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   1249849篇
  免费   97538篇
  国内免费   8583篇
耳鼻咽喉   18038篇
儿科学   32436篇
妇产科学   34442篇
基础医学   176488篇
口腔科学   37086篇
临床医学   109306篇
内科学   241298篇
皮肤病学   25017篇
神经病学   97118篇
特种医学   49436篇
外国民族医学   297篇
外科学   195299篇
综合类   42773篇
现状与发展   9篇
一般理论   321篇
预防医学   85903篇
眼科学   30452篇
药学   98260篇
  64篇
中国医学   6992篇
肿瘤学   74935篇
  2018年   12986篇
  2017年   10294篇
  2016年   11112篇
  2015年   13565篇
  2014年   18780篇
  2013年   25506篇
  2012年   35038篇
  2011年   36588篇
  2010年   21770篇
  2009年   20051篇
  2008年   33188篇
  2007年   35988篇
  2006年   35919篇
  2005年   34627篇
  2004年   33204篇
  2003年   32382篇
  2002年   30958篇
  2001年   61781篇
  2000年   62868篇
  1999年   53003篇
  1998年   14696篇
  1997年   13159篇
  1996年   12494篇
  1995年   11738篇
  1994年   11001篇
  1992年   41565篇
  1991年   39909篇
  1990年   38814篇
  1989年   37745篇
  1988年   34949篇
  1987年   34127篇
  1986年   32132篇
  1985年   30812篇
  1984年   22833篇
  1983年   19276篇
  1982年   11365篇
  1981年   10248篇
  1979年   21897篇
  1978年   15257篇
  1977年   12982篇
  1976年   11450篇
  1975年   12629篇
  1974年   15516篇
  1973年   14817篇
  1972年   14215篇
  1971年   13335篇
  1970年   12621篇
  1969年   12344篇
  1968年   11037篇
  1967年   10084篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
UPSC has been identified as a distinct variant of endometrial cancer and it has been reported to be associated with more aggressive behavior and a worse prognosis compared to endometrioid adenocarcinomas of the endometrium. Various studies have demonstrated survival rates of 15–51% for clinical stage I disease and 35–90% for surgical stage I/II disease. Aside from the very limited number of studies that incorporate comprehensive surgical staging, the majority of these reports used clinical parameters for staging or very limited surgical staging techniques and information.
A significant amount of controversy surrounds the optimal management of patients with stage I UPSC, and appropriate management of these patients has yet to be firmly established. The low incidence of this particular type of cancer, the variety of surgical interventions, and the wide variety of post-operative adjuvant therapies have made it extremely difficult to identify the optimal management of patients with UPSC. Prior to 2004, adjuvant treatment recommendations for surgical stage I UPSC were largely based on very small retrospective patient series (<20 patients), only a fraction of which included surgically staged patients. A recent publication reported the outcomes of surgical stage I UPSC patients from four institutions (1) . Recurrence rates were lower than that published in previous studies, suggesting a potential benefit of comprehensive surgical staging in these patients. The risk of recurrence and mean overall survival were similar between surgical stage I UPSC patients who were managed conservatively versus those treated with adjuvant radiation therapy. Moreover, this study also suggests a potential benefit of adjuvant chemotherapy in these patients.  相似文献   
992.
The detection of antineuronal antibodies against cytoplasm and nuclei of Purkinje cells is considered to be an essential factor in the diagnosis of neurologic paraneoplastic syndromes. Published data rely on different immunological methods and relatively small numbers of patients. The clinical relevance of this phenomenon is not clear from the literature. A positive correlation between antibody detection and the appearance of neurologic paraneoplastic syndromes has been reported, but this finding has been questioned in critical reviews.  相似文献   
993.
994.
An epidemiological study on the incidence and prevalence of Parkinson's disease (PD) was carried out in 29 provinces, cities and autonomous regions in this country in 1986. The survey was conducted in 117 areas, and 566 patients with PD were found among 3,869,162 persons examined, giving a point prevalence for men and women of 16.9/10(5) and 12.4/10(5), with the highest prevalence after the fifth decade of age. The disease was most prevalent in the southern part of China, especially in Hunan and Guangxi provinces. The incidence was 1.5/10(5)/yr in 1986. Both the prevalence and incidence of PD in China are lower than those in the white race and Japanese.
  相似文献   
995.
996.
Terpenes, especially 3-carene, may irritate the skin and mucous membranes and prolonged exposure may result in allergic contact dermatitis or chronic lung function impairment. The toxicokinetics of 3-carene were studied in human volunteers exposed by inhalation (2 hr 50 W) in an exposure chamber on three occasions. The exposure concentrations were approximately 10, 225, and 450 mg/m3 3-carene. The relative pulmonary uptake was high, approximately 70% for the higher exposure levels. Total uptake increased linearly with increasing exposure. The blood clearance of 3-carene observed in this study, 0.9 liter.kg-1.hr-1, indicates that 3-carene is fairly readily metabolized. About 3% of the total uptake was eliminated unchanged via the lungs while less than 0.001% was eliminated in the urine after the end of exposure. A long half time in blood was observed in the terminal phase which indicates a high affinity to adipose tissues. A statistically significant divergence between ratings of irritation during the high exposure level and during the medium and control levels was observed. The difference in airway resistance after exposure to a high concentration of 3-carene compared to control level was not significant (P = 0.02).  相似文献   
997.
The sensitive ELISA assay was used to measure the specific rubella virus IgG & IgM, and also the total IgM in the umbilical cord sera taken from 182 Saudi mothers during delivery in the Maternity Department at Al Ali General Hospital, Riyadh, Saudi Arabia. Nearly 84.6% (154 out of 182) Saudi women tested were found to be immune to rubella virus.  相似文献   
998.
A number of neurotransmitters and neuropeptides in the hypothalamus play a role in the control of food intake, metabolism, and body weight. Particularly, noradrenergic mechanisms in several areas of the hypothalamus are involved. Control of peripheral metabolism by the hypothalamus is achieved via autonomic modulation of the function of hepatocytes, adipocytes, and the endocrine cells in the islets of Langerhans. The autonomic control mechanisms ultimately lead to an appropriate shaping of blood glucose, plasma FFA, and insulin profiles to guarantee an adequate flow of nutrients under different physiological situations. Peripheral insulin and glucose can penetrate into the brain where they might affect the function of those brain structures involved in control of food intake, metabolism, and body weight.  相似文献   
999.
Biodegradable controlled-release microsphere systems made with the biocompatible biodegradable polyester excipient poly [DL lactide-co-glycolide] constitute an exciting new technology for drug delivery to the central nervous system (CNS). The present study describes functional observations indicating that implantation of dopamine (DA) microspheres encapsulated within two different polymer excipients into denervated-striatal tissue assures a prolonged release of the transmitter in vivo. Moreover, in this regard, the results show that there were clear cut temporal differences in the effect of the two DA microsphere formulations compared in this study, probably reflecting variations in the actual composition (i.e., lactide to glycolide ratio) of the two copolymer excipients examined. This technology has considerable potential for basic research with possible clinical application.  相似文献   
1000.
A quantitative assay for ALZ-50 immunoreactivity was evaluated in samples of superior temporal gyrus taken at autopsy from 13 Alzheimer patients and 11 controls. The assayable immunoreactivity appears to be stable for at least 24 hours postmortem but was lost with formalin fixation. The mean value of the Alzheimer patients was tenfold higher than that of the controls (P less than .002). The values of four Alzheimer samples overlapped with the low levels seen in controls, but no controls had elevated levels. In this sample population, therefore, the assay had a sensitivity of 69% and specificity of 100%.  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