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   726篇
  免费   40篇
  国内免费   20篇
耳鼻咽喉   2篇
儿科学   37篇
妇产科学   7篇
基础医学   95篇
口腔科学   27篇
临床医学   145篇
内科学   151篇
皮肤病学   2篇
神经病学   11篇
特种医学   163篇
外科学   35篇
综合类   25篇
一般理论   1篇
预防医学   27篇
药学   24篇
肿瘤学   34篇
  2023年   6篇
  2022年   6篇
  2021年   13篇
  2020年   2篇
  2019年   3篇
  2018年   6篇
  2017年   6篇
  2016年   9篇
  2015年   5篇
  2014年   16篇
  2013年   25篇
  2012年   11篇
  2011年   20篇
  2010年   24篇
  2009年   44篇
  2008年   18篇
  2007年   21篇
  2006年   13篇
  2005年   17篇
  2004年   5篇
  2003年   12篇
  2002年   18篇
  2001年   13篇
  2000年   16篇
  1999年   16篇
  1998年   43篇
  1997年   43篇
  1996年   42篇
  1995年   36篇
  1994年   25篇
  1993年   25篇
  1992年   13篇
  1991年   6篇
  1990年   11篇
  1989年   28篇
  1988年   26篇
  1987年   15篇
  1986年   11篇
  1985年   16篇
  1984年   12篇
  1983年   8篇
  1982年   19篇
  1981年   13篇
  1980年   17篇
  1979年   3篇
  1978年   8篇
  1977年   11篇
  1976年   7篇
  1975年   3篇
排序方式: 共有786条查询结果,搜索用时 15 毫秒
1.
2.
Coronary artery bypass grafts: visualization with MR imaging   总被引:1,自引:0,他引:1  
Gomes  AS; Lois  JF; Drinkwater  DC  Jr; Corday  SR 《Radiology》1987,162(1):175
  相似文献   
3.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.  相似文献   
4.
BACKGROUND: Merkel cell carcinoma is a rare malignant neuroendocrine neoplasm characteristically arising from the dermis of sunlight-exposed skin. It rarely arises outside the skin. OBJECTIVE: We present a patient with primary Merkel cell carcinoma arising from subcutaneous fat, with no involvement of the overlying skin. We describe the clinical manifestations and magnetic resonance imaging (MRI) findings. METHODS: We report a 63-year-old woman with a primary lesion of Merkel cell carcinoma that arose from the subcutaneous fat layer of the left arm. The lesion presented as a subcutaneous nodule with intact overlying skin. MRI showed that the nodular lesion was located entirely in the subcutaneous fat layer, with no involvement of the dermis. Peritumoral infiltration around the lesion and enlarged lymph nodes deep to the lesion were noted. The patient received wide excision of the lesion with dissection of the regional lymph nodes and adjuvant radiotherapy and chemotherapy. RESULTS: Histopathologic examination confirmed the diagnosis of Merkel cell carcinoma with local lymphatic metastasis, and the lesion was completely located in the subcutaneous fat, with no involvement of the dermis. These findings were well correlated with MRI findings. CONCLUSION: Primary Merkel cell carcinoma may arise from the subcutaneous fat and present as an entirely subcutaneous lesion with intact skin. MRI is helpful to evaluate the local extension of the lesion and regional lymphatic metastasis.  相似文献   
5.
表小檗碱对α受体的作用   总被引:2,自引:0,他引:2  
王嘉陵  方达超 《药学学报》1990,25(4):289-292
表小檗碱(epiberberine,EB)是从湖北产黄连(Coptis chinensis Franch)中提取的一种生物碱,属苯喹嗪类原小檗碱,对其药理作用的研究资料甚少,未见其对α肾上腺素体作用的报道。资料表明,许多原小檗碱类化合物有α受体阻滞作用,为从该类化合物中选择  相似文献   
6.
The purpose of this pilot study was to observe both relaxed and deep breathing patterns in a convenience sample to determine the incidence of normal versus faulty patterns of respiration. These observations were then combined with respondent answers to a survey on pain history to determine if there is any correlation between faulty breathing and musculo-skeletal pain patterns. If such a correlation can be made, then we propose that clinicians working with chronic pain patients may have improved outcomes if they address and correct faulty breathing patterns. Based on this study, it is suggested to include the evaluation and treatment of faulty respiration in the rehabilitation of chronic musculo-skeletal conditions, most notably cervical pain.  相似文献   
7.
