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   382879篇
  免费   34357篇
  国内免费   26698篇
耳鼻咽喉   3421篇
儿科学   4103篇
妇产科学   5233篇
基础医学   44358篇
口腔科学   6592篇
临床医学   52166篇
内科学   56215篇
皮肤病学   3492篇
神经病学   20307篇
特种医学   14568篇
外国民族医学   227篇
外科学   39703篇
综合类   64731篇
现状与发展   87篇
一般理论   21篇
预防医学   25237篇
眼科学   10725篇
药学   39246篇
  393篇
中国医学   21855篇
肿瘤学   31254篇
  2024年   1186篇
  2023年   5586篇
  2022年   14539篇
  2021年   18214篇
  2020年   13648篇
  2019年   12040篇
  2018年   12696篇
  2017年   11427篇
  2016年   10669篇
  2015年   16585篇
  2014年   20687篇
  2013年   18746篇
  2012年   27623篇
  2011年   31008篇
  2010年   20190篇
  2009年   16086篇
  2008年   21177篇
  2007年   21156篇
  2006年   20836篇
  2005年   19969篇
  2004年   13548篇
  2003年   12895篇
  2002年   11079篇
  2001年   9512篇
  2000年   9640篇
  1999年   9764篇
  1998年   5863篇
  1997年   5868篇
  1996年   4595篇
  1995年   4146篇
  1994年   3440篇
  1993年   2215篇
  1992年   2921篇
  1991年   2506篇
  1990年   2198篇
  1989年   1916篇
  1988年   1601篇
  1987年   1392篇
  1986年   1133篇
  1985年   928篇
  1984年   536篇
  1983年   375篇
  1982年   251篇
  1981年   243篇
  1980年   188篇
  1979年   225篇
  1978年   82篇
  1977年   89篇
  1974年   102篇
  1973年   83篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
141.
Intrathecal morphine for post-thoracotomy pain   总被引:1,自引:0,他引:1  
We wished to investigate possible differences in the duration of postoperative analgesia and the incidence of respiratory depression after the intrathecal injection in the lumbar area of 10 micrograms/kg morphine in hypobaric and hyperbaric solution for relief of post-thoracotomy pain. Twenty-nine patients received morphine plus dextrose (hyperbaric) and 21 received morphine in preservative-free normal saline. The duration of analgesia was longer with the morphine in the normal saline group than in the hyperbaric group (P less than 0.04). One patient developed delayed respiratory depression. Our data support the use of morphine in normal saline mixtures for greater duration of analgesia after thoracic operations.  相似文献   
142.
Experience in the treatment of 30 cases with gas gangrene from war wounds   总被引:1,自引:0,他引:1  
Z Y Li  X L Wang  X S Wang 《中华外科杂志》1986,24(10):580-1, 637
  相似文献   
143.
五倍南星膏外敷治疗颌下淋巴结炎26例   总被引:2,自引:2,他引:0  
自1998年2月-2004年12月共应用五倍南星膏治疗颌下淋巴结炎病人26例,收到良好的临床效果,现报告如下:  相似文献   
144.
Two samples of kindergarten children's representation and understanding of written number symbols were examined in two time points in one academic year. About 85% of Chinese five year olds (mean = 5 years 10 months) were able to use conventional number symbols to represent the quantity of 30 or larger. At the end of the kindergarten year, 94% of Chinese six year olds (mean = 6 years 4 months) were able to use conventional number symbols to represent the quantity of 100 or larger. Some Chinese six year olds had problems in representing written addition and subtraction tasks. Children's ability to represent written number symbols, ability to represent written addition and subtraction formula and their performance on written addition and subtraction were closely related. The performance of children in a university-affiliated childcare center was better than that of the center serving working-class families in Time 1, but the performance reversed at the end of the kindergarten year.  相似文献   
145.
Tumor metastasis to the pancreas is a rare but recognized cause of acute pancreatitis. Autopsy series have reported a 24-40% of pancreatic involvement in small cell lung cancer. However, only a very few cases of tumor-induced acute pancreatitis have been described. Budd-Chiari syndrome complicating lung cancer is a rarely reported condition. We report a 68-year-old woman with extensive small cell lung cancer with the unusual initial presentation of both acute pancreatitis and acute Budd-Chiari syndrome. This patient suffered from progressive epigastralgia for 3 weeks. Severe epigastralgia with radiation to back and progressive jaundice developed 2 days prior to admission. After admission, the liver enlarged rapidly and the ascites increased markedly. Chest roentgenogram showed a mass lesion over the left lower lung field. Poorly differentiated carcinoma cells were found in ascites and bone marrow. The patient died on the ninth day of hospitalization before chemotherapy was initiated. Prompt diagnosis of extensive-stage small cell lung cancer may allow early chemotherapy treatment which favorably influences recovery when the pancreatitis is mild. Although prolonged survival might have been expected had this patient recovered from pancreatitis and received chemotherapy, diagnosis was delayed due to difficulty in immunohistochemical diagnosis of the tumor and the unusual clinical presentation. The use of stains employing antibodies against neurofilament and neuron-specific enolase cell antigens is important for early diagnosis of poorly differentiated metastatic tumor cells.  相似文献   
146.
