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   976篇
  免费   70篇
耳鼻咽喉   17篇
儿科学   48篇
妇产科学   16篇
基础医学   105篇
口腔科学   24篇
临床医学   106篇
内科学   172篇
皮肤病学   22篇
神经病学   41篇
特种医学   44篇
外科学   154篇
综合类   2篇
一般理论   1篇
预防医学   78篇
眼科学   11篇
药学   121篇
肿瘤学   84篇
  2023年   8篇
  2022年   14篇
  2021年   24篇
  2020年   18篇
  2019年   22篇
  2018年   30篇
  2017年   29篇
  2016年   24篇
  2015年   15篇
  2014年   28篇
  2013年   40篇
  2012年   51篇
  2011年   65篇
  2010年   41篇
  2009年   38篇
  2008年   48篇
  2007年   62篇
  2006年   43篇
  2005年   57篇
  2004年   48篇
  2003年   33篇
  2002年   25篇
  2001年   24篇
  2000年   29篇
  1999年   26篇
  1998年   10篇
  1996年   9篇
  1995年   6篇
  1994年   7篇
  1993年   5篇
  1992年   23篇
  1991年   23篇
  1990年   15篇
  1989年   16篇
  1988年   10篇
  1987年   6篇
  1986年   12篇
  1985年   13篇
  1984年   4篇
  1983年   10篇
  1982年   2篇
  1981年   3篇
  1979年   7篇
  1977年   2篇
  1974年   3篇
  1972年   1篇
  1970年   4篇
  1969年   2篇
  1968年   4篇
  1965年   2篇
排序方式: 共有1046条查询结果,搜索用时 15 毫秒
91.
AIM: Visceral hypersensitivity characterizes the irritable bowel syndrome (IBS). We evaluated the effect of a cold pressor test (CPT)--hand immersion in ice water for 1 minute, which evokes a sympathetic response--on rectosigmoid motility in patients with IBS and normal volunteers. Since many Indian patients with IBS complain of worsening of symptoms following a spicy meal, we also evaluated whether a high-chilli diet affects symptoms or changes rectosigmoid motility. METHODS: Fifteen men with IBS and 13 normal volunteers (all men) were studied. Baseline rectosigmoid manometry was done for 2 h, i.e., 1 h pre- and 1 h post-CPT. The subjects were then kept in hospital on a regular diet (approximately 5 g chilli daily) for 3 days, following which symptoms were reassessed and manometry repeated for 1 h. This was followed by a high-chilli diet (approximately 15 g/day) for 3 days, after which symptoms were reassessed and manometry repeated for 1 h. RESULTS: There was no difference in the baseline study in the pre-CPT period between patients and control subjects. CPT did not change rectosigmoid motility in either group. IBS patients had varied effect on symptoms but no change in rectosigmoid motility after the high-chilli diet. In the normal volunteers, there was increased activity in the low rectum after the high-chilli diet. CONCLUSIONS: Cold pressor test does not affect rectosigmoid motility in patients with IBS or normal subjects. A high-chilli diet has varied effect on symptoms in patients with IBS and does not affect rectosigmoid motility.  相似文献   
92.
93.

Background

Despite the excellent outcomes associated with primary total hip arthroplasty (THA), implant failure and revision continues to burden the healthcare system. THA failure has evolved and displays variability throughout the literature. In order to understand how THAs are failing and how to reduce this burden, it is essential to assess modes of implant failure on a large scale. Thus, we report: (1) etiologies for revision THA; (2) frequencies of revision THA procedures; (3) patient demographics, payor type, and US Census region of revision THA patients; and (4) the length of stay and total costs based on the type of revision THA procedure.

Methods

We queried the National Inpatient Sample database for all revision THA procedures performed between January 1, 2009 and December 31, 2013. This yielded 258,461 revision THAs. Patients specific demographics were identified in order to determine the prevalence of revision procedure performed.

Results

Dislocation was the main indication for revision THA (17.3%), followed by mechanical loosening (16.8%). All-component revision was the most common procedure performed (41.8%). Patients were most commonly white (77.4%), aged 75 years and older (31.6%), and resided in the South US Census region (37.0%). The average length of stay for all procedures was 5.29 days. The mean total charge for revision THA procedures was $77,851.24.