36例踝关节骨折合并下胫腓联合分离的治疗体会   总被引:1,自引:1,他引:0  
李得春 《医学争鸣》2005,26(17):1631-1631
0 引言 踝关节骨折是临床上较常见的关节内骨折,包含了腓骨骨折,内踝骨折,后踝骨折和下胫腓联合的损伤. 处理不当可导致踝穴的变形,下胫腓联合分离后期出现创伤性关节炎.  相似文献   
8.
High altitude residence is known to modify body biochemistry and hormone status. However, the effects of such a sojourn on these status observed at sea level both immediately and later after return are not as well established as are the effects of an intermittent acclimation. The aim of this study was therefore to investigate these changes. To achieve our objectives, nine subjects received intermittent acclimation at low pressure in a barometric chamber (8?h daily for 5 days, day 1 at 4500 m, day 5 at 8500 m) before an expedition to the Himalayas. Hormonal and biochemical changes were studied using samples of venous blood taken at sea level before and after acclimation, after return from the expedition and 1 and 2 months after descent. Concentrations of thyroid hormones, adrenaline, noradrenaline (NA), hormones of hydromineral metabolism (aldosterone, renin, arginine vasopressin, atrial natriuretic peptide) as well as prolactin, cortisol, insulin and endothelin 1 were measured. Biochemical measurements made were plasma osmolality, and concentrations of glucose, total cholesterol, total proteins, pre-albumin, transferrin, complement 3C, apolipoproteins A1 and B and serum iron. Acclimation induced no alteration in hormone (except for NA with increases of about 1.5, fold P<0.05) and biochemistry data. After the expedition, hormone responses were characterized by a higher total triidothyronine concentration (+18%, P<0.05) while other hormones did not vary. A linear relationship was found between thyroid-stimulating-hormone and body mass changes after the expedition (r=0.67, P<0.05). The observed increased concentrations of plasma proteins and total cholesterol (P<0.05) could be related to the restoration of lean body mass. At 1 and 2 months after return, no changes in hormones were observed but a significant decrease in transferrin concentration was noticed. The higher serum iron concentration reported after 1 month (P<0.05) could have been the result of a physiological haemolysis. It was concluded that both acclimation and the expedition in the Himalayas affected hormone status and body biochemistry status even though the observed changes were slight and rapidly reversed.  相似文献   
9.
Reading the minutes of the annual meetings of the Brooklyn visiting nurses over the years, one is reminded of the old French proverb Plus ?a change, plus c'est la même chose (The more things change, the more things stay the same). The questions of 1988 are often the same questions the board members struggled with 50, 80, and 100 years ago. Human nature changes very little. Science, it is true, gives us new instruments with which to work, and additional education is at our disposal. But the well-being of the client and the family, and our advocacy role present the same problems for solution. questions about caseloads to be carried, types of care to be given, and cooperation for community betterment appear in the minutes of the Association from the earliest days. The reactions to these problems have been crucial and vital in guiding the direction the service has taken. Recurrent problems have also demonstrated that no solution is permanent. The same questions will appear and reappear for careful thought according to the demands of the period in which we live and the way in which society has shaped the nature of care required. Over the last 100 years, there has been steady growth, with constant enlargement of vision and constant application of newer methods of advancement in client care. The use of leeches and blood letting of 100 years ago may seem absurd by today's standards. One can only imagine the developments in home nursing over the second century of caring.  相似文献   
10.
Summary Classically, cold induced plasma volume reduction is explained by an increased diuresis which is generated by an inhibition of antidiuretic hormone release. However, most of the haemoconcentration appears to be reversible during rewarming. This observation weakens the former statement. The aim of this study was to clarify the mechanisms involved in the reversal of the cold induced haemoconcentration. Six young males, resting in a dorsal reclining position, were exposed successively to a thermoneutral environment (30 min), a cold environment (1° C; cold) or thermoneutrality (control) for 120 min, and during a 60-min recovery period in thermoneutral conditions. During cold stress, a reduction of 15% (i.e. 510 ml) of the plasma volume was observed, and osmolality was unchanged. After the 60-min recovery under thermoneutral conditions, plasma volume variation between the Cold and the Control experiments was reduced and reached 3% (i.e. 100 ml). This volume equalled the increased amount of urine production observed during the cold stress experiment. Haemoconcentration cannot be explained by increased urinary water loss (± 100 ml) alone. Therefore a transient shift of plasma water from vascular to interstitial spaces, due to an increase of blood pressure, could be involved in the reduction of plasma volume.  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