A number of vitamin D3 metabolites inhibit benzodiazepine- and dimethyl sulfoxide-induced differentiation of Friend erythroleukemia cells. The inhibition is dose dependent and occurs at nM concentrations. The order of potency of these compounds is 1,25-dihydroxycholecalciferol greater than 1,25,26-trihydroxycholecalciferol greater than 1,24R,25-trihydroxycholecalciferol greater than 1 alpha-hydroxycholecalciferol greater than 24R,25-dihydroxycholecalciferol greater than 25S,26-dihydroxycholecalciferol. The inhibition is maximal when the vitamin D3 analogs are added together with the inducer, and becomes progressively decreased with delayed addition. These results suggest that the vitamin D3 metabolites may play a regulatory role in erythropoiesis.  相似文献   
147.
Scintigraphic imaging with (123)I-metaiodobenzylguanidine ((123)I-MIBG) has demonstrated extensive losses of cardiac sympathetic neurons in idiopathic Parkinson's disease (IPD). In contrast, normal cardiac innervation has been observed in (123)I-MIBG studies of multiple-system atrophy (MSA) and progressive supranuclear palsy (PSP). Consequently, it has been hypothesized that cardiac denervation can be used to differentiate IPD from MSA and PSP. We sought to test this hypothesis by mapping the distribution of cardiac sympathetic neurons in patients with IPD, MSA, and PSP by using PET and (11)C-meta-hydroxyephedrine ((11)C-HED). Also, the relationship between cardiac denervation and nigrostriatal denervation was investigated by measuring striatal presynaptic monoaminergic nerve density with PET and (11)C-dihydrotetrabenazine ((11)C-DTBZ). METHODS: (11)C-HED and (11)C-DTBZ scans were obtained for patients with IPD (n = 9), MSA (n = 10), and PSP (n = 8) and for age-matched control subjects (n = 10). Global and regional measurements of (11)C-HED retention were obtained to assess the extent of cardiac sympathetic denervation. (11)C-DTBZ binding was measured in the caudate nucleus, anterior putamen, and posterior putamen. RESULTS: As expected, extensive cardiac denervation was observed in several of the patients with IPD. However, substantial cardiac denervation was also seen in some patients with MSA and PSP. (11)C-DTBZ studies demonstrated striatal denervation in all patients with IPD and in most patients with MSA and PSP. No correlation was found between cardiac (11)C-HED retention and striatal (11)C-DTBZ binding. CONCLUSION: Cardiac sympathetic denervation was found to occur not only in IPD but also in other movement disorders, such as MSA and PSP. This finding implies that scintigraphic detection of cardiac sympathetic denervation cannot be used independently to discriminate IPD from other movement disorders, such as MSA and PSP. Cardiac sympathetic denervation was not correlated with striatal denervation, suggesting that the pathophysiologic processes underlying cardiac denervation and striatal denervation occur independently in patients with parkinsonian syndromes. These findings provide novel information about central and peripheral denervation in patients with neurodegenerative disorders.  相似文献   
148.
螺旋CT三期扫描对肝纤维化诊断价值研究   总被引:5,自引:1,他引:4  
目的探讨螺旋CT三期扫描对肝纤维化的诊断价值。方法对66例经肝穿刺活检病理证实的慢性乙型肝炎肝纤维化患者组和42例正常对照组进行螺旋CT三期增强扫描。根据纤维化程度分期进行影像资料和相关指标的统计分析。结果肝左叶增大,肝表面形态及肝实质密度的改变,脾脏增大,门静脉增宽和侧枝循环的建立等影像学改变,随着肝纤维化严重程度的加重而有统计学差异。本研究显示57例肝纤维化患者螺旋CT三期扫描诊断肝纤维化52例,敏感性91.2%,特异性77.8%。各期肝纤维化分期准确28例,准确率49.1%;准确判断轻度纤维化(S1、S2)或重度纤维化(S3、S4)44例,准确率77.2%,诊断早期肝硬化16例,准确率84.2%。结论螺旋CT三期扫描能判断肝纤维化的程度,而且是动态观察肝纤维化的病程演进和临床随访的有效手段。  相似文献   
149.
点穴推拿治疗睡眠障碍68例   总被引:1,自引:0,他引:1  
目的:观察点穴推拿治疗睡眠障碍的临床疗效。方法:采用点穴推拿治疗睡眠障碍68例不同病因引起的病症。结果:治愈30例,显效20例,有效10例,无效8例,总有效率88.24%。结论:点穴推拿对不同病因引起的睡眠障碍均有很好的疗效。  相似文献   
150.
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