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   1113篇
  免费   47篇
  国内免费   81篇
耳鼻咽喉   1篇
儿科学   54篇
妇产科学   7篇
基础医学   120篇
口腔科学   23篇
临床医学   184篇
内科学   235篇
皮肤病学   25篇
神经病学   17篇
特种医学   286篇
外科学   89篇
综合类   22篇
预防医学   28篇
眼科学   4篇
药学   94篇
肿瘤学   52篇
  2023年   5篇
  2022年   3篇
  2021年   9篇
  2020年   4篇
  2019年   3篇
  2018年   9篇
  2017年   7篇
  2016年   12篇
  2015年   21篇
  2014年   20篇
  2013年   23篇
  2012年   24篇
  2011年   17篇
  2010年   37篇
  2009年   42篇
  2008年   25篇
  2007年   76篇
  2006年   22篇
  2005年   28篇
  2004年   18篇
  2003年   33篇
  2002年   23篇
  2001年   28篇
  2000年   27篇
  1999年   26篇
  1998年   67篇
  1997年   73篇
  1996年   50篇
  1995年   63篇
  1994年   37篇
  1993年   35篇
  1992年   18篇
  1991年   25篇
  1990年   15篇
  1989年   36篇
  1988年   37篇
  1987年   26篇
  1986年   30篇
  1985年   44篇
  1984年   18篇
  1983年   13篇
  1982年   25篇
  1981年   14篇
  1980年   24篇
  1979年   4篇
  1978年   5篇
  1977年   14篇
  1976年   15篇
  1975年   9篇
  1970年   1篇
排序方式: 共有1241条查询结果,搜索用时 0 毫秒
21.
Thrombocytopoietic properties of oncostatin M   总被引:1,自引:2,他引:1  
Oncostatin M (OM) is a 28-kD glycoprotein that exhibits a panoply of biologic effects. Based on histologic observations of increased splenic megakaryocytes in nude mice implanted with an OM-secreting cell line, the thrombocytopoietic properties of OM in mice were investigated in culture and in vivo. Alone, OM did not induce megakaryocytic colony formation, but in combination with murine interleukin-3 (IL-3), OM markedly enhanced colony formation. The effects of OM on colony formation were similar to those of IL-6. OM alone augmented acetylcholinesterase in short-term marrow cultures. In normal mice, the administration of OM augmented platelet counts without increasing other circulating blood cell counts. The increment in counts exceeded that observed with IL-6. The kinetics of the OM response suggested that maximal increases in platelets occurred 3 days after the cessation of OM administration, irrespective of the duration of administration. In irradiated mice, OM administration accelerated platelet recovery and prevented the decrease in red blood cells observed in irradiated control animals. The data show that OM behaves as a megakaryocytic maturation factor in vitro and augments platelet production in vivo. Based on these animal data, OM may have potential clinical utility as a thrombocytopoietic agent.  相似文献   
22.
Aims. To examine the utility and validate the use of the Cardiac Depression Scale in patients who had first‐time coronary artery bypass graft surgery. Background. The Beck Depression Inventory, though frequently used, may not be sufficiently sensitive for use in cardiac patients. The Cardiac Depression Scale has been shown to identify the range of depression in medical cardiac patients. Design. Survey. Methods. The Beck Depression Inventory and Cardiac Depression Scale were administered to 120 men at hospital discharge, as well as six, 12 and 36 weeks postoperatively. Cronbach’s α scores were calculated for the measures at each point. Changes in scores over time were analysed using repeated measures analysis of variance. Associations between the measures scores were calculated using Pearson product–moment correlations. Agreement between the measures’ dichotomised scores (depression/no depression) was examined using Cohen’s Kappa statistic. Results. Internal consistency was similar for the Beck Depression Inventory (0·793–0·904) and Cardiac Depression Scale (0·859–0·910). Depression scores decreased over time with the Beck Depression Inventory [F(2·50, 175·29) = 22·27, p < 0·001] and Cardiac Depression Scale [F(2·68, 190·37) = 13·18, p < 0·001]. The measures had similar power [Cohen’s f = 0·65 (Beck Depression Inventory) and 0·43 (Cardiac Depression Scale)] to reveal changes over time. The continuous scores were highly correlated at each point [0·737 (p < 0·001)–0·819 (p < 0·001)]. However, when dichotomised scores were compared, the chance corrected level of agreement was less impressive [0·198 (p = 0·014)–0·381 (p < 0·001)]. Conclusions. The Cardiac Depression Scale may have utility for use with surgical cardiac patients. However, continued examination of this measure of depression is warranted. Relevance to clinical practice. Given the prevalence of depression and its negative impact on coronary artery disease, it is important to identify even mild depression in cardiac patients. Using a measure of depression specifically for cardiac patients, rather than a generic measure, may best accomplish this goal.  相似文献   
23.
