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   491篇
  免费   43篇
耳鼻咽喉   2篇
儿科学   43篇
妇产科学   13篇
基础医学   60篇
口腔科学   11篇
临床医学   48篇
内科学   108篇
皮肤病学   28篇
神经病学   21篇
特种医学   83篇
外科学   36篇
综合类   21篇
预防医学   9篇
眼科学   7篇
药学   21篇
中国医学   1篇
肿瘤学   22篇
  2021年   2篇
  2020年   2篇
  2019年   2篇
  2018年   2篇
  2017年   6篇
  2016年   6篇
  2015年   8篇
  2014年   13篇
  2013年   24篇
  2012年   4篇
  2011年   6篇
  2010年   23篇
  2009年   26篇
  2008年   18篇
  2007年   13篇
  2006年   14篇
  2005年   15篇
  2004年   7篇
  2003年   13篇
  2002年   11篇
  2001年   4篇
  1999年   6篇
  1998年   20篇
  1997年   42篇
  1996年   30篇
  1995年   20篇
  1994年   23篇
  1993年   21篇
  1992年   9篇
  1991年   4篇
  1990年   9篇
  1989年   26篇
  1988年   13篇
  1987年   11篇
  1986年   13篇
  1985年   14篇
  1984年   7篇
  1982年   2篇
  1981年   4篇
  1980年   6篇
  1979年   3篇
  1978年   5篇
  1977年   9篇
  1976年   4篇
  1975年   4篇
  1969年   2篇
  1963年   1篇
  1956年   1篇
  1955年   1篇
  1932年   1篇
排序方式: 共有534条查询结果,搜索用时 24 毫秒
11.
希—内学习能力测验在中国聋儿中使用的信度和效度   总被引:4,自引:0,他引:4  
采用经部分修改的希-内学习能力测验(H-NTLA)量表对全国21个省、市、自治区1758名3-17岁聋儿逐人测试。样本人群地区分布、家长职业构成与1990年全国人口普查资料一致。1758名聋儿智商呈现正态分布(g1=0.011P>0.05,g2=0.058P>0.05)。测试员间信度系数0.981(N=24),复测信度0.841(N=136),分半信度0.927(3-8岁)及0.854(9-17岁)。各分测验得分随年龄增加而增加,小年龄组增加明显,大年龄组增加缓慢。各分测验之间、各分测验和总离差智商之间大多数相关系数有显著统计学意义。智商与学习成绩(语文及数学)相关系数0.208(P<0.01N=224),与教师评语等级相关系数0.44(P<0.05df=16),表明经修订的H-NTLA量表适用于中国听力语言障碍人群进行智力评定。  相似文献   
12.
The allelic frequency of the gene for the K variant of butyrylcholinesterase (BCHE-K) was 0.17 in 74 subjects with late-onset (age > 65 years) histopathologically diagnosed Alzheimer's disease (AD), which was higher than the frequencies in 104 elderly control subjects (0.09), in 14 early-onset cases of confirmed AD (0.07) and in 29 confirmed cases of other dementia (0.10). The association of BCHE-K with late-onset AD was limited to carriers of the epsilon 4 allele of the apolipoprotein E gene (APOE), among whom the presence of BCHE-K gave an odds ratio of confirmed late-onset AD of 6.9 (95% C.I. 1.65-29) in subjects > 65 years and of 12.8 (1.9-86) in subjects > 75 years. In APOE epsilon 4 carriers over 75 years, only 1/22 controls, compared with 10/24 confirmed late-onset AD cases, had BCHE-K. We suggest that BCHE-K, or a nearby gene on chromosome 3, acts in synergy with APOE epsilon 4 as a susceptibility gene for late-onset AD.   相似文献   
13.
创伤病人的手术与焦虑状态调查   总被引:6,自引:0,他引:6  
采用状态——特质焦虑问卷及10项躯体性焦虑测试题,对40例外科创伤病人手术前后的焦虑状态调查显示:术前状态焦虑量表评分显著高于术后;术前躯体性焦虑评分显著高于术后;高特质焦虑评分亚组与低特质焦虑评分亚组术前状态焦虑评分无显著差异,但术后则前者显著高于后者;急诊手术者手术前后状态焦虑评分显著高于择期手术者。  相似文献   
14.
