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   25837篇
  免费   1896篇
  国内免费   734篇
耳鼻咽喉   469篇
儿科学   784篇
妇产科学   199篇
基础医学   1474篇
口腔科学   42篇
临床医学   3155篇
内科学   7564篇
皮肤病学   50篇
神经病学   1472篇
特种医学   2497篇
外国民族医学   3篇
外科学   4318篇
综合类   3372篇
现状与发展   2篇
预防医学   509篇
眼科学   182篇
药学   1316篇
  12篇
中国医学   357篇
肿瘤学   690篇
  2024年   65篇
  2023年   467篇
  2022年   857篇
  2021年   1149篇
  2020年   1120篇
  2019年   1077篇
  2018年   1124篇
  2017年   875篇
  2016年   872篇
  2015年   970篇
  2014年   1726篇
  2013年   1880篇
  2012年   1303篇
  2011年   1509篇
  2010年   1204篇
  2009年   1212篇
  2008年   1144篇
  2007年   1221篇
  2006年   1056篇
  2005年   910篇
  2004年   739篇
  2003年   656篇
  2002年   562篇
  2001年   492篇
  2000年   422篇
  1999年   373篇
  1998年   362篇
  1997年   310篇
  1996年   299篇
  1995年   290篇
  1994年   287篇
  1993年   235篇
  1992年   215篇
  1991年   178篇
  1990年   146篇
  1989年   138篇
  1988年   118篇
  1987年   105篇
  1986年   98篇
  1985年   117篇
  1984年   110篇
  1983年   42篇
  1982年   100篇
  1981年   77篇
  1980年   69篇
  1979年   50篇
  1978年   39篇
  1977年   26篇
  1976年   23篇
  1974年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
We report herein a new method of performing laparoscopic pyloromyotomy for infantile hypertrophic pyloric stenosis, using refined surgical techniques. The pyloric tumor was immobilized by grasping the first portion of the duodenum and the anterior wall of the stomach, and electrocoagulation was used prior to incising the pyloric tumor to minimize bleeding during the procedure. Although this technique has been applied in only two patients so far, we present the details herein. We believe that with technical and instrumental refinements, the speed and safety of laparoscopic pyloromyotomy will improve and it will become an alternative to open surgery in pediatric patients.  相似文献   
102.
To evaluate the reliability of Doppler ultrasonography (US) in identifying children with renal artery stenosis (RAS) among those with hypertension, we compared Doppler US results in 22 hypertensive children (mean age 8.9±4.3 years), with (13 cases) and without RAS at angiography, and in 33 normotensive children (mean age 8.8±4.7 years). We observed 2 false-negatives and 2 false-positives with Doppler US. Of the 2 false-negative diagnoses, 1 had RAS on an accessory renal artery located behind a normal upper polar artery and the other was observed in a patient with bilateral multiple stenosis of the very distal segments of renal arteries. The 2 false-positive diagnoses were due to sinuous left renal artery and to technical reasons, respectively. In another patient, Doppler US showed a tight RAS, while arteriography was normal. RAS was subsequently confirmed by a second arteriography. Peak systolic velocity values of Doppler US were significantly higher in patients with proven angiographic RAS (3.44±0.66 m/s) than in hypertensive patients with normal renal arteries at angiography (0.99±0.35 m/s, P <0.0001) and normotensive healthy children (1.04±0.23 m/s, P <0.0001). With the use of multiple views, and the experience acquired with practice, false-negatives or false-positives due to the geometry of the renal artery can be avoided. Nevertheless, very distal stenosis can be missed by Doppler US. Received October 30, 1995; received in revised form April 16, 1996; accepted May 14, 1996  相似文献   
103.
A case of insulinoma is reported in a patient in whom selective arterial calcium injection (SACI) tests were performed both to confirm tumor localization before surgery and to confirm complete tumor removal during surgery. An 18-year-old woman with hypoglycemic episodes was diagnosed with an insulinoma in the pancreatic body demonstrated by celiac arteriography. In a preoperative SACI test, calcium was injected into the splenic artery (SpA), gastroduodenal artery (GDA), and superior mesenteric artery (SMA). Serum immunoreactive insulin (IRI) and proinsulin levels were measured in hepatic venous samples. IRI was markedly increased after the injection of calcium into the GDA and SMA, while there was no response in IRI levels when calcium was injected into the SpA. Therefore, no occult insulinoma was revealed in the distal area fed by the SpA, although the presence of insulinoma was uncertain in the proximal pancreas. In the intraoperative SACI test, calcium was injected into the celiac artery. Insulin (determined by enzyme immunoassay) and proinsulin levels were measured in portal venous samples before and after resection of the tumor. After resection, these levels decreased in response to the calcium stimuli, confirming complete removal of the insulinoma. The SACI test was helpful to localize the insulinoma and was useful to confirm the complete removal of the tumor.  相似文献   
104.
Summary. In recent years the continuity equation has been established as a valuable non-invasive method for calculating aortic valve area. The continuity equation cannot be used if there is calcification or sub-valvular stenosis in the left ventricle-outflow tract, because the area of the outflow trace is not circular in those cases. The authors have tested the value of a non-invasive variant of the Gorlin formula, as an alternative method of identifying severe aortic stenosis. They examined 32 consecutive patients with aortic stenosis with both methods. Seventeen patients had severe stenosis (valve area^0–7 cm2), calculated by the continuity equation. The other 15 patients had moderate stenosis (valve area 0–7–1–0 cm2). Using the non-invasive variant of the Gorlin formula, the authors were able to identify 16 of the 17 cases with severe stenosis, thus showing that the method is useful for identifying severe aortic stenosis. (P<0–001 by x2-test).  相似文献   
105.
