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   290篇
  免费   8篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   7篇
妇产科学   8篇
基础医学   30篇
口腔科学   4篇
临床医学   13篇
内科学   102篇
皮肤病学   1篇
神经病学   11篇
特种医学   19篇
外科学   26篇
综合类   1篇
预防医学   25篇
药学   46篇
肿瘤学   4篇
  2022年   7篇
  2021年   8篇
  2020年   4篇
  2019年   3篇
  2018年   4篇
  2017年   4篇
  2016年   4篇
  2015年   3篇
  2014年   4篇
  2013年   12篇
  2012年   10篇
  2011年   13篇
  2010年   6篇
  2009年   8篇
  2008年   26篇
  2007年   16篇
  2006年   21篇
  2005年   28篇
  2004年   31篇
  2003年   29篇
  2002年   25篇
  1999年   4篇
  1997年   1篇
  1996年   1篇
  1995年   4篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1986年   2篇
  1985年   4篇
  1979年   2篇
  1975年   2篇
  1974年   1篇
  1972年   3篇
  1970年   1篇
  1968年   1篇
  1957年   1篇
排序方式: 共有299条查询结果,搜索用时 15 毫秒
1.
The aim of the study was to establish the influence of short-time omeprazole administration on liver function and morphology. Omeprazole was administered intraperitoneally, twice daily, for 3 days to male Wistar rats in two doses: 0.571 mg/kg and 5.71 mg/kg. Control animals were treated with physiological saline. Half of the animals were sacrificed 12 hours after the last injection. The remaining rats were raised for another 6 weeks, without any xenobiotics, and sacrificed on the 47th day of the experiment. The activity of free and bound fractions of hepatic acid phosphatase, beta-galactosidase, beta-N-acetyl-glucosaminidase, cathepsin B, D and L, lipase, and sulphatase were determined spectrophotometrically in homogenates of the liver. The liver sections were examined by light microscopy with hematoxylin-eosin, azan, and periodic acid-Schiff stains. Marginally significant (p < 0.1) differences in activity of free sulphatase fraction, and free and bound fractions of beta-galactosidase were found in animals exposed to the higher dose of omeprazole and sacrificed 12 hours after the last injection. Enzymatic profiles were normalised during the next 6 weeks. Histological evaluation revealed small degenerative and adaptive changes in all examined groups. It could be concluded that observed differences of hepatic lysosomal enzyme activities were the result of accompanied chemical-induced peritonitis as previously reported, and not a direct drug-toxic effect.  相似文献   
2.
3.
Differential scanning calorimetry, dynamical mechanical, and spin probe measurements were conducted to study relaxation and soft-segment crystallization phenomena in block copoly(ether-ester) elastomers obtained through transesterification and melt polycondensation of dimethyl terephthalate, 1,4-butanediol and poly(ethylene oxide). The elastomers investigated differed both in molecular weight of the poly(ethylene oxide) used as well as in their ratio of hard to soft segments. It was found that a crystallization process of the soft-segment phase does not occur for oligoethers with a molecular weight lower than 1000. The spin probe method can be used to monitor the melting process and additionally it supplies information on the relaxation processes taking place in the amorphous part of the soft phase. Some data on the crystallization of the rigid phase are also given.  相似文献   
4.
BACKGROUND AND PURPOSE: Calculation of the effective dose and proposal of a dose specification method for the electron beams. PATIENTS AND METHODS: In a homogenous water phantom the 3D dose distributions for electron beams of energy 6, 9, 12, 15, 18 and 21 MeV and beam size 10x10 cm were calculated. For a volume encompassed with 80, 85 and 90% isodose, the mean dose and the SD were calculated for each energy. Using the Brahme's formulae, the effective dose was calculated. RESULTS: The larger the minimum dose (value of the encompassing isodose), the larger the mean dose and the smaller the SD. The mean doses and SD to the volume encompassed with 80, 85 and 90% are in the range of 91-94%, and 5.1-6.2%, 93-96% and 4.2-4.6%, 94-96% and 3.0-3.2%, respectively. Thus the effective dose for the volume encompassed with 80, 85 and 90% are about 90, 93 and 95%, respectively. CONCLUSION: Taking into account the requirements regarding dose uniformity within the PTV and the sparing effect for normal tissue situated under the PTV, we propose to keep the 85% isodose as a minimum one and to prescribe the dose to the 90% isodose. The present method may be applied for single electron beams and typical cases.  相似文献   
5.
