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   1855510篇
  免费   127250篇
  国内免费   3515篇
耳鼻咽喉   26283篇
儿科学   60067篇
妇产科学   51850篇
基础医学   262998篇
口腔科学   51551篇
临床医学   159959篇
内科学   361650篇
皮肤病学   41087篇
神经病学   143763篇
特种医学   74287篇
外国民族医学   535篇
外科学   286230篇
综合类   38492篇
现状与发展   1篇
一般理论   495篇
预防医学   132094篇
眼科学   42419篇
药学   141271篇
  7篇
中国医学   4355篇
肿瘤学   106881篇
  2018年   19008篇
  2017年   14993篇
  2016年   16596篇
  2015年   18604篇
  2014年   25925篇
  2013年   39007篇
  2012年   52702篇
  2011年   55937篇
  2010年   33500篇
  2009年   31573篇
  2008年   52824篇
  2007年   56281篇
  2006年   57026篇
  2005年   55034篇
  2004年   52754篇
  2003年   50920篇
  2002年   49613篇
  2001年   93794篇
  2000年   96367篇
  1999年   81165篇
  1998年   21153篇
  1997年   18941篇
  1996年   18936篇
  1995年   17620篇
  1994年   16425篇
  1993年   15494篇
  1992年   61674篇
  1991年   59176篇
  1990年   58078篇
  1989年   55903篇
  1988年   51107篇
  1987年   49929篇
  1986年   47377篇
  1985年   44905篇
  1984年   32914篇
  1983年   27817篇
  1982年   15952篇
  1981年   13923篇
  1979年   29911篇
  1978年   20382篇
  1977年   17900篇
  1976年   16090篇
  1975年   18055篇
  1974年   21285篇
  1973年   20456篇
  1972年   19509篇
  1971年   18155篇
  1970年   17070篇
  1969年   16310篇
  1968年   14971篇
排序方式: 共有10000条查询结果,搜索用时 268 毫秒
991.
Positron emission tomography (PET) with fluorodeoxyglucose (FDG), magnetic resonance imaging (MRI), and CT were carried out in a patient with Alzheimer's disease 16 months before he died. At autopsy, the gross appearance of the brain correlated with MRI and CT, which showed some regional atrophy. These were much less revealing than PET, which correlated with microscopic findings of neuronal loss and proliferation of glia. In areas of moderately impaired local cerebral metabolic rate of glucose, as revealed by reduced FDG uptake, there was some gliosis, primarily around the numerous senile plaques. In areas of severe metabolic impairment, there was a profound loss of neurons, extensive gliosis, and a diminished appearance of plaques. PET-FDG is a better measure of the severity of Alzheimer's disease than MRI or CT, because it reflects the degree of neuronal pathology.  相似文献   
992.
A retrospective study was done in 316 patients with primary cervical adenocarcinoma treated at the Research Institute for Clinical and Experimental Oncology in Brno over a period of 40 years (1939-1978). The treatment results were compared to those in 2571 patients with epidermoid carcinomas of the uterine cervix treated at the Institute over the same period. The 5-year survival rate was significantly lower in adenocarcinoma patients (in Stage I patients, 77.8% vs. 84.5%, and, in the whole group, 60.8% vs. 70.3%). The assessment of the treatment results of this study has clearly showed that in cervical adenocarcinomas, surgery combined with radiotherapy was much more effective than radical radiotherapy alone (77.4% vs. 64.7%). In contrast to this, in epidermoid carcinomas the treatment results were better after radical radiotherapy (86.5% vs. 81.3%). Thus, in the prognosis of cervical adenocarcinomas the mass of the tumor, the size of the uterus, as well as the grading play a role. That means that primary cervical adenocarcinomas at early stages can be successfully treated by a combination of radical surgery and radiotherapy, while radiotherapy of advanced stages of this tumor is less successful.  相似文献   
993.