Conclusion

Dislocation and mechanical loosening is the predominant indication for revision THA in the United States. With the frequency of revision THAs projected to double in the next decade, orthopedists must take steps to mitigate this potentially devastating complication.  相似文献   
94.
Blood platelet receptors are widely used as peripheral models of central nervous system receptors, particularly in attempts to understand the biological basis of a number of neurological and psychiatric disorders. It is important to differentiate factors other than the primary disease process which may influence platelet receptors. One such potential factor is the menstrual cycle. In this study we have determined platelet high-affinity alpha 2-adrenoceptor binding, using the agonist ligand 3H-UK-14,304 and platelet aggregatory responses to adrenaline in 14 healthy young women, sampled on four occasions at weekly intervals. Our results indicate that, within the limits of individual variation, neither the KD or Bmax of high-affinity 3H-UK-14,304 binding or the aggregatory responses to adrenaline differed significantly between various stages of the menstrual cycle.  相似文献   
95.
Thirty-two patients with suspected coronary artery disease were studied by single photon emission computed tomography (SPECT) imaging with oblique reconstructions of the myocardium following the intravenous administration of technetium-99m methoxy isobutyl isonitrile at peak exercise. All patients also underwent three-vessel coronary angiography. The SPECT technique produced very detailed images allowing easy delineation of localized myocardial defects. Segmental myocardial uptake defects were compared with diseased vessels as shown at angiography. A good correlation was shown between right coronary artery (RCA) disease and mid and proximal inferior segments and between left circumflex (LCx) artery disease and mid and proximal lateral segments, allowing accurate localization of a defect to one of these two vessels' territories. Sensitivity and specificity of detection of disease of the RCA and LCx artery were high. Defects associated with a lesion of the left anterior descending vessel were more variable.  相似文献   
96.
97.
Ertapenem is a Group 1 carbapenem that was licensed in the USA in November 2001 and in Europe in April 2002. Its safety profile has been assessed in 240 healthy volunteers participating in 12 clinical pharmacology studies and in 2046 patients enrolled in five Phase IIa and eight Phase IIb/III clinical trials. The most common drug-related adverse events (AEs) reported in trials comparing ertapenem and piperacillin-tazobactam and in trials comparing ertapenem and ceftriaxone were: diarrhoea (ertapenem versus piperacillin-tazobactam 5.0% versus 7.0%; ertapenem versus ceftriaxone 5.6% versus 5.9%); infused vein complications (ertapenem versus piperacillin-tazobactam 4.5% versus 7.9%; ertapenem versus ceftriaxone 3.2% versus 4.6%); nausea (ertapenem versus piperacillin-tazobactam 2.5% versus 3.4%; ertapenem versus ceftriaxone 3.4% versus 3.3%); and elevations in alanine aminotransferase levels (ertapenem versus piperacillin-tazobactam 8.8% versus 7.3%; ertapenem versus ceftriaxone 8.3% versus 6.9%). Most ertapenem-related AEs were reported as mild-to-moderate in intensity. Ertapenem was not associated with prolongation of the QTc interval. Local reactions of moderate-to-severe intensity at the infusion site were infrequent and occurred with similar frequency in the ertapenem and comparator treatment groups. No overall differences in safety were observed between elderly (aged > or = 65 years and > or = 75 years) and younger patients. Ertapenem, 1 g once a day given by intravenous infusion or intramuscular injection, was generally well tolerated and had overall safety and tolerability profiles similar to those of piperacillin-tazobactam and ceftriaxone.  相似文献   
98.
1. Nifedipine ameliorates cyclosporin A-induced renal impairment in surgically intact (two-kidney) rats. This study investigates the effect of nifedipine on cyclosporin A nephrotoxicity in spontaneously hypertensive rats after either uninephrectomy or uninephrectomy with contralateral renal denervation. 