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   9507篇
  免费   410篇
  国内免费   40篇
耳鼻咽喉   107篇
儿科学   223篇
妇产科学   89篇
基础医学   1150篇
口腔科学   339篇
临床医学   555篇
内科学   2293篇
皮肤病学   160篇
神经病学   669篇
特种医学   467篇
外科学   1735篇
综合类   35篇
预防医学   196篇
眼科学   136篇
药学   509篇
中国医学   18篇
肿瘤学   1276篇
  2023年   42篇
  2022年   79篇
  2021年   124篇
  2020年   64篇
  2019年   111篇
  2018年   166篇
  2017年   161篇
  2016年   187篇
  2015年   177篇
  2014年   262篇
  2013年   319篇
  2012年   516篇
  2011年   604篇
  2010年   353篇
  2009年   360篇
  2008年   565篇
  2007年   611篇
  2006年   628篇
  2005年   622篇
  2004年   649篇
  2003年   611篇
  2002年   599篇
  2001年   100篇
  2000年   114篇
  1999年   158篇
  1998年   169篇
  1997年   161篇
  1996年   156篇
  1995年   115篇
  1994年   122篇
  1993年   123篇
  1992年   74篇
  1991年   72篇
  1990年   63篇
  1989年   58篇
  1988年   48篇
  1987年   47篇
  1986年   53篇
  1985年   48篇
  1984年   48篇
  1983年   53篇
  1982年   43篇
  1981年   45篇
  1980年   34篇
  1979年   21篇
  1978年   33篇
  1977年   17篇
  1974年   17篇
  1973年   17篇
  1971年   17篇
排序方式: 共有9957条查询结果,搜索用时 15 毫秒
81.
A 58-year-old woman with bronchiectasis presented with massive hemoptysis and severe respiratory failure, which required long-term extracorporeal membrane oxygenation with continuous heparin infusion. Bronchial artery embolization using hydrogel coils, which provide a greater volume occlusion than bare platinum coils, was performed; hemoptysis stopped and she fully recovered. No recanalization was observed on follow-up computed tomography angiography 2 months postbronchial artery embolization, and there had been no recurrence of bleeding at the time of this report (at least 6 months). Although continuous anticoagulation during extracorporeal membrane oxygenation might hinder complete vessel occlusion by metallic coils or induce early recanalization (because the homeostatic mechanism of coils depends on the patient''s coagulability), our experience showed that bronchial artery embolization using hydrogel coils was effective and safe. Additionally, this case presents a successful example of anticoagulation management for patients with hemoptysis on extracorporeal membrane oxygenation who undergo bronchial artery embolization using coils.  相似文献   
82.
83.
Summary Rennin is regarded as being similar to viruses such as vaccinia and phage in its physical and chemical properties. Rennet activity is carried by a lipoprotein existing in particles or micells of very great dimensions.Coagulation of milk by rennin can be considered to be a chain reaction to some extent.  相似文献   
84.
Summary The resorption and excretion of glucose by living cells can be explained to be due to a property of the minute-body-forming proteid existing in the cells.Also in this property, there is no difference between virus proteid (vaccinia) and the normal minute-body-forming proteid having no virus action.  相似文献   
85.
Summary The salt-impenetrable space of vaccinia particles isolated from vaccine pulp by isoelectric precipitation method was estimated by measuring the salt quantity added to the suspension of the vaccinia particles of a known concentration, which were centrifuged off after the addition of the salt at a weakly acid pH (about 5,4). The salts used were NaCl, KCl and CaCl2. It was found thus that salt-impenetrable space of the particles varied with the concentrations of the salts, in the solution of which the particles were suspended. There was no definite relation between the concentration of the salt and the volume of the space.The shape of the curve representing the relation between the volume of the space and the concentration of a salt was different with each preparation of the vaccinia particles, and the curve was also different with each kind of the salts; even with the same preparation different curves were obtained if the experiments were carried out at different temperature.Similar experiments were made also with glucose and fructose. These two monosaccharides behaved themselves in a very complicated manner towards the particles, in assuming a different attitude from each other, although the shape of the curve tended in most cases to be alike with each other. As already pointed out lactose did not assume so complicated an attitude as did glucose.These phenomena were not peculiar to the vaccinia particles, but also found with coagulated casein particles as well as with protoplasmprotein particles having no virus action.  相似文献   
86.
