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991.
In addition to the known compounds (+/-)-threo-guaiacylglycerol and the phenethyl alcohols, 3-methoxy-4-dihydroxyphenethyl alcohol and 3,4-dimethoxyphenethyl alcohol, a new irregular phenylpropanoid 2-(3-methoxy-4-hydroxyphenyl)-1,3-propanediol was isolated from the ethanolic extract of the leaves of Apollonias barbujana (Lauraceae). Their structures were elucidated on the basis of spectroscopic methods and chemical transformations.  相似文献   
992.
Thrombosis of the hepatic artery (HAT) is a severe complication of liver transplantation, and most cases need regrafting. The aim of this study was to review our experience with this complication. From January 1986 through January 1992, 76 liver transplants were performed in 59 pediatric patients at the Children's Hospital La Paz, Madrid. The diagnosis of HAT was made in 12 cases (15.7%). The common patterns of clinical presentation were: fulminant liver necrosis (5), bile leak due to necrosis of the bile duct (4), and relapsing bacteremia (3). Clinical symptoms of fulminant liver necrosis started within the first 2 weeks after transplantation, with rapid deterioration and steep rises in SGOT and SGPT levels. All these patients were retransplanted on an urgent basis, but only 1 is alive 4 years later. Four patients developed bile leaks 13 to 60 days after transplantation; SGOT, SGPT, and total bilirubin were only slightly increased. Three children were retransplanted electively and are alive with a mean follow-up of 3 years. One exceptional patient had a Roux-en-Y jejunostomy and is doing well 30 months later with his original graft. The 3 remaining children had episodes of septicemia with hepatic abscess, liver infarction, and pleural effusion. Liver function tests were normal, with bilirubin levels below 2 mg/dl. All patients were retransplanted, but only 1 is alive and well 13 months later. In the present series, we found that early HAT produces fulminant clinical deterioration requiring an urgent regraft. Late HAT presenting with either infection or bile leak allows time for treatment by elective retransplantation. The best survival was obtained in the latter group. Correspondence to: J. Vázquez  相似文献   
993.
Urinary delta-aminolaevulinic acid (-ALA) excretion was evaluated in random urine samples of 191 healthy children, aged 2–14 years, with blood lead levels <0.8 mol/l (mean ± SD: 0.34±0.13), erythrocyte zinc-protoporphyrin <70 mol/mol haem (mean ± SD: 50.4±8.0) and blood haemoglobin >6.8 mmol/l (mean ± SD: 8.2±0.5). It was found that uncorrected -ALA concentration and -ALA/creatinine ratio are age-dependent, whereas the ratio of -ALA/logarithm of creatinine concentration (mean ± SD: 55.3±13.5 mol/log mmol) is independent of age and sex. The authors recommend the use of this parameter for the assessment of -ALA excretion in random urine samples in children  相似文献   
994.
A dengue epidemic that Cuba reported in 1997 registered more than 500,000 cases of dengue fever produced by viral serotype 1. In 1981, there was an epidemic of dengue hemorrhagic fever produced by serotype 2 of the virus. This time 344,203 clinical cases were reported, 10,312 of which were severe cases of hemorrhagic fever that led to 158 fatalities (101 of them among children). The reintroduction of dengue, and specifically of dengue viral serotype 2 (Jamaica genotype), was quickly detected in January 1997 through an active surveillance system with laboratory confirmation of cases in the municipality of Santiago de Cuba, in the province of the same name. The main epidemiological features of this outbreak are reported in this paper. A total of 3,012 cases were reported and serologically confirmed. These included 205 cases classified as dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), 12 of which were case fatalities (all among adults). Secondary infection with dengue virus was one of the most important risk factors for DHF/DSS. Ninety-eight percent of the DHF/DSS cases and 92% of the fatal cases had contracted a secondary infection. It was the first time dengue hemorrhagic fever was documented as a secondary infection 16 to 20 years after initial infection. Belonging to the white racial group was another important risk factor for DHF/DSS, as had been observed during the 1981 epidemic. During the most recent epidemic it was demonstrated that the so called "fever alert" is not useful for early detection of an epidemic. Measures taken by the country's public health officials prevented spread of the epidemic to other municipalities plagued by Aedes aegypti.  相似文献   
995.
996.
How much global ill health is attributable to environmental factors?   总被引:3,自引:0,他引:3  
Over the years, estimates have been made of the portions of human mortality and morbidity that can be attributed to environmental factors. Frustratingly, however, even for a single category of disease such as cancer, these estimates have often varied widely. Here we attempt to explain why such efforts have come to such different results in the past and to provide guidance for doing such estimates more consistently in the future to avoid the most important pitfalls. We do so by carefully defining what we mean by the terms "environmental," "ill health," and "attributable." Finally, based on these recommendations, we attempt our own estimate, appropriately qualified according to the many remaining uncertainties. Our estimate is that 25-33% of the global burden of disease can be attributed to environmental risk factors. Children under 5 years of age seem to bear the largest environmental burden, and the portion of disease due to environmental risks seems to decrease with economic development. A summary of these estimates first appeared in the 1997 report, "Health and Environment in Sustainable Development," which was the World Health Organization's contribution to the 5-year anniversary of the Rio Earth Summit. A full explanation of how these estimates were made is first presented here. We end with a call for a program of "strategic epidemiology," which would be designed to fill important gaps in the understanding of major environmental health risks in important population groups worldwide.  相似文献   
997.
