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   7158篇
  免费   394篇
  国内免费   56篇
耳鼻咽喉   42篇
儿科学   143篇
妇产科学   99篇
基础医学   851篇
口腔科学   193篇
临床医学   525篇
内科学   1866篇
皮肤病学   261篇
神经病学   481篇
特种医学   205篇
外科学   1275篇
综合类   23篇
预防医学   153篇
眼科学   121篇
药学   525篇
中国医学   16篇
肿瘤学   829篇
  2023年   76篇
  2022年   148篇
  2021年   264篇
  2020年   145篇
  2019年   170篇
  2018年   260篇
  2017年   181篇
  2016年   217篇
  2015年   207篇
  2014年   226篇
  2013年   294篇
  2012年   447篇
  2011年   515篇
  2010年   276篇
  2009年   233篇
  2008年   346篇
  2007年   380篇
  2006年   364篇
  2005年   362篇
  2004年   361篇
  2003年   344篇
  2002年   323篇
  2001年   117篇
  2000年   109篇
  1999年   106篇
  1998年   76篇
  1997年   59篇
  1996年   60篇
  1995年   50篇
  1994年   51篇
  1993年   48篇
  1992年   58篇
  1991年   68篇
  1990年   43篇
  1989年   80篇
  1988年   62篇
  1987年   62篇
  1986年   44篇
  1985年   43篇
  1984年   35篇
  1983年   38篇
  1981年   18篇
  1980年   22篇
  1979年   36篇
  1978年   21篇
  1977年   18篇
  1976年   15篇
  1975年   14篇
  1974年   23篇
  1972年   17篇
排序方式: 共有7608条查询结果,搜索用时 15 毫秒
11.
We investigated the effects of mild and non-lethal ischemic insult on neuronal death following subsequent lethal ischemic stress in various brain regions, using a gerbil model of bilateral cerebral ischemia. Single 10-min ischemia consistently caused neuronal damage in the hippocampal CA1, CA2, CA3 and CA4, layer III/IV of the cerebral cortex, dorsolateral part of the caudoputamen and ventrolateral part of the thalamus. On the other hand, in double ischemia groups, 2-min ischemic insult 2 days before 10-min ischemia exhibited significant protection in the CA1 and CA3 of the hippocampus, the cerebral cortex, the caudoputamen and the thalamus. Five-min ischemic insult 2 days before 10-min ischemia also showed protective effect in the same areas as those of 2-min ischemia except for the CA1 region of the hippocampus, while 1-min ischemic insult exhibited no protective effect in any brain regions. In the immunoblot analysis, both 2- and 5-min ischemia caused increased synthesis of heat shock protein 72 (HSP 72) in the hippocampus, but 1-min ischemia did not. The present study demonstrated that the ‘ischemic tolerance’ phenomenon was widely found in the brain and also suggested that ischemic treatment severe enough to cause HSP 72 synthesis might be needed for induction of ‘ischemic tolerance’.  相似文献   
12.
We report a case of advanced gallbladder cancer in a 37-year-old man who presented in June 1993 with malignant obstructive jaundice. After percutaneous transhepatic biliary drainage and several diagnostic imaging examinations, the patient underwent laparotomy under a diagnosis of extremely advanced gallbladder cancer involving the confluence of the hepatic ducts. The tumor, however, was judged to be unresectable because of its massive spread into the liver along Glisson's sheath, and because of histologically proven peritoneal dissemination. After exploratory laparotomy, one course of anticancer chemotherapy (cisplatin, 100 mg/body IV, on day 1, and 5-fluorouracil, 1000 mg/body, on days 1–5, by continuous infusion) was administered and the completely obstructed hepatic duct was dramatically re-canalized. Four courses of chemotherapy were administered over a 16-month period until jaundice recurred. For these 16 months, the patient's quality of life was well maintained without biliary drainage. He died of increased peritoneal dissemination approximately 2 years after the first course of anticancer chemotherapy.  相似文献   
13.
A 60-year-old man had been administered diphenylhydantoin (DPH) for prevention of convulsive seizures following clipping of an aneurysm of the middle cerebral artery. About one month after the commencement of DPH administration, he developed cough and low grade fever. He was treated with various antibiotics, but his condition increasingly worsened. Chest X-ray film revealed bilateral interstitial processes throughout the entire lung fields. Transbronchial lung biopsy was performed and the obtained specimen showed histological findings compatible with drug-induced pneumonitis. Administration of DPH was stopped immediately and 50 mg/day of prednisolone was started. The patient's condition rapidly improved, and the abnormal shadows on chest X-ray film gradually diminished. The lymphocyte stimulation test by DPH was positive with a stimulation index of 282%.  相似文献   
14.
