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   4566篇
  免费   382篇
  国内免费   28篇
耳鼻咽喉   24篇
儿科学   221篇
妇产科学   175篇
基础医学   435篇
口腔科学   111篇
临床医学   582篇
内科学   906篇
皮肤病学   68篇
神经病学   372篇
特种医学   383篇
外科学   380篇
综合类   72篇
一般理论   4篇
预防医学   442篇
眼科学   36篇
药学   545篇
  1篇
中国医学   4篇
肿瘤学   215篇
  2022年   24篇
  2021年   48篇
  2020年   48篇
  2019年   53篇
  2018年   70篇
  2017年   51篇
  2016年   54篇
  2015年   94篇
  2014年   103篇
  2013年   167篇
  2012年   164篇
  2011年   165篇
  2010年   146篇
  2009年   164篇
  2008年   148篇
  2007年   171篇
  2006年   159篇
  2005年   147篇
  2004年   160篇
  2003年   154篇
  2002年   144篇
  2001年   144篇
  2000年   135篇
  1999年   138篇
  1998年   141篇
  1997年   148篇
  1996年   138篇
  1995年   116篇
  1994年   97篇
  1993年   120篇
  1992年   87篇
  1991年   92篇
  1990年   95篇
  1989年   105篇
  1988年   97篇
  1987年   76篇
  1986年   81篇
  1985年   74篇
  1984年   64篇
  1983年   42篇
  1982年   40篇
  1981年   60篇
  1980年   34篇
  1979年   44篇
  1978年   29篇
  1977年   50篇
  1976年   47篇
  1975年   31篇
  1974年   26篇
  1970年   23篇
排序方式: 共有4976条查询结果,搜索用时 15 毫秒
21.
OBJECTIVES: The wider study aimed to evaluate specialists' outreach clinics in relation to their costs, processes, and effectiveness, including patients' and professionals' attitudes. The data on processes and attitudes are presented here. DESIGN: Self administered questionnaires were drawn up for patients, their general practitioners (GPs) and specialists, and managers in the practice. Information was sought from hospital trusts. The study formed a pilot phase prior to a wider evaluation. SETTING: Nine outreach clinics in general practices in England, each with a hospital outpatient department as a control clinic were studied. SUBJECTS: The specialties included were ear, nose, and throat surgery; rheumatology; and gynaecology. The subjects were the patients who attended either the outreach clinics or hospital outpatients clinics during the study period, the outreach patients' GPs, the outreach patients' and outpatients' specialists, the managers in the practices, and the NHS trusts which employed the specialists. MAIN OUTCOME MEASURES: Process items included waiting lists, waiting times in clinics, number of follow up visits, investigations and procedures performed, treatment, health status, patients' and specialists' travelling times, and patients' and doctors' attitudes to, and satisfaction with, the clinic. RESULTS: There was no difference in the health status of patients in relation to the clinic site (ie, outreach and hospital outpatients' clinics) at baseline, and all but one of the specialists said there were no differences in casemix between their outreach and outpatients' clinics. Patients preferred, and were more satisfied with, care in specialists' outreach clinics in general practice, in comparison with outpatients' clinics. The outreach clinics were rated as more convenient than outpatients' clinics in relation to journey times; those outreach patients in work lost less time away from work than outpatients' clinic patients due to the clinic attendance. Length of time on the waiting list was significantly reduced for gynaecology patients; waiting times in clinics were lower for outreach patients than outpatients across all specialties. In addition, outreach patients were more likely to be first rather than follow up attenders; rheumatology outreach patients were more likely than hospital outpatients to receive therapy. GPs' referrals to hospital outpatients' clinics were greatly reduced by the availability of outreach clinics. Both specialists and GPs saw the main advantages of outreach clinics in relation to the greater convenience and better access to care for patients. Few of the specialists and GPs in the outreach practices held formal training and education sessions in the outreach clinic, although over half of the GPs felt that their skills/expertise had broadened as a result of the outreach clinic. CONCLUSIONS: The processes of care (waiting times, patient satisfaction, convenience to patients, follow up attendances) were better in outreach than in outpatients' clinics. However, waiting lists were only significantly reduced for gynaecology patients, despite both GPs and consultants reporting reduced waiting lists for patients as one of the main advantages of outreach. Whether these improvements merit the increased cost to the specialists (in terms of their increased travelling times and time spent away from their hospital base) and whether the development of what is, in effect, two standards of care between practices with and without outreach can be stemmed and the standard of care raised in all practices (eg, by sharing outreach clinics between GPs in an area) remain the subject of debate. As the data were based on the pilot study, the results should be viewed with some caution, although statistical power was adequate for comparisons of sites if not specialties.  相似文献   
22.
23.
