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   8337篇
  免费   637篇
  国内免费   29篇
耳鼻咽喉   163篇
儿科学   323篇
妇产科学   145篇
基础医学   623篇
口腔科学   1759篇
临床医学   479篇
内科学   1458篇
皮肤病学   110篇
神经病学   395篇
特种医学   249篇
外科学   1591篇
综合类   89篇
现状与发展   1篇
一般理论   5篇
预防医学   252篇
眼科学   133篇
药学   547篇
中国医学   28篇
肿瘤学   653篇
  2024年   8篇
  2023年   136篇
  2022年   59篇
  2021年   206篇
  2020年   115篇
  2019年   148篇
  2018年   257篇
  2017年   227篇
  2016年   238篇
  2015年   288篇
  2014年   399篇
  2013年   431篇
  2012年   611篇
  2011年   659篇
  2010年   446篇
  2009年   428篇
  2008年   485篇
  2007年   505篇
  2006年   485篇
  2005年   471篇
  2004年   418篇
  2003年   377篇
  2002年   354篇
  2001年   111篇
  2000年   77篇
  1999年   73篇
  1998年   121篇
  1997年   93篇
  1996年   83篇
  1995年   63篇
  1994年   80篇
  1993年   71篇
  1992年   50篇
  1991年   70篇
  1990年   47篇
  1989年   50篇
  1988年   33篇
  1987年   24篇
  1986年   27篇
  1985年   24篇
  1984年   18篇
  1983年   11篇
  1982年   21篇
  1981年   21篇
  1980年   17篇
  1979年   18篇
  1978年   14篇
  1977年   8篇
  1976年   11篇
  1974年   4篇
排序方式: 共有9003条查询结果,搜索用时 46 毫秒
1.
2.
3.
BACKGROUND: Penetrating injuries of the perineum are rare but very dangerous. Since the genitourinary and colorectal organs may be injured, how to evaluate surgical management of the injury is very important.METHODS: The present report presents a case of penetrating injury of the perineum by a wooden stick when the patient fell on the upright wooden stick from a tree. The three feet long stick entered the perineal region just left lateral to the anal opening. Upon reaching the thoracic cavity, it broke and only a foot stick was left in the subcutaneous plane. These injuries are potentially serious with risk of damage to multiple organs. Exploratory laprotomy was done, and bladder injury was repaired. The entry wound and the track of stick was thoroughly washed and allowed for secondary intention healing.RESULTS: The post operative period was uneventful and the patient recovered fully.CONCLUSION: Meticulous evaluation and surgical management of perineal injuries are the key to prevent devastating complications.  相似文献   
4.
PURPOSE: The purpose of this study was to compare the dentin/adhesive interfacial characteristics when bonding to noncarious as well as caries-affected dentin. MATERIALS AND METHODS: Seven extracted, unerupted, third molars were sectioned into halves. Artificial caries was created on one-half of each tooth, leaving the other half as a control. Dentin surfaces were treated with UNO adhesive according to the manufacturer's instructions for the wet-bonding technique and under environmental conditions present in the oral cavity. Dentin/adhesive interface sections of each half-tooth were stained with Goldner's trichrome, a classic bone stain, and examined using light microscopy. The width of exposed collagen was measured directly from photomicrographs, and adhesive penetration was analyzed qualitatively. RESULTS: The degree and extent to which the adhesive encapsulated the demineralized dentin matrix were reflected in the color difference in the stained sections with the noncarious dentin sections showing a degree of collagen encapsulation superior to that of the caries-affected dentin sections. The overall mean widths of exposed collagen were significantly (p < or = .05) greater at the caries-affected dentin/adhesive interface, 8.6 (1.7) microm, as compared with those at the noncarious dentin/adhesive interface, 6.0 (1.5) microm. CONCLUSIONS: The morphologic characteristics of the caries-affected dentin/interface suggest an increase in the exposed collagen zone and a decrease in the quality of the adhesive infiltration when compared with noncarious dentin. The evidence suggests that dentin substrate characteristics have a significant effect on the dentin/adhesive interface structure.  相似文献   
5.