It is possible to determine the management and prognosis of mushroom poisoning from the history and initial symptoms with a high degree of confidence. The most important intoxications are those involving Amanita phalloides or other potentially fatal amatoxin-containing mushrooms, which have a latent period of ten to 12 hours before the patient becomes symptomatic. Because aggressive gastroenteric decontamination can reduce the extent of hepatic damage, it is important to attempt to determine during this asymptomatic period whether amatoxin exposure has occurred. Various laboratory methods that might be useful are reviewed.  相似文献   
994.
K A Roth  K G Bensch  A R Hoffman 《Cancer》1987,59(9):1594-1598
A thyroid medullary carcinoma from a man with the multiple endocrine neoplasia syndrome Type IIB was examined for the presence of opioid peptides. The tumor contained peptides derived from all three opioid precursors: pro-opiomelanocortin (POMC), pro-dynorphin, and pro-enkephalin. The tissue concentrations of the various opioid peptides varied considerably. beta-Endorphin, a POMC-derived peptide, was present in concentrations between 9 to 12 pmoles/g tissue; 8 pmoles/g tissue of alpha-neo-endorphin, a pro-dynorphin-derived product, were seen, whereas the pro-enkephalin-associated peptides were present in much lower concentrations (0.6-2.1 pmoles/g tissue). Immunohistochemical studies showed scattered opioid-positive cells in the tumor tissue and in two other thyroid medullary carcinomas. These data demonstrate that malignant neuroendocrine tumors may contain peptides derived from all three families of the endogenous opioids.  相似文献   
995.
996.
997.
K Nagai  T Suda  K Kawasaki  S Mathuura 《Surgery》1986,100(5):815-821
In rats treat-given hydrocortisone to suppress healing, tensile strength of the skin at the site of an incision wound was significantly higher in rats locally treated with carnosine than in untreated animals. Similar effects on the tensile strength of the skin were observed by the administration of beta-alanine and histidine, but not of beta-alanine alone. Exogenous carnosine was degraded in the body by carnosinase and histidine decarboxylase to yield histamine. Since beta-alanine, the other degradation product of carnosine, was found to stimulate the biosynthesis of nucleic acids and collagen, histamine derived from carnosine is considered to have enhanced the process of wound healing by stimulating effusion at the initial stage of inflammation. Thus, the enhancement by carnosine of wound healing may be ascribed to stimulation of early effusion by histamine and of collagen biosynthesis by beta-alanine. The wound-healing effects of carnosine were further demonstrated by the observation that carnosine significantly increased granulation suppressed by cortisone, mitomycin C, 5-fluorouracil, and bleomycin.  相似文献   
998.
999.
Clinical experience of phototherapy for non-haemolytic hyperbilirubinaemia in 3999 infants in Kandang Kerbau Hospital, Singapore, is documented. Phototherapy was most effective in extremely preterm infants with very low birth weight (gestation less than or equal to 32 weeks, birth weight less than or equal to 1500 g) and least effective in full term infants with very low birth weight (gestation greater than or equal to 37 weeks, birth weight less than or equal to 1500 g) and large preterm infants (gestation less than 37 weeks, birth weight greater than 2270 g). Overall, phototherapy was effective in almost all the infants, with a failure rate of only 2.00/1000 infants. No characteristic features common to all the failures could be detected. The bilirubin rebound was usually mild; repeat phototherapy was required in only 30 infants (7.50/1000), with the response to the second exposure comparable to that to the first. No infant required a third exposure. All the infants tolerated phototherapy well, none developing any illness that could be attributed to the treatment. This clinical experience shows that phototherapy for the treatment of nonhaemolytic hyperbilirubinaemia is effective and safe.  相似文献   
1000.
Roentgen endovascular occlusion with spiral emboli was used in 240 patients with different diseases. The introduction of spiral emboli into the arteries of abdominal and retroperitoneal organs was fulfilled through usual angiographic catheters. Duration of the arterial occlusion was checked up in the following angiographic examinations and showed the devices described to be appropriate for a continuous arterial blockade. No complications resulting from the introduction of the spiral embolus were noted.  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