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   51312篇
  免费   5444篇
  国内免费   674篇
耳鼻咽喉   464篇
儿科学   2194篇
妇产科学   1017篇
基础医学   6255篇
口腔科学   1499篇
临床医学   9090篇
内科学   4697篇
皮肤病学   311篇
神经病学   5539篇
特种医学   892篇
外国民族医学   4篇
外科学   3632篇
综合类   4917篇
现状与发展   6篇
一般理论   12篇
预防医学   9376篇
眼科学   594篇
药学   3769篇
  47篇
中国医学   1449篇
肿瘤学   1666篇
  2024年   487篇
  2023年   1133篇
  2022年   1457篇
  2021年   2215篇
  2020年   2421篇
  2019年   2403篇
  2018年   2141篇
  2017年   2186篇
  2016年   2053篇
  2015年   2092篇
  2014年   3061篇
  2013年   3983篇
  2012年   2747篇
  2011年   2892篇
  2010年   2588篇
  2009年   2504篇
  2008年   2406篇
  2007年   2389篇
  2006年   2046篇
  2005年   1808篇
  2004年   1529篇
  2003年   1327篇
  2002年   1098篇
  2001年   940篇
  2000年   828篇
  1999年   752篇
  1998年   696篇
  1997年   566篇
  1996年   514篇
  1995年   482篇
  1994年   425篇
  1993年   360篇
  1992年   326篇
  1991年   268篇
  1990年   265篇
  1989年   197篇
  1988年   193篇
  1987年   170篇
  1986年   187篇
  1985年   221篇
  1984年   209篇
  1983年   124篇
  1982年   112篇
  1981年   136篇
  1980年   126篇
  1979年   78篇
  1978年   76篇
  1977年   40篇
  1976年   47篇
  1974年   21篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
? The benefits of informing patients before undergoing surgery or other investigative procedures are clearly demonstrated in the literature. ? This study aimed to determine the amount and type of information given to patients before, during and after undergoing gastroscopy investigations. ? A survey approach incorporating structured interviews and structured observation was utilized. ? There were statistically significant differences between the information acquired by younger and older patients prior to, but not during or after, the procedure. ? Nurses appear to be the most important source of information for older patients while the information leaflet was perceived as the most important source of information for younger patients.  相似文献   
62.
用9周-39周引产胎儿标本72例,取右耳廓石蜡切片,HE和Weitert弹性纤维染色,光镜观察其弹性软骨、弹性纤维、耳廓肌和结缔组织的发生。  相似文献   
63.
Purpose: The purposes of this survey were to identify the current participation in Continuing Professional Development (CPD) of radiographers in the South and West Regional Health Authority (SWRHA), and to invite them to comment on issues related to CPD activities.Methods: A questionnaire was sent to 1686 diagnostic and therapy radiographers in the SWRHA. This was designed to gain a profile of those radiographers currently practising and their participation in, and comments on, CPD activities.Results: A response rate of 51% was achieved, although only 634 questionnaires were used for the final analysis. The population of radiographers who responded were predominantly diagnostic, in the age range 26–45 years, female and employed on a full-time basis. Most respondents did not hold any post-registration qualifications, and only 149 respondents were involved in formal studies. Most respondents were involved in statutory CPD activities such as resuscitation and manual lifting, and fewer, although a majority, were involved in activities associated with changing roles and developing new competencies. Other CPD activities which respondents considered as benefiting their professional role were wide ranging. Most of the issues raised concerning CPD related to provision, support and funding.Conclusions: The challenge for the future is to develop a coherent, progressive and affordable scheme of CPD to meet the needs of individual radiographers, the health services, the patient and the profession.  相似文献   
64.
AIMS: Scarcity of resources, expertise and evidence-based models have so far limited delivery of patient-centred diabetes education. We have developed and validated a group care approach that is applicable to everyday clinical practice and cost-effective in improving metabolic control, knowledge of diabetes, health behaviours, and quality of life in Type 2 diabetes. A clinical trial (ROMEO) was planned to evaluate applicability and reproducibility of group care in other outpatients facilities and assess its impact on a larger patient population. METHODS: Multicentre, randomized, controlled clinical trial of group vs. individual care in the routine management of Type 2 diabetes. Nine hundred patient aged < 80, with diabetes of > or =1 year known duration, treated by either diet alone or diet and oral agents, will be recruited in 15 centres and followed for 4 years. Training of physicians, nurses and dietitians included preparation of operating manual and videos, interactive sessions, and evaluation of local facilities and resources. RESULTS: Primary measurements: 3-monthly HbA1c, fasting blood glucose, body weight, waist-hip ratio, yearly blood lipids, and bi-yearly assessment of knowledge of diabetes, health behaviours and quality of life. Secondary outcomes: systolic and diastolic blood pressure, evaluation of ECG for ischaemia and QT interval, hypoglycaemic and anti-hypertensive medication and cardiovascular events. Analysis will be by intention-to-treat. DISCUSSION: If ROMEO confirms that group care can be successfully implemented in different clinics, a novel clinico-pedagogic tool will have been acquired to support patient-centred education, improve lifestyle and outcomes, support team work, enhance providers' attitudes and competencies and ameliorate diabetes care organization.  相似文献   
65.