Posttransplant lymphoproliferative disorders are infrequent tumors related to chronic immunosuppressive therapy. We present a liver transplant recipient who developed such a tumor in the porta hepatis that provoked obstruction of the entire portal triad. Treatment consisted of systemic chemotherapy, percutaneous dilatation, and placement of Wallstent endoprostheses across both biliary and portal vein stenoses. The patient died 3 weeks later of pneumonia and sepsis. At necropsy, the tumor was completely necrosed and the prostheses in both the common bile duct and the portal vein were patent.  相似文献   
106.
Objective. The objective of this study was to compare blood pressure (BP) measured by the sphygmooscillographic method with that measured by the direct and auscultatory methods.Methods. In 15 adult patients undergoing cardiac surgery, blood pressure was measured by the sphygmooscillographic and direct methods simultaneously on the same upper extremity. In another group of 86 children and 11 adults, blood pressure was measured by the sphygmooscillographic and auscultatory methods simultaneously, with one cuff. For the sphygmooscillographic measurement, we used sphygmomanometer-S, which measures blood pressure on the basis of the amplitude height (oscillometric) and the morphology (sphygmographic) of pulse waves recorded by a transducer placed in the cuff.Results. The systolic and diastolic blood pressure measured by the sphygmooscillographic method were both 2 mm Hg higher than those from the direct method; the mean blood pressure was 0.6 mm Hg higher. These differences were not significant. Compared with the auscultatory method, sphygmooscillographic systolic values were higher by 7 mm Hg, while diastolic values were lower by 9 mm Hg. These differences were significant.Conclusions. Blood pressure measurements obtained by the sphygmooscillographic method correlate well with the direct method for measuring blood pressure in children and adults; but, they do not correlate well with the auscultatory method.  相似文献   
107.
氟骨症性椎管狭窄症的手术治疗   总被引:2,自引:1,他引:1  
1987~1990年手术治疗氟骨症性椎管狭窄症100例。包括颈椎9例,胸椎8例,腰、骶椎83例。术后随访1~4年,复查结果:临床治愈93例(93%):显效3例(3%)、有效3例(3%)、无效1例(1%)。手术原则是彻底减压,因氟骨症具有椎骨及其骨周组织严重退变、异化和骨化的临床病理特点,故在胸、腰椎减压术后,一般不影响其稳定性,在颈椎施行双开式或单开式椎管扩大加植骨融合术,则可收减压、稳定及防止或减少椎板间隙瘢痕狭窄的效果。  相似文献   
108.
L- Tetrahydropalmatine (L- THP) ,a kind of al-kaloid extracted from traditional Chinese medicineRhizoma corydalis,posseses sedative,analgesic andhypnotic effects.Recently,it has been demonstratedthat L- THPalso had calcium- antagonistic and antiar-rythmic effects.Studies showed that L- THP had aprotective effect on acute focal and global cerebral is-chemia- reperfusion injury[1,2 ] .Many studies provedthat the production of NO wasincreased significantlyduring ischemia- reperfusion.The o…  相似文献   
109.
椎板后移回植的椎管扩大术治疗椎管狭窄症   总被引:43,自引:0,他引:43  
作者报告棘突劈开、椎板后移回植的椎管扩大术治疗椎管狭窄症182例,使椎管容积扩大34.8%,横径扩大3.8mm,矢径扩大6.1mm。随访2年9个月,优良率86.6%,椎板愈合率96.9%。本文探讨少数椎板迟延愈合的原因和预防措施,如斜切椎板、缝合固定和腰背筋膜与棘上韧带悬吊缝合等。术后卧床10~12周,用石膏型保护。作者认为本法能有效的预防术后脊柱不稳,顽固性腰痛等并发症。  相似文献   
110.
矽肺患者肺功能与动脉血气分析的研究   总被引:6,自引:1,他引:5       下载免费PDF全文
本文对88例矽肺病人和37名接尘工人进行了肺功能和动脉血气分析,结果表明各期矽肺的VC、FVC、FEV_1、MMF、FEV_1/FVC均值低于接尘组,而异常检出率则高于接尘组,通气功能的下降呈进行性,但早期不很明显,与接尘组无显著差异。各期矽肺组V_(50)及V_(25)均有明显降低,显示早期即有小气道的广泛损害。矽肺的通气功能损害类型,Ⅰ期矽肺组以阻塞型多见,Ⅱ、Ⅲ期矽肺组以混合型为主。RV和RV/TLC在Ⅲ期矽肺组有明显增高,表明矽肺晚期多并发肺气肿。另外DL_(CD)和K_(CD)在各矽肺组均低于接尘组,差异有显著性,说明矽肺早期即可有弥散功能的损害。血气分析表明PaO_2及SatO_2降低主要见于Ⅱ、Ⅲ期矽肺。Ⅲ期矽肺组有1/3患者(33.33%)在有低氧血症的同时合并有高碳酸血症。对比肺功能和血气分析结果,认为通气功能指标FEV_1、FEV_1/FVC、VC、FVC、MMF以及弥散功能指标DL_(CO)和K_(CO)为早期反映矽肺呼吸功能的灵敏指标。血气分析对病情和预后的判断有重要参考价值。  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