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   12386篇
  免费   965篇
  国内免费   435篇
耳鼻咽喉   41篇
儿科学   204篇
妇产科学   485篇
基础医学   424篇
口腔科学   73篇
临床医学   4703篇
内科学   1770篇
皮肤病学   91篇
神经病学   318篇
特种医学   665篇
外国民族医学   3篇
外科学   1460篇
综合类   2105篇
预防医学   363篇
眼科学   162篇
药学   399篇
  4篇
中国医学   75篇
肿瘤学   441篇
  2024年   82篇
  2023年   316篇
  2022年   361篇
  2021年   518篇
  2020年   524篇
  2019年   572篇
  2018年   356篇
  2017年   384篇
  2016年   347篇
  2015年   389篇
  2014年   630篇
  2013年   622篇
  2012年   537篇
  2011年   760篇
  2010年   636篇
  2009年   569篇
  2008年   588篇
  2007年   638篇
  2006年   751篇
  2005年   627篇
  2004年   552篇
  2003年   506篇
  2002年   451篇
  2001年   380篇
  2000年   225篇
  1999年   218篇
  1998年   284篇
  1997年   173篇
  1996年   145篇
  1995年   126篇
  1994年   101篇
  1993年   60篇
  1992年   63篇
  1991年   52篇
  1990年   58篇
  1989年   34篇
  1988年   25篇
  1987年   17篇
  1986年   14篇
  1985年   11篇
  1984年   17篇
  1983年   10篇
  1982年   11篇
  1981年   8篇
  1980年   10篇
  1979年   4篇
  1978年   7篇
  1977年   5篇
  1975年   4篇
  1974年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
先天性无阴道的非手术治疗:附27例报告   总被引:1,自引:0,他引:1  
夏捷  薛培 《上海医学》1992,15(2):84-86
  相似文献   
62.
目的:探讨联合应用高低频超声诊断急性阑尾炎的价值。方法:回顾性分析经手术证实为急性阑尾炎的127例患者的高低频超声声像图特征。结果:127例患者中:急性单纯性阑尾炎41例,超声检出36例,占87.8%;化脓性阑尾炎53例,超声检出50例,占94.3%;坏疽性阑尾炎24例,超声检出21例,占87.5%;阑尾周围脓肿9例,超声检出8例,占88.9%。结论:联合应用高低频超声能提高急性阑尾的诊断准确率,并初步对阑尾炎进行分型,为临床首选的影像学检查。  相似文献   
63.
目的 研究彩色多普勒超声诊断房间隔缺损(ASD)的准确性。方法 回顾性分析经手术证实的64例ASD患者的超声检查结果并和手术结果对照。结果 64例患者中有1例三房心合并房间隔缺损畸形,1例合并右下肺静脉异位引流漏诊,术前超声正确诊断63例,定性诊断准确率达98.4%,有1例混合型定位不准确,定位准确率在98.4%,而且64例患者中超声检查结果显示在无合并其他畸形时房间缺损大小与右心系统扩大及肺动脉扩张呈正相关关系。结论 ASD是以右室容量超负荷为特征,彩色多普勒超声是诊断房间隔缺损的首选检查方法,并具有较高的准确性。  相似文献   
64.
Clinical diagnosis of chronic cholecystitis is made based on diffuse hyperechoic thickening of the gallbladder wall as shown by ultrasonographic examination. We herein report three cases of chronic cholecystitis showing localized hypoechoic thickening of the gallbladder wall that mimicked gallbladder cancer by ultrasonography. Histologically, hypertrophy of the muscularis propria was a common characteristic finding in these three patients. A smooth surface of the inner hypoechoic layer of the thickened wall was considered to be a reliable finding in the differential diagnosis between this type of chronic cholecystitis and gallbladder cancer.  相似文献   
65.
杨谦 《医学争鸣》2005,26(18):1710-1712
目的:研究偏头痛患者经颅彩色多谱勒(TCD)和脑干听觉诱发电位(BAEP)变化并探讨其临床意义. 方法:偏头痛患者350(男128,女222)例,年龄17~49岁,病程5 mo~12 a. 典型偏头痛185例(单侧头痛105例,双侧头痛80例),普遍偏头痛165例(单侧头痛95例,双侧头痛70例). 对照选择健康体检者135(男55,女80)例,年龄20~48岁. 全部患者在偏头痛发作期间同时进行TCD和TBAEP检查. 结果:在350例偏头痛患者中脑血流增快224例(64.0%),血流减慢110例(31.4%),血流正常16例(4.6%),总异常率95.43%. 典型偏头痛患者MCA(cm/s,大脑中动脉)和PCA(cm/s,大脑后动脉)均高于对照[(70± 7) vs (62±8),P<0.05; (48±9) vs (37±8),P<0.05]和普通偏头痛(61±6, P<0.05; 40±9, P<0.05). 偏头痛患者发作期脑干听觉诱发电位(BAEP)异常率为52.9%(185/350),表现为Ⅰ, Ⅲ, Ⅴ波潜伏期及Ⅲ~Ⅴ峰间期延长. 偏头痛发作间期BAEP正常. 偏头痛病程越长BAEP异常率越高,听神经损害的可能性越大. 结论:偏头痛发作期间有部分脑血流改变,同时有BAEP改变,病程越长BAEP异常率越高,听神经损害的可能性越大. 提示TCD和BAEP对偏头痛有一定诊断价值.  相似文献   
66.
