全文获取类型
收费全文 | 709660篇 |
免费 | 49005篇 |
国内免费 | 1322篇 |
专业分类
耳鼻咽喉 | 9189篇 |
儿科学 | 23355篇 |
妇产科学 | 17643篇 |
基础医学 | 110773篇 |
口腔科学 | 20044篇 |
临床医学 | 64061篇 |
内科学 | 135057篇 |
皮肤病学 | 16347篇 |
神经病学 | 49690篇 |
特种医学 | 25929篇 |
外国民族医学 | 76篇 |
外科学 | 105280篇 |
综合类 | 14833篇 |
现状与发展 | 2篇 |
一般理论 | 161篇 |
预防医学 | 51481篇 |
眼科学 | 16437篇 |
药学 | 54301篇 |
3篇 | |
中国医学 | 2363篇 |
肿瘤学 | 42962篇 |
出版年
2021年 | 5517篇 |
2018年 | 7917篇 |
2017年 | 6158篇 |
2016年 | 6868篇 |
2015年 | 7612篇 |
2014年 | 10338篇 |
2013年 | 15477篇 |
2012年 | 20640篇 |
2011年 | 21683篇 |
2010年 | 12809篇 |
2009年 | 12009篇 |
2008年 | 20094篇 |
2007年 | 21636篇 |
2006年 | 22027篇 |
2005年 | 20588篇 |
2004年 | 20139篇 |
2003年 | 19102篇 |
2002年 | 18611篇 |
2001年 | 36431篇 |
2000年 | 37031篇 |
1999年 | 30486篇 |
1998年 | 7918篇 |
1997年 | 6696篇 |
1996年 | 7002篇 |
1995年 | 6668篇 |
1994年 | 6122篇 |
1993年 | 5619篇 |
1992年 | 23061篇 |
1991年 | 23020篇 |
1990年 | 22400篇 |
1989年 | 22186篇 |
1988年 | 20126篇 |
1987年 | 19510篇 |
1986年 | 18551篇 |
1985年 | 17431篇 |
1984年 | 12756篇 |
1983年 | 10779篇 |
1982年 | 5939篇 |
1979年 | 11554篇 |
1978年 | 8153篇 |
1977年 | 6858篇 |
1976年 | 6623篇 |
1975年 | 7294篇 |
1974年 | 8533篇 |
1973年 | 8174篇 |
1972年 | 7702篇 |
1971年 | 7152篇 |
1970年 | 6889篇 |
1969年 | 6338篇 |
1968年 | 5802篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
A case of the neuroleptic malignant syndrome occurred in a 40-year-old male after administration of chlorpromazine while on an Intensive Therapy Unit. Treatment with dantrolene sodium was successful, and a muscle biopsy was examined in the recovery phase of the illness. The importance of this condition and the difficulties in establishing a diagnosis at an early stage in patients on an Intensive Therapy Unit are discussed, along with implications for treatment. 相似文献
992.
M N Burnier I W McLean L E Zimmerman S H Rosenberg 《Investigative ophthalmology & visual science》1990,31(10):2037-2040
In 150 retinoblastomas the authors found a uniform thickness of the cuff of viable retinoblastoma cells that surrounds blood vessels. The mean thickness was 98.7 microns with a standard deviation of 11.9 microns. The cross-sectional area of the cuff was negatively correlated with the mitotic activity in the cuff and positively correlated with the diameter of the central vessel. The mitotic activity in the cuff of cells was inversely related to the distance from the central blood vessel. When the cuff was divided into three concentric rings, the inner ring contained a mean of 6.2 mitotic figures, the middle ring contained a mean of 2.9 mitotic figures, and the outer ring contained a mean of 0.6 mitotic figures. This pattern of growth is similar to that observed in other rapidly growing neoplasms in humans and experimental animals. In these tumors this pattern results from reduction in oxygen tension with increased distance from the central blood vessel. 相似文献
993.
Poisoning due to class IA antiarrhythmic drugs. Quinidine, procainamide and disopyramide 总被引:4,自引:0,他引:4
Quinidine, procainamide and disopyramide are antiarrhythmic drugs in the class 1A category. These drugs have a low toxic to therapeutic ratio, and their use is associated with a number of serious adverse effects during long term therapy and life-threatening sequelae following acute overdose. Class 1A agents inhibit the fast inward sodium current and decrease the maximum rate of rise and amplitude of the cardiac action potential. Prolonged Q-T interval and, to a lesser extent, QRS duration may be observed at therapeutic concentrations of quinidine. With increasing plasma concentrations, progressive depression of automaticity and conduction velocity occur. 'Quinidine syncope' (a transient loss of consciousness due to paroxysmal ventricular tachycardia, frequently of the torsade de pointes type) occurs with therapeutic dosing, often in the first few days of therapy. Extracardiac adverse effects of quinidine include potentially intolerable gastrointestinal effects and hypersensitivity reactions such as fever, rash, blood dyscrasias and hepatitis. Procainamide produces electrophysiological changes that are similar to those of quinidine, although Q-T interval prolongation with the former is less pronounced at therapeutic concentrations. Hypersensitivity reactions including fever, rash and (more seriously) agranulocytosis are associated with procainamide, and a frequent adverse effect requiring cessation of therapy is the development of systemic lupus erythematosus. Of the 3 drugs, disopyramide has the most pronounced negative inotropic effects, which are especially significant in patients with pre-existing left ventricular dysfunction. As with quinidine, unexpected 'disopyramide syncope' at therapeutic concentrations has been described. Anticholinergic side effects are common with this drug and may require cessation of therapy. Disopyramide therapy may unpredictably induce severe hypoglycaemia. Severe intoxication with the class 1A agents may result from acute accidental or intentional overdose, or from accumulation of the drugs during long term therapy. Acute overdose can result in severe disturbances of cardiac conduction and hypotension, frequently accompanied by central nervous system toxicity. Decreased renal function can cause significant accumulation of procainamide and its active metabolite acecainide (N-acetyl-procainamide), resulting in severe intoxication. Mild to moderate renal dysfunction is less likely to lead to quinidine or disopyramide intoxication, unless renal failure is severe or concurrent hepatic dysfunction is present. Management of acute intoxication with class 1A drugs includes gut decontamination with provision of respiratory support and treatment of seizures as needed. Hypertonic sodium bicarbonate, by antagonising the inhibitory effect of quinidine on sodium conductance, may reverse many or all manifestations of cardiovascular toxicity.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
994.
