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   11356篇
  免费   688篇
  国内免费   73篇
耳鼻咽喉   163篇
儿科学   408篇
妇产科学   398篇
基础医学   1028篇
口腔科学   359篇
临床医学   967篇
内科学   2437篇
皮肤病学   193篇
神经病学   543篇
特种医学   396篇
外科学   2216篇
综合类   359篇
现状与发展   1篇
一般理论   12篇
预防医学   709篇
眼科学   258篇
药学   915篇
中国医学   75篇
肿瘤学   680篇
  2023年   119篇
  2022年   345篇
  2021年   537篇
  2020年   302篇
  2019年   382篇
  2018年   473篇
  2017年   276篇
  2016年   375篇
  2015年   382篇
  2014年   503篇
  2013年   652篇
  2012年   896篇
  2011年   856篇
  2010年   484篇
  2009年   376篇
  2008年   610篇
  2007年   666篇
  2006年   621篇
  2005年   541篇
  2004年   480篇
  2003年   400篇
  2002年   382篇
  2001年   127篇
  2000年   111篇
  1999年   101篇
  1998年   67篇
  1997年   53篇
  1996年   43篇
  1995年   36篇
  1994年   41篇
  1993年   27篇
  1992年   88篇
  1991年   52篇
  1990年   66篇
  1989年   58篇
  1988年   43篇
  1987年   47篇
  1986年   24篇
  1985年   41篇
  1984年   29篇
  1983年   37篇
  1982年   20篇
  1980年   19篇
  1979年   33篇
  1978年   20篇
  1977年   26篇
  1976年   18篇
  1974年   34篇
  1973年   32篇
  1972年   23篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
91.
PURPOSE: To prospectively assess ureteric obstructive uropathy using three-dimensional ultrasound (3D US) methods when the etiology of ureteral obstruction was proved difficult to evaluate with two-dimensional ultrasound (2D US) and plain radiography. METHODS: The study had the local Ethics Committee approval. All patients gave informed consent. 318 patients: 219 men and 99 women (including 16 pregnant women) were selected within a 3-year period for 3D US based on clinical presentation, two dimensional ultrasound (2D US) results and preliminary plain radiography except for pregnant women. 3D US was performed on all patients. 301 patients had further excretory urogram before intervention decisions. RESULTS: The study showed a high accuracy of detection of different levels of ureteric calcular obstruction; 99.1% in men and 96.7% in women. 3D XI technology proved more efficient in stone count (88.9%) than sectional planes and rendering method altogether (55.6%). The success rate of identifying obstructive uropathy due to inflammatory variants showed a perfect diagnostic value of 100%. Similar percentages could be obtained in cases secondary to neoplastic infiltration or permeation of the ureters. Cases compared with excretory urography revealed close correlation with 3D US and superiority of the latter when renal function physiologically altered in some cases of calcular obstructive uropathy. CONCLUSIONS: The 3D US methods in case of obstructive uropathy have proved to be useful as an easy, mobile and non-invasive diagnostic tool, improving 2D US diagnostic utility.  相似文献   
92.
Familial Mediterranean Fever (FMF) is an autosomal recessive disease characterized by periodic attacks of fever and polyserositis. The effects of the MEFV genotype differences on clinical picture and inflammatory activity have not been well documented. The aim of this study was to investigate levels of conventional inflammation markers, procalcitonin, interleukin levels, TNF-alpha, and C5a levels in patients with FMF who had different MEFV genotypes and compare them with those of healthy subjects. The study consisted of 41 patients with FMF (F/M: 23/18), and 31 healthy subjects (F/M: 18/13). Tests were performed during the attack-free period. White-blood cell count, CRP and IL-8 levels were higher in patients with FMF than in healthy subjects (p < 0.05) and also higher in M680I carriers than in the patients with M694V allele carriers. However, ESR, fibrinogen, procalcitonin, IL-6, C5a, TNF-alpha, and IgD levels were not significantly different between patients and healthy subjects (p > 0.05). Arthralgia or arthritis was significantly higher in M694V carriers than in non-M694V carriers (p < 0.05). It is concluded that the clinical features and inflammatory-cytokine activities were higher in patients with FMF during the attack-free period than in healthy subjects, and the different genotype might be related to different clinical pictures.  相似文献   
93.

OBJECTIVE

To asses the efficacy and safety of bidirectional synchronous twin‐pulse extracorporeal shock wave lithotripsy (ESWL) compared with standard ESWL.

