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   6484篇
  免费   275篇
  国内免费   11篇
耳鼻咽喉   23篇
儿科学   96篇
妇产科学   97篇
基础医学   724篇
口腔科学   203篇
临床医学   469篇
内科学   1575篇
皮肤病学   96篇
神经病学   550篇
特种医学   321篇
外国民族医学   1篇
外科学   1419篇
综合类   29篇
预防医学   179篇
眼科学   88篇
药学   410篇
中国医学   8篇
肿瘤学   482篇
  2022年   54篇
  2021年   90篇
  2020年   46篇
  2019年   80篇
  2018年   92篇
  2017年   76篇
  2016年   82篇
  2015年   97篇
  2014年   127篇
  2013年   141篇
  2012年   250篇
  2011年   233篇
  2010年   143篇
  2009年   127篇
  2008年   262篇
  2007年   223篇
  2006年   255篇
  2005年   261篇
  2004年   233篇
  2003年   239篇
  2002年   260篇
  2001年   232篇
  2000年   237篇
  1999年   212篇
  1998年   76篇
  1997年   66篇
  1996年   47篇
  1995年   49篇
  1994年   49篇
  1992年   181篇
  1991年   207篇
  1990年   188篇
  1989年   169篇
  1988年   163篇
  1987年   169篇
  1986年   134篇
  1985年   140篇
  1984年   112篇
  1983年   98篇
  1982年   48篇
  1979年   78篇
  1978年   51篇
  1975年   50篇
  1973年   40篇
  1971年   49篇
  1970年   41篇
  1969年   53篇
  1968年   53篇
  1967年   42篇
  1966年   52篇
排序方式: 共有6770条查询结果,搜索用时 15 毫秒
61.
Plastics are extensively used as a material for orthoses. However, one remaining problem is the ventilation of the orthosis. This is a real problem in countries such as Japan, where it is hot and humid especially in summer. The authors have invented a new orthosis "POROPLAST", which is made of mesh plastic sheets, combined in a cross-like weave. These orthoses provide good ventilation and are very comfortable to wear. They have been fitted to seventy-four cases with satisfactory results.  相似文献   
62.
Psychological effects of aromatherapy on chronic hemodialysis patients   总被引:2,自引:0,他引:2  
Effects of aromatherapy (odorless condition, lavender, and hiba oil) on mood and anxiety were investigated in 14 female patients who were being treated with chronic hemodialysis. A control period consisting of natural hospital smells was established before each test session, and then aromatic test conditions were systematically evaluated for odorless conditions as well as aromatic conditions containing lavender and hiba oil aromas. The effects of aromatherapy were measured using the Hamilton rating scale for depression (HAMD) and the Hamilton rating scale for anxiety (HAMA). Hiba oil aroma significantly decreased the mean scores of HAMD and HAMA, and lavender aroma significantly decreased the mean scores of HAMA. The mean scores of HAMD and HAMA in an odorless condition were not significantly different from those of the control conditions. These results indicate that in chronic hemodialysis patients hiba oil is an effective, non-invasive means for the treatment of depression and anxiety, and that lavender alleviates anxiety.  相似文献   
63.
MRI of orbital schwannomas   总被引:5,自引:0,他引:5  
The literature on MRI of orbital schwannomas is limited. The appearances in three patients with an orbital schwannoma were reviewed. A superior orbitotomy through a subfrontal craniotomy revealed a schwannoma in all cases. MRI characteristics of very low signal on T 1-weighted images and homogeneous postcontrast enhancement may be helpful for differentiating schwannomas from other intraconal masses. Received: 21 June 1999/Accepted: 20 September 1999  相似文献   
64.
Growth failure is a common presentation of patients with pancreatic insufficient cystic fibrosis. However, full blown kwashiorkor is extremely rare. Cystic fibrosis is also considered to be rare in the South Asian population. This report describes a Sri Lankan infant with cystic fibrosis who presented with clinical features of severe kwashiorkor.  相似文献   
65.
A low serum phosphate concentration is characteristic in individuals in whom kidney stones form, this being related to serum 1,25-dihydroxyvitamin D, parathyroid hormone and urinary phosphate excretion. In order to determine whether these parameters are related to recurrence of stone formation, they were analyzed in single and recurrent stone formers as well as controls. An inverse correlation between serum levels of phosphate and 1,25-dihydroxyvitamin D was observed in control subjects, indicating that a drop in serum phosphate results in upregulated circulating 1,25-dihydroxyvitamin D level in controls. While the circulating low phosphate level upregulated the 1,25-dihydroxyvitamin D level in single stone formers, the elevation was less than expected from the drop in serum phosphate in recurrent stone formers. The results thus suggest that loss of upregulation of 1,25-dihydroxyvitamin D by serum levels of phosphate might be important for stone formation. The possibility of deregulation of 1,25-dihydroxyvitamin D to maintain physiological requirements in stone formers and prevent further nephrolithiasis therefore warrants attention. Received: 27 January 1999 / Accepted: 25 June 1999  相似文献   
66.
