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   3808篇
  免费   329篇
  国内免费   23篇
耳鼻咽喉   44篇
儿科学   58篇
妇产科学   36篇
基础医学   434篇
口腔科学   148篇
临床医学   353篇
内科学   872篇
皮肤病学   74篇
神经病学   232篇
特种医学   111篇
外科学   551篇
综合类   204篇
预防医学   260篇
眼科学   218篇
药学   186篇
中国医学   32篇
肿瘤学   347篇
  2023年   40篇
  2022年   63篇
  2021年   123篇
  2020年   96篇
  2019年   104篇
  2018年   164篇
  2017年   107篇
  2016年   102篇
  2015年   123篇
  2014年   161篇
  2013年   176篇
  2012年   229篇
  2011年   296篇
  2010年   147篇
  2009年   127篇
  2008年   209篇
  2007年   215篇
  2006年   236篇
  2005年   163篇
  2004年   205篇
  2003年   179篇
  2002年   120篇
  2001年   97篇
  2000年   87篇
  1999年   74篇
  1998年   23篇
  1997年   23篇
  1996年   21篇
  1995年   13篇
  1994年   10篇
  1993年   18篇
  1992年   39篇
  1991年   44篇
  1990年   37篇
  1989年   37篇
  1988年   43篇
  1987年   31篇
  1986年   32篇
  1985年   16篇
  1984年   11篇
  1983年   15篇
  1980年   8篇
  1979年   13篇
  1977年   10篇
  1976年   5篇
  1975年   8篇
  1974年   9篇
  1972年   7篇
  1971年   8篇
  1970年   6篇
排序方式: 共有4160条查询结果,搜索用时 15 毫秒
31.
32.
33.
Summary Between January 1982 and December 1989, 12 patients with 13 acute extradural haematomas as a result of injury involving the venous sinuses were treated by the first author. The CT scan appearances in 6 cases were remarkable in that there were large bubbles of low density in the hyperdense haematomas and liquid blood was found during the operation. The possible underlying pathophysiological changes that gave rise to this appearance are discussed. The CT scan appearance and the proximity of the clot to the venous sinuses should alert the neurosurgeon to the high probabilities of venous sinus tear such that proper treatment can be offered.  相似文献   
34.
Papillary fibroelastoma is a rare primary tumor of the heart valves. This lesion can occur on any of the valves or endothelial surface of the heart and has been detected by echocardiography, by cardiac catheterization, during open heart operations for other conditions, and at autopsy. Because of the potential for comorbidities, this tumor should be removed. We present the case of an elderly man with a diagnosis of severe mitral valve regurgitation and moderate tricuspid valve regurgitation who was suspected to have a tricuspid valve vegetation. Mitral valve replacement, tricuspid valve repair, and excision of the lesion were performed successfully. A histologic examination of the vegetation confirmed it to be a papillary fibroelastoma. We present this case to emphasize the rarity of this tumor and the importance of a correct diagnosis to avoid delaying its prompt and definitive management.  相似文献   
35.
BackgroundThe pancreas is one of the primary organs affected by dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. While exocrine pancreatic insufficiency is a well-recognized complication of cystic fibrosis (CF), symptomatic pancreatitis is often under-recognized.ResultsThe aim of this review is to provide a general overview of CFTR mutation-associated pancreatitis, which affects patients with pancreatic sufficient CF, CFTR-related pancreatitis, and idiopathic pancreatitis. The current hypothesis regarding the role of CFTR dysfunction in the pathogenesis of pancreatitis, and concepts on genotype–phenotype correlations between CFTR and symptomatic pancreatitis will be reviewed.Symptomatic pancreatitis occurs in 20% of pancreatic sufficient CF patients. In order to evaluate genotype–phenotype correlations, the Pancreatic Insufficiency Prevalence (PIP) score was developed and validated to determine severity in a large number of CFTR mutations. Specific CFTR genotypes are significantly associated with pancreatitis. Patients who carry genotypes with mild phenotypic effects have a greater risk of developing pancreatitis than patients carrying genotypes with moderate–severe phenotypic consequences at any given time.ConclusionsThe genotype–phenotype correlation in pancreatitis is unique compared to other organ manifestations but still consistent with the complex monogenic nature of CF. Paradoxically, genotypes associated with otherwise mild phenotypic effects have a greater risk for causing pancreatitis; compared with genotypes associated with moderate to severe disease phenotypes. Greater understanding into the underlying mechanisms of disease is much needed. The emergence of CFTR-assist therapies may potentially play a future role in the treatment of CFTR-mutation associated pancreatitis.  相似文献   
36.
Aim To review the preliminary results of the ligation of the intersphincteric fistula tract (LIFT) technique in treating complex anal fistulas at our hospital. Method Between March and November 2010, patients with cryptoglandular anal fistulas were recruited prospectively from the colorectal clinic and treated using the LIFT procedure. A database was set up to collect information on demographics, past surgical treatments, fistula characteristics, MRI scan results, operative data and follow‐up findings. The primary end‐point measured was cure of the disease. The secondary end‐point was the degree of postoperative continence. Preoperative and postoperative incontinence rates were recorded using Wexner’s Incontinence Scale. Results Twenty‐five patients (eight women and 17 men; median age, 40 years) underwent the LIFT procedure. Ten patients had recurrent fistulas and previous fistula surgery. The median operating time was 39 min. No intraoperative complications were documented. The median follow‐up duration was 22 (3–43) weeks. Primary healing was observed in 17 (68.0%) patients and the median healing time was 6 weeks; one wound remained incompletely healed. Seven patients (28.0%) had disease recurrence presenting between 7 and 20 weeks postoperatively. No patients reported any incontinence postoperatively. Conclusion The LIFT procedure has favourable healing rates with little or no risk of incontinence. This operation is safe and easy to learn. The early results from this pilot study show promise and affirm some of the findings of other researchers. These results will suggest opportunities to conduct further controlled studies comparing the LIFT procedure with standard therapies.  相似文献   
37.
38.
ObjectiveTo evaluate the rates of technical success, clinical success, and complications of fluoroscopy-guided lumbar cerebrospinal fluid drainage.ResultsThe technical and clinical success rates were 99.0% (95/96) and 89.6% (86/96), respectively. The mean hospital stay for an external lumbar drain was 4.84 days. Nine cases of minor complications and eight major complications were observed, including seven cases of meningitis, and one retained catheter requiring surgical removal.ConclusionFluoroscopy-guided external lumbar drainage is a technically reliable procedure in difficult patients with failed attempts at a bedside procedure, history of lumbar surgery, difficulties in cooperation, or obesity.  相似文献   
39.