Objective The degree of Left Ventricular Mass Index (LVMI) regression following aortic valve replacement correlates with long-term survival. This study aims to assess the extent of LVMI regression at 3 months following aortic valve replacement (AVR) with different types and sizes of mechanical valves in rheumatic aortic valve disease. Methods The LVMI regression was studied in 34 consecutive patients, undergoing elective AVR for rheumatic aortic stenosis and/or regurgitation. They were grouped in A and B, matched in age, body surface area and pre-operative LVMI, receiving respectively a tilting disc and a bileaflet mechanical valve. The LVMI was calculated by M-mode echocardiography using the Devereux' formula pre-operatively and three months post-operatively. The trend of LVMI reduction was compared between the two groups and amongst the patients with stenotic, regurgitant and mixed aortic valve, pathologies; and receiving different sizes of valves. Results The mean preoperative LVMI was 199g±79.5 g/m2. At three months post aortic valve replacement, the mean LVMI was 130g±49.0 g/m2. There was a significant reduction of LVMI post-operatively (p=0.001) at three months follow-up. The extent of LVMI regression following surgery amongst the groups A and B did not vary significantly (p=0.92). The extent of LVMI regression did not vary significantly in patients with different aortic valve pathology nor with different sizes of the valves implanted. Conclusions There is a significant early LVMI regression following aortic valve replacement in rheumatic aortic valve disease. The type and the size of the mechanical prosthesis or the rheumatic pathology do not appear to influence this regression.  相似文献   
6.
This prospective clinic-based study evaluated the pretreatment periodontal status of the orthodontic patients seen at the University College Hospital, Ibadan, Nigeria, and assessed the relationship between dental aesthetic index (DAI) scores and periodontal status according to community periodontal index of treatment needs (CPITN) scores. One hundred forty five patients-70 (48.3%) males and 75 (51.7%) females from 6 to 45 years (mean 15.8 +/- 7.5)-were seen. World Health Organization (WHO) guidelines were followed in the examination and reporting of the periodontal status, and DAI scores were assessed based on WHO guidelines. The chi-square test was used to determine the association between the DAI and the CPITN scores. Most patients were in the 6-15 (55.9%) or 16-25 (35.9%) age groups. Based on the WHO preferred cumulative calculations of treatment need (TN), 35.2% of the patients had TN 0, 64.9% had TN 1, 24.9% had TN 2, and only 0.7% had TN 3. The relationship between DAI scores and periodontal treatment needs was not statistically significant (P >.05). Although many patients were yet to attain the WHO goal of no more than 1 sextant affected by bleeding or calculus at the age of 15, over one third had satisfactory periodontal health.  相似文献   
7.
8.
9.
BACKGROUND CONTEXT: Pseudoaneurysm of the aorta in association with vertebral tuberculosis is a rare phenomenon. With the resurgence of human immunodeficiency virus (HIV) and associated resistant tuberculosis, this life-threatening complication requires greater awareness. PURPOSE: Our purpose is to report the rare presentation and successful management of tubercular pseudoaneurysm of the aorta in association with vertebral tuberculosis, and to highlight the clinicoradiological features for early and prompt diagnosis of this potentially fatal, but treatable, disease. STUDY DESIGN: A single case report and overview of the disease comprises the design of this study. PATIENT SAMPLE: The patient, already surgically intervened, is a 27-year-old male with increasing abdominal and back pain, upper motor neuron signs, and constitutional signs and symptoms. OUTCOME MEASURES: At 33 months follow-up, there is complete resolution of the signs and symptoms, and the patient is back to his previous vocation. METHODS: The diagnosis was confirmed by magnetic resonance imaging and contrast computed tomography. Endoaneurysmorrhaphy of the pseudoaneurysm along with a complete course of antitubercular treatment was given to the patient, and he has presently been followed up for 33 months. RESULTS: The patient's signs and symptoms have been completely resolved without any recurrence. CONCLUSION: Despite the use of modern chemotherapy and imaging techniques, this disastrous complication still occurs and reinforces the need for early suspicion, diagnosis, surgical resection, and antitubercular therapy along with close postoperative follow-up to prevent recurrence. With the resurgence of HIV (and other immunocompromised states) associated and resistant tuberculosis, we should be more alert than ever to this life-threatening complication.  相似文献   
10.
A child had two to three generalized tonic-clonic (GTC) seizures per week unresponsive to phenobarbital (PB) and valproate (VPA). Interictal EEG demonstrated left occipital spikes. When carbamazepine (CBZ) therapy was started, he developed very frequent (4-6/day) complex partial seizures (CPS) characterized on ictal EEG by focal right temporal lobe discharges. The seizure exacerbation, which was associated with development of nonepileptic, multifocal myoclonus, resolved 24 h after CBZ was discontinued. The exacerbation occurred with therapeutic CBZ serum levels, but may have been related to the toxic levels of carbamazepine-10, 11-epoxide (CBZE).  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