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   392篇
  免费   16篇
耳鼻咽喉   1篇
儿科学   3篇
妇产科学   8篇
基础医学   23篇
口腔科学   3篇
临床医学   29篇
内科学   141篇
皮肤病学   18篇
神经病学   9篇
特种医学   13篇
外科学   97篇
现状与发展   1篇
预防医学   10篇
眼科学   1篇
药学   22篇
肿瘤学   29篇
  2023年   4篇
  2022年   1篇
  2021年   7篇
  2020年   4篇
  2019年   9篇
  2018年   13篇
  2017年   5篇
  2016年   10篇
  2015年   8篇
  2014年   15篇
  2013年   18篇
  2012年   29篇
  2011年   25篇
  2010年   18篇
  2009年   11篇
  2008年   29篇
  2007年   38篇
  2006年   30篇
  2005年   22篇
  2004年   29篇
  2003年   20篇
  2002年   24篇
  2001年   8篇
  2000年   3篇
  1999年   8篇
  1998年   1篇
  1997年   3篇
  1996年   3篇
  1994年   2篇
  1991年   2篇
  1990年   2篇
  1988年   1篇
  1987年   2篇
  1985年   1篇
  1983年   1篇
  1981年   1篇
  1978年   1篇
排序方式: 共有408条查询结果,搜索用时 15 毫秒
1.
Location and morphology of chloride cells were studied in the sea bass ( Dicentrarchus labrax) from hatching to the juvenile stage to determine the development of the adult osmoregulatory function as seen in adult fish. During the studied developmental sequence changes were observed in the location, number, size and structure of these cells, that were studied by microscopy (light, scanning electron, transmission electron and confocal) and immunocytochemistry. Chloride cells were found on the tegument and on the gills. They were present on the tegument already at hatching, before the development of the gills. Their density as well as their association in multicellular complexes decreased during the postembryonic development. In old larvae and in juveniles, cutaneous chloride cells were associated with the fins, the developing scales and the lateral line. Gills developed gradually during the prelarval stage and the gill arches were present at mouth opening. At that time chloride cells were already numerous on the gill arches. In older larvae, during the progressive development of the gill filaments, chloride cells were numerous on these structures and formed multicellular complexes. Several stages in the differentiation of these cells were studied, including the development of the tubulovesicular system at the end of the prelarval stage, as well as the stratification appearance of the cytoplasm that was concomitant with the considerable development of the tubular system and its association with the endoplasmic reticulum during the larval period. The involvement of different epithelia in the osmoregulatory process during the postembryonic development of this species, as well as the role of chloride cells during successive developmental stages, is discussed.  相似文献   
2.
Arthrodesis of the first metatarsophalangeal (MTP) joint has been established as the “gold standard” for the treatment of several first ray disorders, due to its perceived efficacy and the consistently reported good results in the literature. Arthrodesis is a commonly performed procedure for the treatment of end stage arthritis, rheumatoid arthritis with severe deformity, selected cases of severe hallux valgus (with or without signs of degenerative joint disease), as well as a salvage procedure after failed previous operation of the first ray. The goals of a successful 1st MTP arthrodesis are pain alleviation and deformity correction in order to restore a comfortable gait pattern and to improve shoe wear. Several techniques have been reported with several proposals regarding the preparation of the articular surfaces and the method of definitive fixation. As with any given surgical procedure, various complications may occur after arthrodesis of the 1st MTP joint, namely delayed union, nonunion, malunion, irritating hardware, etc.   相似文献   
3.
4.
Background. The intention of buttressing the staple line in lung volume reduction surgery is to reduce air leaks and to shorten the hospital stay. A randomized three-center study was carried out to test this hypothesis.