The prevalence of selected illnesses and symptoms during 1977-85 was compared between 175 employees potentially exposed to the organophosphate insecticide chlorpyrifos and 335 matched controls with no history of exposure to organophosphates. Subjects were subdivided into three exposure intensity groups on the basis of job title and air monitoring data for dose response testing. This classification scheme was shown roughly to correlate with plasma cholinesterase inhibition in the workers. No statistically significant differences in illness or prevalence of symptoms were observed between the exposed and unexposed groups or among the three exposure subgroups. Potentially exposed employees did report symptoms of dizziness and of malaise and fatigue relatively more often than subjects from the comparison group; however, further analyses by exposure level, process area, or time did not support a relation with exposure. No cases of peripheral neuropathy were seen among the exposed workers. Although the sample size was small and the statistical power limited, the cumulative exposures likely to have been experienced by this workforce exceed those to be expected for individuals using the product as recommended. The absence of exposure related adverse effects, including neurological impairment, is reassuring.  相似文献   
24.
Barnett  MJ; Zussman  WV 《Radiology》1986,160(1):223-225
Granulocytic sarcoma (chloroma), a rare tumor usually associated with myelogenous leukemia, is capable of invading the meninges or brain parenchyma. Radiologic findings in a case of granulocytic sarcoma of the brain, as well as those in 11 previously reported cases of intracranial leukemic masses, are interpreted. On computed tomographic scans, the lesions can appear isodense or hyperdense, edema and necrosis are variable, and there is uniform enhancement following intravenous administration of contrast material. There may be some affinity for the posterior fossa.  相似文献   
25.
Increasing interest in audit in the health service has focused attention on the tools and methods used to achieve it. These can be extremely expensive, so a tendency to opt for off-the-shelf packages has developed. This article reviews how one such instrument, The Central Nottinghamshire Psychiatric Nursing Audit, has been used in two settings over the past three years, with particular emphasis on its cost-effectiveness.  相似文献   
26.
27.
A comprehensive anatomic and radiographic analysis of the peribursal fat plane in 12 cadavers confirmed that the fat plane seen on radiographs represents extrasynovial fat lining the subacromial bursa and documented the anatomic relations of the bursa. A three-part retrospective clinical evaluation of rotator cuff tears, calcific tendinitis, and rheumatoid arthritis was performed. Two osteoradiologists blindly graded the appearance of the peribursal fat plane with the shoulder in external versus internal rotation in 21 patients with arthrographically intact rotator cuffs and 21 patients with disrupted rotator cuffs. The peribursal fat plane was seen better with disrupted rotator cuffs. The peribursal fat plane was seen better with the shoulder in internal rotation and was seen in 60% of control subjects but only 21% of patients with rotator cuff tears. Partial or complete obliteration of this fat plane is a sensitive (79%) but less specific (60%) indicator of rotator cuff tears. Obliteration of the peribursal fat plane by inflammatory processes in adjacent tissues, including calcific tendinitis and rheumatoid arthritis, occurred with a high frequency.  相似文献   
28.
Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.  相似文献   
29.
The chick chorioallantoic membrane was used to determine whether the carotid atherosclerotic plaque stimulates angiogenesis. Carotid endarterectomy specimens (1 mm3) with fibromuscular plaque (n = 8) and complicated plaque (n = 11) were implanted on the membrane on day nine of incubation and the response evaluated on day 11. Following fixation in situ with 10% formalin the angiogenic response was evaluated by: (1) examining whole membrane mounts, (2) quantitatively from a vascular density index and (3) from a histological study. Unmanipulated chorioallantoic membrane (n = 11) and plaque boiled prior to implantation (n = 6) served as controls. The vascularity of whole mounts of both fibromuscular and complicated plaque was greater than the controls. Vessel density of the membrane was estimated by counting the number of vessels intersecting four concentric circles (144.5 mm total circumference) placed on the formalin fixed membrane. The vascular density index due to the fibromuscular plaque (390.6 +/- 8.3) and complicated plaque (391.0 +/- 14.9) were similar (P greater than 0.9) but were significantly greater (P less than 0.001) than the unmanipulated membrane (327.9 +/- 5.6) or after treatment with the boiled plaque (283.8 +/- 15.6). Transforming growth factor beta 1 confirmed the validity of the experimental model to study angiogenesis. The histology of the chorioallantoic membrane due to either type of plaque was similar. Numerous vessels surrounded the plaque, and intraplaque vessels containing nucleated chick erythrocytes were observed. Although scattered vessels surrounded the boiled plaque, intraplaque vessels were not observed. This study demonstrates that the atherosclerotic plaque has angiogenic properties that may account for the increase in vasa vasorum that is associated with the plaque.  相似文献   
30.
The use of biological markers in toxicology   总被引:1,自引:0,他引:1  
  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