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   63188篇
  免费   4874篇
  国内免费   1734篇
耳鼻咽喉   833篇
儿科学   1184篇
妇产科学   2213篇
基础医学   8005篇
口腔科学   1160篇
临床医学   6779篇
内科学   11760篇
皮肤病学   1186篇
神经病学   3936篇
特种医学   2605篇
外国民族医学   6篇
外科学   8493篇
综合类   4181篇
现状与发展   7篇
一般理论   11篇
预防医学   3419篇
眼科学   1394篇
药学   5298篇
  20篇
中国医学   1673篇
肿瘤学   5633篇
  2023年   462篇
  2022年   923篇
  2021年   2142篇
  2020年   1292篇
  2019年   1617篇
  2018年   1995篇
  2017年   1515篇
  2016年   1565篇
  2015年   2324篇
  2014年   2913篇
  2013年   3392篇
  2012年   4814篇
  2011年   4688篇
  2010年   2983篇
  2009年   2611篇
  2008年   3537篇
  2007年   3537篇
  2006年   3383篇
  2005年   3123篇
  2004年   2823篇
  2003年   2706篇
  2002年   2348篇
  2001年   1843篇
  2000年   1609篇
  1999年   1335篇
  1998年   551篇
  1997年   456篇
  1996年   416篇
  1995年   377篇
  1994年   348篇
  1993年   242篇
  1992年   711篇
  1991年   582篇
  1990年   531篇
  1989年   484篇
  1988年   421篇
  1987年   423篇
  1986年   355篇
  1985年   295篇
  1984年   229篇
  1983年   191篇
  1982年   114篇
  1981年   122篇
  1980年   99篇
  1979年   205篇
  1978年   161篇
  1977年   103篇
  1976年   110篇
  1975年   102篇
  1974年   99篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
Objectives: Congenital tracheal stenosis is a rare disease. Various methods for treatment exist but there is still much debate as to the appropriate surgical procedure. We present our surgical experiences of patch tracheoplasty and slide tracheoplasty as viable methods for the treatment of congenital tracheal stenosis. Methods: From 1994 to 2002, 13 patients were diagnosed with congenital tracheal stenosis. Eight patients (7 symptomatic and 1 asymptomatic) had their stenosis corrected, three by means of pericardial patch tracheoplasty, four by slide tracheoplasty, and one by resection and anastomosis. Concomitant operations were performed on six patients to treat congenital cardiovascular disease. Five patients showing no significant symptoms did not undergo tracheal surgery and received only cardiac procedures. A retrospective review of the hospital course, complications, and long-term results was conducted. Results: Among the patch tracheoplasty group, every patient suffered from granulation tissue formation. One patient died of respiratory acidosis and one was hospitalized due to recurrent granulation tissue, which required frequent bronchoscopy. The third patient from this group is free of all symptoms. Among the slide tracheoplasty group, one patient died of anastomosis disruption. The three remaining patients are alive and well. The one patient who received resection and anastomosis is alive without symptoms. Conclusions: Surgical repair of long-segment congenital tracheal stenosis exhibited high mortality and morbidity rates. Every patient that underwent pericardial patch tracheoplasty suffered from troublesome granulation tissue. As slide tracheoplasty provided relatively good results in the short and mid-term follow-up periods, it seems to be a preferred method for the treatment of long-segment congenital tracheal stenosis.  相似文献   
122.
Dural sinus thrombosis: study using intermediate field strength MR imaging   总被引:1,自引:0,他引:1  
The magnetic resonance (MR) images of six patients with thrombosis of a dural sinus were reviewed. The diagnosis had been verified by computed tomographic scans in three patients and arteriograms in two; in the sixth patient, only MR imaging was used to confirm the clinical syndrome. In all patients, high-intensity signal was seen from the thrombus within the affected dural sinus on all echoes. This persistent signal intensity allowed intravascular clot to be distinguished from normal causes of increased signal such as flow-related enhancement (entry phenomenon) and even-echo rephasing. MR imaging demonstrated the cause of the thrombosis in three patients: two were secondary to adjacent tumors, and one was secondary to unsuspected mastoiditis. Complications such as infarction were also demonstrated. Using MR imaging, one can easily and safely diagnose thrombosis of a dural sinus. MR should be the imaging method of choice in patients suspected of having thrombosis of a dural sinus.  相似文献   
123.
Aneurysms of the posterior cerebral artery: report of ten cases   总被引:3,自引:0,他引:3  
Ten cases of posterior cerebral artery (PCA) aneurysm are presented. There were 13 aneurysms in the 10 patients: 6 saccular, 5 fusiform, 1 broad-based, and 1 giant fusiform serpentine aneurysm. Eight patients underwent operation: clipping for 2 saccular aneurysms, trapping for 1 saccular and 3 fusiform aneurysms, and coating for 2 fusiform or broad-based aneurysms. Microsurgical cerebral revascularization techniques were attempted in 2 cases: after a fusiform aneurysm had been excised, end-to-end anastomosis of the residual two ends of the PCA was performed and, after a giant serpentine aneurysm had been trapped, the superficial temporal artery was anastomosed transcortically to the distal PCA. Two patients died before operation because of rebleeding and vasospasm. Postoperative neurological deficits include contralateral hemiparesis, homonymous hemianopsia, hemihypesthesia, and ipsilateral 3rd nerve palsy. Our results suggest that, despite the good collateral circulation of the PCA, some ischemic events may occur after trapping procedures and that cerebral revascularization techniques may have some benefit in the treatment of unclippable aneurysms in this region.  相似文献   
124.