We report a case of primary central nervous system (CNS) malignant lymphoma of the central nervous system originating from the cerebellum and growing along the lower cranial nerves. A 67-year-old woman presented with hoarseness, vertigo, nausea, and vomiting. Gd-DTPA enhanced MRI showed a homogeneous enhanced mass lesion extending from the cerebellum to the medulla oblongata around the jugular foramen on the right side. Although pre- and intra-operative diagnosis had been schwannoma, histopathological examination revealed a B-cell, diffuse malignant lymphoma. The growth pattern of malignant lymphoma in the present case, which extended extra-axially, is considered to be rare. We discuss here the growth patterns and difficulties of diagnosis of primary CNS malignant lymphoma in this area.  相似文献   
67.
Esophageal motor disorders can be primarily focused in the esophagus or secondarily related to a systemic disease. Based on the manometric findings, primary esophageal motor disorders can also be classified into achalasia and spastic disorders, such as diffuse esophageal spasm, nutcracker esophagus, hypertensive lower esophageal sphincter, and nonspecific esophageal motility disorders.  相似文献   
68.
Protein C inhibitor (PCI), a plasma serine protease inhibitor of activated protein C, is present at high concentrations in the seminal plasma of normal subjects and is decreased in some infertile patients. We measured the concentrations of PCI, prostate-specific antigen, and fructose in the seminal plasma of infertile patients (n = 125) and of normal subjects (n = 13). We also measured time-dependent changes in the concentrations of PCI and fructose in seminal plasma after ejaculation. A weak correlation was found between the levels of PCI and fructose (r = 0.268, P = 0.016). The PCI level in seminal plasma of patients with seminal vesicle and/or vasal agenesis was significantly lower (P < .01) than in normal subjects. The level of fructose in seminal plasma decreased in vitro in a time-dependent manner after ejaculation, whereas the concentration of PCI was stable at 48 hours after ejaculation. These data suggest that PCI in seminal plasma, as well as fructose, may become one of the markers for agenesis of seminal vesicles and/or the vas deferens.  相似文献   
69.
The authors investigated the process of denervation and reinnervation of the interarytenoid (IA) muscle in the guinea pig using transmission electron microscopy and glycogen depletion technique after unilateral transection of the recurrent laryngeal nerve (RLN) and superior laryngeal nerve to clarify the innervation pattern of the unpaired IA muscle. Anastomosis between the bilateral arytenoid branches was confirmed in the belly of the IA muscle. Five weeks after transection, all of the IA muscle fibers appeared to have been reinnervated by the contralateral RLN. As the arytenoid branch of the RLN runs together with that of the contralateral RLN in a single intramuscular nerve funiculus, it is possible that collateral sprouting branches grow and extend into the adjacent denervated Schwann's sheaths. The authors conclude that the unpaired IA muscle, as a whole, receives specific motor nerve supply from the bilateral RLNs, although each muscle fiber is innervated unilaterally.  相似文献   
70.
The antitumor effects of FK317, a novel substituted dihydrobenzoxazine, were evaluated using human tumor xenografts (small cell lung cancer, non-small cell lung cancer, stomach cancer, colon cancer, pancreatic cancer, breast cancer, cervical cancer and ovarian cancer). Tumor growth-inhibitory effects and the effective dose-range of FK317 were much stronger and broader, respectively, than those of reference drugs such as mitomycin C, adriamycin, cisplatin, taxol and irinotecan. Furthermore, the body weight decrease and myelosuppression in FK317-treated mice were less than in the animals given any of the reference drugs. To explain this tumor selectivity, the distribution of FK317 was investigated after dosing tumor-bearing mice with the 14C-labelled compound. The concentration of FK317 in tumor tissues was relatively low, and long tumor retention was not observed. However, thin-layer chromatographic separation revealed that the radioactivity in the tumor resided mainly in strongly cytotoxic metabolites, while that in other tissues resided mainly in non-cytotoxic metabolites. These results suggest that FK317 shows strong antitumor activity without side effects, and one reason for this is its specific metabolite pattern. FK317 is now undergoing phase I clinical trials.  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