Methods. Sixty-five patients with a mean age of 59.2 ± 1.2 years underwent bilateral lung volume reduction surgery by video-assisted thoracoscopy using endoscopic staplers (ET 45B; Ethicon Endo-Surgery, Cincinnati, OH) either without or with bovine pericardium for buttressing (Peri-Strips Dry; Bio-Vascular, Inc, Saint Paul, MN). There were no differences between the control and treatment groups in lung function, degree of dyspnea, and arterial blood gases before and 3 months after LVRS.

Results. Seven patients (3 in the treatment group) needed a reoperation because of persistent air leak. The median duration of air leaks was shorter in the treatment group (0.0 day [range, 0 to 28 days versus 4 days [range, 0 to 27 days); p < 0.001), confirmed by a shorter median drainage time in this group (5 days [range, 1 to 35 days] versus 7.5 days [range, 2 to 29 days); p = 0.045). Hospital stay was comparable between the two groups (9.5 days [range, 6 to 44 days] versus 12.0 days [range, 5 to 46 days]; p = 0.14).

Conclusions. Buttressing the staple line significantly shortens the duration of air leaks and the drainage time. As hospital stay did not differ significantly between the two groups, cost-effectiveness may depend on the local situation.  相似文献   

5.
The Frank''s sign (FS) is a diagonal earlobe crease running from the tragus to the edge of the auricle. In this case, we describe a 71 years‐old male patient with FS who presented to the emergency department complaining of epigastric pain. A non‐ST elevation myocardial infarction was diagnosed.  相似文献   
6.
OBJECTIVE: The purpose of this study was to identify the prognostic impact of unexpected lymph node metastases in patients undergoing resection of pulmonary metastases from colorectal cancer and specify the influence of pulmonary and mediastinal nodal involvement according to the modified Narukes lymph node mapping [Mountain CF, Dresler CM. Regional lymph node classification for lung cancer. Chest 1997;111(6):1718-23.]. METHODS: From January 1993 to December 2003, 175 patients were diagnosed and resected for pulmonary metastases of colorectal cancer. Follow up informations were collected for 169 patients and an analysis of prognostic factors was performed. Ninety-six men (56.8%) and 73 women (43.2%) with a median age of 62 (range 34-81) were identified, 28 (16.7%) patients were found to have lymph node metastases, five of them were identified during a recurrent procedure. Probability of survival was calculated according to the method of Kaplan-Meier. The prognostic influence of lymph node metastases on survival was analyzed with the log-rank test. RESULTS: Median survival was 47.2 months after first metastasectomy. Ten patients with intrapulmonary nodal involvement had a median survival of 86 months whereas 12 patients with hilar and six patients with mediastinal lymph node metastases had a median survival of 24.5 and 34.7 months. The survival difference between pulmonary and hilar/mediastinal metastases was statistically significant (p=0.008/p=0.07). Five year survival with pulmonary, hilar, and mediastinal metastases was 78.5, 0, and 0%, respectively. Perioperative mortality was 0%. CONCLUSIONS: Resection of pulmonary metastases secondary to colorectal cancer is safe and indicated in highly selected patients. Because tumor involvement of lymph nodes has a strong impact on survival; depending on their location, at least a lymph node sampling should always be performed. Adjuvant chemotherapy in case of proven lymph node metastases might be a good option to improve prognosis.  相似文献   
7.
Introduction: The usefulness of nasogastric aspiration and nasogastric lavage in patients with gastrointestinal bleeding is controversial, as evidenced by conflicting recommendations, both among and within society guidelines.

Areas covered: Considering these controversies, we reviewed the evidence regarding the following questions: 1) Can nasogastric lavage stop or slow down the bleeding and improve subsequent endoscopic visualization? 2) Is nasogastric aspiration helpful for the localization of bleeding? 3) Can nasogastric aspiration identify high risk patients that might benefit from earlier endoscopy? 4) Is there evidence for benefit in terms of outcomes from using nasogastric aspiration? 5) Is nasogastric intubation safe in patients with possible esophageal varices? Our review was conducted according to PRISMA guidelines.

