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   7482篇
  免费   271篇
  国内免费   49篇
耳鼻咽喉   255篇
儿科学   295篇
妇产科学   359篇
基础医学   449篇
口腔科学   407篇
临床医学   622篇
内科学   1673篇
皮肤病学   71篇
神经病学   455篇
特种医学   390篇
外科学   1639篇
综合类   112篇
预防医学   178篇
眼科学   265篇
药学   243篇
中国医学   9篇
肿瘤学   380篇
  2024年   3篇
  2023年   51篇
  2022年   78篇
  2021年   192篇
  2020年   119篇
  2019年   128篇
  2018年   189篇
  2017年   160篇
  2016年   252篇
  2015年   268篇
  2014年   336篇
  2013年   411篇
  2012年   556篇
  2011年   505篇
  2010年   306篇
  2009年   273篇
  2008年   504篇
  2007年   632篇
  2006年   564篇
  2005年   552篇
  2004年   521篇
  2003年   354篇
  2002年   374篇
  2001年   105篇
  2000年   60篇
  1999年   63篇
  1998年   33篇
  1997年   24篇
  1996年   22篇
  1995年   16篇
  1994年   13篇
  1993年   7篇
  1992年   16篇
  1991年   16篇
  1990年   3篇
  1989年   7篇
  1988年   8篇
  1987年   11篇
  1985年   9篇
  1984年   5篇
  1983年   4篇
  1981年   4篇
  1979年   4篇
  1972年   5篇
  1970年   2篇
  1969年   4篇
  1968年   2篇
  1967年   2篇
  1966年   4篇
  1955年   2篇
排序方式: 共有7802条查询结果,搜索用时 15 毫秒
121.
122.
123.

PURPOSE

We aimed to investigate the effectiveness and complications of transthoracic CT-guided biopsy techniques.

METHODS

A total of 94 CT-guided percutaneous transthoracic biopsy procedures performed in 85 patients were retrospectively evaluated. Core biopsy technique was used in 87 procedures and transthoracic fine-needle aspiration biopsy was used in seven procedures.

RESULTS

Diagnostic results were achieved in 79 of 94 biopsy procedures. Pathology results were malignant in 54 patients, suspicious for malignancy in three patients, benign in five patients, and benign nonspecific in 17 patients. Specific diagnoses were obtained in 59 patients (62.8%) using core biopsy, but no specific diagnosis could be reached with transthoracic fine-needle aspiration biopsy. Complications included pneumothorax in 27 patients (28.7%) and parenchymal hemorrhage during and after the procedure in eight patients (8.5%).

