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   904篇
  免费   65篇
  国内免费   63篇
耳鼻咽喉   2篇
儿科学   47篇
妇产科学   31篇
基础医学   91篇
口腔科学   29篇
临床医学   75篇
内科学   179篇
皮肤病学   24篇
神经病学   21篇
特种医学   260篇
外科学   45篇
综合类   57篇
预防医学   28篇
眼科学   5篇
药学   96篇
肿瘤学   42篇
  2023年   2篇
  2022年   3篇
  2021年   11篇
  2020年   4篇
  2019年   3篇
  2018年   7篇
  2017年   6篇
  2016年   9篇
  2015年   13篇
  2014年   17篇
  2013年   20篇
  2012年   5篇
  2011年   9篇
  2010年   22篇
  2009年   33篇
  2008年   11篇
  2007年   38篇
  2006年   16篇
  2005年   27篇
  2004年   11篇
  2003年   12篇
  2002年   10篇
  2001年   26篇
  2000年   11篇
  1999年   24篇
  1998年   57篇
  1997年   64篇
  1996年   57篇
  1995年   57篇
  1994年   34篇
  1993年   44篇
  1992年   17篇
  1991年   20篇
  1990年   21篇
  1989年   49篇
  1988年   38篇
  1987年   33篇
  1986年   20篇
  1985年   21篇
  1984年   14篇
  1983年   7篇
  1982年   15篇
  1981年   20篇
  1980年   25篇
  1979年   14篇
  1978年   12篇
  1977年   18篇
  1976年   11篇
  1975年   9篇
  1971年   3篇
排序方式: 共有1032条查询结果,搜索用时 15 毫秒
51.
Multiple myeloma: evaluation by CT   总被引:3,自引:0,他引:3  
Schreiman  JS; McLeod  RA; Kyle  RA; Beabout  JW 《Radiology》1985,154(2):483-486
Although patients who have multiple myeloma usually have straightforward clinical symptoms and corroborative radiographs, in some instances, these patients will present atypically, with symptoms suggesting active disease but radiographs that are normal or nonspecific. We reviewed the records of 32 patients who had documented multiple myeloma and had undergone CT examinations, assessing the value of those examinations. Although CT is not indicated in all patients who have multiple myeloma, it is especially useful in patients who have bone pain and normal or nonspecific radiographs. CT provided confirmatory information in all cases in which lesions were seen on radiographs. CT also frequently demonstrated a greater extent of disease than could be appreciated on the radiographs.  相似文献   
52.
53.
54.
Tarsal navicular stress fractures: radiographic evaluation   总被引:3,自引:0,他引:3  
Pavlov  H; Torg  JS; Freiberger  RH 《Radiology》1983,148(3):641-645
Tarsal navicular stress fractures are a potential source of disabling foot pain in physically active individuals. The diagnosis of tarsal navicular stress fracture requires a high index of clinical and radiographic suspicion because the fracture is only rarely evident on routine radiographs or standard tomograms. The radiographic diagnosis of a tarsal navicular stress fracture may require anatomic anteroposterior tomograms or a radionuclide bone scan with plantar views. Radiographic examinations of 23 fractures in 21 patients are evaluated.  相似文献   
55.
In 26 patients with hypothalamic amenorrhea cyclic ovarian function was reestablished by pulsatile LH-RH substitution. Two LH-RH regimens were tested. In group A (n = 13) LH-RH pulses (12 micrograms i.v.) were administered by means of a portable mini-pump (Auto-Syringe) at the unvaried frequency of one pulse every 96 min throughout the follicular phase. In group B (n = 13) LH-RH pulse intervals of 4 h (for 2 consecutive days), 3 h (for 1 day) and 96 min (for the rest of the follicular phase) were selected for initiation of follicle growth. After ovulation pump-assisted pulsatile LH-RH substitution was either maintained at the 96-min rhythm or replaced by LH-RH nasal-spray (200 micrograms/sniff) applied once every 4 h until the onset of menstruation or detection of pregnancy. While in group A patients changes in the pattern of luteal LH-RH support (pump-assisted versus nasal-spray assisted) resulted in rapid luteolysis, such effects did not occur in group B patients. It is suggested that LH-RH pulse frequency at the initial stage of follicular development is of importance for the quality of follicular development and thus luteal function. Both LH-RH regimens resulted in pregnancies (six times singletons and once twins). In the meantime, all children have been born and are healthy.  相似文献   
56.
