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   737篇
  免费   52篇
  国内免费   60篇
耳鼻咽喉   4篇
儿科学   42篇
妇产科学   7篇
基础医学   82篇
口腔科学   16篇
临床医学   104篇
内科学   179篇
皮肤病学   14篇
神经病学   14篇
特种医学   90篇
外科学   153篇
综合类   21篇
预防医学   39篇
眼科学   4篇
药学   43篇
中国医学   2篇
肿瘤学   35篇
  2021年   3篇
  2020年   4篇
  2019年   10篇
  2018年   11篇
  2017年   4篇
  2016年   10篇
  2015年   11篇
  2014年   23篇
  2013年   31篇
  2012年   15篇
  2011年   19篇
  2010年   29篇
  2009年   28篇
  2008年   29篇
  2007年   50篇
  2006年   19篇
  2005年   23篇
  2004年   17篇
  2003年   14篇
  2002年   15篇
  2001年   17篇
  2000年   12篇
  1999年   22篇
  1998年   35篇
  1997年   41篇
  1996年   25篇
  1995年   28篇
  1994年   30篇
  1993年   22篇
  1992年   15篇
  1991年   15篇
  1990年   15篇
  1989年   25篇
  1988年   26篇
  1987年   18篇
  1986年   7篇
  1985年   15篇
  1984年   10篇
  1983年   6篇
  1982年   13篇
  1981年   15篇
  1980年   10篇
  1979年   4篇
  1978年   9篇
  1977年   9篇
  1976年   11篇
  1975年   4篇
  1971年   7篇
  1969年   3篇
  1966年   2篇
排序方式: 共有849条查询结果,搜索用时 15 毫秒
31.
Fifty-one patients with previously untreated or minimally treated chronic myelogenous leukemia in chronic phase received human alpha interferon 3 to 9 X 10(6) units intramuscularly (IM) daily until complete hematologic remission, then at doses ranging from 3 X 10(6) units every other day to 9 X 10(6) units daily. Forty-one (80%) patients achieved a hematologic response, 36 (71%) of them attaining a complete hematologic remission with normal peripheral WBC and differential counts. Responding patients showed continuous but slow normalization of several other blood and marrow parameters including platelet counts, serum lactic dehydrogenase and B12 levels, and marrow cellularity and maturation index. Suppression of the Philadelphia chromosome on serial cytogenetic studies of marrow metaphases was documented in 20 of the 36 patients who achieved complete hematologic remission (56%; 39% of total group), eight of whom (22%) had a decrease of the Philadelphia chromosome-positive metaphases to less than 35%. These changes were persistent for 6 months or longer in 18 patients, seven of whom had continuous suppression of the Philadelphia chromosome to less than 90% for a median of 30+ months (range 21+ to 39+ months). After a median follow-up period of 37 months, 25 patients remain in continued disease control with interferon therapy. The projected 3-year survival rate is 76%, with a yearly death rate of 6%, 9%, and 9% in the first 3 years. Response, Philadelphia chromosome suppression, and survival were significantly better among patients in the low-risk category compared to intermediate- and high-risk categories, as defined by a multivariate analysis-derived prognostic model. The projected 3- year survival rate was 94% for patients who achieved a complete hematologic remission on interferon therapy and 45% for those who did not. Thirteen patients have developed blastic crisis, six with lymphoid and three with undifferentiated morphology. We conclude that human leukocyte alpha interferon effectively controls chronic myeloid leukemia and allows reappearance of diploid hemopoietic cells in some patients.  相似文献   
32.
Long-term bone marrow cultures (LTBMC) from patients with multiple myeloma (MM) and normal donors were analyzed for immunophenotype and cytokine production. Both LTBMC adherent cells from myeloma and normal donor origin expressed CD10, CD13, the adhesion molecules CD44, CD54, vascular cell adhesion molecule 1, very late antigen 2 (VLA-2), and VLA- 5, and were positive for extracellular matrix components fibronectin, laminin, and collagen types 3 and 4. LTBMC from myeloma patients and normal donors spontaneously secreted interleukin-6 (IL-6). However, levels of IL-6 correlated with the stage of disease; highest levels of IL-6 were found in LTBMC from patients with active myeloma. To identify the origin of IL-6 production, LTBMC from MM patients and normal donors were cocultured with BM-derived myeloma cells and cells from myeloma cell lines. IL-6 was induced by plasma cell lines that adhered to LTBMC such as ARH-77 and RPMI-8226, but not by nonadhering cell lines U266 and FRAVEL. Myeloma cells strongly stimulated IL-6 secretion in cocultures with LTBMC adherent cells from normal donors and myeloma patients. When direct cellular contact between LTBMC and plasma cells was prevented by tissue-culture inserts, no IL-6 production was induced. This implies that intimate cell-cell contact is a prerequisite for IL-6 induction. Binding of purified myeloma cells to LTBMC adherent cells was partly inhibited by monoclonal antibodies against adhesion molecules VLA-4, CD44, and lymphocyte function-associated antigen 1 (LFA-1) present on the plasma cell. Antibodies against VLA-4, CD29, and LFA-1 also inhibited the induced IL-6 secretion in plasma cell-LTBMC cocultures. In situ hybridization studies performed before and after coculture with plasma cells indicated that LTBMC adherent cells produce the IL-6. These results suggest that the high levels of IL-6 found in LTBMC of MM patients with active disease are a reflection of their previous contact with tumor cells in vivo. These results provide a new perspective on tumor growth in MM and emphasize the importance of plasma cell-LTBMC interaction in the pathophysiology of MM.  相似文献   
33.