刘畅  胡毅倩  徐承慧  祝肇荣 《眼科研究》2007,25(10):778-781
目的研究Moorfields回归分析(MRA)及多变量区别分析(MDA)的2个指标FSM和RB诊断开角型青光眼的能力,及MRA在视盘整体和视盘分区间的差异。方法对23例正常人(26眼)、26例可疑开角型青光眼患者(32眼)和21例开角型青光眼患者(21眼)进行HRT-Ⅱ和OCTOPUS视野计G2-TOP程序两项检查。结果视盘整体MRA、FSM、RB与视野缺损指数间相关系数分别为0.537、-0.565、-0.716(P<0.01),且3个组间差异均有统计学意义(P<0.01),随着视盘面积增大,MRA、FSM和RB特异性均下降。可疑组中视盘分区MRA与视野检查一致率均高于整体,一致率最高分区为颞下(78.13%)。各分区中MRA敏感性、特异性最高的分区为颞上和颞下。结论MRA和MDA检测开角型青光眼能力较强,且与视野检查间存在较好的相关性,但应用于大视盘分析时须谨慎下结论。  相似文献   
125.
Piceatannol (3,4,3',5'-tetrahydroxy-trans-stilbene) (NSC 365798) has recently been isolated and was subsequently synthesized for NCI tumor panel testing as a new antileukemic natural product from the seeds of Euphorbia lagascae. During the synthesis, a bioactive reaction mixture of several partially O-methylated piceatannol analogues was obtained. This mixture has now been maximized and subjected to bioactivity-directed fractionation, using brine shrimp lethality, to yield 3,3',5'-tri-O-methylpiceatannol (NSC 381281); this new compound has improved stability and better bioactivity in several systems than piceatannol itself. To confirm the structure, 5 was synthesized from vanillin. In addition, the isovanillin analogue, 4,3',5'-tri-O-methylpiceatannol (NSC 381864), another new compound, was synthesized and found to be bioactive.  相似文献   
126.
Background Health-related quality of life (HRQL) is an accepted outcome measure in patients with mood and anxiety disorders. Yet, surprisingly little attention has been paid to the determinants. In this paper we test the hypothesis that it is associated with personality traits while controlling for mental disorders. Methods A large sample of outpatients (n=640) with mood and anxiety disorders was studied. The empirically supported five factor model of normal personality traits was assessed using the NEO-FFI and includes: neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness. Mental disorders were assessed with the CIDI, and HRQL with the SF-36. Results Regression analyses revealed that the NEO-FFI scores, with the exception of conscientiousness, were significantly associated with SF-36 subscales and summary scores, independently from the mental disorders. The percentage of explained variance due to the personality traits was highest for the subscales Vitality (10.0%), Mental Health (13.3%) and the Mental Health Summary Score (9.5%). Furthermore, specific personality traits were related to specific SF-36 subscales. Conclusions A low HRQL of patients with mood or anxiety disorders is not only determined by the disease or the current health but is also shaped by personality traits that are relatively stable throughout an individual's life time.  相似文献   
127.
Public health law has been one of the leading contributors to the extension of life expectancy in the 20th century. Nonetheless, the legal infrastructure supporting public health law in the United States is underdeveloped and nonuniform. With national interest growing in public health agency accreditation, the individual legal approach taken by states may pose an obstacle to wholesale adoption of a proposed voluntary national model. This article describes the legal foundations supporting accreditation or assessment programs in states participating in the Multi-State Learning Collaborative, a project funded by the Robert Wood Johnson Foundation. The Turning Point Model State Public Health Act is recommended as one option to resolve the current impasse, assist in acceptance of a national accreditation model, and provide a common public health legal infrastructure.  相似文献   
128.
Zinc phosphide ingestion: a case report and review   总被引:1,自引:0,他引:1  
We present the case of a patient who attempted suicide by ingestion of the rodenticide zinc phosphide. Zinc phosphide manifests its immediate toxicity through production of phosphine gas. Signs and symptoms of toxicity include nausea, vomiting, dyspnea, and changes in mental status; immediate death results from pulmonary edema. Delayed effects are secondary to the absorption of phosphide, affecting primarily the liver, heart and kidneys. Delayed deaths are related to a direct cardiotoxicity. Treatment is mainly symptomatic and supportive; aggressive airway management and circulatory support are critical to a successful outcome.  相似文献   
129.
130.
While two prophylactic HPV vaccines have been proven notably efficacious in clinical trials, the effectiveness of these vaccines at the population level remains to be evaluated. To lay the foundation for understanding the strengths and limitations of different endpoints for future effectiveness research, we present a comprehensive review of HPV-related clinical outcomes, including: (i) HPV type-specific positivity and persistence, (ii) Pap diagnoses (ASC-US, LSIL, and HSIL), (iii) histologic cervical cancer precursor lesions (i.e., CIN1, CIN2, and CIN3), (iv) invasive cervical cancer (ICC), (v) anogenital warts, (vi) recurrent respiratory papillomatosis (RRP), and (vii) other HPV-associated cancers (vulvar, vaginal, anal, penile, and oropharyngeal). While research on the vaccines’ effects on these HPV clinical outcomes in the general population is presently limited, numerous large trials will soon be completed, making a priori discussion of these potential outcomes especially urgent. Furthermore, population level systems to track HPV-associated clinical outcomes may need to be developed for HPV vaccine effectiveness evaluation.  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