2. Fourteen days after uninephrectomy pair-fed rats were injected for 14 days with cyclosporin A (25 mg/kg body weight) via the subcutaneous route and with nifedipine (0.1 mg/kg body weight) via the intraperitoneal route. Renal and systemic haemodynamics were measured in conscious unrestrained rats. 3. Whole-blood levels of cyclosporin A did not differ between groups (overall 352 +/- 22 ng/ml, means +/- SEM). After uninephrectomy, cyclosporin A decreased the glomerular filtration rate (olive oil versus cyclosporin A: 0.96 +/- 0.04 versus 0.70 +/- 0.06 ml min-1 100 g body weight, P less than 0.02) and effective renal plasma flow (1.94 +/- 0.10 versus 1.38 +/- 0.13, P less than 0.01), and increased renal vascular resistance [(20.2 +/- 1.8) x 10(4) versus (31.6 +/- 3.3) x 10(4) kPa l-1 s [(20.2 +/- 1.8) x 10(3) versus (31.6 +/- 3.3) x 10(3) dyn s cm-5], P less than 0.02] and mean arterial pressure (146.7 +/- 6.7 versus 167.3 +/- 2.9 mmHg, P less than 0.05). Neither renal denervation nor nifedipine prevented the reduction in glomerular filtration rate or effective renal plasma flow induced by cyclosporin A. 4. This study infers that the sympathetic nervous system does not play an active role in cyclosporin A nephrotoxicity and demonstrates that the concomitant administration of nifedipine to rats with reduced renal mass does not ameliorate cyclosporin A-induced renal impairment.  相似文献   
99.
Diarrhoea, the most common disease directly related to water, sanitation, and hygiene (WASH), still remains one of the most significant health problems among children under-five worldwide. In this reality, BRAC, the largest NGO in the world initiated a comprehensive WASH intervention in 50 upazilas (sub-districts) of Bangladesh in 2007 which was later scaled up to cover 150 upazilas in two subsequent phases. The intervention period of the programme was 2007–2011.The present study encompassed 30 upazilas of the first phase of intervention. The aim of the study was to investigate the effectiveness of this intervention on reduction of diarrhoea among under-five children, and to identify the factors associated with childhood diarrhoea. A repeated cross-sectional study design was followed, and a population-based survey was carried out on four occasions: baseline (2007), midline (2009), endline (2011), and post-endline (2015) among 4,775 households. This analysis considers only households having at least one under-five children.Absence of handwashing practice with soap after defecation and before eating food, unclean latrine condition, and unsafe disposal of child faeces were identified as significant risk factors associated with under-five diarrhoea from Log-binomial regression. The prevalence of under-five diarrhoea within the past 2 weeks of the survey declined from 13.7% at baseline to 3.6% at end-line (p < 0.001) in the WASH intervention area. However, the progress seemingly stalled after 2011, which may have occurred due to the lack of improvement in unsafe disposal of child faeces and unclean latrine condition after the intervention period.Study findings suggest that, to reduce the prevalence of childhood diarrhoea it is important to promote safe disposal of child faeces, maintaining cleanliness of latrines, and washing hand with soap at critical times, beyond merely increasing the sanitation coverage. Findings also underline the necessity of maintaining a small-scale monitoring component involving local community, such as a WatSan committee (a local committee comprising the user communities for supervising WASH related activities) for periodic monitoring at household level for a certain period after the program intervention works to make the behavioural change more sustainable and to keep the reduction rate of under-five diarrhoeal prevalence steady.  相似文献   
100.
Ertapenem is a new once-a-day parenteral carbapenem antimicrobial agent. The pharmacokinetics of unbound and total concentrations of ertapenem in plasma were investigated in elderly subjects and compared with historical data from young adults. In a single- and multiple-dose study, healthy elderly males and females (n = 14) 65 years old or older were given a 1-g intravenous (i.v.) dose once daily for 7 days. Plasma and urine samples collected for 24 h on days 1 and 7 following administration of the 1-g doses were analyzed by reversed-phase high-performance liquid chromatography. Areas under the concentration-time curve from 0 h to infinity (AUC(0- infinity )) for elderly females and males were similar following administration of 1-g single i.v. doses, and thus, the genders were pooled in subsequent analyses. Concentrations in plasma and the half-life of ertapenem were generally higher and longer, respectively, in elderly subjects than in young adults. The mean AUC(0- infinity ) of total ertapenem in the elderly was 39% higher than that in young subjects following administration of a 1-g dose. The differences were slightly greater for the mean AUC(0- infinity ) of unbound ertapenem (71%). The unbound fraction of ertapenem in elderly subjects ( approximately 5 to 11%) was generally greater than that in young adults ( approximately 5 to 8%). As in young adults, ertapenem did not accumulate upon multiple dosing in the elderly. The pharmacokinetics of ertapenem in elderly subjects, while slightly different from those in young adults, do not require a dosage adjustment for elderly patients.  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