BACKGROUND: Most of the studies which demonstrate the existence of a short-term relationship between air pollution and morbidity and the Mortality analyze the impact of "classic" pollutants which are by-products of combustion. However, the changes in the sources of these emissions, shifting basically toward road traffic, has made a change in air pollution, heightening the importance of the photochemical components, such as ozone (O3) and nitrogen dioxide (NO2). Barcelona is a city located in a mild climate zone, and its air pollution comes mainly from vehicle emissions. The main objective of this article is that of analyzing the relationship between the photochemical pollutants, NO2 and O3 and the death rate for different causes in the city of Barcelona throughout the 1991-1995 period, using the procedure for analysis set out as part of the EMECAM Project. METHODS: Daily changes in the number of deaths resulting from all causes, of the number of deaths for all causes of those over age 70, of the number of deaths resulting from cardiovascular diseases, and of the number of deaths resulting from respiratory-related causes are related to the daily changes in the photochemical pollutants using autoregressive Poisson models, controlling confusion-causing variables such as the temperature, the relative humidity, the systematic time structure and the autoregressive structure. RESULTS: Except for the relationship between O3 and the mortality for causes involving respiratory diseases, the relationships between photochemical pollutants and the mortality for all the causes considered were statistically significant. The risks related to dying as a result of rises in O3 were greater than as a result of rises in NO2, almost triple among cardiovascular diseases. The risks related to dying for all the causes are lower than for specific causes and than for those individuals over age 70. The results of the analysis by six-month periods are quite similar to the overall results, revealing, in any event, relative risks somewhat greater during the warm months (May to October). CONCLUSIONS: Photochemical pollution, especially that which is caused by O3, comprises a health risk. In the case of NO2, this might not be more than an indicators of the suspended particles or of other pollutants stemming from city traffic. There may be a certain adjustment between six-month periods of the impact of O3 on the mortality for causes of the circulatory system.  相似文献   
998.
An evaluation is made of the effect of smoking during the period of life between 20 and 50 years of age and idiopathic Parkinson's disease in a case-control study carried out in Navarra. An inverse association is observed: for the number of smokers (OR = 0.66, CI 90% 0.41-1.05); for the number of years smoking (OR =0.22, CI 90% 0.05-0.97); and for the quantity of cigarettes smoked (z = 2.2298, p = 0.02). Likewise, a dose-response relationship exists between the number of cigarettes consumed and the risk of Parkinson's disease (p = 0.01). The same effect is maintained on analysing the data by matching 1:1 (OR = 0.59, CI 90% 0.31-1.10). All of this contributes to giving consistency to the protective effect of smoking against idiopathic Parkinson's disease. The anti-oxidant status, measured by means of different parameters in peripheral blood, is lower in the cases than in the tests for reduced glutathione (GSH) (p = 0.001) and is an independent variable with respect to smoking.  相似文献   
999.
Intrauterine foetal growth retardation (IUGR) implies increased risk of morbidity and mortality of the newborn. Aetiology of intrauterine retardation is probably multifactorial and may include maternal infection, malnutrition, placental dysfunction, hypertension, toxaemia, smoking, professional and environmental exposure. The work concentrates on the lead, zinc and lysozyme levels in blood and placental tissues of 50 females in the IUGR group and 43 females from a control group. Statistically significant differences in zinc and lead levels between the compared group were found. The IUGR group had lower zinc and higher lead levels. A significant negative correlation of zinc and lead levels was observed. We found a statistically significant relationship between lead levels in placental tissues and the age of the pregnant women. Higher age is associated with higher lead levels in placental tissue, whereas zinc levels decrease. In placental tissues of pregnant females of the IUGR group higher lysozyme levels were found. On the basis of the discussed results the authors recommend zinc supplementation during the pregnancy.  相似文献   
1000.
In the 1996/97 period, 1,413 Pseudomonas aeruginosa (PA) strains were isolated from 843 patients of the Brno teaching hospitals of St. Anne and Bohunice together with small groups from other hospitals. In the same period, 203 PA strains, used as controls, were isolated from 187 patients treated outside hospitals. Statistical evaluation was based on 1,023 hospital isolates and 189 control strains. A total of 16 isolates were recovered from the hospital environments and two from therapeutic swimming pools. The epidemiological analysis of these PA strains was based on pyocin typing, serological typing and phage typing. The most frequently occurring pyocin types amongst our strains fell into 8 pyocin-type groups. The prevailing groups differed significantly between the hospital patient and control groups. Similarly, serological typing identified differences in the predominant serotypes between hospital and control patients. The phage typing method revealed that the control PA strains were significantly more sensitive to 21 polyvalent bacteriophages used than the hospital isolates. In relation to pyocin and serological typing, strains isolated from the hospital environment showed characteristics similar to those of the PA strains isolated from hospital patients. Our results indicate that the majority of strain isolated from hospitalised patients had their origin from human or inanimate contacts in the hospitals.  相似文献   
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