In previous studies, atopic patients showed attenuated cortisol responses to psychosocial stress which is suggestive of a hyporeactive hypothalamus-pituitary-adrenal (HPA) axis in this patient group. Regarding the anti-inflammatory role of glucocorticoids, reduced responsiveness of the HPA axis under stress may be one potential explanation of stress-induced exacerbation of atopic symptoms. The present study evaluated whether hyporeactivity of the HPA axis is a feature related to the disposition of atopy rather than a consequence of an ongoing chronic allergic inflammatory process. Newborns with an atopic disposition (parental atopy; n=31) and without atopic disposition (no parental atopy; n=20) were recruited. To further assess atopic disposition, total IgE levels were determined in the cord blood of the neonates. Three days after birth, a blood sample was obtained by a heel prick which is part of a standard pediatric examination. Blood sampling by heel prick is well known to be a significant stressor resulting in activation of the HPA axis in newborns. Analysis of salivary cortisol indicated a significant increase of cortisol levels in the newborns after the stressor with a trend towards an elevated cortisol response in babies with a family history of atopy or with elevated levels of cord IgE (> or = 0.5 kU/l). Neonates with a positive parental atopic heritage and elevated cord IgE were found to show significantly elevated cortisol responses to the heel prick stress when compared to newborns without a parental atopic history and normal cord IgE values. Moreover, cord IgE levels were significantly correlated with basal cortisol levels and the cortisol response to the stressor. These findings suggest that atopic disposition in neonates is associated with altered responsiveness of the HPA axis to stress which may increase the vulnerability to develop manifestation of atopy in later life.  相似文献   
57.
There are few breast-conserving therapies (BCT) for centrally located breast cancer. The present paper describes a BCT for breast cancers in such a location, which permits conservation of the nipple-areola complex (NAC), provided this has not been infiltrated. After histological detection of the breast cancer by punch biopsy, a central segmental mastectomy and an axillary dissection are performed. An immediate reconstruction of the subareolar defect is carried out by means of a local flap technique, thus conserving the NAC.  相似文献   
58.
The clinicopathological associations of 33 singleton infants who died with intraventricular haemorrhage (IVH) without hyaline membrane disease (HMD) ('IVH only') were compared with those of 39 infants who died with IVH+HMD over the same gestation range in order to determine what factors other than those related to HMD may contribute to the pathogenesis of IVH. The incidence of 'IVH only' was inversely related to gestational age in the Hammersmith birth population, whereas the incidence of IVH+HMD rose to a peak at 28-29 weeks' gestation. Infants with 'IVH only' lived longer on average than those with IVH+HMD despite a lower birthweight and shorter gestation. Infants who died in the first 12 hours from 'IVH only' had suffered severe birth asphyxia but in those who died later the main symptom was recurrent apnoea. Fewer infants with asphyxia but in those who died later the main symptom was.recurrent apnoea. Fewer infants with 'IVH only' were given alkali therapy or were connected to the ventilator as compared to those with IVH+HMD, but there were no differences in alkali therapy in those who lived for 12 hours or more. In the 'IVH only' group there was a high incidence of haemorrhage from other sites and of bacterial infections. It is suggested that, in the absence of HMD, extreme immaturity is the main factor determining the occurrence of IVH. Birth asphyxia, apnoeic attacks, haemorrhage, and infections may play subsidiary roles, possibly through development of metabolic acidosis.  相似文献   
59.
SARS-CoV isa newly identified coronavirus that causes severe acute respiratory syndrome (SARS). Currently, there is no effective method available for prophylaxis and treatment of SARS-CoVinfections. In the present study, the influence of small interfering RNA (siRNA) on SARS-CoV nucleocapsid (N) protein expression was detected in cultured cells and mouse muscles. Four siRNA expression cassettes driven by mouse U6 promoter targeting SARS-CoV N gene were prepared, and their inhibitory effects on expression of N and enhanced green fluorescence protein (EGFP) fusion protein were observed.  相似文献   
60.
0 引言 人类免疫缺陷病毒 (human immunodeficiencyvirus,HIV) - 1编码的反式激活蛋白 TAT具有独特的跨膜运转方式 ,而且有转导速度快 ,效率高的特点 ,被称为蛋白转导结构域 (protein transduction domain,PTD) [1 ,2 ] .本研究用PCR扩增了慢性粒细胞白血病慢粒 bcr/ abl融合蛋白的基因片段 ,在其 5′端融合 PTD结构域的编码区后在大肠杆菌中进行了表达 .表达产物经纯化后 ,加入培养的 HL 6 0细胞 ,表达的蛋白可直接进入细胞内 .这一结果为用外源蛋白负载(L oading)免疫细胞提供了新的途径 .1 材料和方法1.1  DNA重组 人工合…  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