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   9469篇
  免费   812篇
  国内免费   5篇
  2023年   33篇
  2021年   143篇
  2020年   102篇
  2019年   110篇
  2018年   150篇
  2017年   166篇
  2016年   225篇
  2015年   406篇
  2014年   524篇
  2013年   624篇
  2012年   746篇
  2011年   668篇
  2010年   440篇
  2009年   375篇
  2008年   492篇
  2007年   504篇
  2006年   491篇
  2005年   463篇
  2004年   428篇
  2003年   399篇
  2002年   390篇
  2001年   147篇
  2000年   131篇
  1999年   139篇
  1998年   122篇
  1997年   94篇
  1996年   80篇
  1995年   73篇
  1994年   87篇
  1993年   78篇
  1992年   123篇
  1991年   97篇
  1990年   98篇
  1989年   97篇
  1988年   89篇
  1987年   70篇
  1986年   55篇
  1985年   77篇
  1984年   65篇
  1983年   73篇
  1982年   55篇
  1981年   63篇
  1980年   34篇
  1979年   37篇
  1978年   37篇
  1977年   35篇
  1976年   31篇
  1974年   43篇
  1973年   32篇
  1972年   37篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
81.
82.
83.
84.
85.
Ninety nine consecutive insulin dependent and 101 non-diabetic pregnant women were examined by ultrasonograph to assess early fetal growth. In 42 of the diabetic mothers and three of the non-diabetic mothers the scan showed early intrauterine growth delay. At 4-5 years of age all children available for study were evaluated by the Denver developmental screening test. Only 23 of the 34 children of diabetic mothers with early intrauterine growth delay had normal test scores compared with 46 of the 50 children of diabetic mothers with normal intrauterine growth. The children failed in personal-social development, gross motor development, and particularly in language and speech development. Children of diabetic mothers with normal early fetal growth had scores very similar to those of the children of non-diabetic mothers, of whom 76 of the 86 tested had normal scores.This study suggests that children with a history of growth delay in early diabetic pregnancy should be screened for possible developmental impairment.  相似文献   
86.
Fibrin degradation products (F.D.P.) were determined in the serum of 163 women in whom ovarian tumours had been suspected on palpation at gynaecological examination and who were afterwards examined by laparoscopy or subjected to laparotomy. F.D.P. were found in the serum (0·5-30 mg/100 ml) of 23 (72%) out of 32 patients with malignant tumours. Of 131 patients with benign findings F.D.P. (traces to 2 mg/100 ml) were found in six (4·5%), and in most of these the occurrence of F.D.P. could be explained on other clinical grounds. The findings suggest that the examination of F.D.P. in suspected malignant ovarian tumour may be of diagnostic value.Determination of F.D.P. in malignant ascitic fluid showed very high values, ranging between 40 and 350 mg/ 100 ml. This argues for the occurrence of F.D.P. in the blood being due to an extravascular breakdown of fibrin caused by tumour cells, but they may also be due to thromboplastic and fibrinolytic agents from the tumour entering the blood stream.  相似文献   
87.
88.
Fibrinolytic components after venous occlusion and concentrations of tissue plasminogen activator inhibitor were studied in 100 consecutive patients with confirmed recurrent deep vein thrombosis or pulmonary embolism. After 20 minutes of venous occlusion the fibrinolytic response was decreased in 33 patients, as measured both amidolytically with S-2251 and on fibrin plates. Two different mechanisms responsible for the poor fibrinolytic response could be distinguished. Twenty two of the patients in whom the response was poor released normal amounts of tissue plasminogen activator antigen, as assayed by immunoradiometric assay, but had appreciably increased concentrations of tissue plasminogen activator inhibitor. The 11 other patients in whom the response was poor had both low tissue plasminogen activator activities and low tissue plasminogen activator antigen concentrations but normal concentrations of tissue plasminogen activator inhibitor. The results show not only that defective synthesis or release of tissue plasminogen activator may be important in the pathogenesis of venous thrombosis but also that a large group of patients with thrombosis have an increased concentration of the inhibitor to tissue plasminogen activator.  相似文献   
89.
90.
An inv itro model for studying the biosynthesis of prostaglandins by isolated human epidermal cells is described. Production of prostaglandin E2-equivalent activity over an 18-hour incubation period was measured using a radioimmunoassay. Prostaglandin production was significantly inhibited by indomethacin and aspirin in a concentration-dependent manner.  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