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   36532篇
  免费   2306篇
  国内免费   1076篇
耳鼻咽喉   241篇
儿科学   833篇
妇产科学   843篇
基础医学   1596篇
口腔科学   244篇
临床医学   5251篇
内科学   4930篇
皮肤病学   105篇
神经病学   4833篇
特种医学   1389篇
外国民族医学   6篇
外科学   3279篇
综合类   7262篇
现状与发展   3篇
预防医学   1998篇
眼科学   602篇
药学   3663篇
  75篇
中国医学   1647篇
肿瘤学   1114篇
  2024年   102篇
  2023年   572篇
  2022年   1212篇
  2021年   1625篇
  2020年   1406篇
  2019年   1220篇
  2018年   1163篇
  2017年   1289篇
  2016年   1389篇
  2015年   1421篇
  2014年   2739篇
  2013年   2682篇
  2012年   2372篇
  2011年   2466篇
  2010年   2138篇
  2009年   1880篇
  2008年   1710篇
  2007年   1706篇
  2006年   1677篇
  2005年   1451篇
  2004年   1151篇
  2003年   964篇
  2002年   812篇
  2001年   715篇
  2000年   560篇
  1999年   441篇
  1998年   345篇
  1997年   329篇
  1996年   252篇
  1995年   277篇
  1994年   222篇
  1993年   190篇
  1992年   189篇
  1991年   155篇
  1990年   128篇
  1989年   121篇
  1988年   105篇
  1987年   106篇
  1986年   93篇
  1985年   110篇
  1984年   78篇
  1983年   56篇
  1982年   59篇
  1981年   70篇
  1980年   38篇
  1979年   27篇
  1978年   31篇
  1977年   17篇
  1976年   17篇
  1975年   10篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
A 66-year-old man died of massive gastrointestinal hemorrhage caused by a fistula between the third portion of the duodenum and the abdominal aorta. An autopsy revealed that duodenal tuberculosis had resulted in the development of a fistula into the aorta with no pathological changes, and no active pulmonary tuberculosis was found. Duodenal tuberculosis and primary aortoduodenal fistula (ADF) without an aneurysm are both extremely rare. Thus, we report herein a unique case of primary aortoduodenal fistula without an abdominal aortic aneurysm, but associated with duodenal tuberculosis, and review the current literature.  相似文献   
102.
This case report illustrates atypical magnetic resonance (MR) imaging findings in a liver hemangioma mimicking a malignant lesion—lower signal intensity than cerebrospinal fluid on T2-weighted spin-echo images and lack of early enhancement on dynamic contrast material—enhanced gradient-echo images. Pathologic analysis demonstrated nearly total replacement of the vascular cavities by dense fibrous tissue. In this rare, sclerosed form, this lesion could not be defined as a hemangioma with MR imaging.  相似文献   
103.
Introduction and background A 3-year-old Bosnian girl with a large symptomatic brainstem and multiple supratentorial cavernous angiomas, who underwent neurosurgical treatment, is presented. As multiple cavernomas are more common in familial cases, genetic analyses and neuroradiological imaging were performed in the patient and her parents to see whether there was any evidence for inheritance. This information is important for genetic counseling and provision of medical care for at-risk relatives. Currently, no recommendation is available on how to manage these cases.Results Genetic analyses demonstrated a novel CCM1 frameshift mutation (c.1683_1684insA; p.V562SfsX6) in the child and the asymptomatic 27-year-old mother. Sensitive gradient-echo magnetic resonance imaging of the mother revealed multiple supratentorial lesions, whereas analogous imaging of the father showed no pathological findings.Conclusion This case exemplifies that seemingly sporadic cases with multiple lesions might well be hereditary and that presymptomatic genetic testing of family members may identify relatives for whom clinical and neuroradiological monitoring is indicated.  相似文献   
104.
Hemoglobin-heme is variably converted to porphyrin during enterocolic transit. This intestinal converted fraction, as measured by HemoQuant, was elevated as a predictor of the occult bleeding site in 152 patients with discrete lesions. The intestinal converted fraction, expressed as the percentage of total fecal hemoglobin, was similar with upper gastrointestinal and proximal colon lesions. Within the colon, values trended downward with more distal location: means ± standard deviations were 18±14 proximal colon, 16 ±15 sigmoid, and 10±10 rectum. The amount of fecal blood also affected the intestinal converted fraction; correcting for hemoglobin concentration improved separation by site. Corrected intestinal converted fraction values were significantly lower with rectal (P< 0.0005) and sigmoid (P<0.02) lesions than with proximal colon lesions. Unfortunately, large within-site variation caused considerable overlap between sites. We conclude that the intestinal converted fraction is influenced by the site and amount of bleeding. However, its clinical utility is compromised by substantial individual differences in luminal hemoglobin metabolism.Presented in part at the Annual meeting of the American Gastroenterological Association in San Francisco in May of 1986 (Gastroenterology 90:1431, 1986).Supported by the Mayo Foundation.  相似文献   
105.
