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   246063篇
  免费   13386篇
  国内免费   6922篇
耳鼻咽喉   2977篇
儿科学   8416篇
妇产科学   4766篇
基础医学   18376篇
口腔科学   4421篇
临床医学   29433篇
内科学   40334篇
皮肤病学   3195篇
神经病学   12208篇
特种医学   13918篇
外国民族医学   22篇
外科学   38736篇
综合类   23807篇
现状与发展   26篇
预防医学   16588篇
眼科学   4450篇
药学   25250篇
  92篇
中国医学   5710篇
肿瘤学   13646篇
  2023年   2135篇
  2022年   4627篇
  2021年   11057篇
  2020年   5963篇
  2019年   11697篇
  2018年   6486篇
  2017年   5719篇
  2016年   7764篇
  2015年   10617篇
  2014年   19736篇
  2013年   17283篇
  2012年   20585篇
  2011年   17538篇
  2010年   16071篇
  2009年   15447篇
  2008年   13850篇
  2007年   13959篇
  2006年   11755篇
  2005年   7888篇
  2004年   4210篇
  2003年   3673篇
  2002年   2930篇
  2001年   2375篇
  2000年   2127篇
  1999年   1417篇
  1998年   1780篇
  1997年   1646篇
  1996年   1342篇
  1995年   1395篇
  1994年   1291篇
  1993年   1029篇
  1992年   1227篇
  1991年   1092篇
  1990年   1108篇
  1989年   1080篇
  1988年   995篇
  1987年   888篇
  1986年   721篇
  1985年   1650篇
  1984年   1793篇
  1983年   1280篇
  1982年   1379篇
  1981年   1351篇
  1980年   1157篇
  1979年   1010篇
  1978年   775篇
  1977年   770篇
  1976年   672篇
  1974年   458篇
  1973年   443篇
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
991.
本文对100例慢性粒细胞白血病(CML)患者进行组织病理学研究,应用Hannover国际分类法进行分类,观察到骨髓组织病理学中巨核细胞增多者临床症状较重,中位生存时间较短,认为该分类法对临床及预后判断有指导意义,比既往应用的Bartl及Frisch分类法优越。  相似文献   
992.
1970年至1987年,我院收治158例颈椎及颈髓损伤的病人,男125例、女33例各年龄组发病率没有显著差异,共损伤189个椎体,72%病人合并颈髓损伤或颈神经根损伤。本文讨论了:伤后24小时以内就诊者可达46.8%,由于 X 线片显示阴性和并发损伤给早期定位诊断带来一定困难;颈髓损伤的死亡率高达23.5%,在颈椎各种损伤中颈椎脱位是引起颈髓或颈神经根损伤的主要原因,颈推损伤后不宜主观的行屈曲位或后伸位颅骨牵引,而应顺从伤后颈屈度椎平行牵引;颈髓完全性损伤,手术效果不佳,而部分性颈髓损伤的病例,尽早手术治疗,可明显提高治愈率。  相似文献   
993.
A case is reported of fatal acute cerebral oedema occurring in a 15-year-old child suffering diabetic ketoacidosis. He had severe gastro-enteritis, with a weight lose of 8 kg over a period of 8 days (initial weight = 50 kg). He was admitted in a stupor with pH 7.15, 129 mmol.l-1 natraemia, and 31 mmol.l-1 blood glucose concentration. Blood osmolaity was calculated to be 310 mosmol.l-1. He was rehydrated with 416 ml.h-1 normal saline and 416 ml.h-1 of 1.4% sodium bicarbonate. At the same time a total dose of 75 i.u. of ordinary insulin was given. After 2 h, the patient's condition suddenly worsened with unreactive coma, bilateral fixed mydriasis, respiratory pauses, and impairment of haemodynamic state (heart rate 150 b.min-1, blood pressure 80/50 mmHg). The diagnosis of cerebral oedema with severe intracranial hypertension was confirmed by different investigations. Despite ventilatory support and continued intensive care, the patient died a few hours later. It is concluded that some degree of subclinical brain swelling could be common occurrence during diabetic ketoacidosis, present maybe even before the start of treatment. Such cases of cerebral oedema are often reported, but the pathophysiological mechanisms remain unclear. However, unlike this case, rehydration must be moderate (less than 41.m-2.day-1), especially in case of hyponatraemia. Insulin and sodium bicarbonate must be used with care. Early rigorous clinical and biological monitoring is essential. Treatment should aim at a progressive correction of the metabolic disturbances.  相似文献   
994.