Summary Moriyama has previously isolated a vaccinia virus protein which is severely inactivated if its acidified solution is neutralized in the presence of inorganic salts, while the inactivation scarecely occurs if no salt is present in the neutralization process. Afterwards we have also observed a similar phenomenon with a phage protein though not so manifest as with the vaccinia protein.We have lately found that a phage protein (coli-phage) can possess sometimes a property to be damaged severely if its acidified solution is neutralized in a water medium containing no salt: in this case inorganic salts can, on the contrary, prevent the inactivation. This fact must be taken into considerations in our isolating method of virus proteins. Namely in some cases a proper salt solution such asRinger's and a dilute CaCl2 solution should be used instead of water.  相似文献   
87.
Ohne ZusammenfassungZum Schlusse möchte ich Herrn Prof.E. Mangold für die Anregung und Anleitung bei diesen Untersuchungen meinen herzlichsten Dank aussprechen.  相似文献   
88.
89.
Objective Diabetes mellitus is an independent risk factor for acute myocardial infarction. Thus, a surveillance study was conducted as part of studies to create a national database related to electrocardiogram (ECG)-gated myocardial perfusion single-photon emission computed tomography (SPECT) of ischemic heart disease. Methods Single-photon emission computed tomography was conducted in patients with type 2 diabetes mellitus and their prognoses will be followed for 3 years, stratified by patients’ clinical background and SPECT findings. Results A total of 513 patients from 50 institutions were enrolled in this study, 297 of whom were men (age 66.2 ± 0.4 years, mean ± SEM) and 261 women (age 67.8 ± 0.5 years). They have a history of retinopathy (25.3%), neuropathy (19.9%), cerebrovascular disorder, chronic obstructive pulmonary disease, and photocoagulation. Major risk factors for present disease were hypertension (82.3%) and hyperlipidemia (79.7%). In 244 patients (129 men and 115 women), body mass index (BMI) was 25 or more. Fifty-two of them (10.1%) underwent coronary angiography; of these, 26 (50.0%) had no coronary artery lesions with 75% or more stenosis, and only 1 (1.9%) had a left main trunk with 50% or more stenosis. An overwhelming majority of patients (94.3%) underwent SPECT imaging by a 1-day stress-followed-by-rest procedure. Stress procedure was exercise in most (70.8%) patients, followed by dipyridamole infusion in 14.6%, adenosine infusion in 6.6%, and adenosine triphosphate infusion in 5.7%. Endpoint of stress examination was most often fatigue in lower limbs (40.7%), followed by completion of pharmacological stress protocol (28.7%), and achievement of target heart rate (26.3%). The largest number of patients (198, 38.6%) received 99mTc-tetrofosmin at an initial dosage of 200–300 MBq (mean 331 ± 3 MBq) followed by a second dosage of 700–800 MBq (mean 748 ± 8 MBq). Among them, 491 (95.7%) received some kind of therapeutic drug: hypoglycemic drugs were used by the largest number (83.2%), followed by hypotensive (66.7%), hypolipidemic (40.7%), and antiplatelet drugs (27.7%), vasodilators (5.5%), and antioxidants and others (2.3%). Conclusions This study was designed to clarify the correlation between coronary artery disease and diabetes mellitus as its risk factor based on the clinical and imaging findings. Patient enrollment was closed on September 30, 2005, and follow-up is now under way.  相似文献   
90.
Mucinous cystadenoma of the appendix is a type of appendiceal mucocele and a rather rare condition usually found incidentally in the course of other abdominal surgery. A previous evaluation of 73 appendiceal mucoceles showed that this disease was often associated with adenocarcinoma and other epithelial atypia. This observation suggested that patients with mucinous cystadenoma of the appendix also have some underlying disorders. However, non-epithelial changes associated with appendiceal mucocele have not been reported so far. In this study, we presented for the first time a mucinous cystadenoma of the appendix associated with muscular and neuromatous hyperplasia.  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