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   17994篇
  免费   941篇
  国内免费   76篇
耳鼻咽喉   137篇
儿科学   411篇
妇产科学   253篇
基础医学   2272篇
口腔科学   491篇
临床医学   1260篇
内科学   4279篇
皮肤病学   865篇
神经病学   1405篇
特种医学   475篇
外科学   3108篇
综合类   74篇
一般理论   1篇
预防医学   503篇
眼科学   384篇
药学   1149篇
中国医学   45篇
肿瘤学   1899篇
  2023年   78篇
  2022年   186篇
  2021年   314篇
  2020年   173篇
  2019年   237篇
  2018年   324篇
  2017年   273篇
  2016年   325篇
  2015年   304篇
  2014年   414篇
  2013年   467篇
  2012年   738篇
  2011年   767篇
  2010年   537篇
  2009年   430篇
  2008年   745篇
  2007年   816篇
  2006年   893篇
  2005年   915篇
  2004年   844篇
  2003年   850篇
  2002年   818篇
  2001年   668篇
  2000年   678篇
  1999年   642篇
  1998年   210篇
  1997年   158篇
  1996年   177篇
  1995年   144篇
  1994年   99篇
  1993年   123篇
  1992年   416篇
  1991年   357篇
  1990年   383篇
  1989年   405篇
  1988年   359篇
  1987年   327篇
  1986年   322篇
  1985年   273篇
  1984年   215篇
  1983年   168篇
  1982年   72篇
  1979年   148篇
  1978年   105篇
  1977年   106篇
  1974年   104篇
  1973年   79篇
  1972年   96篇
  1971年   83篇
  1970年   89篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
We assessed the results of Chiari pelvic osteotomy in 64 hips with early osteoarthritis in terms of acetabular labral detachment detected pre-operatively by arthrography. At an average follow-up of four years, assessment by the Merle d'Aubigńe score showed 83% excellent or good results. These satisfactory results were achieved in only half the cases with a detached labrum, but in nearly all cases with normal or torn acetabular labra. Other factors such as the acetabular index, the level and angle of osteotomy, and the displacement following osteotomy did not affect the results. Chiari pelvic osteotomy is a worthwhile procedure for early osteoarthritis in selected cases, but a detached acetabular labrum increases the risk of clinical failure.  相似文献   
72.
During the last 10 years, we have demonstrated morphological and biochemical abnormalities of skin extracellular matrices in amyotrophic lateral sclerosis (ALS). However, currently little is known concerning collagen of the spinal cord in ALS. We measured the amount of collagen and characterized collagen at light and electron microscopic levels in posterior funiculus, posterior half of lateral funiculus and anterior horn of cervical enlargement of the spinal cord obtained from ten patients with ALS, 11 patients with other neurologic diseases (control group A), and ten patients without neurologic ones (control group B). In posterior half of lateral funiculus and anterior horn, (1) by light microscopy, there was no significant difference in vessel wall area between ALS patients and control groups A and B; (2) ultrastructurally, collagen bundles were more fragmented and widely separated, and the fibrils were randomly oriented in the perivascular space of capillaries in ALS patients, which were not observed in any areas of control groups or in posterior funiculus of ALS patients; and (3) the collagen contents in ALS were significantly lower (P<0.001 and P<0.001, respectively) than those in control groups A and B. Fragmented and widely separated collagen bundles in the interstitial tissue surrounding capillaries and markedly decreased amount of collagen in posterior half of lateral funiculus and in anterior horn of ALS could be related to the degeneration of the upper and lower motor neurons in the spinal cord in ALS, that is, selective neuronal vulnerability in ALS.  相似文献   
73.
Optimal initial palliation and a subsequent staged approach is mandatory for high-risk Fontan candidates. We describe the case of mitral atresia with severe tricuspid regurgitation and pulmonary hypertension successfully managed by repeated palliation from the neonatal period and 2-stage Fontan surgery. A 1-month-old boy diagnosed with mitral atresia and double-outlet right ventricle underwent pulmonary artery banding at 1 month of age, followed by repeated pulmonary artery banding accompanied by tricuspid annuloplasty and atrial septal defect enlargement at 6 months. Because of the presence of pulmonary artery distortion, right ventricular dysfunction, and borderline pulmonary vascular resistance, a hemi-Fontan procedure was conducted with extended pulmonary artery plasty when the boy was 3 years and 8 months old. Cardiac catheterization done 3 months after showed improvement in risk factors, and the final Fontan operation (total cavopulmonary connection) was successfully done in conjunction with repeated tricuspid annuloplasty when the boy was 4 years and 5 months old. The patient remains in excellent clinical condition at the last follow-up 5 years after the final Fontan procedure with sinus rhythm and good ventricular function.  相似文献   
74.