白术茯苓汤及其配伍对脾虚大鼠胃肠激素的影响   总被引:3,自引:0,他引:3  
目的:探讨益气健脾方剂治疗脾虚证的配伍规律。方法:采用苦寒泻下法复制大鼠脾虚模型,运用放射免疫分析法(RIA)检测白术茯苓汤及其与补气药。行气药及除湿药的不同配伍对脾虚大鼠胃泌素(GAS)、胃动素(MTL)及血管活性肠肽(VIP)的含量影响。结果:与正常对照组比较,脾虚模型大鼠GAS、MTL降低(P<0.01),VIP升高(P<0.01);与自然恢复组比较,各治疗组以上部分或全部指标均有不同程度的改善,其中,以综合配伍组改善作用最优。结论:白术茯苓汤的脾虚大鼠胃肠激素的紊乱的某些指标,有一定的改善作用,综合配合组以上指标的改善,优于白术茯苓汤组及其余各配伍组,说明中医关于复方配伍的理论与实践,有其科学价值。  相似文献   
106.
上消化道出血798例分析   总被引:33,自引:0,他引:33  
目的 探讨上消化道出血的病因和相关因素。方法 回顾性分析我院 8年来 798例上消化道出血病人的临床资料。结果 男性并发上消化道出血占 80 .2 0 %、女性占 19.80 % ,男性明显高于女性 (χ2 =6 .5 6 ,P <0 .0 5 ) ;青年人、中年人及老年人各占 2 7.82 %、5 7.6 1%和 14 .5 7% (P <0 .0 1) ,老年人合并重度上消化道出血多见 ;不同性别、年龄者出血的原因不尽相同。结论 上消化道出血的病人以消化性溃疡、胃癌、急性胃粘膜损害、食道胃底静脉曲张为最常见的病因 ,性别、年龄等均为上消化道出血的相关因素  相似文献   
107.
门静脉高压症名称的由来至今巳有100多年的历史.它的治疗则经历了一个逐步发展和完善的过程.回顾这一历史,有利于进一步完善门静脉高压症的治疗.  相似文献   
108.
ELFP方案治疗晚期鼻咽癌及上消化道癌疗效分析   总被引:3,自引:1,他引:2  
目的探索ELFP方案治疗转移复发的晚期鼻咽癌、食管癌、胃癌的临床疗效和毒性.方法选择病理证实的64例晚期鼻咽癌、食管癌、胃癌采用Vp-16 0.1 g静滴,d1-3;CF 0.1 g静滴,d1-3 5-FU 0.5 g静滴,d1-3;DDP 50 mg静滴,d1-2;21 d为1周期.治疗2~6个周期.结果鼻咽癌,食管癌、胃癌有效率(CR PR)分别为75%、70%、43.8%,其中胃癌与鼻咽癌及食管癌分别比较有差异;单病灶与多病灶之间疗效无差异.全组病例总生存期为3~41月,中位生存期分别为11.5、10、7.5个月.主要毒性为骨髓抑制,其中Ⅲ、Ⅳ度白细胞下降占21.9%;Ⅲ、Ⅳ度血红蛋白下降占15.6%;Ⅲ、Ⅳ度血小板下降占3.1%.Ⅲ、Ⅳ度恶心、呕吐发生率为7.8%.结论ELFP对晚期鼻咽癌及食管癌有较好的疗效,其毒性可以耐受,是临床治疗鼻咽癌,食管癌切实可行的方案.  相似文献   
109.
A 42-year-old female presented with subarachnoid hemorrhage (SAH), presumably from a radiation-induced anterior communicating artery aneurysm. Six years earlier, she had undergone radiation treatment for an optic glioma that was diagnosed based on imaging criteria. The aneurysm was successfully clipped, and the optic glioma was biopsied to verify the diagnosis histologically. Radiation-induced cerebral aneurysms often manifest with a fatal SAH. These aneurysms typically develop in the field of radiation and are diagnosed a mean of 8.52 years after radiation. Rarely, the aneurysm sac thromboses spontaneously. Clipping or coiling of the aneurysm can be an effective treatment.  相似文献   
110.
Background: Gastrointestinal strictures are the most often and serious complication in Crohn's disease. Because of the frequent postoperative recurrence in Crohn's disease, endoscopic therapy of gastrointestinal stricture is one of the best therapeutic options. Method: The present study sets out the results from a prospective study of endoscopic dilation therapy on 48 Crohn's disease patients with severe gastrointestinal stenoses. All patients who could not undergo endoscopic balloon dilation therapy (EBD) were operated on. Results: Long‐term success was attained in 32 of the 48 patients; cumulative avoidance of surgery after EBD was 86% at one year and 71% at three. Second, the most hazardous factor was recurrent inflammation causing restenosis. Patients who had strictures with oral luminal dilatation and patients with frequent recurrence had a tendency to be operated on. As a complication, perforation occurred in two cases (3.3%). Conclusions: EBD therapy for Crohn's stricture in the gastrointestinal tract is recommended before surgical intervention.  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