鼻咽癌证型与颈淋巴结肿大关系的临床观察   总被引:3,自引:0,他引:3  
  相似文献   
995.
Summary Optical isomers (d and l) and racemic compounds (dl) of methamphetamine (MAMP) and amphetamine (AMP), and biologic materials including those substances, could be analyzed by high performance liquid chromatography. Examining the temperature for the analysis, 40°C was the optimal condition in the reproducibility of separated MAMP-isomers. The reproducibility at the temperature did not vary significantly. The measured values of optical isomers were 0.116±0.012, 1.082±0.070 and 8.984±0.136 for the mixing ratios (l/d) of 0.111, 1.000, and 9.000, respectively. The detection limit for both d- and l-isomers was 25 ng.The analytic result of hair specimens from two stimulant abusers by the present method indicates that they contained only d-MAMP and d-AMP, which is believed to have the strongest pharmacologic effect among the optical isomers of MAMP. The coefficient of variation in the analysis of five replicate standards, prepared by adding 1,000 ng each of racemate MAMP and AMP to hair, was less than 4%. The measured value against l/d=1.000 was 1.040±0.040 in MAMP and 0.980±0.030 in AMP. The detection limit for both racemate MAMP and AMP accumulated in hair was 250 ng.The analysis of the optical isomers by our method would contribute to identifying the smuggling routes or the illicit method.  相似文献   
996.
Branhamella catarrhalis is being isolated with increasing frequency from patients with symptoms and signs of respiratory tract infection. Records of 77 patients were reviewed to define the spectrum of respiratory illness and to compare clinical and laboratory features with those of respiratory infection due to Haemophilus influenzae. Both B catarrhalis and H influenzae caused respiratory infection predominantly in elderly males with underlying heart or lung disease. There were no clinical or laboratory features aside from sputum Gram stain and culture which differentiated the two groups. Although fewer than one-half of each group received antibiotics, no patient developed progressive respiratory disease.  相似文献   
997.
Investigation was carried out in ten children aged between one month and six years, who were anaesthetized by the T-piece circuit. The volume of the reservoir tubing of the T-piece was 250 ml. Ventilation was controlled automatically by oxygen jets which were delivered via an injector attached to the reservoir tubing. The oxygen jets were regulated by an electronically-controlled solenoid valve. The children were ventilated by a tidal volume about 12 ml±kg?1 at a rate of 12-20 per min depending on their age, while the FGF varied between 3 and 6 l min?1 depending on their body weight. The resulting FIO2 ranged between 0.32 and 0.34 which was expected from the oxygen:nitrous oxide mixture (1:2), denoting no mixing of the oxygen jets with the anaesthetic mixture. The PAco2 was ventilation-dependent, and ranged between 4±6-5±3 kPa (35-41 mmHg). The results suggest that automatic jet ventilation facilitates controlled ventilation in children anaesthetized by the T-piece circuit, while maintaining the original simplicity of the T-piece.;  相似文献   
998.
营养液浓度对丹参生长的影响   总被引:15,自引:2,他引:13  
对丹参进行不同浓度营养液的砂培试验。结果表明,丹参是一种喜肥作物,在盐分总浓度达0.37%的条件下仍生长良好,产量也高。  相似文献   
999.
Current concepts on monoclonal gammopathies   总被引:1,自引:0,他引:1  
This is a review of the monoclonal gammopathies, including a discussion of cause. The role of T lymphocytes and B lymphocytes is presented. The recognition of a monoclonal protein in the serum and urine is presented in detail.
The frequency of benign and malignant monoclonal gammopathies is provided. A long-term follow-up of 241 patients with apparently benign monoclonal gammopathy is examined closely. In this series, multiple myeloma, macroglobulinaemia, amyloidosis, or related disorders developed in 22% of the 241 patients with long-term disease. The median duration from the recognition of the monoclonal protein until the development of serious disease was approximately eight to ten years.
The differentiation of benign from malignant monoclonal gammopathics is examinad in detail. The point is made that paticnu must be folld indefinitely because malignancy may develop more than 20 years later. The association of monoclonal gammopathies with other apparently unrelated diseases discussed. (Aust NZ J Med 1992; 22: 291–302.)  相似文献   
1000.
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