During T cell development, thymocytes which are tolerant to self-peptides but reactive to foreign peptides are selected. The current model for thymocyte selection proposes that self-peptide–major histocompatibility complex (MHC) complexes that bind the T cell receptor with low affinity will promote positive selection while those with high affinity will result in negative selection. Upon thymocyte maturation, such low affinity self-peptide–MHC ligands no longer provoke a response, but foreign peptides can incidentally be high affinity ligands and can therefore stimulate T cells. For this model to work, thymocytes must be more sensitive to ligand than mature T cells. Contrary to this expectation, several groups have shown that thymocytes are less responsive than mature T cells to anti-T cell receptor for antigen (TCR)/CD3 mAb stimulation. Additionally, the lower TCR levels on thymocytes, compared with T cells, would potentially correlate with decreased thymocyte sensitivity. Here we compared preselection thymocytes and mature T cells for early activation events in response to peptide–MHC ligands. Remarkably, the preselection thymocytes were more responsive than mature T cells when stimulated with low affinity peptide variants, while both populations responded equally well to the antigenic peptide. This directly demonstrates the increased sensitivity of thymocytes compared with T cells for TCR engagement by peptide–MHC complexes.  相似文献   
66.
67.
《Nutrition reviews》1986,44(10):327-328
Giving foods as rewards can enhance consumption of those foods, while giving rewards to induce consumption of foods can decrease subsequent consumption of those foods.  相似文献   
68.
69.
Functional vascular connections must form rapidly to prevent ischemic damage to grafted neural tissues. The temporal sequence by which transplant circulation is re-established provides information about the angiogenic capacity of either intact or damaged CNS blood vessels. This study compares the time course and mechanism of vascular reperfusion in allografts of superior cervical ganglia or adrenal medulla inserted either into the fourth ventricle or directly into the parietal cortex of perinatal rats. Tritiated thymidine was administered to recipients to determine angiogenic patterns at various postoperative time periods. After processing for light microscopic autoradiography, host and graft endothelial labelling indices were determined in order to establish the temporal sequence and location of vascular proliferation. Correlative electron microscopy depicted the morphological changes in transplant vasculature. Some recipients were prelabelled with 3H thymidine prior to transplantation to determine if host vessels invaded the grafts. Intraventricular graft vessels initially collapsed but sustained minimal ischemic damage and were completely reperfused by 24 hours postoperative. Adjacent intact host vessels attained peak 3H thymidine incorporation at 20 hours. Intrinsic graft vessels were radioactively labelled only after 48 hours. Intraparenchymal transplants surrounded by minimal trauma exhibited a similar temporal sequence of reperfusion and host endothelial proliferation. Intrinsic graft vessels in intraparenchymal grafts sustained more severe damage. With increased trauma, a concomitant delay in graft reperfusion time was observed. Grafts within prelabelled hosts rarely contained any labelled endothelium, indicating that anastomotic connections were made between original, intrinsic graft vessels and nearby host vascular sprouts. This study demonstrates that mature autonomic tissue stimulates the growth of adjacent host vessels when transplanted to undamaged brain surfaces. The anastomosis of nascent host vessels with pre-existing graft vessels is responsible for the rapid re-establishment of circulation within the transplants. A similar mechanism occurs within intraparenchymal grafts, although the rapidity of reperfusion appears to be predicated on the amount of trauma present at the graft site.  相似文献   
70.
Summary Seventy-one first-born infants who had been nursed in prone position since birth, were referred for motor assessment at 3 months, 5 months and 9 months. All infants were administered the same checklist of motor items, based on the Amiel-Tison Infant Neurological Evaluation and on the Brunet-Lézine Developmental Psychomotor Scale. Abnormalities in muscular shortening and delay in motor skills were found. These findings are critical as regards environmental influences on postural development, continuities in motor development and issues of early primary prevention. Early identification and follow-up programmes, including frequent changes in posture, are suggested in order to avoid abnormalities of motor behaviour and subsequently in postural patterns.  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