This study was undertaken in an attempt to find factors which affected the recent declining birth rate in Tokyo. Vital statistics of the female population, age 20-39, for the period of 1970 through 1985 for Tokyo were compared to national averages. Indices examined were birth rate, percentage of married women, birth rate for married women, and birth rate for married women by live birth order. Results thus obtained were as follows: 1. Birth rates for females aged 20-24 and 25-29 were largely dependent on percentages of married women rather than birth rates for married women both in Tokyo and in the nation as a whole, while the birth rates for females aged 30-34 and 35-39 were more dependent on birth rates for married women. 2. Percentages of married women aged 20-24 and 25-29 decreased during the observation period both in Tokyo and in the nation as a whole. 3. Birth rates for married women aged 30-34 and 35-39 dropped in the first 5 or 10 years of observation in both groups as a result of the reduction in high order live births. Thereafter, the decline changed to an upturn trend. 4. Yearly changes of birth rate, percentage of married women, birth rate for married women, birth rate for married women by live birth order, and birth rate of first child for married women appeared to have the same timing both in Tokyo and in Japan as a whole in each age category.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
15.
16.
17.
The effects of glucocorticoids on the proportion of lymphocytes in bronchoalveolar lavage (BAL) fluid in relation to humoral and cellular immunity were studied in 56 patients with steroid-dependent intractable asthma. To analyze the mechanism responsible for reduced numbers of BAL lymphocytes, we divided the subjects into 4 groups according to their BAL lymphocyte proportions: 0—4.9%, 5.0-9.9%, 10.0-14.9%, and 15.0-20.0%. Serum IgG levels and the peripheral lymphocyte count were significantly reduced in patients with a low proportion of BAL lymphocytes (less than 9.9%) than in those with more than 10% BAL lymphocytes. Delayed cutaneous reactivity to purified protein derivative was suppressed in patients with a low proportion of BAL lymphocytes (less than 4.9%). The mean proportion of BAL neutrophils tended to increase as the proportion of BAL lymphocytes decreased. These results show that the reduction in BAL lymphocytes produced by glucocorticoids is associated with suppressed humoral and cellular immunity, and that under such conditions the proportion of BAL neutrophils increases.  相似文献   
18.
A 47-year-old woman visited a clinic with dyspnea which had continued for two months and was followed by general fatigue and fever. Antibiotics were not effective. Edematous erythema occurred on her face, elbows, knees and feet, and she entered our hospital. A skin biopsy revealed interface dermatitis with severe edema and mucinosis in dermis. Diffuse bilateral infiltration was observed in the chest X-ray, and laboratory findings showed increased LDH, GPT, GOT and CPK. No antinuclear factor was detected. Her respiratory condition rapidly worsened, and she died eight days after hospitalization in spite of corticosteroid pulse therapy. The autopsy revealed that the main cause of death was diffuse alveolar damage (DAD). Interstitial pneumonia related to dermatomyositis is not histologically uniform; the response to the therapy depends on its histological type. The patients with dermatomyositis who have poor prognosis are clinically characterized by acute onset with general symptoms and less pronounced muscle weakness; they generally show DAD in their lungs. We need to establish a simple method for distinguishing histological types of interstitial pneumonia and adequate therapy for each one.  相似文献   
19.
The histogenesis of stromal cells in hemangioblastoma is inconclusive despite a long-term controversy. An immunohistochemical and ultrastructural study was conducted for 17 cases of cerebellar hemangioblastoma. A wide range of immunohistological markers, targeting epithelial, mesenchymal, endothelial and neuroectodermal tissues, was used. In all cases, the microscopic hallmark characterizing hemangioblastomas, that is, lipid-containing stromal cells and a fine capillary network, known as a reticular variant, was noted. Stromal cells showed a variable immunoreactivity for neuroectodermal markers, such as S-100 protein, CD56, CD57, CD99, and neuron-specific enolase. This result, in conjunction with the absence of immunoreactivity for epithelial, mesenchymal, and endothelial markers, likely suggests neuroectodermal differentiation of stromal cells. In three cases, another component, known as a cellular variant, where epithelioid tumor cells were arranged in nests encircled by capillaries and/or in pseudorosette-like structures, was noted. Glial fibrillary acidic protein-immunoreactivity, which was totally absent in cases only showing the reticular pattern, was noted in two of them, suggesting a distinctive sign of glial differentiation in a proportion of hemangioblastomas. Ultrastructurally, microvilli-like projections in intracytoplasmic vacuoles were demonstrated in stromal cells. This result, taken together with the neuroectodermal hypothesis of stromal cells, suggests that hemangioblastomas may occasionally exhibit morphological similarities to ependymomas.  相似文献   
20.
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