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   86378篇
  免费   4043篇
  国内免费   346篇
耳鼻咽喉   2343篇
儿科学   2791篇
妇产科学   2674篇
基础医学   11082篇
口腔科学   2530篇
临床医学   5653篇
内科学   20568篇
皮肤病学   2554篇
神经病学   7419篇
特种医学   1755篇
外国民族医学   1篇
外科学   9523篇
综合类   504篇
一般理论   23篇
预防医学   8336篇
眼科学   1805篇
药学   7138篇
中国医学   501篇
肿瘤学   3567篇
  2023年   612篇
  2022年   1526篇
  2021年   2976篇
  2020年   1427篇
  2019年   2616篇
  2018年   3272篇
  2017年   2005篇
  2016年   1983篇
  2015年   2097篇
  2014年   3233篇
  2013年   4515篇
  2012年   6107篇
  2011年   6687篇
  2010年   3697篇
  2009年   2855篇
  2008年   4639篇
  2007年   5112篇
  2006年   4880篇
  2005年   4864篇
  2004年   4560篇
  2003年   4273篇
  2002年   3777篇
  2001年   2019篇
  2000年   2188篇
  1999年   1707篇
  1998年   553篇
  1997年   435篇
  1996年   323篇
  1995年   302篇
  1994年   251篇
  1993年   193篇
  1992年   542篇
  1991年   443篇
  1990年   441篇
  1989年   317篇
  1988年   326篇
  1987年   297篇
  1986年   265篇
  1985年   255篇
  1984年   163篇
  1983年   162篇
  1982年   135篇
  1981年   156篇
  1980年   114篇
  1979年   161篇
  1978年   130篇
  1974年   114篇
  1971年   91篇
  1969年   89篇
  1968年   81篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
In neurons, a network of endocytic proteins accomplishes highly regulated processes such as synaptic vesicle cycling and the timely internalization of intracellular signaling molecules. In this review, we discuss recent advances on molecular networks created through interactions between proteins bearing the Eps15 homology (EH) domain and partner proteins containing the Asn–Pro–Phe (NPF) motif, which participate in important aspects of neuronal function as the synaptic vesicle cycle, the internalization of nerve growth factor (NGF), the determination of neuronal cell fate, the development of synapses and the trafficking of postsynaptic receptors. We discuss novel functional findings on the role of intersectin and synaptojanin and then we focus on the features of an emerging family of EH domain proteins termed EHDs (EH domain proteins), which are important for endocytic recycling of membrane proteins.  相似文献   
62.
Summary BACKGROUND: Endometriosis is a relatively common pathology in women of childbearing age and of low parity but rarely shows extraperitoneal involvement. The main aim of this paper is to raise the attention of specialists to the necessity of carrying out penetrating diagnosis of nonspecific extraperitoneal masses occurring in women of reproductive age. METHODS: We performed a retrospective review of six patients diagnosed with extraperitoneal endometriosis who were treated at the Vega Baja University Hospital (Spain) during the last 5 years. RESULTS: Surgical treatment had positive results in five patients. The preoperative diagnosis was correctly made in only two patients. The accurate aetiology of endometriosis remains unknown and diagnosis is based on clinical and cytopathological findings. CONCLUSIONS: Surgical treatment of extraperitoneal endometriosis is recommended. However, postoperative follow-up is obligatory and hormonal suppressive therapy may be necessary. Medical treatment with gestagens, Danazol, or agonists of the gonadotropin-releasing hormone are ineffective in endometriomas which are bigger than 2 cm.   相似文献   
63.
A neonate vaccinated against HBV was the source of an occupational exposure to blood. She was tested for hepatitis B surface antigen and found to be positive, leading to unnecessary treatment, retesting, and concern. Evaluation of the infectious status of HBV should rely on other means if vaccination has recently occurred.  相似文献   
64.
65.