75.
To find antiviral agents, various sulfonamidobenzophenone oximes (II) were synthesized from the appropriate m-sulfonamidobenzophenones by hydroxylamine reaction. The reaction products were generally obtained as syn/anti mixtures which were separable by fractional crystallization. The anti isomer had more potent antipoliovirus activity than the syn isomer. Various sulfonamidobenzamides (III) which were structurally related to II were synthesized by the reactions of amino-substituted benzamides with sulfuryl chloride or amines with (aminosulfonyl)benzoyl chloride. Antiviral activity was examined by the plaque-inhibition test. Compounds 5, 36, and 69 exhibited strong antipicornavirus activity. The structure-activity relationships are discussed.  相似文献   
76.
77.
The veno-venous bypass (VVB) with a membrane lung is one of the effective procedures to provide respiratory assistance even in patients with a high mortality rate when assisted only with mechanical ventilation. The purpose of this experimental study was to reveal the efficacy of respiratory assistance and the hemodynamic changes by VVB in acute respiratory failure. VVB was carried out in 22 mongrel dogs with acute respiratory failure induced by intratracheal seawater infusion. The ventilation-perfusion ratio (V/Q) of a membrane lung was changed to 1.0, 2.0 and 3.0 for each of the bypass flow rates of 20%, 40%, 60% and 80% of pre-perfusion cardiac output. For each condition variables indicating blood gas status and hemodynamic parameters were measured. As the indicator evaluating the efficiency of CO2 removal by VVB, the index of VVBCO2R was used, indicating the blood CO2 tension differences between IVC and the pulmonary artery. Arterial oxygen saturation was increased with bypass flow rates greater than 60% compared with pre-VVB, but the change was not marked. VVB was considered to be inadequate as a method of oxygenation. Besides, oxygenation was not able to be controlled by changing V/Q. However, significant reduction of arterial CO2 tension (PaCO2) could be obtained even with a bypass flow rate of 20%. As the blood flow rate increased, PaCO2 was lowered. But no more significant reductions of PaCO2 were obtained even with the flow rate of 60% and 80%. VVBCO2R was increased by changing the bypass flow rate from 20% to 40%, while no further increases were observed even with changes from 40% to 60% and 80%.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
78.
79.
We reported a case of the biliary cystadenoma of the liver. The cystic mass had labulation and septation and showed marked hyperintensity on T1-weighted images and hypointensity on T2-weighted images; MR findings were very unusual for cystadenoma. The content of the cystic mass was jelly-like, thick mucinous fluid without intracystic hemorrhage. We concluded that these unusual signal intensities of the cyst were due to hyperproteinous mucinous fluid.  相似文献   
80.
The relationship between the age and the spread of analgesia from different epidural anesthetic doses was examined by studying analgesic dose responses in cervical epidural analgesia. Two different anesthetic doses (5ml or 10ml) of 2% mepivacaine were injected into the cervical epidural space at a constant pressure (80mmHg) using an intravenous apparatus, and the spread of analgesia to pinprick was assessed. The significant correlation was found between the patients age and the number of spinal segments blocked (5ml:r = 0.8498, P < 0.01, 10ml:r = 0.5988, P < 0.01). The inverse linear relationship was found between the patients age and the segmental dose requirement (5ml:r = –0.6754, P < 0.01, 10ml:r = –0.5784, P < 0.01). Patients under 39 years of age showed a direct relationship between the dose injected and the number of spinal segments blocked, enabling prediction of the number of segments blocked with a given dose of local anesthetic. Doubling the epidural dose approximately doubled the number of spinal segments blocked. The analgesic dose-response relation in patients over 60 years of age differed from that in patients under 39 years of age and doubling the epidural dose did not double the number of spinal segments blocked. Progressively more extensive analgesia was obtained from a given dose of local anesthetic with advancing age. It was difficult to limit the extent of analgesia by injecting a smaller dose of local anaesthetic in the elderly.(Hirabayashi Y, Matsuda I, Inoue S et al.: Analgesic dose-response relation in cervical epidural block. J Anesth 2: 22–27, 1988)  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