Tuberculosis of the female genital tract in patients attending an infertility clinic 总被引:2,自引:0,他引:2
Mycobacterium tuberculosis plays a major role in infertility, which is the commonest symptom of genital tuberculosis in women. From August 1987 to July 1988, 109 women presenting with infertility were investigated for tuberculosis. None had any other symptoms or signs of the disease. In all cases it was diagnosed by culture of M. tuberculosis in one or more of the 5 specimens (3 menstrual fluid specimens, endometrial tissue and peritoneal fluid) obtained from each woman. In addition Ziehl-Neelsen staining and histological examination were performed on all the specimens. Twenty-three patients (21%) had positive cultures for M. tuberculosis. Of the 26 positive specimens, 16 (69.6%) were menstrual fluid, 4 (17%) endometrial tissue and 6 (26%) peritoneal fluid (3 patients had more than one positive culture). Chest radiographs were normal in all cases. M. tuberculosis cultured in human tissue must be recognized as a pathogen and necessitates treatment. Selective screening procedures should be done to exclude genital tuberculosis as a cause of infertility. 相似文献
995.
Comparative bactericidal exposures for selected oral bacteria using carbon dioxide laser radiation 总被引:2,自引:0,他引:2
D N Dederich M A Pickard A S Vaughn J Tulip K L Zakariasen 《Lasers in surgery and medicine》1990,10(6):591-594
Although relatively high CO2 laser energies have been shown to sterilize root canals, the response of several bacterial strains to decreasing exposures of CO2 laser energy remains unknown. Freshly grown bacterial cells were irradiated on glass microscope coverslips. A comparison of equivalent energy exposures with differing parameters was made on the bacterial viability. No statistically significant difference was found in the energy required to kill closely related bacterial species. However, the energy density required to kill greater than 99.5% of the bacteria is less than 200 J/cm2, much less than that shown to sterilize in a previous study. 相似文献
996.
E M Sacks L L Fajardo B J Hillman G W Drach J A Gaines H R Claypool N J Clinger D J Fillmore K R Hunt G D Pond 《The Journal of urology》1990,144(6):1341-1346
Most publications citing the effectiveness of renal extracorporeal shock wave lithotripsy have used plain abdominal radiography to assess residual calculi after treatment. We compared radiologist sensitivity and specificity in the detection of calculi on plain abdominal radiographs versus conventional film-screen and digital renal tomograms in extracorporeal shock wave lithotripsy patients. Of the patients 50 were imaged before and within 24 hours after lithotripsy. Six radiologists evaluated the resultant 300 studies for the presence and location of calculi. The mean sensitivity for digital tomograms was 83% for pre-lithotripsy and post-lithotripsy studies, which was significantly higher than for plain abdominal radiography and conventional tomography after lithotripsy. However, there were significantly more false positive stone diagnoses associated with digital tomogram interpretation. Signal detection analysis verified the over-all superiority of digital tomography for post-extracorporeal shock wave lithotripsy imaging. Calculus detection by conventional and digital tomography is superior to detection by plain abdominal radiography. However, because we did not perform delayed imaging, it is not possible to say what impact digital tomography might have on the management of extracorporeal shock wave lithotripsy patients. 相似文献
997.
998.
As the result of immunological examination of 21 children with developmental defects of the chest and analysis of the course of the postoperative period in 136 children, among which 36 had hereditary syndromes of systemic connective-tissue dyshistogenesis, it was found that suppurative complications of thoracoplasty, which are encountered in 15% of children with isolated developmental chest defects and in 33.3% of those with the above mentioned syndromes, were caused to a great measure by disorders of the immune status. The most serious immunological deviations were encountered in the Marfan syndrome due to impaired phagocytic activity of neutrophils and monocytes, decreased number of T, T active, and B lymphocytes, and diminished function of T helpers. In unclassified complexes of developmental defects with Marfaneic ++ phenotypes, the immunological disorders were similar, but less deep. In the Ehlers-Danlos syndrome, a decrease of the number of immunocompetent cells, function of T helpers, and neutrophils was mainly revealed. In isolated forms of funnel chest the function of monocytes and the number of immunoglobulins are mainly decreased. 相似文献
999.
1000.