC agent and has no anticholinergic properties, and the occurrence of 1:1 AV conduction at a rate of about 250 beats/min is an important side, effect that, although uncommon, should be recognized.  相似文献   
2.
Postgraduate continuing education for community pharmacists in England has undergone a radical change since the establishment of the Centre for Pharmacy Postgraduate Education (CPPE) in 1992. The present study was undertaken to assess the impact of the introduction of the CPPE on levels of participation and attitudes towards continuing education. Comparisons are drawn with an analysis made in 1991. Results showed that 76.8 per cent of respondents had participated in CPPE-based continuing education, as either workshops or distance learning. This level of participation is far higher than that previously recorded. Those pharmacists who attended the workshops also tended to request distance learning packages, while a significant proportion of users of distance learning declined to attend workshops. Owners of community pharmacies were significantly more likely than managers to use computer assisted learning material. Attitudes concerning restraints against participation in continuing education focused on the value pharmacists place on their spare time and the absence of a postgraduate education allowance for community pharmacists.  相似文献   
3.
We examined records of sedations provided by the paediatric anaesthesiology staff for 455 children (ages 1 mo-17 yr) undergoing MRI or CT scans at our institution over a twelve-month period with regard to the monitoring of adverse events: excessive sedation, agitation, vomiting, hypoxaemia, and major airway compromise. One hundred-and-thirty-one patients (29%) received chloral hydrate; 324 patients (71%) received propofol. All patients were monitored with continuous noninvasive pulse oximetry and received supplemental oxygen via nasal cannulae. Of the patients who received chloral hydrate, 64 (49%) were over one year of age; of the patients who received propofol, 318 (98%) were one year of age or older. In the chloral hydrate group, 23 patients (19%) were deemed excessively sedated and four patients (3%) were agitated; no patients in the propofol group experienced any of the adverse outcomes reviewed. Furthermore, no patients in either group had significant airway compromise and none was admitted to the hospital as a result of the sedation.  相似文献   
4.
5.
Atrioventricular Conduction Variability. Introduction: Atrioventricular AV) conduction time varies on a beat-by-beat basis in response to the influences of cardiac efferent autonomic activity and rate-dependent electrical recovery processes. The goals of this study were to distinguish these effects on AV conduction time and to compare the variability in sinoatrial and AV nodal function. Methods and Results: The PR interval on the surface ECG served as an index of AV conduction time in this study of 14 adult human subjects undergoing a random interval breathing protocol. P and R waves were located by a template-matching algorithm. Spectral analysis allowed frequency-domain comparisons between PR and RR interval variability. Spectra of PR and RR intervals had similar power distributions, although the power of the RR interval spectra was much greater. Autonomic blockade with atropine plus propranolol reduced the power of both spectra. Standing significantly decreased the spectral power from 0.15 to 0.5 Hz for PR and RR spectra, and introduced a peak near 0.1 Hz in the mean PR and RR spectra, although the latter finding was significant only for the RR interval spectra. Propranolol had no significant effects on the PR and RR interval spectra. Linear regression analysis allowed quantification of the autonomic and recovery effects on AV conduction and showed which effect predominated. Simple linear regression confirmed in adults a previous finding in children that conduction time may be either positively or negatively correlated with cycle length. By multiple regression and transfer function analysis, the inverse relation seen in some subjects was attributed to the effect of recovery from the preceding cycle. With the preceding recovery period accounted for, the conduction time and cycle length of the current beat were positively correlated, presumably due to the parallel autonomic effects on the sinoatrial and AV nodes. The magnitude of the recovery effect predicted by the regression analysis was similar to published values. Conclusion: A noninvasive evaluation of the surface ECG can be used to compare variability in AV conduction time and cycle length and characterize the effects of autonomic efferent activity and rate-related recovery on AV nodal function.  相似文献   
6.
