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   5659篇
  免费   371篇
  国内免费   9篇
耳鼻咽喉   73篇
儿科学   317篇
妇产科学   74篇
基础医学   748篇
口腔科学   175篇
临床医学   396篇
内科学   1297篇
皮肤病学   92篇
神经病学   424篇
特种医学   140篇
外科学   619篇
综合类   165篇
一般理论   1篇
预防医学   370篇
眼科学   111篇
药学   416篇
中国医学   52篇
肿瘤学   569篇
  2023年   22篇
  2022年   74篇
  2021年   203篇
  2020年   96篇
  2019年   125篇
  2018年   136篇
  2017年   91篇
  2016年   117篇
  2015年   130篇
  2014年   193篇
  2013年   264篇
  2012年   412篇
  2011年   377篇
  2010年   222篇
  2009年   175篇
  2008年   255篇
  2007年   268篇
  2006年   236篇
  2005年   241篇
  2004年   220篇
  2003年   215篇
  2002年   192篇
  2001年   163篇
  2000年   170篇
  1999年   160篇
  1998年   69篇
  1997年   58篇
  1996年   40篇
  1995年   48篇
  1994年   34篇
  1993年   30篇
  1992年   104篇
  1991年   80篇
  1990年   84篇
  1989年   86篇
  1988年   70篇
  1987年   62篇
  1986年   54篇
  1985年   53篇
  1984年   49篇
  1983年   43篇
  1982年   23篇
  1981年   19篇
  1979年   39篇
  1978年   25篇
  1976年   16篇
  1974年   22篇
  1973年   22篇
  1971年   16篇
  1970年   22篇
排序方式: 共有6039条查询结果,搜索用时 0 毫秒
51.
We present an interesting case of a preterm Omani newborn that had delayed onset of congenital diaphragmatic hernia in association with group B streptococcus infection. The association and the pathogenesis are supported by literature review. The message to follow is that any neonate with prolonged course of streptococcal pneumonia, with unusual course, should be investigated for presence of congenital diaphragmatic hernia.  相似文献   
52.
Angiogenesis, the growth of new blood vessels, is believed to aid tumor progression and metastasis. Tumor progression is also influenced by the extent of proliferation and apoptosis. This study, therefore, analyzed in lesions of the oral cavity, the significance of angiogenesis in relation to apoptosis, expression of apoptosis regulatory p53, bax and bcl-2 proteins as well as tissue proliferation defined by cyclin D1 expression. Results from this study suggest that angiogenesis increases as histological abnormality increases in the oral mucosa. The expression of apoptosis regulatory proteins also appears to be altered in a histologically dependent manner. The correlation seen between CD34 expression, cyclin D1 and TUNEL reactive cells suggests that increased angiogenesis, decreased apoptosis and deregulated proliferation occur simultaneously during tumor progression in the oral mucosa. Presence of a mutant p53, increased bcl-2 expression and altered bax expression are also involved in this complex process.  相似文献   
53.
Smoking is the leading preventable cause of death in the United States. The US Centers for Disease Control and Prevention (CDC) estimate that smoking kills approximately 419,000 people in the United States each year. Cigarette smoking is the nation's leading cause of premature mortality, and is responsible for one-third of all deaths among working-age Americans. Smoking cigarettes is both psychologically and physiologically addictive. Smoking is an important risk factor for cardiovascular diseases, especially coronary artery disease, stroke, carcinoma of the lung, chronic bronchitis, chronic obstructive pulmonary disease, and emphysema. It also increases the risk for peripheral vascular disease and is associated with cancers of the larynx, oral cavity, esophagus, pancreas, and urinary bladder. Smoking by pregnant women can cause adverse health effects on their babies, like low birth weight and preterm delivery; increases the risk of miscarriage; and has also been found to be an important cause of sudden infant death syndrome. Careless smoking also can cause severe burn injuries and death. Many of these adverse effects of smoking occur in "second-hand" smokers.  相似文献   
54.
Gunshot injuries of the popliteal artery   总被引:1,自引:0,他引:1  
BACKGROUND: Guidelines for the management of popliteal artery trauma emanate mainly from military experience. This study was undertaken to describe the management of popliteal injuries in a civilian vascular surgical unit with a large trauma workload. METHODS: A retrospective review of records of patients treated between 1983 and 1997 was undertaken. RESULTS: Some 117 popliteal artery gunshot injuries were treated (83 low velocity, 16 high velocity, 18 shotgun). Associated fractures occurred in 44 patients and 40 had popliteal vein injuries. Treatment of the arterial injury included vein graft interposition in 71, primary reanastomosis in 19, prosthetic graft interposition in four, lateral suture in one, vein patch in one and ligation in one patient; 84 fasciotomies were performed. No perioperative deaths occurred. There were 20 primary and 14 secondary amputations. Factors associated with amputation were high-velocity injuries, delay in revascularization in excess of 7 h, arterial transection, associated fracture, and compartment syndrome or muscle infarction. CONCLUSION: Civilian popliteal gunshot injuries are attended by a high amputation rate. Prompt resuscitation and revascularization appear to be the only correctable factors that may improve limb salvage rates.  相似文献   
55.
