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   1313篇
  免费   0篇
电工技术   7篇
综合类   1篇
化学工业   25篇
建筑科学   3篇
轻工业   36篇
石油天然气   1篇
无线电   27篇
一般工业技术   10篇
冶金工业   1176篇
原子能技术   1篇
自动化技术   26篇
  2020年   2篇
  2018年   2篇
  2016年   2篇
  2014年   2篇
  2013年   4篇
  2012年   9篇
  2011年   4篇
  2010年   4篇
  2009年   6篇
  2008年   3篇
  2007年   5篇
  2006年   2篇
  2004年   4篇
  2003年   4篇
  2002年   3篇
  2001年   3篇
  2000年   3篇
  1999年   40篇
  1998年   321篇
  1997年   188篇
  1996年   128篇
  1995年   95篇
  1994年   68篇
  1993年   76篇
  1992年   9篇
  1991年   20篇
  1990年   18篇
  1989年   17篇
  1988年   21篇
  1987年   22篇
  1986年   13篇
  1985年   17篇
  1984年   2篇
  1983年   5篇
  1982年   7篇
  1981年   10篇
  1980年   10篇
  1979年   2篇
  1978年   6篇
  1977年   41篇
  1976年   75篇
  1975年   4篇
  1973年   4篇
  1972年   8篇
  1971年   7篇
  1970年   6篇
  1967年   1篇
  1965年   1篇
  1957年   3篇
  1955年   1篇
排序方式: 共有1313条查询结果,搜索用时 0 毫秒
91.
Three consecutive cases of pediatric myelodysplastic syndrome (MDS) diagnosed over a three-year period in Queen Mary Hospital, Hong Kong, were described. Depending on the classification system used, they comprised two cases of chronic myelomonocytic leukemia (CMMoL) of which one can be reclassified as juvenile chronic myeloid leukemia (JCML) and one cases of refractory anemia with excess of blasts (RAEB) or an alternative diagnosis of atypical CML. Cytogenetic abnormalities were detected in all of them on examination of bone marrow cells. Of the two CMMoL, one had monosomy 21, whereas the other had hypodiploidy. The patient with RAEB had a complex karyotype of 46,X,del(X)(q24),t(1;7) (p22;q32),add(15)(q26)(8). The balanced translocation (1;7) seen in this patient was exceedingly rare and, to the best of our knowledge, was reported only twice in the literature. The karyotypic abnormalities that we saw in our patients were not well recognized in pediatric MDS. This report emphasizes the importance of cytogenetic study in children suspected of suffering from MDS, which remains a rare disorder of childhood, and a need to rationalize current classification schemes.  相似文献   
92.
Numerous events over several years culminated in recognition of the need to explicitly evaluate the nervous system as a potential target for environmental chemicals. Based on recommendations from several international expert panels, the International Programme on Chemical Safety (IPCS) sponsored the Collaborative Study on Neurobehavioral Screening Methods. A Steering Committee was created to oversee the project, develop the testing protocol, recruit participating laboratories and review and analyze the data. The protocol specified the tests, the chemicals (supplied from a common source) and the exposure conditions (acute and repeated dosing). Test methods were based upon existing practices in toxicological screening as well as recent advances in neurotoxicity screening. Chemicals were selected to produce different profiles of neurobehavioral effects. Considerable latitude was afforded the participating laboratories in the choice of several key variables (e.g., strain of rat, testing device for motor activity assessment) that could potentially affect the results of the experiments. The approach therefore provided a standardized yet flexible protocol for evaluating the reproducibility of neurobehavioral screening data in diverse laboratory settings.  相似文献   
93.
94.
A multicylinder somatic shunt model for spiny, passive neurones is considered. The spines are modelled as a continuum (after Baer & Rinzel, 1991), coupled through the spread of dendritic voltage. A general solution is developed and a relationship governing the contribution of dendrites, soma, and spines to the voltage response is derived.  相似文献   
95.
The purpose of this contribution is to inform about the activities of the local ethics commission established at one of our largest teaching (University) hospitals. In 1995 the following priorities were recognized: studying international ethical standards of research involving human subjects and strictly adhering to them; bilingual administrative agenda in Czech and English; enforcing the patients' rights in health care and emphasizing them in education of medics and other students of health related disciplines; stimulating effective communication between doctors, other health care workers and lay persons in the commission as well as between the members of the commission and authors of research projects applying for ethical evaluation. Since 1993 the commission has been revising and storing in the archives more than 600 research projects. In 1996, 181 new research projects were reviewed, which is 35% more than in 1995. Approval was granted in 154 cases (85.08%), 3 cases (1.66%) were rejected, 15 cases (8.29%) approved on condition of complying with the recommendations of the commission, 6 cases (3.31%) recommended for another commission, and in 3 cases reviewing the project was postponed for lack of necessary data. The members of the commission agree that the future activities should lead to forming a broader group of consultants of the commission and other professional and lay people interested in clinical ethics. According to their meaning, legislation concerning ethical commissions in the Czech Republic, including material and financial support and administrative help, is urgently needed.  相似文献   
96.
A case of sacrococcygeal teratoma is presented with characteristics of fetus-in-fetu. This pseudo-fetus presented a rudimentary single cavity heart, which beat at a different rate to that of the affected infant. X-ray examination showed no spinal column. This case confirms that fetus in fetu can be a remarkably complex, well-differentiated, highly organized teratoma.  相似文献   
97.
98.
99.
The paper presents several mnemonics to assist clinicians in recalling DSM-IV diagnostic criteria for personality disorders. The mnemonics are acronyms, and each letter is associated with a specific criterion. Each acronym reflects a facet of the related disorder; for example, the acronym for the diagnostic criteria for paranoid personality disorder is SUSPECT, and for histrionic personality disorder it is PRAISE ME. The mnemonics have been used to teach students and residents the conceptual nature of DSM-IV disorders and to help them remember the criteria.  相似文献   
100.
OBJECTIVE: The aim of this study was to assess the frequency and severity of depressive symptoms, to determine the rate of depressive disorder, to explore possible reasons for the development of depressive symptoms and to examine the effects of depression in a group of human immunodeficiency virus (HIV)-positive patients. METHOD: HIV-positive patients attending an outpatient treatment facility were assessed by the research psychologist and completed a number of questionnaires: the Beck Depression Inventory (BDI); the Life Event Inventory (LEI); the Core Bereavement Item (CBI-17) questionnaire; and the Psychosocial Adjustment to illness Scale (PAIS). Patients scoring > or = 14 on the BDI were seen by the psychiatrist for further assessment, and where appropriate, diagnoses were made according to DSM-III-R criteria. RESULTS: One hundred and ninety-two patients participated in the study; 95 scored > or = 14 on the BDI and one-third of these were found to have a depressive disorder. Factors significantly predictive of a BDI score > or = 14 were: an LEI score > 77; a diagnosis of acquired immunodeficiency syndrome (AIDS); being on sickness benefits or a pension; no current relationship; and a past history of depression. Few differences were demonstrated between those with a depressive disorder and those with a BDI score > or = 14 but no diagnosis of depressive disorder. Both groups had high mean PAIS scores indicating significant illness effects in multiple areas of function. CONCLUSIONS: Depressive symptoms are common among patients with HIV infection. Few factors differentiate between patients with a depressive disorder and those whose depressive symptoms do not meet diagnostic criteria. Substantial disability is present in both groups.  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