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   42771篇
  免费   3650篇
  国内免费   1269篇
耳鼻咽喉   112篇
儿科学   1289篇
妇产科学   198篇
基础医学   2776篇
口腔科学   78篇
临床医学   5977篇
内科学   13257篇
皮肤病学   170篇
神经病学   618篇
特种医学   2180篇
外国民族医学   9篇
外科学   3179篇
综合类   8655篇
现状与发展   2篇
预防医学   2148篇
眼科学   54篇
药学   3943篇
  45篇
中国医学   1865篇
肿瘤学   1135篇
  2024年   168篇
  2023年   733篇
  2022年   1449篇
  2021年   2032篇
  2020年   2055篇
  2019年   1735篇
  2018年   1693篇
  2017年   1782篇
  2016年   1866篇
  2015年   1790篇
  2014年   3198篇
  2013年   3364篇
  2012年   2697篇
  2011年   2757篇
  2010年   2236篇
  2009年   1947篇
  2008年   1860篇
  2007年   1857篇
  2006年   1684篇
  2005年   1458篇
  2004年   1185篇
  2003年   1040篇
  2002年   834篇
  2001年   760篇
  2000年   630篇
  1999年   558篇
  1998年   468篇
  1997年   472篇
  1996年   454篇
  1995年   379篇
  1994年   338篇
  1993年   274篇
  1992年   264篇
  1991年   213篇
  1990年   205篇
  1989年   155篇
  1988年   150篇
  1987年   129篇
  1986年   131篇
  1985年   158篇
  1984年   122篇
  1983年   72篇
  1982年   68篇
  1981年   62篇
  1980年   52篇
  1979年   34篇
  1978年   28篇
  1977年   28篇
  1976年   24篇
  1975年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Brain-dead donors are the major source of lungs for transplantation. Brain death is characterized by two hemodynamic phases. Initially, massive sympathetic discharge results in a hypertensive crisis. This is followed by neurogenic hypotension. Up-regulation of pro-inflammatory mediators occurs in all organs and lung injury develops; this can adversely affect graft function post-transplantation. The mechanisms of the systemic and lung inflammation are unknown. We hypothesized that the hemodynamic changes are responsible for these inflammatory phenomena. Brain death was induced by intra-cranial balloon inflation in rats. This resulted in hypertensive crisis, followed by hypotension. There was a significant increase in blood neutrophil CD11b/CD18 expression and pro-inflammatory cytokine levels in serum and bronchoalveolar lavage, compared with control animals. Rupture of the capillary-alveolar membrane was demonstrated by electron microscopy. Elimination of the hypertensive response by α-adrenergic antagonist pre-treatment prevented inflammatory lung injury, reduced the systemic inflammatory markers and preserved capillary-alveolar membrane integrity. Correction of the neurogenic hypotension with noradrenaline ameliorated the systemic inflammatory response and improved oxygenation. We conclude that the sympathetic discharge triggers systemic and lung inflammation, which can be further enhanced by neurogenic hypotension. Management of the brain-dead donor with early anti-inflammatory treatment and vasoconstrictors is warranted.  相似文献   
72.
目的探讨综合疗法并用小剂量肝素、巯甲丙脯酸治疗慢性肺心病急性发作期的疗效.方法慢性肺心病急性发作期患者随机分为治疗组(66例)、对照组(62例),两组均进行综合治疗,但治疗组加用了小剂量肝素和巯甲丙脯酸,然后观察并比较其症状、体征、血气指标和血液黏稠度.结果治疗组的血液流变学变化、症状与体征的改善及总好转率明显优于对照组P<0.01.结论慢性肺心病急性发作期病人在综合治疗的基础上加用小剂量肝素和巯甲丙脯酸可显著提高疗效.  相似文献   
73.
Aim: The prognosis of patients with disseminated colorectal carcinoma is poor except for those with single organ pulmonary or hepatic metastases. The objective of the present study was to evaluate the result of pulmonary metastasectomy for colorectal secondary and to identify the prognostic factors. Methods: This was a retrospective study of 80 patients who had pulmonary metastasectomy for pulmonary secondary from colorectal carcinoma in Queen Elizabeth Hospital, Hong Kong. Results: The overall 5‐year and 10‐year survival rates of the entire cohort were 42.5% and 35.5%, respectively. High premetastasectomy carcinoembryonic antigen (> 20 μg/dL), short disease‐free interval (< 12 months) and incomplete resection were the independent prognostic factors. Neither the characteristics of the primary colorectal tumour nor the number of metastatic nodules had a significant contribution to the long‐term survival. Six patients underwent second pulmonary metastasectomy and three were still free from tumour recurrence after the second operation. Conclusion: Patients with pulmonary metastases from colorectal carcinoma would benefit from pulmonary metastasectomy. High premetastasectomy carcinoembryonic antigen and short disease‐free interval were negative predictive factors for survival. Long‐term follow‐up study is required, as recurrence can occur more than 5 years after pulmonary metastasectomy. Also, whether the survival benefit is due to surgical treatment effect or lead‐time bias remains undecided.  相似文献   
74.