CONCLUSIONS

CT-guided percutaneous transthoracic needle biopsy is a highly accurate procedure for histopathological diagnosis of thoracic masses. In addition, percutaneous transthoracic biopsy has an acceptably low complication rate and it reduces the need for more invasive surgical procedures.Since the beginning of the 21st century, lung cancer has been cited as one of the most common causes of death (1). World Health Organization declared lung cancer as the first leading cause of death in men and second in women, among all types of cancers (2).Percutaneous transthoracic biopsies are performed either using fine-needle aspiration biopsy (transthoracic fine-needle aspiration biopsy, TTFNAB) method or using the incisional or core biopsy method. Incisional biopsy and core biopsy are used to obtain a part of tissue from the lesion for histological diagnosis. On the other hand, TTFNAB is used to obtain aspiration material, which is used for cytological examination and lesion diagnosis (3, 4).Indications of transthoracic needle biopsy include solitary and multiple pulmonary nodules, mass lesions, persistent focal infiltration, consolidation, presence of cavities and abscesses, pleural lesions, and mediastinal and hilar mass diagnosis (3, 5).The aim of this study was to investigate the technique, suitability, and complications in CT-guided transthoracic biopsy of lung masses.  相似文献   
124.
ObjectiveThe aim of the present study was to determine the prevalence and reporting rate of incidental findings (IF) in adult outpatients undergoing lumbar magnetic resonance imaging (MRI).ResultsA total of 253 IFs were found in 241 patients (18.8% of 1278). Among these, clinically significant IFs (n = 34) included: 2 renal masses (0.15%), 2 aortic aneurysms (0.15%), 2 cases of hydronephrosis (0.15%), 11 adrenal masses (0.86%), 7 lymphadenopathies (0.55%), 6 cases of endometrial or cervical thickening (0.47%), 1 liver hemangioma (0.08%), 1 pelvic fluid (0.08%) and 2 ovarian dermoid cysts (0.15%). Overall, 28% (71/253) of IFs were included in the clinical reports, while clinically significant findings were reported in 41% (14/34) of cases.ConclusionExtraspinal IFs are commonly detected during a routine lumbar MRI, and many of these findings are not clinically significant. However, IFs including clinically important findings are occasionally omitted from formal radiological reports.  相似文献   
125.
The aim of this study is to investigate postoperative complications, mortality rates, and to determine the factors affecting mortality on the patients receiving warfarin therapy preoperatively, as well as comparing the results obtained from emergency and elective surgeries. Surgical outcomes of 61 patients on long-term oral anticoagulation with warfarin who underwent surgery in our center were retrospectively reviewed over an 8-year period. Thirty-three (54.1%) patients were female, with a mean age of 53 years. Mitral valve replacement (62.3%) was the most frequent indication for chronic anticoagulation therapy. Twelve out of 61 (19.2%) patients underwent emergency surgery; 59 (96.7%) operations were classified as major surgery. We did not observe any thromboembolic events on patients receiving our bridging therapy protocol. Cardiopulmonary dysfunction (CPD; 19.7%) and hemorrhage (16.4%) were the most encountered postoperative complications. Presence of CPD, bleeding, endocarditis, and mortality were statistically significant for emergency surgeries when compared with the results obtained from elective surgeries. There were 5 (8.2%) deaths observed during follow-up. It was found that advanced age, prolonged duration of operations, and presence of CPD had a statistically significant effect on mortality (P < 0.05). The patients receiving oral anticoagulant had high postoperative complication and mortality rates. This case was more evident in emergency surgeries. It is recommendable that as mortality is more apparent in the patients who undergo emergency surgeries—being older, having long duration of operations as well as CPD. Therefore during the postoperative follow-up process, the patients should be closely monitored.Key words: Emergency, Postoperative complications, Morbidity, Mortality, WarfarinThromboembolism is a major global health concern contributing to more than 0.5 million deaths in Europe and up to 300,000 deaths in the United States each year.1 Versatile arrays of anticoagulant and/or anti-aggregant agents are available. They are used to treat and prevent thrombosis occurring as a result of venous stasis, valvular heart disease, prosthetic valves, atrial fibrillation, or myocardial infarction. After using these medications, patients who require elective or emergency surgery represent a specific population; moreover, they are prone to developing either excessive bleeding or thrombosis.The annual incidence of major bleeding as a result of oral anticoagulant (OAC) use is reported between 2 and 5%.2 Patients on OAC may require elective or sometimes emergency surgical or invasive procedures. There is no consensus on standard protocol to follow for those who require perioperative management.3In the current literature, there are limited numbers of studies regarding the discussions about the operations in general surgery patient population receiving warfarin treatments. In this retrospective study, our aim was to document the complications and outcomes of general surgical procedures implemented on patients receiving warfarin. Along with the comparison of the emergency and elective surgeries performed, we also aimed to determine the factors affecting mortality.  相似文献   
126.
127.
ObjectiveAltered serum S100B protein levels have been shown in several psychiatric disorders. Our aim was to investigate whether plasma S100B is different in patients with panic disorder (PD) when compared with controls. Our second aim was to investigate whether treatment with SSRIs have an effect on S100B levels in patients with PD.MethodsThe sample included 32 patients diagnosed with PD (21 women, 11 men) per DSM-IV criteria and 21 healthy controls (11 women, 10 men). S100B levels were measured with BioVendor Human S100B ELISA (Enzyme Linked Immunosorbent Assay) kit.Results14 patients were not on drug treatment (43.8%) while 18 patients were taking various SSRIs. Median S100B value was 151.7 pg/mL (minimum-maximum: 120.4-164.7 pg/mL) in the control group, 147.4 pg/mL (minimum-maximum: 138.8-154.1 pg/mL) in the drug free group and 153.0 pg/mL (minimum-maximum: 137.9-164.7 pg/mL) in the treatment group. Kruskal-Wallis analysis showed a significant diffrerence among the three groups (z=9.9, df=2, p=0.007). Follow up Mann-Whitney-U tests indicated that while the control and the patients with treatment were not significantly different (z=-0.05, p=0.96), there were significant differences between the control group and untreated patients (z=-2.6, p=0.009) and treated and untreated patients (z=-3.0, p=0.003).ConclusionOur results suggested that, serum S100B protein level might be decreased in untreated PD patients and that patients who were treated with SSRIs had similar S100B level to healthy controls.  相似文献   
128.
Increased deposition of the extracellular matrix components, particularly collagen, is a central phenomenon in liver fibrosis. Stellate cells, the central mediators in the pathogenesis of fibrosis are activated by free radicals, and synthesize collagen. Melatonin is a potent physiological scavenger of hydroxyl radicals. Melatonin has also been shown to be involved in the inhibitory regulation of collagen content in tissues. At present, no effective treatment of liver fibrosis is available for clinical use. We aimed to test the effects of melatonin on dimethylnitrosamine (DMN)-induced liver damage in rats. Wistar albino rats were injected with DMN intraperitoneally. Following a single dose of 40 mg/kg DMN, either saline (DMN) or 100 mg/kg daily melatonin was administered for 14 days. In other rats, physiologic saline or melatonin were injected for 14 days, following a single injection of saline as control. Hepatic fibrotic changes were evaluated biochemically by measuring tissue hydroxyproline levels and histopathogical examination. Malondialdehyde (MDA), an end product of lipid peroxidation, and glutathione (GSH) and superoxide dismutase (SOD) levels were evaluated in blood and tissue homogenates. DMN caused hepatic fibrotic changes, whereas melatonin suppressed these changes in five of 14 rats (P < 0.05). DMN administration resulted in increased hydroxyproline and MDA levels, and decreased GSH and SOD levels, whereas melatonin reversed these effects. When melatonin was administered alone, no significant changes in biochemical parameters were noted. In conclusion, the present study suggests that melatonin functions as a potent fibrosuppressant and antioxidant, and may be a therapeutic choice.  相似文献   
129.
We evaluated the short-term results of percutaneous excimer laser angioplasty in acute myocardial infarction. Of the 18 patients studied, 2 were female and 16 male with a mean age of 56.6 +/- 12.1 years. Thrombolysis in myocardial infarction grades 0, 1, and 2 flow was observed in 10, 5, and 3 cases, respectively, prior to the procedure. The degree of stenosis was 97.9% +/- 5.1%. The lesion was crossed with a laser catheter in all cases, using a mean number of 808 +/- 384 laser pulses. Type C dissection developed in only 1 case (6%). Except for this case, distal flow was grade 3 in all the patients. Following the procedure, ST segment resolution exceeding 70% was achieved in 14 cases (78%) within the first 90 minutes. The success rate of laser ablation was 94% (17 patients). Stent implantation was performed in all the cases. In conclusion, laser angioplasty is an effective and reliable treatment for acute myocardial infarction.  相似文献   
130.
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