Polyunsaturated fatty acids of the omega-3 series, especially very long chain – eicosapenta- and docosahexaenoic acid (EPA, DHA) – exert a strongly desirable influence on health. However, their intake with the western-style diet is usually too low which favours development of many diseases (CVD, cancers, allergies, etc.). Nowadays elevation of EPA and DHA intake is commonly recommended, but almost the only dietary source of them is seafoods, especially fish. A new way to increase the intake of long-chain omega-3 without radical changes of eating patterns is enrichment of regularly consumed foods with unhydrogenated fish oil. The aim of this study was to establish sensory and nutritionally acceptable enrichment level of low-calorie spreadable fats (soft margarine and mix of butter and vegetable oil) with EPA and DHA by addition of fish oil preparations (ROPUFA – 30% EPA, DHA and MARITEX – 10%), and evaluation of the stability of enriched spreads during storage (sensory and chemical). It was shown that tested spreadable fats might be enriched up to 1% EPA, DHA (i.e. 3% ROPUFA, 8% MARITEX), and that this had no significant influence on sensory acceptability. Both used fish oils which exerted similar influence on the quality of fats. An enriched mix of butter and vegetable oil and margarine may be stored up to 3 and 6 weeks respectively without significant decrease of quality. Peroxide value and acid numbers were not much affected by enrichment and storage. Daily portion (25–30 g/day) of spreadable fats enriched on the level established in the study may provide 0.2–0.3 g EPA, DHA, significantly increasing the amount of long-chain omega-3 in the diet above those eaten normally.  相似文献   
6.
7.
A case of a 51 year old patient with a history of myocardial infarction (MI) and recurrent ventricular tachycardia (VT) is presented. Three months after MI the patient underwent coronary angioplasty and one year later received prophylactic implantable cardioverter-defibrillator (ICD) due to complex ventricular arrhythmias, detected on Holter ECG monitoring, and depressed left ventricular ejection fraction. Later on the patient started to experience palpitations and ICD shocks during physical activity (cycling). Interrogation of the ICD memory showed appropriate shocks due to slow (160 betas/min) VT. The device was reprogrammed and new antitachycardia pacing (ATP) algorithms were enabled, however, it occurred proarrhythmic due to the ATP-induced acceleration of VT rate. Finally, in April 2005 he received 37 appropriate ICD shocks during a few hours. The patient was selected for RF ablation and underwent successful procedure with the use of the electro-anatomical CARTO mapping system.  相似文献   
8.
OBJECTIVES: The goal of this study was to describe the mapping and ablation of polymorphic ventricular tachycardia (VT) after myocardial infarction (MI). BACKGROUND: The initiating mechanisms of polymorphic VT after MI have not been reported. METHODS: Five patients (four males; age 61 +/- 7 years) with recurrent episodes of polymorphic VT after anterior MI (left ventricular ejection fraction 32 +/- 7%) despite revascularization and antiarrhythmic drugs were studied. All patients demonstrated frequent ventricular premature beats (PBs) initiating polymorphic VT. Pace mapping and activation mapping were used to identify the earliest site of PB activity. The presence of a Purkinje potential preceding PB defined its origin from the Purkinje network. Electroanatomic voltage mapping was performed to delineate the extent of MI. RESULTS: The PBs were observed in all cases to arise from the Purkinje arborization in the MI border zone. These PBs were right bundle-branch block in all five patients, with morphologic variations in the limb leads in four; one also had a left bundle-branch block morphology. The coupling interval of the PB to the preceding QRS complex demonstrated significant variations (320 to 600 ms). During PB, the Purkinje potential at the same site preceded the QRS complex by 20 to 160 ms and was associated with different morphologies. Repetitive Purkinje activity was documented during polymorphic VT. Splitting of Purkinje activity and Purkinje to muscle conduction block were also observed. Ablation at these sites eliminated all PBs. At 16 +/- 5 months follow-up using defibrillator memory interrogation, no patient has had recurrence of arrhythmia. CONCLUSIONS: The Purkinje arborization along the border-zone of scar has an important role in the mechanism of polymorphic VT in patients after MI. Ablation of the local Purkinje network allows suppression of polymorphic VT.  相似文献   
9.
Patients with chronic pain (CP) and substance use disorder (SUD) are complex, not yet adequately described, and in need of comprehensive treatments that address both diseases concurrently. Our objectives were to (a) describe a cohort of CP patients who failed traditional treatment (mainly opioids) – then developed opioid use disorder (OUD) and other SUDs and (b) evaluate a comprehensive inpatient treatment program for these patients. Patients were enrolled in an inpatient CP program. Treatment consisted of medical detoxification, group process/education, external and internal qigong, osteopathic manual medicine, and qigong-based mindfulness. Patients also received 20 h per week of 12-step recovery-based SUD treatment. Patients were evaluated at the beginning of treatment (first assessment, day 1–5 range) and at days 30 and 45. Assessments were: Beck Depression Inventory-II, Brief Pain Inventory, West Haven-Yale Multidimensional Pain Inventory (patient section), and McGill Pain Questionnaire. The Global Impression of Change Scale was administered at day 45. A mixed model analysis was used to evaluate treatment progress. Demographic data revealed an older cohort with OUD, other SUDs, and multiple pain diagnoses who failed traditional treatment. Questionnaire evaluations were consistent and similar across all of the above measures: patients’ scores showed marked, statistically significant improvements in depression, pain, and quality of life ratings. The most substantial improvements occurred between the first and second assessments. The findings are sufficiently encouraging to warrant further evaluation of the protocol and to plan comparative studies.  相似文献   
10.
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