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   48942篇
  免费   2944篇
  国内免费   115篇
耳鼻咽喉   698篇
儿科学   2186篇
妇产科学   1085篇
基础医学   6220篇
口腔科学   1980篇
临床医学   4581篇
内科学   9972篇
皮肤病学   1221篇
神经病学   4199篇
特种医学   1518篇
外国民族医学   10篇
外科学   7554篇
综合类   181篇
一般理论   17篇
预防医学   3192篇
眼科学   1340篇
药学   3130篇
中国医学   186篇
肿瘤学   2731篇
  2023年   353篇
  2022年   332篇
  2021年   868篇
  2020年   593篇
  2019年   927篇
  2018年   1437篇
  2017年   1028篇
  2016年   1143篇
  2015年   1166篇
  2014年   1453篇
  2013年   2199篇
  2012年   3391篇
  2011年   3798篇
  2010年   1984篇
  2009年   1479篇
  2008年   3204篇
  2007年   3461篇
  2006年   3348篇
  2005年   3381篇
  2004年   3268篇
  2003年   3006篇
  2002年   2897篇
  2001年   1021篇
  2000年   1106篇
  1999年   758篇
  1998年   426篇
  1997年   363篇
  1996年   278篇
  1995年   253篇
  1994年   234篇
  1993年   214篇
  1992年   231篇
  1991年   188篇
  1990年   175篇
  1989年   165篇
  1988年   144篇
  1987年   143篇
  1986年   158篇
  1985年   117篇
  1984年   127篇
  1983年   98篇
  1982年   82篇
  1981年   64篇
  1980年   69篇
  1979年   101篇
  1978年   72篇
  1977年   77篇
  1974年   59篇
  1973年   66篇
  1970年   56篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
Spinocerebellar ataxia (SCA) types 2 and 3 are autosomal-dominant neurodegenerative disorders caused by mutations in two different genes. We identified mutations for SCA2 and SCA3 segregating simultaneously in a single Brazilian family. The index patient had SCA2, whereas her two second-degree cousins had SCA3. Disease was more rapidly progressive in the SCA2 patient, who presented severe brainstem and pancerebellar atrophy, as opposed to the two SCA3 patients, who had only mild cerebellar vermian atrophy. In such situations, molecular confirmation of all patients may avoid misdiagnosis of SCA subtypes and eventual errors in predictive testing of unaffected family members.  相似文献   
22.
The present study evaluated99mTc(V) DMSA as an agent for the visualization of inflammatory lesions in comparison to99mTc(HI) DMSA and99mTc-HIG. All three radiopharmaceuticals were prepared with commercial kits.99mTc(V) DMSA was prepared at neutral pH by the addition of first bicarbonate and then pertechnetate to the kit contents. The labeling efficiency was 99% as determined by ITLC. Abscesses were induced by i.m. injection of 50 μl turpentine into the right thighs of 36 Swiss albino mice. Six days later 3.7 MBq of each radiopharmaceutical was i.v. administered to 12 mice. The mice were sacrificed at 1,3,6 and 24 h later. Scintigrams were obtained with a gamma camera. The abscesses were better visualized on scintigrams with99mTc(V) DMSA compared to99mTc(III) DMSA, starting at 1 h. The animals were dissected and the organs were removed, weighed and the radioactivity determined with a gamma counter. The abscess to other tissue ratios were higher with99mTc(V) DMSA than the other radiopharmaceuticals. The max. abscess/muscle ratios were 9.46 ± 3.20 (24 h), 4.19 ± 1.39 (6 h) and 5.98 ± 1.17 (24 h) and max. abscess/blood ratios were 6.22 ± 1.41, 4.09 ± 0.84 and 0.914 ± 0.351 all at 24 h for99mTc(V) DMSA,99mTc(III) DMSA and99mTc-HIG, respectively. Experimental arthritis was produced in 6 New Zealand white rabbits by intra-articular injection of ovalbumin. Four days later 37 MBq of99mTc(V) DMSA and99mTc-HIG were each i.v. administered to 3 rabbits. Scintigrams obtained at 1, 3, 6, and 24 h clearly demonstrated arthritic joints. ROFs over arthritic joints were compared to contralateral normal joints (A/C). The max. A/C ratios were 2.10 ± 0.31 (3 h) and 2.92 ± 0.99 (24 h) for99mTc(V) DMSA and99mTc-HIG, respectively. Our results indicated the feasibility of imaging inflammatory lesions with99mTc(V) DMSA.  相似文献   
23.