24.
JB Ma  SX Yao  H  Li  Q  Pei JF  Yao 《美中国际创伤杂志》2014,(1):1-4,9
In this case, a male patient presented with a clinically and radiographieally unstable slipped capital femoral epiphysis (SCFE) as well as slipped calcaneal epiphysis years. Subsequent thorough at the age of 23 work-up revealed that he had some features of rickets and labo- ratory test demonstrated he had hypophos- phatemia (2.3mg/dl), normocalcemia, normal vi- tamin D metabolite levels, and secondary hy- perparathyroidism.  相似文献   
25.
There is increasing evidence that genetic factors have a role in differential susceptibility to depression in response to severe or chronic adversity. Studies in animals suggest that nitric oxide (NO) signalling has a key role in depression-like behavioural responses to stress. This study investigated whether genetic variation in the brain-expressed nitric oxide synthase gene NOS1 modifies the relationship between psychosocial stress and current depression score. We recruited a population sample of 1222 individuals who provided DNA and questionnaire data on symptoms and stress. Scores on the List of Life-Threatening Experiences (LTE) questionnaire for the last year and self-rated current financial hardship were used as measures of recent/ongoing psychosocial stress. Twenty SNPs were genotyped. Significant associations between eight NOS1 SNPs, comprising two regional haplotypes, and current depression score were identified that survived correction for multiple testing when current financial hardship was used as the interaction term. A smaller three-SNP haplotypes (rs10507279, rs1004356 and rs3782218) located in a regulatory region of NOS1 showed one of the strongest effects, with the A-C-T haplotype associating with higher depression scores at low adversity levels but lower depression scores at higher adversity levels (p=2.3E-05). These results suggest that NOS1 SNPs interact with exposure to economic and psychosocial stressors to alter individual''s susceptibility to depression.  相似文献   
26.
A human malignant melanoma cell line (M3Dau) was observed by electron microscopy to interact directly with human platelets and induced platelet aggregation. Fab fragments of a monoclonal antibody MoAb (LYP18), directed against the platelet glycoprotein (GP) IIb-IIIa complex, inhibited platelet-melanoma interactions and platelet-platelet aggregation. M3Dau melanoma cells bind LYP 18 and synthesize IIb-IIIa- like GPs. When the melanoma cells were preincubated with LYP 18, tumor- platelet interaction did not occur, suggesting that the interaction may be mediated by the IIb-IIIa-like GPs present on the melanoma cell surface. Glanzmann's thrombasthenic platelets, lacking GPIIb and IIIa, did not interact with melanoma cells, indicating that the platelet GPIIb-IIIa complex is also necessary for the platelet-melanoma cell interaction. This work demonstrates the importance of the IIb-IIIa-like GPs, present on M3Dau melanoma cells, in mediating tumor-platelet interactions.  相似文献   
27.
The functional capacities of granulocytes in patients with chronic granulocytic leukemia are still a subject of controversy, probably due to the heterogeneity of the abnormalities observed from patient to patient. For a better definition of these abnormalities, 14 patients with untreated chronic granulocytic leukemia were studied. The patients were divided into three groups on the basis of the functional activities of their phagocytosing granulocytes. In four patients (group I), the granulocytes were normal in respect to particle ingestion, nitroblue tetrazolium (NBT)-stimulated reduction, cyanide-insensitive oxygen (O2) consumption, superoxide anion (O2-)-stimulated production, hydrogen peroxide (H2O2) production, and iodination. They also had a normal myeloperoxidase (MPO) content. In four patients (group III), the granulocytes were significantly defective in all of these activities. In the six remaining patients (group II), all the initial metabolic steps of the phagocytosing granulocytes (ingestion, NBT reduction, O2 consumption, O2-production, H2O2 production) were normal, as were the MPO content of the granulocytes, while iodination was strikingly decreased. These metabolic features suggested a degranulation defect which was observed ultrastructurally in the only patient studied among these six. The phagocytosing granulocytes of this patient did not degranulate and no deposits of MPO activity were seen in the phagosomes.  相似文献   
28.
29.
30.
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