PATIENTS AND METHODS

Between March 2003 and December 2006, 240 patients with a radio‐opaque single renal stone of ≤25 mm were randomized to treatment either by the Twinheads (TH) lithotripter (FMD, Lorton, Virginia, USA) or the Dornier Lithotripter S (DLS, Dornier MedTech Europe GmbH, Germering, Germany). Before and after ESWL, urinary N‐acetyl‐B‐glucosaminidase (NAG) levels were assessed and patients were evaluated with dynamic MRI. The efficacy and complications were compared, with success defined as no residual fragments.

RESULTS

For stones of >10 mm the rate for the failure of disintegration was 13.3% for the DLS vs 1.4% for the TH (P = 0.009). For stones of ≤10 mm the stone‐free rate was 74.4% for the TH vs 67.7% for the DLS (P = 0.6), while for stones of >10 mm it was 78.1% and 66.7%, respectively (P = 0.14). The median (range) number of sessions in both groups was 2 (1–5). After ESWL urinary NAG levels were increased significantly in both groups; in the TH group it declined below the level before ESWL after 2 days, while in the DLS group it remained high after 7 days. In the DLS group four patients developed subcapsular or parenchymal haematoma after ESWL, vs none in the TH group. There was loss of corticomedullary differentiation after ESWL in three patients in the DLS group and only one in the TH group. In the DLS group there was a statistically significantly decrease in bilateral renal perfusion after ESWL, but no changes in the TH group.

