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   25151篇
  免费   1335篇
  国内免费   166篇
耳鼻咽喉   246篇
儿科学   484篇
妇产科学   220篇
基础医学   3331篇
口腔科学   590篇
临床医学   1638篇
内科学   6452篇
皮肤病学   534篇
神经病学   2161篇
特种医学   1282篇
外科学   3944篇
综合类   135篇
预防医学   758篇
眼科学   710篇
药学   1607篇
中国医学   68篇
肿瘤学   2492篇
  2023年   138篇
  2022年   243篇
  2021年   524篇
  2020年   279篇
  2019年   422篇
  2018年   543篇
  2017年   448篇
  2016年   565篇
  2015年   587篇
  2014年   719篇
  2013年   890篇
  2012年   1447篇
  2011年   1598篇
  2010年   904篇
  2009年   742篇
  2008年   1420篇
  2007年   1609篇
  2006年   1514篇
  2005年   1663篇
  2004年   1533篇
  2003年   1552篇
  2002年   1486篇
  2001年   514篇
  2000年   451篇
  1999年   466篇
  1998年   354篇
  1997年   279篇
  1996年   229篇
  1995年   230篇
  1994年   194篇
  1993年   176篇
  1992年   292篇
  1991年   259篇
  1990年   224篇
  1989年   242篇
  1988年   204篇
  1987年   206篇
  1986年   194篇
  1985年   185篇
  1984年   147篇
  1983年   107篇
  1982年   72篇
  1981年   64篇
  1980年   56篇
  1979年   88篇
  1978年   62篇
  1977年   47篇
  1976年   51篇
  1975年   59篇
  1969年   45篇
排序方式: 共有10000条查询结果,搜索用时 688 毫秒
101.
We assessed the relations of visual hallucinations (VH) to cardiovascular autonomic dysfunction in patients with Parkinson's disease (PD). The subjects were 37 patients without VH (VH(-)) and 31 with VH (VH(+)). Autonomic function was evaluated on the basis of cardiac 123-radioiodinated metaiodobenzylguanidine (123I-MIBG) uptake and hemodynamic testing with Valsalva maneuver. Systolic blood pressure (SBP) and plasma norepinephrine concentrations (NE) were measured by tilt-table testing. 123I-MIBG uptake was lower in VH(+) than VH(-). Hemodynamic studies showed that VH(-) had only cardiac sympathetic and parasympathetic dysfunction, while VH(+) additionally had reduced vasomotor sympathetic functions. The fall in SBP during tilt-table testing was greater in VH(+) than VH(-). NE and its difference in the supine and upright positions were decreased in VH(+). We conclude that cardiac and vasomotor sympathetic dysfunction is more severe in VH(+) than in VH(-). Severe dysfunction in PD with VH is probably attributed to Lewy-body lesions or neuronal loss in sympathetic ganglia, the central autonomic system, or both.  相似文献   
102.
A 61-year-old man had been treated for malignant fibrous histiocytoma with the pulmonary and the lymph node metastasis in the department of orthopedics in our hospital. He was admitted to our department because of an acute onset of conscious disturbance and non-fluent aphasia. Diffusion-weighted imaging (DWI) showed high signal intensity areas in the bilateral cerebella, thalami and posterior lobes. T2WI did not show any mass effects. Enhanced CT did not reveal any enhanced lesion. He was diagnosed as having cerebral embolism, and his conscious disturbance was improved after medication. Eight weeks later, he presented dysphagia, dysarthria, and ataxia in his extremities. DWI showed multiple lesions of low signal intensity located at the identical place where had showed high signal intensity in the initial DWI. T2WI showed high signal intensity area with mass effect. It was indicated that cerebral metastasis might grow after tumorgenic embolism. This is a rare case that tumor emboluses were developed to the metastatic brain tumors.  相似文献   
103.
104.
Although the causes of stroke are diverse, thromboembolism due to a mobile aortic thrombus is rare. We describe a surgical case of acute massive pulmonary embolism after critical cerebral infarction associated with a mobile ascending aortic thrombus in a 52-year-old woman. Concomitant surgical removal of the aortic thrombus and pulmonary embolectomy was performed successfully, and the patient has been stable without recurrent thromboembolic complications after 18 months of follow-up.  相似文献   
105.
Standard imaging techniques using a curved linear array echoendocope are summarized to facilitate the attainment of expertise in endoscopic ultrasonography and endoscopic ultrasound‐guided fine needle aspiration, and to promote the widespread use of this diagnostic and therapeutic tool. Typical images of the mediastinal organs, the bilio‐pancreatic systems and neighboring organs by scanning from the esophagus, stomach, duodenal bulb, and descending portion of the duodenum, are shown in a sequential manner. The basic techniques of endoscopic ultrasound‐guided fine needle aspiration are also presented.  相似文献   
106.
This study evaluated the usefulness of midazolam in inducing a anesthetic state in 60 patients who underwent surgery under general anesthesia. The patients were divided into 3 groups; a geriatric group, a hepatic dysfunction group, and a control group (adults without complications). To induce sleep 0.15 mg.kg-1 or 0.2 mg.kg-1 of midazolam was administered intravenously to all three groups. After the administration of midazolam, the mean time for obtaining absence of response to calling name and absence of ciliary reflex were not significantly different in the three groups. The pulse rate and respiratory rate also did not change remarkably. But significant decreases were observed in the systolic blood pressure and tidal volume in all three groups. However, they were not significantly different among the three groups. These results indicate that midazolam is a useful drug for inducing anesthetic state in geriatric patients and patients with hepatic dysfunction.  相似文献   
107.
Risk of gallstones following gastrectomy in Japanese men   总被引:3,自引:0,他引:3  
The risk of gallstones developing after gastrectomy in middle-aged Japanese men was investigated in a study of 2,738 men aged between 48 and 56 years who underwent both gallbladder ultrasonography (US) and a barium study of the upper digestive tract. It was revealed that 61 men had gallstones, 37 had had their gallbladder removed previously, and 55 had a history of gastrectomy. The prevalence of gallstones was 3.5 times higher in the men who had previously undergone gastrectomy (7.7%) than in those who had not (2.2%) (P=0.03). Moreover, gallstones tended to be more prevalent in those who had undergone Billroth II gastrectomy (12.5%) compared with those who had undergone Billroth I gastrectomy (5.6%); however, the difference was not significant. These results indicate that gastrectomy using either Billroth I or Billroth II reconstruction predisposes to gallstone formation. Nevertheless, it was estimated that prior gastrectomy was responsible for no more than 5% of gallstones in the study population.  相似文献   
108.
109.
110.
A transparent polyvinyl alcohol (PVA) hydrogel was prepared from a PVA solution in a mixed solvent consisting of water and a water miscible organic solvent by cooling. The physical properties were evaluated in comparison with commercially available soft contact lens materials, such as polyhydroxyethyl methacrylate (PHEMA) and copolymers of methyl methacrylate (MMA) and N-vinyl pyrrolidone (VP). The PVA hydrogel showed higher tensile strength and elongation at break than the other materials, while it had high water content and oxygen permeability the latter being comparable to those of PMMA/VP copolymers. The protein adsorption of the PVA hydrogel was much less than those of the other materials. The PVA hydrogel soft contact lenses were applied on rabbit eyes for 12 weeks. The influence on the cornea was studied by biomicroscopy, ultrasonic corneal pachymetry and histopathological examination. These examinations revealed no abnormal findings in the cornea. These results suggest that the PVA hydrogel may be promising as a new soft contact lens material.  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