Plasma levels of soluble T-suppressor/cytotoxic antigen (sCD8) were measured at diagnosis or before systemic treatment in 69 patients with hairy cell leukemia (HCL). The 49 nonsplenectomized patients were characterized by high concentrations of sCD8 antigen as compared with 17 controls (P less than .0001). The median sCD8 level in non- splenectomized patients was 1,050 U/mL (range: 160 to 2,400 U/mL) and was significantly higher (P less than .0001) than the median of 275 U/mL (range: 20 to 1,080 U/mL) in splenectomized patients. The relationship of sCD8 to clinical response to subsequent interferon alpha (IFN alpha) treatment was analyzed. Patients who showed subsequent hematologic response with normalization of all blood counts had significantly lower levels of sCD8 concentrations at diagnosis than those who did not (P = .0056). Furthermore, normalization of sCD8 during IFN alpha treatment paralleled the achievement of normal counts in peripheral blood, whereas soluble interleukin-2 receptor (sIL-2R) levels remained high in most patients after 12 to 15 months of treatment. We speculate that activation of suppressor/cytotoxic T cells might play a role in myelosuppression, and its modulation during treatment with IFN alpha correlates with normalization in peripheral blood counts.  相似文献   
15.
Two kindreds with the multiple endocrine neoplasia type 2A syndrome were studied. Of one of these we examined 150 members, 20 of whom were treated with thyroidectomy for medullary carcinoma and nine with bilateral adrenalectomy for pheochromocytoma. Of the second kindred 59 members were examined, seven of whom were thyroidectomized and seven treated with bilateral adrenalectomy. Pheochromocytomas were invariably found on both sides, even in four cases in which the adrenals on one side appeared to be completely normal, not only at preoperative roentgenologic examination but also on inspection during the operation. The microscopic finding of micronodules and a cluster of abnormal medullary cells identical with those found in pheochromocytomas in one of the apparently normal adrenals represents a first stage in the development of diffuse medullary hyperplasia as well as nodular hyperplasia. This is in accordance with the fact that in the MEN type 2A syndrome pheochromocytomas are always multicentric and multiple in origin. On the basis of these findings we conclude that all patients with the MEN 2A syndrome who show symptoms and signs of active pheochromocytoma should be subjected to bilateral adrenalectomy, even when one or both of the adrenals appear to be normal at roentgenologic investigation.  相似文献   
16.
A prospective evaluation of color flow mapping and real-time ultrasound was performed to determine if pseudoaneurysms could be distinguished from other causes of masses surrounding vascular grafts of the lower extremities. Twelve palpable pulsatile masses were imaged. Diagnoses were confirmed at angiography (n = 11), computed tomography (n = 7), aspiration biopsy (n = 5), and operative intervention (n = 6). A swirling pattern of blood flow was seen in six of seven cases of pseudoaneurysm. Lack of flow signals was noted in four of the five collections representing hematoma (n = 2) or infection (n = 2). The seventh case was later shown to be an infected, thrombosed pseudoaneurysm. The single false-positive diagnosis was made early in the series when the flow signals detected were due to transmitted arterial pulsations. The authors conclude that color Doppler flow imaging is useful in the differential diagnosis of pulsatile masses associated with prosthetic grafts. Prosthetic graft pseudoaneurysms have a specific appearance of swirling blood flow arising from a wide neck and are distinguishable from traumatic or iatrogenic pseudoaneurysms of the native vascular tree.  相似文献   
17.
Pulmonary histiocytosis X: comparison of radiographic and CT findings   总被引:6,自引:0,他引:6  
The authors retrospectively evaluated radiographs, computed tomographic (CT) scans, and results of pulmonary function tests (when available) for 17 patients with biopsy-proved pulmonary histiocytosis X. In 11 patients, high-resolution CT was used. In 12 patients, CT demonstrated cystic air spaces, usually less than 10 mm in diameter. In three of these 12, cysts were the only abnormality, but in six others, nodules (usually less than 5 mm in diameter) were also present. Two patients had only nodules and one, only emphysema. CT showed that many lesions that appeared reticular on plain radiographs were actually cysts. CT showed no central or peripheral concentration of lesions, but it did reveal that many small nodules were distributed in the centers of secondary lobules around small airways. CT findings correlated better with the diffusing capacity (rho = -0.71) than did the plain radiographic findings (rho = -0.57). Thus, CT was better than radiography at showing the morphology and distribution of lung abnormalities.  相似文献   
18.
19.
20.
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