34.
A 54-year-old man with a unilocular hydatid cyst within the infero-posterior angle of the orbit and a 6-year-old male child with a unilocular hydatid cyst within the supero-medial angle of the orbit are presented. The retrobulbar cysts were diagnosed with computed tomography and ultrasonography and were treated after serologic confirmation.  相似文献   
35.
Childhood tuberculosis is perceived by many as a disease of the past. Experience in a children's hospital serving a deprived population suggested that tuberculosis and other mycobacterial infections were not declining in clinical practice. Fifty three tuberculous and 11 atypical mycobacterial infections were identified between 1978 and 1992. There was no decline in tuberculosis and nine of the 11 atypical infections occurred in the last five years. Altogether 40% of cases of tuberculosis were in non-Asian children; 32% had arrived in the UK or visited family overseas in the previous year; and 38% had a history of tuberculosis contact, usually a close adult relative. Nationally, the previous decline in tuberculosis in all ages has reversed. In the local health districts in London's east end, childhood tuberculosis has also stopped declining and seems to be increasing. It is regrettable that BCG vaccination has been abolished by some districts in the UK, against current recommendations. Childhood tuberculosis is still common in the practice described here, including among children who do not fall into conventionally recognised high risk groups. Inner city dwellers and junior doctors are both highly mobile populations, adding to the risk that paediatricians, particularly those in training, may encounter tuberculosis with little or no previous experience of the condition.  相似文献   
36.
This paper explores the role of milk-based formulae in achieving four aspects of nutritional health in infants and toddlers: in the suckling, to mimic the amino acid metabolism and the faecal flora of a breast-fed baby; in the weanling, to achieve adequate protein intakes in later infancy and beyond and to achieve satisfactory haemoglobin concentrations in the early toddler years. Milk-based formulae have two roles in infant nutrition: as so-called breast milk substitutes and as a safety net during the weaning period; the latter role may be the more important.  相似文献   
37.
One hundred and twenty eight Brazilian children with lymphoblastic leukaemia were intensively treated with a Berlin-Frankfurt-Munich based protocol. More children had a white cell count above 50 x 10(9)/l (31%) then observed in developed countries. After a median follow up of 31 months (11-58 months), the estimated probability of relapse free survival was 41% (7%) for the whole group. After adjustment in the Cox's multivariate model, malnutrition was the most significant adverse factor affecting duration of complete remission. Age above 8 years and high peripheral white cell count were also significant adverse factors. Among the nutritional indices, the height for age and weight for age z scores were both significant, whether the cut off points of z-2 or z = -1.28 were chosen to define malnutrition. A strong statistical association between the two indices was found; the contribution of height for age z score to the prediction of relapse free survival was more significant. Children with height for age z score < -2 had a relapse risk of 8.2 (95% confidence interval 3.1 to 21.9) relative to children with z score > -2. The results of this study suggest that socioeconomic and nutritional factors should be considered in the prognostic evaluation of children with leukaemia in developing countries.  相似文献   
38.
39.
Hemodynamic effects of isoproterenol, dopamine, and epinephrine were studied before and after acute beta-adrenergic blockade in 16 open-chest, anesthetized mongrel dogs. Beta blockade was induced with 1 mg. per kilogram of intravenous propranolol. Cardiac output measurements were obtained by thermal dilution, and pressure recordings were obtained in the right ventricle, pulmonary artery, left atrium, left ventricle, and aorta. Derived parameters included stroke volume, pulmonary and systemic vascular resistances, and peak left ventricular dP/dt. In the presence of propranolol, epinephrine became a lethal drug in large doses and did not increase cardiac output in standard doses. Dopamine, in 25 to 50 mcg. per kilogram per minute doses, increased arterial pressure and systemic resistance; cardiac output was diminished compared with dopamine, 10 mcg. per kilogram per minute, prior to propranolol, as a result of increased resistance and decreased LV contractility. Isoproterenol, 0.6 to 0.9 mcg. per kilogram per minute, 15 to 20 times standard dosages, had moderately positive inotropic effects and increased cardiac output. Left ventricular systolic pressure with isoproterenol after propranolol was reduced when compared with effects of smaller doses prior to propranolol. These observations suggest that none of the catecholamines studied would be optimal for circulatory support in heart failure in the presence of propranolol. The present results define a pharmacologic basis for design of appropriate drug combinations for circulatory support in beta-blocked animals.  相似文献   
40.
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