AIM: To check on reproducibility of parameters of the cutaneous electrogastrogram registered at a close or a distant time span. METHODS: Twenty-two volunteers recruited by an advertisement (11 females and 11 males, median age 25 years, range: 18-35) underwent three surface electrogastrography examinations of which two were taken on consecutive days and the third one was accomplished at least 2 weeks before or after the two other sessions. The examination involved a 30-min fasted recording, followed by a 90-min postprandial registration after intake of a 394-kcal mixed solid-liquid test meal. RESULTS: Parameters of the electrogastrogram pertaining to the frequency of the gastric slow waves exhibited good to moderate reproducibility, whereas fair reproducibility characterized parameters expected to describe the power of gastric slow waves. With the exception of the difference fed minus fasted power (DeltaDP), in no instance was the medium term reproducibility any worse than the short term one. Categorical data analysis revealed that the relative time share of normogastria postprandially exhibited a better reproducibility than in the fasted period. The Cohen's kappa-value of 0.459 for the DeltaDP for the medium term reproducibility placed this parameter within the range of moderate agreement between repeat examinations. Of the two two-parameter combinations considered, the alliance of the fasted and fed normogastria performed worse than any of those parameters considered alone, whereas a combination of the DeltaDP with the fed-state normogastria revealed a kappa-value amounting to 0.510 for the medium term reproducibility. CONCLUSIONS: The feasibility of some electrogastrographic parameters to convey clinically useful information may be hampered by their fair reproducibility. Recoding of parameters of the cutaneous electrogastrogram from primary continuous to secondary categorical may help achieve a better agreement between repeat examinations.  相似文献   
66.
Extracts from Erodium cicutarium L. Herit were tested for antiviral and interferon inducing properties. Both water extract and methanol extract as well as its fractions were observed to exert antiviral effect in relation to myxoviruses, Herpes virus type 1, Vesicular stomatitis and vaccinia virus. None of these extracts did induce interferon in a suspension of human leukocytes.  相似文献   
67.
68.
Functional dyspepsia (FD) is associated with impaired gastric accommodation and autonomic dysregulation. The aim of this study was to investigate the effects of autonomic manipulation on distension-induced gastric accommodation in subjects with and without FD, using a newly developed gastric barostat paradigm. Twelve healthy subjects (HS) and 18 subjects with FD had four barostat examinations each: no intervention, intravenous atropine (1 mg), vagal stimulation (mental relaxation with deep breathing) and acute stress stimulation (serial subtraction task). Intrabag pressure increased from 1 to 15 mmHg in 5 min (ramp phase), and was maintained at 15 mmHg for 5 min (tonic phase). Volume responses were analysed using predefined parameters. There were no significant group differences in accommodation variables between HS and subjects with FD. The FD group could be subdivided into two distinct subgroups: subgroup 1 (n = 7, 38%) with low maximum volume and accommodation rate, and subgroup 2 with normal accommodation (n = 11). In subgroup 1, but not in subgroup 2 atropine increased maximum volume and accommodation rate substantially. Neither mental stress nor mental relaxation changed any of the accommodation variables. In a subgroup of subjects with FD, impairment of distension-induced gastric accommodation can be improved by cholinergic blockade, but not by acute physiological autonomic manipulation.  相似文献   
69.
Hybrid tumours are very rare salivary gland lesions composed of two or more different tumoural entities in a single neoplasm that arise within a definite topographical region. In most cases adenoid cystic carcinoma has been the predominant component in these lesions. In this study we describe two patients with hybrid tumours located in the palate, one in a 49-year-old woman and one in a 71-year-old man. The first case involved adenoid cystic carcinoma and mucoepidermoid carcinoma, and the patient in the second case exhibited adenoid cystic carcinoma and epithelial-myoepithelial carcinoma. Both patients were treated with surgery and radiotherapy, and there has been no evidence of recurrence after 13 and 36 months of follow-up, respectively. The recognition of the histologic component with the higher grade of malignancy in every case of hybrid tumour of the salivary glands is a necessary step to determine the biological behaviour and, consequently, to determine the proper therapeutic approach.  相似文献   
70.
Apical ballooning is a novel clinical entity reported in different contexts of physical and psychological stress, which is more common in middle-aged women. Of unknown etiology, the syndrome is characterized by a sudden and transient dilatation of the left ventricular apex in the absence of obstructive atherosclerotic coronary disease or evidence of myocardial necrosis, with total late recovery of ventricular function. The authors report the case of a 53-year-old woman who was admitted to the emergency room with left arm ischemia and low cardiac output, requiring ventilatory support. Left catheterization showed typical medial and apical myocardial dysfunction, with normal coronary arteries. Transesophageal echocardiography revealed a thrombus attached to the lower face of the aortic arch, which probably explained the thromboembolism of the arm but was unlikely to be the cause of the left ventricular dysfunction since there were no enzymatic or electrocardiographic signs of myocardial necrosis and normal wall motion was fully recovered.  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