Abstract   Early detection and characterization of small hepatocellular carcinoma (HCC) by imaging is possible with high confidence, and is important for the improvement of the prognosis of the patient with liver cirrhosis. In this lecture, screening of HCC and its characterization by imaging, with special reference to imaging features of human multi step hepato carcinogenesis will be discussed.  相似文献   
75.
15例肺心病血液高粘滞患者自体血250ml用XZY-Ⅰ型量子血液治疗机进行紫外线照射和充以纯氧后再输入,每周一次,最多连续做三次(平均1.86±0.71次)后,作者发现血液全血高切、低切粘度,全血高切、低切还原粘度,血浆比粘度,血浆纤维否白原含量,红细胞聚集指数,红细胞电泳率等有显著性改变,单纯常规治疗组15例患者血液流变无此变化,分析认为,这些变化可能与红细胞聚集性降低、纤维蛋白源溶解度提高及血氧饱和度增加有关。  相似文献   
76.
作者报道28例经手术及病理证实的肺部囊性病变,其中21例为先天性,7例为后天性.x线表现可分为:①单发气囊腔.②多发性气囊腔.③单发液囊腔.④单或多发液气囊腔,内有液平面.⑤肺隔离症.讨论了形成机理以及与肺结核,肺脓肿,肺癌,转移性肺肿瘤,肺包虫囊肿等的x线鉴别诊断  相似文献   
77.
A case is reported of Wilms' tumor associated with multiple pulmonary metastases histologically showing maturation of the tumor cells at 9 years after the resection of the primary tumor and intensive therapy. A huge tumor of a 22-month-old patient's right kidney was resected. The tumor was diagnosed as Wilms' tumor of mesenchymal type (stage 1), which consisted of predominantly immature mesenchymal tissue including rhabdomyoblasts, smooth muscle and fibrous tissue, and few blastemal and epithelial components. Intensive preoperative and postoperative chemotherapy with actinomycin D and vincristine and postoperative irradiation therapy totaling 16 Gy were carried out. The patient was regularly followed up uneventfully until 9 years after the surgery. On routine chest x ray at the age of 10 years 11 months, multiple pulmonary nodules were found. The excised nodules from the bilateral lungs disclosed similar histology, exclusively composed of dense collagen bundles and fibrocytes intermingled with mature striated muscle bundles. No immature tumor components were detected. The possible effect of intensive therapy in this maturation was stressed, although spontaneous benign differentiation of tumor cells cannot be excluded.  相似文献   
78.
目的 探讨慢性阻塞性肺疾病(慢阻肺)患者的家庭支持与自我概念的关系。方法 用方便抽样法选取108位慢阻肺患者,应用修订的个人资源问卷、自我概念量表和一般资料问卷分别测定其家庭支持、自我概念水平和一般资料。结果 该组患者家庭支持程度为中到高度,自我概念中度积极;家庭支持与总的自我概念呈中度正相关,与自我概念中的体感、自我一致性、理想自我及道德一伦理一精神自我有显著相关.与体象无关。结论 慢阻肺患者的家庭支持水平越高,其自我概念越积极。  相似文献   
79.
Summary Partial anomalous pulmonary venous connections (PAPVCs) are rare in association with an intact atrial septum. However, the diagnosis should be considered in patients with otherwise unexplained findings of left-to-right shunt and right heart enlargement. An unusual variant is presented, which we considered unsuitable for operative repair, based on findings at catheterization. Developmental, hemodynamic, and surgical considerations are discussed.  相似文献   
80.
Background : A patient with a solitary pulmonary metastasis who had breast cancer in the past may benefit from pulmonary resection. Methods : Between 1984 and 1996, 17 patients underwent metastatectomy for metastatic breast cancer. There were 15 females and two males whose average age was 59 (range: 40–74 years). The median tumour-free interval after the primary breast-cancer operation was 5.1 years (range: 8 months-18.2 years). Sixteen patients had complete resections, which included six lobectomies and 10 lesser resections. Results : The postoperative mortality was nil and the morbidity rate was 6%. Follow-up was complete in all patients. Recurrent disease developed in four patients and two patients died of their disease. The 5-year survival was 62%. Conclusion : An aggressive surgical approach is warranted in patients with isolated resectable pulmonary metastases from breast cancer.  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