CONCLUSIONS

Synchronous twin‐pulse ESWL has clinical advantages over standard ESWL in terms of safety and efficacy.  相似文献   
94.
Anomalies of pulmonary veins are uncommon and vary widely in their anatomic spectrum and clinical presentation. A 20-year-old woman with complaints of effort-induced dyspnea and easy fatigability was diagnosed with a third left pulmonary vein with abnormal return and arteriovenous fistula accompanied by a secundum atrial septal defect (ASD). Complete surgical repair was performed by ASD closure with a pericardial patch and triple ligation of the left vertical vein and associated third pulmonary vein. The patient was discharged on the seventh postoperative day in good health. Her last control examination was performed in the second postoperative year, revealing normal echocardiographic findings with an excellent clinical course.  相似文献   
95.
BACKGROUND: Since the fibula is linked to the ankle as well as the knee joint, its importance for knee and ankle disabilities should be investigated. This study evaluates its movement during range of motion of the ankle. MATERIALS AND METHODS: An instrument, together with the experimental protocol, was devised to determine the relative motion of the fibula in reference to the tibia with motion of the ankle joint on 20 paired lower extremity cadaver specimens. RESULTS: It was demonstrated in all specimens that the fibula had a relative rotation around its longitudinal axis and mediolateral translation with reference to the tibia with ankle motion. The distal end of the fibula rotates more compared to the proximal end. The mediolateral translation of the proximal end of the fibula is rather close to that of the distal end. Although there was no consistent pattern for rotation, dorsiflexion caused lateral translation and plantarflexion caused medial displacement for most of the specimens. CONCLUSION: A novel, invasive but relatively simple test setup was devised. Movement of the fibula which is important for the kinematics and kinetics of the knee and ankle joints was evaluated by this new device. CLINICAL RELEVANCE: Evaluation of the fibula movement in normal lower extremities may lead to better understanding of its dynamic function which could have treatment implications for pathological conditions.  相似文献   
96.
AIM: Effects of off-pump CABG on LIMA-LAD anastomotic dimensions vs. on-pump CABG assessed by epicardial ultrasound imaging. MATERIAL AND METHODS: LIMA-LAD anastomoses were performed off-pump in 38 patients and on-pump in 12. Intra-operative imaging was by a GE Vivid 7 ultrasound scanner and i13L transducer. Length of the anastomosis (DA), LAD diameters at the toe (D1) and heel (D3) of the anastomosis, the reference downstream LAD (D2) were measured in diastole by two-dimensional imaging (B-mode). Relationships between these dimensions were compared between on- and off-pump patients. RESULTS: In off-pump patients, D3 dimension was smaller than D1 (p=0.004). Both D3 and D1 were smaller than D2 (p<0.01). Ratio D3/D2 was smaller than D1/D2 (p=0.009). In on-pump patients, these ratios were similar. D3/D2 ratio was smaller in off- than in on-pump patients (p=0.01), D1/D2 were similar in the two groups. CONCLUSION: Off-pump CABG may cause a narrowing of the coronaries, especially at the anastomotic heel. The anastomotic technique at the heel may have to be modified to improve its patency.  相似文献   
97.
Surgical intervention to repair a torn anterior cruciate ligament (ACL) with autogenous hamstring tendons has become popular. However, hamstring graft harvesting complications can occur. This article presents a case of skin dimpling over the pes anserinus during active hamstring contraction in a 32-year-old man following arthroscopic ACL reconstruction.  相似文献   
98.
BACKGROUND: Mitral stenosis after mitral valve repair for non-rheumatic mitral regurgitation is rare. METHODS: From 1990 to 1999, 478 patients had mitral valve repair for myxomatous and 40 patients had mitral valve repair for ischemic mitral regurgitation. The Carpentier annuloplasty ring (Edwards Lifesciences, Irvine, CA) was used in 72 patients, the Duran ring (Medtronic, Minneapolis, MN) in 152, a posterior band in 221 and no ring or band in 73 patients. RESULTS: Four patients developed mitral stenosis late after mitral valve repair: 2 for myxomatous disease and 2 for ischemic mitral regurgitation. All 4 patients had Duran annuloplasty rings (sizes 25 to 31). The diagnosis of mitral stenosis was made by Doppler echocardiography. The mitral valve area in these 4 patients decreased from 2.7 cm2 (range, 2.3 to 3.2 cm2) early postoperatively to 0.85 cm2 (0.4 to 1.2 cm2) after a mean follow-up of 66 months (range, 38 to 110 months). Three patients had mitral valve replacement and the etiology of the mitral stenosis was the same in all patients (ie, pannus overgrowth on the annuloplasty ring with extension onto both leaflets rendering them stiff and immobile). The fourth patient had a mitral valve area of 1.2 cm2, which was mildly symptomatic with normal pulmonary artery pressure, and this patient has not had reoperation. CONCLUSIONS: Mitral stenosis may develop after mitral valve repair for myxomatous disease or ischemic mitral regurgitation when a Duran ring is used for annuloplasty. The stenosis is caused by pannus on the annuloplasty ring with extension onto the leaflets.  相似文献   
99.
BACKGROUND: The term "Marjolin's ulcer" is now synonymous with malignant transformation, usually ectodermal and rarely mesenchymal, of chronic ulcers, sinus tracts, and burn scars. DESIGN: Literature search and personal experience with 5 patients during a 30-year period in a spinal cord injury center. FINDINGS: Five cases of Marjolin's ulcer diagnosed among approximately 10,000 patients indicate the rarity of the metaplasia. All cases were fatal. CONCLUSIONS: Chronic pressure ulcers of more than 10 years' duration should be biopsied to rule out malignancy, especially with any change in the nature of the ulcer (eg, exuberant granulation and/or bleeding).  相似文献   
100.
INTRODUCTION AND OBJECTIVES: Transrectal ultrasound guided biopsy is an essential part in the diagnosis of prostate cancer. Although this procedure is well tolerated by most patients, sometimes it can result in some uneasiness. In this randomised double-blind placebo controlled study, we evaluated the effectiveness of intrarectal lidocaine during TRUS guided biopsy. MATERIALS AND METHODS: 100 consecutive eligible patients who had elevated total prostate specific antigen (tPSA) and/or abnormal digital rectal examination (DRE) were included into this study. Patients were randomised into two groups. Group I received 20 cc of 2% intrarectal lidocaine 20 minutes before transrectal ultrasound guided biopsy and Group II received same amount of serum physiologic. Pain was assessed using a 10 point modified visual analog scale. RESULTS: Mean patient age was 65.5+/-2.5 and 64.5+/-11.5 years, mean tPSA was 12.3+/-3.6 and 11.3+/-1.7 ng/ml, mean biopsy duration was 6.8+/-2.5 and 6.6+/-2.2 minutes, mean pain score during transrectal ultrasound guided biopsy was 4.8+/-2.2 and 4.4+/-2.1 in Groups I and II, respectively. No statistically significant difference was observed with respect to age, tPSA, mean biopsy duration and pain score between these groups. There was only one patient who could not tolerate the procedure at all, and he was paradoxically in the lidocaine group. CONCLUSION: The use of intrarectal lidocaine is not superior to placebo during transrectal prostate biopsy for pain control.  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