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   20474篇
  免费   2102篇
  国内免费   47篇
耳鼻咽喉   128篇
儿科学   665篇
妇产科学   745篇
基础医学   3003篇
口腔科学   551篇
临床医学   2497篇
内科学   4087篇
皮肤病学   298篇
神经病学   1829篇
特种医学   684篇
外科学   2519篇
综合类   515篇
一般理论   17篇
预防医学   2080篇
眼科学   218篇
药学   1720篇
中国医学   32篇
肿瘤学   1035篇
  2021年   241篇
  2020年   159篇
  2019年   258篇
  2018年   306篇
  2017年   210篇
  2016年   258篇
  2015年   307篇
  2014年   418篇
  2013年   641篇
  2012年   909篇
  2011年   949篇
  2010年   547篇
  2009年   544篇
  2008年   815篇
  2007年   979篇
  2006年   891篇
  2005年   784篇
  2004年   850篇
  2003年   793篇
  2002年   759篇
  2001年   708篇
  2000年   699篇
  1999年   632篇
  1998年   275篇
  1997年   269篇
  1996年   236篇
  1995年   241篇
  1994年   184篇
  1993年   196篇
  1992年   519篇
  1991年   500篇
  1990年   443篇
  1989年   551篇
  1988年   450篇
  1987年   405篇
  1986年   445篇
  1985年   367篇
  1984年   309篇
  1983年   324篇
  1982年   190篇
  1981年   173篇
  1980年   144篇
  1979年   243篇
  1978年   190篇
  1977年   169篇
  1976年   163篇
  1974年   153篇
  1973年   181篇
  1972年   152篇
  1971年   160篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
32.
33.
The benefits of nutritional supplementation, with or without psychosocial stimulation, on the growth of stunted children were evaluated. Children aged 9-24 mo with lengths less than -2 SD of the National Center for Health Statistics references (n = 129) were randomly assigned to four groups: control, nutritional supplementation, stimulation, and both interventions. A fifth group with lengths greater than -1 SD was also enrolled. Length, weight, head and arm circumferences, and triceps and subscapular skinfold thicknesses were measured on enrollment and 6 and 12 mo later. Multiple-regression analysis was used to determine the effects of the interventions in which age, sex, initial status, initial dietary intake, and several socioeconomic variables were controlled for. Stimulation had no effect on growth and there was no interaction between the interventions. After 12 mo supplemented children had significantly increased length, weight, and head circumference (all P less than 0.01). The effects of supplementation were not cumulative but occurred in the first 6 mo.  相似文献   
34.
35.
BACKGROUND: Merkel cell carcinoma is a rare malignant neuroendocrine neoplasm characteristically arising from the dermis of sunlight-exposed skin. It rarely arises outside the skin. OBJECTIVE: We present a patient with primary Merkel cell carcinoma arising from subcutaneous fat, with no involvement of the overlying skin. We describe the clinical manifestations and magnetic resonance imaging (MRI) findings. METHODS: We report a 63-year-old woman with a primary lesion of Merkel cell carcinoma that arose from the subcutaneous fat layer of the left arm. The lesion presented as a subcutaneous nodule with intact overlying skin. MRI showed that the nodular lesion was located entirely in the subcutaneous fat layer, with no involvement of the dermis. Peritumoral infiltration around the lesion and enlarged lymph nodes deep to the lesion were noted. The patient received wide excision of the lesion with dissection of the regional lymph nodes and adjuvant radiotherapy and chemotherapy. RESULTS: Histopathologic examination confirmed the diagnosis of Merkel cell carcinoma with local lymphatic metastasis, and the lesion was completely located in the subcutaneous fat, with no involvement of the dermis. These findings were well correlated with MRI findings. CONCLUSION: Primary Merkel cell carcinoma may arise from the subcutaneous fat and present as an entirely subcutaneous lesion with intact skin. MRI is helpful to evaluate the local extension of the lesion and regional lymphatic metastasis.  相似文献   
36.
Pulmonary artery aneurysms are rare lesions for which operative management is not frequently undertaken. When operation is indicated, central lesions involving the pulmonary trunk, right main pulmonary artery, or left main pulmonary artery are repaired using cardiopulmonary bypass. Peripheral aneurysms in segmental intrapulmonary arteries have been managed most frequently by lobectomy, but occasionally by aneurysmectomy and pulmonary arterial repair. We used cardiopulmonary bypass for peripheral pulmonary aneurysmectomy in a patient with limited respiratory reserve because he had undergone prior contralateral bilobectomy; this allowed controlled resection while preserving a maximal amount of pulmonary parenchyma.  相似文献   
37.
The sera from 660 healthy blood donors from Canberra were tested for antibodies to Toxocara canis by the ELISA test. The results were compared with those from patients with suspected or confirmed visceral larva migrans or ocular toxocariasis. Over 7% of Canberra sera showed elevated levels of antibody reacting with T. canis antigen. Sera from patients resident in Australia with other helminth parasites did not cross-react with T. canis antigen in our tests. However, studies of sera collected in several tropical countries with other parasitic infection, show that cross-reactions with other parasites are possible. The use of purified glycoprotein antigen does not alter the possibility of cross-reaction. Observations and experiments show that people in Canberra may be exposed to the infective eggs of T. canis.  相似文献   
38.
39.
40.
Conclusions Brain death (or cerebral death) means definitive cessation of all neural functions above the spinal cord, thus implying the irreversible loss of all cerebral and brain stem functions.Spinal cord activity may persist after brain death-priapism, persistence of myotatic reflexes- for a few minutes and this spinal activity may be responsible for coarse limb movements after life-support machines have been turned off.The preservation of these spinal reflexes reinforces the advice to allow only responsible doctors to assist at the declaration of death of the patient.  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