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   3384篇
  免费   445篇
  国内免费   23篇
耳鼻咽喉   6篇
儿科学   131篇
妇产科学   300篇
基础医学   278篇
口腔科学   142篇
临床医学   973篇
内科学   384篇
皮肤病学   87篇
神经病学   449篇
特种医学   274篇
外科学   242篇
综合类   128篇
一般理论   26篇
预防医学   205篇
眼科学   24篇
药学   117篇
中国医学   1篇
肿瘤学   85篇
  2023年   45篇
  2021年   20篇
  2020年   45篇
  2019年   40篇
  2018年   80篇
  2017年   108篇
  2016年   106篇
  2015年   117篇
  2014年   137篇
  2013年   156篇
  2012年   95篇
  2011年   131篇
  2010年   138篇
  2009年   137篇
  2008年   108篇
  2007年   127篇
  2006年   102篇
  2005年   92篇
  2004年   94篇
  2003年   84篇
  2002年   77篇
  2001年   76篇
  2000年   68篇
  1999年   120篇
  1998年   122篇
  1997年   121篇
  1996年   117篇
  1995年   105篇
  1994年   77篇
  1993年   65篇
  1992年   71篇
  1991年   75篇
  1990年   62篇
  1989年   79篇
  1988年   76篇
  1987年   50篇
  1986年   63篇
  1985年   64篇
  1984年   30篇
  1983年   41篇
  1982年   31篇
  1981年   22篇
  1980年   29篇
  1979年   22篇
  1978年   43篇
  1977年   25篇
  1976年   24篇
  1975年   24篇
  1967年   11篇
  1966年   15篇
排序方式: 共有3852条查询结果,搜索用时 0 毫秒
11.
A fatality due to the ingestion of isoniazid, a tuberculostatic agent, is presented. Isoniazid was extracted by a single step extraction procedure, derivatized with trifluoroacetic anhydride, and identified and quantified by gas chromatography/mass spectrometry (GC/MS). The distribution of isoniazid was as follows: heart blood 43 mg/L, subclavian blood 94 mg/L, urine 470 mg/L, bile 900 mg/L, liver 650 mg/Kg, kidney 110 mg/Kg, and stomach contents 4 mg.  相似文献   
12.
An Australian school of nursing's attempt to introduce an evaluation process required by management for clinical educators involved in undergraduate preregistration education is discussed Reliance on student feedback and clinical agencies' perceptions of the quality of teaching were seen as inadequate mechanisms for evaluation The evaluation process adopted incorporated observation of the educators together with self-reflection on their performance We conclude that post-briefings were poorly used and generally not reflective Educators relied heavily on their clinical skills and used a limited range of teaching strategies Whilst evaluation of clinical educators was time consuming and therefore costly, it is argued that it is essential to the integrity of the course The evaluation process has provided direction for support and development of clinical educators within the context of the curriculum  相似文献   
13.
Recent studies indicate that 15-22% of American children and adolescents suffer from diagnosable mental disorders. Researchers estimate that 25-50% engage in risk behaviors for negative health and behavior outcomes, such as drug abuse, unwanted pregnancy, AIDS, delinquency, and school dropout. The prevalence of problem behaviors, as well as current social trends, demands that effective primary prevention programs be developed and disseminated. This article reviews successful family-, school-, and community-based prevention efforts aimed at reducing the incidence and severity of children's psychosocial problems. High-quality, comprehensive, competence-promotion programs that focus on both children and their socializing environments represent the state of the art in prevention. Establishing enduring, effective preventive interventions requires increased attention to program design, implementation, and institutionalization.  相似文献   
14.
A national study was conducted between 1991 and 1994 to explore and describe the changing role of the nurse teacher following the introduction of Project 2000 pre-registration nursing courses. Multiple methods were used to collect data from a wide variety of respondents (nurse teachers, midwife teachers, clinical nurses, health service managers and higher education lecturers). This paper presents the findings relating to the impact of Project 2000 and the move into higher education on the continuing educational needs of nurse teachers. Views on college strategies for staff development, the changing nature of teachers'academic and professional development needs and the problems of the conflicting demands experienced are reported. The research highlights the need for clinical credibility to be clearly defined in relation to nurse teachers and for educational institutions to place more emphasis on teachers'clinical development if the rhetoric of policy is to become a reality.  相似文献   
15.
Twenty-five persons with diabetes (aged 55–83 years) who were living independently in the community, and 40 age- and sex-matched non-diabetic controls were assessed for tactile sensitivity, vibration sense, proprioception, quadriceps strength and body sway. In both men and women, those with diabetes performed significantly worse in tests of body sway on firm and compliant surfaces compared with the control subjects after controlling for weight and body mass index. The female diabetic subjects also performed significantly worse in tests of peripheral sensation and strength compared with controls. Age-related declines in sensori-motor function were greater in the diabetic group (r = 0.55–0.75) than in the controls (r < 0.44), while within the diabetic group, duration of diabetes and vibration sense were significantly correlated with sway on a compliant (foam rubber) surface with the eyes open (partial r = 0.52, p < 0.01 and r = 0.55, p < 0.01, respectively). The study findings provide evidence that older people with diabetes have problems with stability and related sensori-motor factors which may place them at increased risk of falls.  相似文献   
16.
Summary We present a case with a characteristic magnetic resonance image (MRI) of bilateral open-lipped schizencephaly and atypical clinical presentation. The patient is still alive and in good health in her forties, she has never presented seizures, and although the motor dysfunction is well correlated with cerebral lobe involvement, neurobehavioral dysfunction is not proportional to the MR image of the cerebral malformation.
Un cas inhabituel de schizencéphalie bilatérale
Résumé Nous présentons un cas de schizencéphalie bilatérale ouverte caractérisé par une présentation clinique atypique et une imagerie par résonance magnétique nucléaire caractéristique. La patiente est encore vivante, en bonne santé, à plus de 40 ans, elle n'a jamais présenté de crise comitiale et, bien que les troubles moteurs soient bien corrélés aux altérations cérébrales, les troubles neuro-comportementaux ne sont pas proportionnels aux images IRM de cette malformation cérébrale.
  相似文献   
17.
18.
19.
The presence of checkpoint mechanisms which are able to recognize damaged chromatin and thereafter to prevent exit from metaphase I has been investigated in giant mouse oocytes produced by fusion of a normal metaphase I oocyte with an equivalent oocyte with damaged chromatin. The presence of damaged chromatin did not prevent the onset of anaphase I in both sets of chromatin in the fused cells. Interestingly, fused or unfused cells containing only damaged chromatin failed to enter anaphase and persisted instead in a metaphase-like state. These results demonstrate the fragility of checkpoint controls in mammalian female germ cells.   相似文献   
20.
Axel  L; Summers  RM; Kressel  HY; Charles  C 《Radiology》1986,160(3):795-801
Respiratory and other regular motions during two-dimensional Fourier transform magnetic resonance imaging produce image artifacts consisting of local blurring and more or less regularly spaced "ghost" images propagating along the direction of the phase-encoding magnetic field gradient. The patterns of these ghost artifacts can be understood in terms of the technique of image production and basic properties of the discrete Fourier transform. This understanding permits, without respiratory gating, production of images of improved quality in body regions in which there is significant respiratory motion. In particular, the ghosts can be maximally separated from the primary image by choosing intervals between phase-encoding gradient pulse increments that are equal to one-half the respiratory period; they can be minimally separated by choosing an interval equal to the respiratory period. Increasing the number of signal averages between each phase-encoding increment decreases the intensity of the ghosts.  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