A survey was conducted to ascertain general medical practitioners' (GPs') attitudes to community pharmacists' use of patient medication records (PMRs) and to assess whether GPs envisage a role for family health service authorities (FHSAs) in maintaining records of patients' data. The survey questionnaire was sent by post to all 1,257 GPs in contract with Avon and Devon FHSAs. A total of 811 questionnaires was returned, an overall response rate of 64.5 per cent. A majority (59 per cent) of GPs considered that community pharmacists should keep patient medication records and there was strong support for pharmacists holding PMRs for the elderly and confused, and also for patients with diabetes, asthma, epilepsy, and those patients who had experienced major adverse drug reactions or allergies. Some GPs, however, remained unconvinced of the usefulness of a pharmacy PMR. Seventy four per cent of respondents considered that patients should keep their own medication records. In contrast, only 4 per cent were in agreement with patient medication data being stored by FHSAs. The community pharmacist's role in maintaining PMRs received less support from doctors in dispensing practices than from their non-dispensing counterparts. Some 80 per cent of respondents were in favour of pharmacists providing PMR system-generated patient information leaflets with dispensed medicines. Most GPs considered that such leaflets had a positive effect on patient compliance. Recently registered GPs were found to be more supportive than their older colleagues of community pharmacists recording patients' clinical conditions and providing information leaflets.  相似文献   
7.
We report an adult female with a rare giant choledochal cyst. The patient presented following a normal pregnancy with the classical triad of an abdominal mass associated with jaundice and right upper quadrant abdominal pain. The cyst was excised using an intramural technique and biliary reconstruction achieved with a Roux-en-Y hepaticojejunostomy. Our patient has remained well with no evidence of malignancy over a 12 year review period. The aetiology and current management of this condition are discussed.  相似文献   
8.
The most common cause of death in patients with colorectal cancer is metastatic liver disease. In order to identify patients at a high risk of developing hepatic secondaries from colorectal cancers, DNA content was measured in metastasizing colorectal primaries (Group I, n= 32) as well as in their subsequently resected liver secondaries and in sections of non-metastasizing colorectal cancers (Group II, n= 25). A modified interpretation system involving both a DNA index and percentage of cycling cells (those in S and G2 + M phases) was developed. DNA content was measured in paraffin-embedded sections by flow cytometry using internal controls (human peripheral blood mononuclear cells) and non-malignant tissue controls (19 patients with diverticular disease). In Group I there were significantly more tumours with both abnormal ploidy (aneuploid or abnormal tetraploid peak) and > 15% cycling cells compared with Group II (Chi-squared; P= 0.034). The combination of abnormal ploidy and > 15% cycling cells was superior to Dukes’ classification for identifying metastasizing tumours (Logistic Regression; P= 0.047). However, it was not possible to discriminate between the two groups using either DNA ploidy or the percentage of cycling cells alone. The metastasizing colorectal cancers exhibited similar DNA ploidy characteristics and had a similar percentage of cycling cells compared with their liver metastases. These results suggest that tumour DNA ploidy plus the percentage of cycling cells may predict the development of liver metastases and thus survival in patients with colorectal cancer.  相似文献   
9.
The responses of ex-smokers to an experimental cue exposure trial, and the effect of caffeine on these responses, were compared with those of a matched group of control subjects in a placebo controlled single-blind cross-over design. In contrast to placebo, caffeine protected the ex-smokers from a surge of anxiety and rise in blood pressure associated with exposure to smoking-related cues. Caffeine had no significant effects on the control group at this dose (equivalent to a single cup of strong coffee). The results are discussed with reference to Stewart's conditioned appetitive motivational model of addiction. It is suggested that further work may identify caffeine as an adjunct to smoking relapse prevention measures.  相似文献   
10.
Summary. The association of cardiolipin with polystyrene beads was studied using 31P-NMR and electron microscopy. In the presence and absence of fetal calf serum, cardiolipin appeared to bind to the polystyrene beads in lamellar phase as assessed by 31P-NMR imaging. Electron microscopic analysis revealed an even coating of phospholipid about the beads with extensive micelle binding. Cardiolipin-coated beads challenged with ACA-positive sera followed by immunogold indicated antibody bound to micelles associated with the bead. Studies conducted with ACA IgG purified from patient sera indicated that some ACA bound to CL beads in the absence of a source of ACA cofactor (i.e. gelatin-blocked beads), some ACA required β2-GPI for binding (i.e. no binding in the presence of β2-GPI-depleted plasma), whereas other ACA which showed negliglible binding with gelatin-blocked beads, showed enhanced binding in the presence of /?2-GPI-depleted plasma. The data indicate that: (1) cardiolipin binds to polystyrene beads in lamellar phase, (2) ACA bind to phospholipid micelles bound directly to the polystyrene beads, and (3) ACA differ between individuals displaying varying phospholipid and phospholipid/cofactor substrate specificities.  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