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   323篇
  免费   7篇
  国内免费   19篇
儿科学   35篇
妇产科学   6篇
基础医学   29篇
口腔科学   5篇
临床医学   21篇
内科学   66篇
神经病学   2篇
特种医学   96篇
外科学   5篇
综合类   14篇
预防医学   38篇
药学   23篇
肿瘤学   9篇
  2018年   2篇
  2015年   3篇
  2014年   8篇
  2013年   4篇
  2012年   7篇
  2011年   3篇
  2010年   5篇
  2009年   3篇
  2008年   5篇
  2007年   18篇
  2006年   5篇
  2005年   7篇
  2004年   7篇
  2003年   12篇
  2002年   6篇
  2001年   9篇
  2000年   8篇
  1999年   6篇
  1998年   11篇
  1997年   21篇
  1996年   12篇
  1995年   9篇
  1994年   13篇
  1993年   10篇
  1992年   3篇
  1991年   4篇
  1990年   4篇
  1989年   19篇
  1988年   7篇
  1987年   12篇
  1986年   15篇
  1985年   12篇
  1984年   4篇
  1983年   8篇
  1982年   10篇
  1981年   8篇
  1980年   9篇
  1978年   3篇
  1977年   2篇
  1976年   4篇
  1975年   3篇
  1974年   2篇
  1973年   3篇
  1972年   2篇
  1971年   2篇
  1969年   3篇
  1968年   2篇
  1967年   5篇
  1966年   1篇
  1965年   1篇
排序方式: 共有349条查询结果,搜索用时 11 毫秒
11.
12.
Six normal and 16 neoplastic colorectal specimens were examined with 8.5-MHz ultrasound (US). An articulated system facilitated precise spatial correlation between US and histologic sections. Images were blindly interpreted and then compared with histologic results. All six normal specimen showed five distinct echo layers and were distinguished from neoplastic specimens by all the observers. The central echogenic layer, corresponding to the submucosa, is useful in determining the depth of origin of a neoplasm and the presence of submucosal invasion. US had an accuracy of 92.5% in demonstrating invasion of the submucosa and 77% for invasion of the muscularis externa. For mucosal neoplasms with invasion through the muscularis externa and extension into the subserosal tissues, nearly 90% of US interpretations were correct. High-frequency US may be useful in determining the depth of invasion of mucosal tumors with respect to the submucosa and in differentiating mucosal from extramural masses.  相似文献   
13.
PEG-rHuMGDF injected daily in normal mice causes a rapid dose-dependent increase in megakaryocytes and platelets. At the same time that platelet numbers are increased, the mean platelet volume (MPV) and platelet distribution width (PDW) can be either decreased, normal, or increased depending on the dose and time after administration. Thus, PEG-rHuMGDF at a low dose causes decreases in MPV and PDW, MGDF at an intermediate dose causes an initial increase followed by a decrease in MPV and PDW, and PEG-rHuMGDF at higher doses causes an increase in MPV and PDW followed by a gradual normalization of these platelet indices. In addition to the expected thrombocytosis after 7 to 10 days of daily injection of high doses of PEG-rHuMGDF, a transient decrease in peripheral red blood cell numbers and hemoglobin is noted accompanied in the bone marrow by megakaryocytic hyperplasia, myeloid hyperplasia, erythroid and lymphoid hypoplasia, and deposition of a fine network of reticulin fibers. Splenomegaly, an increase in splenic megakaryocytes, and extramedullary hematopoiesis accompany the hematologic changes in the peripheral blood and marrow to complete a spectrum of pathologic features similar to those reported in patients with myelofibrosis and megakaryocyte hyperplasia. However, all the PEG-rHuMGDF-initiated hematopathology including the increase in marrow reticulin is completely and rapidly reversible upon the cessation of administration of PEG-rHuMGDF. Thus, transient hyperplastic proliferation of megakaryocytes does not cause irreversible tissue injury. Furthermore, PEG-rHuMGDF completely ameliorates carboplatin-induced thrombocytopenia at a low-dose that does not cause the hematopathology associated with myelofibrosis.  相似文献   
14.
Glezen WP 《Vaccine》2000,19(Z1):S56-S58
Human experimental challenge studies with influenza virus infection and controlled intervention trials have demonstrated beyond doubt the role of influenza virus infection in the pathogenesis of acute otitis media. Influenza virus infections not only disrupt eustachian tube function, but also impair recovery from infection and facilitate attachment of bacterial pathogens to respiratory epithelial cells. Immunization of young children with either inactivated or live, attenuated influenza vaccine will significantly reduce the incidence of acute otitis media. Early treatment of influenza with antiviral medication will reduce eustachian tube dysfunction that results from influenza virus infection. Influenza produces high morbidity in children that could be averted by universal immunization with attenuated nasal spray vaccine.  相似文献   
15.