PURPOSE: A randomized three-arm phase II study was undertaken to evaluate the optimum administration schedule of pemetrexed and gemcitabine in chemotherapy-na?ve patients with non-small-cell lung cancer. PATIENTS AND METHODS: Patients were randomly assigned to three schedules of pemetrexed 500 mg/m2 plus gemcitabine 1,250 mg/m2, separated by a 90-minute interval, on a 21-day cycle as follows: schedule A, pemetrexed followed by gemcitabine on day 1 and gemcitabine on day 8; schedule B, gemcitabine followed by pemetrexed on day 1 and gemcitabine on day 8; and schedule C, gemcitabine on day 1 and pemetrexed followed by gemcitabine on day 8. RESULTS: One hundred fifty-two eligible patients (schedule A, n = 59; schedule B, n = 31, and schedule C, n = 62) received a median of five (schedule A), two (schedule B), and four (schedule C) treatment cycles. Overall, 66% of patients experienced grade 3 or 4 neutropenia. Common grade 3 and 4 nonhematologic toxicities were dyspnea (11%), fatigue (16%), and transaminase elevation (9%). Schedule A seemed less toxic compared with schedule C (grade 3 or 4 events: 86% v 94%, respectively; P = .19; grade 4 events: 39% v 48%, respectively; P = .30). Schedule B was closed at interim analysis for inferior efficacy. Schedule A, with a confirmed response rate of 31% (95% CI, 20% to 45%), met the protocol-defined efficacy criteria, whereas schedule C, with a confirmed response rate of 16.1% (95% CI, 11% to 34%), did not. Median survival time and time to progression were 11.4 and 4.4 months, respectively, with no observable difference between the arms. CONCLUSION: Pemetrexed and gemcitabine administered as outlined for schedule A met the protocol-defined efficacy criteria, was less toxic compared with the other treatment schedules, and should be further evaluated.  相似文献   
56.
57.
58.
A retrospective analysis of 343 consecutive patients with histologically proven carcinoma of the cervix, treated at the Ottawa General Hospital, was undertaken to evaluate the prognostic significance of endometrial extension. All these patient had a D + C as part of their work-up. Sixty-seven patients had a (+) D + C: 34/150 (23%) in Stage IB, 21/106 (20%) in Stage II, and 12/87 (14%) in Stage III. Survival was closely related to the D + C findings in early stages. In Stage IB, the 5-year survival of D + C (-) patients was 90% vs 50% in D + C (+) patients (P less than 0.003) and in Stage II, the 5-year survival was 77% and 55%, respectively (P = 0.089). There was, however, no difference in survival in Stage III patients (35% vs 29%). Pelvic failures were similar in both groups, stage for stage, but those with a (+) D + C had a higher incidence of distant metastasis. In Stage IB, distant metastases were found in 8.5% (10/116) of D + C (-) patients compared to 38% (13/34) in D + C (+) patients (P less than 0.001) and in Stage II, in 18.5% (16/85 and 33% (7/21) of the patients (P = 0.126), respectively. There was no difference in Stage III patients (28% vs 25%). This study suggests that endometrial extension is a significant prognostic factor in early stages and is associated with a higher risk of distant metastases. Management of these high risk patients is discussed.  相似文献   
59.
Thirty-seven patients undergoing surgical operations were studied to detect transfer of oropharyngeal organisms into the trachea during endotracheal intubation. Nine of 27 patients with potentially pathogenic bacteria in the pharynx immediately before intubation were found to have these organisms, mainly Haemophilus influenzae, in the trachea at the end of operation. There was a trend for systemic antibiotic prophylaxis to reduce the persistence of bacteria in the trachea.  相似文献   
60.
We present the case of a 51-year-old lady who developed a CSF leak following a Cloward's procedure (anterior cervical surgery with fusion), which settled with conservative management. Two months following the surgery she was assessed by an otolaryngologist for persistent dysphagia and a swelling in the anterior triangle of her neck. A computed tomography (CT) scan identified a fluid-filled mass displacing the trachea and communicating with the anterior cervical vertebrae, thus confirming the persistence of a CSF leak.  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