Considering that the 1.32-μm Nd-YAG laser should have physicothermal properties close to those of the CO2 laser, a series of experiments were conducted on rat cortex (N = 51). Three laser wavelengths were compared: CO2 laser (10.6 μm), 1.06-μm Nd-YAG, and 1.32-μm Nd-YAG lasers. For each shot, temperature measurements were recorded with an infrared thermographic videocamera. The digitized signals were figured as thermal profiles and temperature developments. Ninety-five shots were correctly studied and analyzed: CO2, N = 29; 1.06-μm Nd-YAG, N = 20; 1.32-μm Nd-YAG, N = 46. The histological lesions produced by these three lasers were compared on animals killed 24 hours (N = 20), 8 days (N = 20), and 30 days (N = 5) after the laser impacts. For equivalent densities of energy, the depth of cortical necrosis was comparable for the CO2 laser (200–250 μm) and the 1.32-μm Nd-YAG laser (210–260μm) whatever the date of death; the 1.06-μm Nd-YAG laser shots were responsible for much more important damage (400–550μm). Because of its important absorption in water and nervous tissue, the authors consider the 1.32-μm Nd-YAG laser most suitable for neurosurgery, particularly because it is conducted through optic fibers, and therefore is easy to handle during neurosurgical procedures.  相似文献   
24.
E. Soncini  A. Petit   《ITBM》2002,23(3):172
Regulations evolve and risks management becomes one of the biomedical engineers' preoccupations. Thus, risks are various, and consequently it is difficult to identify, to manage and to bring them under control. Furthermore, regulations exist for sectors like healthcare technology monitoring, but it is not the same thing for instance for the risks linked to the maintenance. Thus regulation in the sector of maintenance evolves and the decree of the 1st July law of health safety is going to modify the biomedical environment. The goal of this work is to study the tools and the methods of risks management that have been used for several years in the industrial field and to use them for some biomedical equipment like monitors or IV pumps. These methods adapted to these equipment will allow us to determine some appropriate rules of maintenance.  相似文献   
25.
We report two patients with severe hypoglycorrhachia after a subarachnoid hemorrhage. They had no obvious meningeal infection, and they spontaneously recovered within a few weeks. Such cases have previously been reported in neonates, but exceptionally in adults. Contrary to detailed cases from the literature, our patients recovered without antibiotics, and hypoglycorrhachia was very severe.  相似文献   
26.
The authors report a case of massive haemolytic anaemia with acute mitral valve regurgitation and left cardiac failure, which occurred one year after surgical reconstruction of the mitral valve for rupture of smaller leaflet chordae. Anaemia, mitral regurgitation and cardiac failure disappeared after mitral valve replacement, using a Carpentier Edwards No. 29 valve. Haemolytic anaemia following mitral valve reconstruction is exceptional. It seems to be due to the suture material lying in a turbulent regurgitation stream when mitral incompetence develops again.  相似文献   
27.
To compare pulmonary effects, postoperative pain and fatigue, morbidity, patient satisfaction, and cost of different anesthetic techniques for inguinal hernia repair, 50 patients were randomized to local and general anesthesia groups (LA and GA). All patients received the same premedications and the same postoperative analgesic regimen. The standardized postoperative analgesic, intramuscular pyroxicam 20 mg, was given to all patients in the recovery room and an additional 20 mg on the same day was given as requested by each patient. Pulmonary function studies and arterial blood gas analysis were performed 1 h prior to the operation and at the postoperative 8th and 24th hours. All patients underwent Lichtenstein's tension-free hernioplasty. Postoperative pain and fatigue were registered 8 h and 24 h after the operation. A questionnaire was filled out by the patients, and they were asked to give grades for the general comfort of the anesthesia and the surgical procedure (1=worst, 10=best). Postoperative pulmonary function tests were significantly poorer in the GA group both on 8th- and 24th-hour measurements (P<0.05). Patients who underwent LA had significantly lower PCO2 and higher PO2 at the postoperative 8th hour (P<0.05). Mean postoperative pain and fatigue scores revealed a significant difference in favor of local anesthesia at only the 8th hour (P<0.05). There were two complications, one in each group (a hematoma in LA and a urinary retention in GA). Patient satisfaction grades were not different in the two groups. We conclude that LA in inguinal hernia repair does not adversely affect pulmonary functions, patients feel less pain, and patient satisfaction is comparable to that with GA. Electronic Publication  相似文献   
28.
29.
30.
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