Effectiveness of rimantadine prophylaxis of children within families   总被引:3,自引:0,他引:3  
With recent studies suggesting that children are the main introducers of influenza infections into families, we conducted a placebo-controlled, double-blind, randomized trial to study the prophylactic effectiveness of rimantadine hydrochloride in children on the transmission of influenza A infections within families. One hundred forty-five volunteers from 35 families completed this study during a naturally occurring outbreak of influenza A (H1N1) infection. Influenza infections, defined as a positive viral throat culture or a fourfold increase in antibody titer, occurred in 31.7% of children in the placebo group and 2.9% of children in the rimantadine group. Clinical illness with laboratory evidence of influenza infection occurred in 17.0% of children in the placebo group and 0% of children in the rimantadine group. Rimantadine was well tolerated by the children, with no significant difference in reported side effects between the placebo and rimantadine groups. Influenza A infection occurred in 19.0% of adults whose children were receiving a placebo and 8.8% of adults whose children were receiving rimantadine. On the basis of our study, rimantadine prophylaxis of children appears to be an effective method to prevent influenza A infection in children. Additional studies are needed to demonstrate the effects of rimantadine prophylaxis of children on the incidence of influenza A infection in their parents.  相似文献   
16.
Both ultrasonography (US) and cholescintigraphy are used to study gallbladder dynamics. The present study was undertaken to determine whether the two methods provide the same or different information relating to gallbladder emptying. Emptying was simultaneously studied with both methods during infusion of graded physiologic doses of cholecystokinin (CCK) in six healthy subjects. Infusion of stepwise increasing doses of CCK, ranging from 0.03 to 0.5 Ivy dog units per kilogram of body weight per hour (IDU/kg.h), induced significant dose-related increases in plasma CCK, decreases in gallbladder volume assessed with US, and gallbladder emptying assessed with cholescintigraphy. The threshold dose for inducing significant gallbladder emptying was 0.13 IDU/kg.h, as determined with both techniques, indicating similar detection limits. There was a highly significant correlation between decreases in gallbladder volume and decreases in radioactive counts over the gallbladder region, with a tendency toward greater gallbladder responses at sonography during the early phase of gallbladder contraction and toward greater responses at cholescintigraphy during the later phase of gallbladder contraction. It is concluded that these methods can be used interchangeably for the quantitation of gallbladder emptying.  相似文献   
17.
Major motor atrophic patterns in the face and neck: CT evaluation   总被引:1,自引:0,他引:1  
Harnsberger  HR; Dillon  WP 《Radiology》1985,155(3):665-670
Cranial nerve deficits from various pathologic processes of the head and neck may result in characteristic patterns of denervation muscular atrophy. Such atrophic patterns may be clues to the location and extent of the lesion, particularly when cranial nerves are involved early in the course of the disease process. Thirty-six patients with computed tomographic (CT) evidence of muscular atrophy secondary to pathologic conditions involving the motor division of cranial nerves were examined. Five characteristic denervation muscular atrophy patterns seen on CT scans were identified. In several patients, identification of the muscular atrophy pattern was the only clue to the presence of a pathologic condition. Recognition of these atrophic patterns can prevent misinterpretation of their CT appearance and direct the CT examination to the course of the compromised cranial nerve from the brainstem to its peripheral innervation.  相似文献   
18.
19.
Englund JA  Glezen WP 《Vaccine》2003,21(24):3455-3459
Haemophilus influenzae type b (Hib) vaccines provide an excellent model for maternal immunization because effective vaccines are readily available and the vaccines are safe and reliable, and markers of efficacy have been established and standardized. Studies of polysaccharide and conjugate Hib vaccines administered to pregnant women and women of childbearing ages are reviewed in this paper. The type of vaccine has been shown to be important in increasing transplacental passage of maternal antibody. The timing of vaccine during pregnancy is also important in the transfer of this antibody. The total amount of IgG antibody in the mother, as well as the isotype class and subclass of IgG antibody, influences the final levels of antibody in the neonate. Placental integrity has been shown to be important in the active transport of antibody from mother to fetus. The impact of increased levels of Hib antibody in infants at the time of primary immunization with Hib does not appear to interfere with vaccine efficacy, although higher antibody levels in infants at the time of immunization may result in lower total antibody levels following all doses of vaccine. Principles observed in these studies have potential application against other important neonatal pathogens.  相似文献   
20.
Breast cancer is one of the leading causes of cancer deaths among women[1].In the past 40 years,breast cancer incidence has doubled or even tripled in developed countries such as South Korea and Japan; whereas it is about 20% to 30% in China and India in the past decade[2-4]. An increasing incidence rate of 3%  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