The heels of 23 patients who were diagnosed with unilateral/bilateral plantar fasciitis were evaluated via ultrasonography and compared with their asymptomatic feet and a control group of 23 people. Plantar fascial thickness, echogenity, and heel pad thickness were evaluated, and the results were statistically analyzed. For symptomatic feet, increased thickness of the fascia and reduced echogenity were constant ultrasonographic findings (mean, 4.79 mm for symptomatic feet; 2.17 mm for control group, P < .05). No significant difference was found between heel pads of the diseased and healthy feet (mean, 12.96 mm for symptomatic feet; 13.10 mm for control group; P > .05). Ultrasonography seems to be a valuable, noninvasive diagnostic tool for the evaluation of plantar fasciitis.  相似文献   
67.
OBJECTIVE: Tumours of the upper rectum, and many in the middle third, are not accessible to endorectal ultrasound staging because of the difficulty in reaching all sites of the rectum with a rigid probe. The aim of this prospective study was to assess whether using a dedicated rectosigmoidoscope, endorectal ultrasonography (ERUS) can accurately stage any rectal lesion irrespective of its distance from the anal verge. METHOD: A total of 173 consecutive patients with a primary rectal tumour were included. A rotating, high multifrequency (5.0-10 MHz) endoprobe was introduced through a dedicated rectosigmoidoscope and advanced above the lesion. A computer allowed for three-dimensional (3D) reconstruction of 2D images. Treatment was selected on the basis of 3D-ERUS findings. ERUS staging was correlated with pathological staging. RESULTS: The depth of invasion was correctly determined by 3D-ERUS in 78.2% of tumours of the lower rectum, 76.4% of tumours extending between the lower and middle third of the rectum, 80.9% of tumours of the middle third of the rectum, 78.5% of tumours extending between the middle and upper third of the rectum and 78.9% of tumours of the upper rectum. The accuracy for the absence of lymph node metastases was 81.2% for tumours of the lower rectum, 78.5% for tumours extending between the lower and middle third of the rectum, 85.7% for tumours of the middle third of the rectum, 83.3% for tumours extending between the middle and upper third of the rectum and 78.5% for tumours of the upper rectum. Analysis showed that there was no difference between the various tumour sites. CONCLUSION: Our findings indicate that using a dedicated proctosigmoidoscope, tumours of the upper and middle third of the rectum are equally accessible to ultrasonographic evaluation. The distance of the tumour from the anal verge does not influence the accuracy of examinations considered adequate by the operator.  相似文献   
68.
The common ultrasonographic features of pilomatricoma.   总被引:3,自引:0,他引:3  
OBJECTIVES: The purpose of this series was to describe typical ultrasonographic features of 20 cases of pilomatricoma and to improve its diagnostic rate with the use of an ultrasonographic approach. METHODS: For 20 pilomatricomas in 19 patients with preoperative ultrasonography from 1995 to 2004, we reviewed age, sex, symptoms, duration, referring clinician, and tumor sites. The ultrasonographic findings were retrospectively analyzed for tumor location, shape, size, margin, echo texture, echogenicity, presence, amount, and shape of calcification, presence of a hypoechoic rim, and Doppler flow pattern. RESULTS: The mean age of the 19 patients was 6.9 years (range, 1-21 years), and the female-male ratio was 1.1:1. Patients had a painful palpable mass in 10 cases (50%). Nine lesions occurred in the neck, 5 in the cheek, 2 in the preauricular region, and 4 in the extremity. All tumors were located in the subcutaneous layer. The mean size of the tumors was 13.4 mm. Fourteen pilomatricomas (70%) appeared as well-defined oval masses. Tumors were heterogeneously hyperechoic in 80% of cases. All tumors had internal echogenic foci. A hypoechoic rim was seen in 17 cases (85%). Doppler flow signals were observed in the peripheral region in 14 cases (70%). A correct preoperative diagnosis was made in 33% on the basis of clinical findings and in 76% by ultrasonography. CONCLUSIONS: Diagnosis of pilomatricoma should be considered when a well-defined mass with inner echogenic foci and a peripheral hypoechoic rim or a completely echogenic mass with strong posterior acoustic shadowing in the subcutaneous layer of the head, neck, or extremity is found on ultrasonography.  相似文献   
69.
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   
70.
Objective: To compare the sensitivities, specificities, and accuracies between a single-view ultrasonography (US) technique and a multiple-view technique for identifying hemoperitoneum in multiple-trauma patients.
Methods: Data from a prior prospective study of US for trauma diagnosis at a level I trauma center were retrospectively analyzed. A convenience sample of adult patients (≥ 18 years of age) who had presented with major blunt or penetrating torso trauma and had undergone rapid trauma US examinations to detect hemoperitoneum were reviewed. The US interpretations by emergency physicians had been recorded prior to obtaining other diagnostic tests. Five views were evaluated, including the right intercostal oblique view examining Morison's pouch. Evidence of free intraperitoneal fluid by exploratory laparotomy, CT, or diagnostic peritoneal lavage (DPL) was used as the criterion standard.
Results: Of the 245 patients entered into the study, 37 had free intraperitoneal fluid, confirmed by CT, DPL, or exploratory laparotomy. With the multiple-view technique, US was 87% (95% CI = 71%, 96%) sensitive, 100% (95% CI = 97%, 100%) specific, and 98% (95% CI = 95%, 100%) accurate. The single-view technique, evaluating only Morison's pouch, was 51% (95% CI = 34%, 68%) sensitive, 100% (95% CI = 98%, 100%) specific, and 93% (95%. CI = 89%, 96%) accurate.
Conclusions: An initial trauma US examination using a multiple-view technique is more sensitive than that using a single-view technique for detecting hemoperitoneum in trauma patients.  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