Expert commentary: Based on the available literature, nasogastric lavage or aspiration cannot be routinely recommended unless a large properly designed randomized trial (which is currently lacking) proves otherwise. It is a painful and time-consuming procedure with no demonstrated benefit for the patient in terms of outcomes. Other clinical and laboratory parameters, and risk scores, are less invasive and are effective for guiding the stratification and management of patients, while pre-endoscopic erythromycin infusion is a good if not better alternative for improving visualization of the stomach.  相似文献   
8.
Congenital deformities, various forms of trauma, foreign bodies, granulomatous infection and tumors are the most common causes of tracheoesophageal fistulas. This is a rare but life-threatening complication with mortality rates up to 60% due to chronic aspiration and innominate artery arrosion and bleeding. Bronchoscopy should be done promptly if a fistula is suspected, followed by esophagoscopy. Radiologic examinations are only helpful for operational planning. Surgical treatment is mandatory for benign fistulas with excellent short-term and long-term results. However, for malignant fistulas the survival time is often only weeks to months and are best treated by palliative stenting, which offers a short-term improvement in the quality of life.  相似文献   
9.
Beekeepers are at increased risk for honeybee (Hb) venom allergy and they represent a unique population for Hymenoptera venom studies. The aim of this was to prospectively examine the pattern of Hb venom sensitization over a 5-year period in new beekeepers and define possible predisposing factors. Thirty-five beekeepers were tested every 6 months for 5 years with in vivo and in vitro methods to detect the possible development of sensitization to Hb and common wasp (Cw) venom. Inclusion criteria included the lack of previous beekeeping activity and absence of sensitization or reported reaction to Hymenoptera stings. Subjects with both in vivo and in vitro tests that were definitely positive or with one definitely positive and the other doubtful were considered sensitized. Ten of 35 new beekeepers (28.6%) and 3 of 36 controls (8.3%) developed sensitivity to Hb venom during the 5-year period. The risk ratio in incidence studies was calculated at 3.43 (SE of log risk ratio = 0.61; 95% CI of risk ratio = 1.03-11.42). All sensitized beekeepers were detected within the first 18 months of occupational exposure; 8 of 10 (80%) beekeepers were detected during the initial 12 months and the 2 remaining beekeepers were detected between 12 and 18 months. One of 35 (2.9%) beekeepers and 1 of 36 controls (2.8%) were sensitized to Cw venom. The number of stings per year and atopy had no effect on sensitization rate. Although predisposing factors to sensitization or anaphylaxis could not be identified, beekeepers developed sensitization to bee venom in <18 months.  相似文献   
10.
Pulmonary aspergilloma and pleural aspergillosis are a potentially lifethreatening disease resulting from the colonization of lung or pleural cavities by the ubiquitous fungus Aspergillus fumigatus. Twenty four patients with pulmonary aspergilloma and five with pleural aspergillosis underwent major thoracic procedures at our hospital between 1976 and 1986. Fourteen of the patients had haemoptysis, in 9 it was recurrent, and in 5 life-threatening. Tuberculosis, pneumonia, and sarcoidosis were the most common preexisting lung lesions. Surgical procedures included 7 pleuropneumonectomies, 18 lobectomies and 4 wedge resections. The postoperative mortality rate was approximately 7% (2 pat.). Based on the pathological examination 4 patients had unexpectedly a bronchial carcinoma in addition to the aspergilloma. Bronchopleural fistula with persistent air space was a serious complication only for patients after pleuropneumonectomy. 23 patients including those with complex aspergilloma and pleural infection had no postoperative complications; in none of the 27 operative survivors were there any recurrent symptoms over a follow-up between one and ten years. Good-risk patients with documented aspergilloma, even asymptomatic, should be resected, because of the danger of exsanginating haemorrhage. For patients with pleural aspergillosis only the aggressive resection can provide effective long term palliation.  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