Purpose

To introduce a new clinical neck tilt grading and to investigate clinically and radiologically whether neck tilt and shoulder imbalance is the same phenomenon in AIS patients.

Methods

89 AIS Lenke 1 and 2 cases were assessed prospectively using the new clinical neck tilt grading. Shoulder imbalance and neck tilt were correlated with coracoid height difference (CHD), clavicle\rib intersection distance (CRID), clavicle angle (CA), radiographic shoulder height (RSH), T1 tilt and cervical axis.

Results

Mean age was 17.2 ± 3.8 years old. 66.3 % were Lenke type 1 and 33.7 % were type 2 curves. Strong intraobserver (0.79) and interobserver (0.75) agreement of the clinical neck tilt grading was noted. No significant correlation was observed between clinical neck tilt and shoulder imbalance (0.936). 56.3 % of grade 3 neck tilt, 50.0 % grade 2 neck tilt patients had grade 0 shoulder imbalance. In patients with grade 2 shoulder imbalance, 42.9 % had grade 0, 35.7 % grade 1, 14.3 % grade 2 and only 7.1 % had grade 3 neck tilt. CHD, CRID, CA and RSH correlated with shoulder imbalance. T1 tilt and cervical axis measurements correlated with neck tilt.

Conclusions

In conclusion, neck tilt is distinct from shoulder imbalance. Clinical neck tilt has poor correlation with clinical shoulder imbalance. Clinical neck tilt grading correlated with cervical axis and T1 tilt whereas clinical shoulder grading correlated with CHD, RSH CRID and CA.
  相似文献   
40.

Purpose

To directly compare the safety of fluoroscopic guided percutaneous thoracic pedicle screw placement between Caucasians and Asians.

Methods

This was a retrospective computerized tomography (CT) evaluation study of 880 fluoroscopic guided percutaneous pedicle screws. 440 screws were inserted in 73 European patients and 440 screws were inserted in 75 Asian patients. Screw perforations were classified into Grade 0: no violation; Grade 1: <2 mm perforation; Grade 2: 2–4 mm perforation; and Grade 3: >4 mm perforation. For anterior perforations, the pedicle perforations were classified into Grade 0: no violation, Grade 1: <4 mm perforation; Grade 2: 4–6 mm perforation; and Grade 3: >6 mm perforation.

Results

The inter-rater reliability was adequate with a kappa value of 0.83. The mean age of the study group was 58.3 ± 15.6 years. The indications for surgery were tumor (70.3 %), infection (18.2 %), trauma (6.8 %), osteoporotic fracture (2.7 %) and degenerative diseases (2.0 %). The overall screw perforation rate was 9.7 %, in Europeans 9.1 % and in Asians 10.2 % (p > 0.05). Grade 1 perforation rate was 8.4 %, Grade 2 was 1.2 % and Grade 3 was 0.1 % with no difference in the grade of perforations between Europeans and Asians (p > 0.05). The perforation rate was the highest in T1 (33.3 %), followed by T6 (14.5 %) and T4 (14.0 %). Majority of perforations occurred medially (43.5 %), followed by laterally (25.9 %), and anteriorly (23.5 %). There was no statistical significant difference (p > 0.05) in the perforation rates between right-sided pedicle screws and left-sided pedicle screws (R: 10.0 %, L: 9.3 %).

Conclusions

There were no statistical significant differences in the overall perforation rates, grades of perforations, direction of perforations for implantation of percutaneous thoracic pedicle screws insertion using fluoroscopic guidance between Europeans and Asians. The safety profile for this technique was comparable to the current reported perforation rates for conventional open pedicle screw technique.
  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