全文获取类型
收费全文 | 269597篇 |
免费 | 21793篇 |
国内免费 | 10104篇 |
专业分类
耳鼻咽喉 | 1282篇 |
儿科学 | 9085篇 |
妇产科学 | 1700篇 |
基础医学 | 23906篇 |
口腔科学 | 3678篇 |
临床医学 | 27516篇 |
内科学 | 69048篇 |
皮肤病学 | 2953篇 |
神经病学 | 27009篇 |
特种医学 | 8390篇 |
外国民族医学 | 20篇 |
外科学 | 23301篇 |
综合类 | 39279篇 |
现状与发展 | 47篇 |
一般理论 | 9篇 |
预防医学 | 20327篇 |
眼科学 | 2563篇 |
药学 | 20319篇 |
220篇 | |
中国医学 | 13956篇 |
肿瘤学 | 6886篇 |
出版年
2024年 | 843篇 |
2023年 | 5417篇 |
2022年 | 9732篇 |
2021年 | 13662篇 |
2020年 | 12968篇 |
2019年 | 10075篇 |
2018年 | 9882篇 |
2017年 | 10123篇 |
2016年 | 10834篇 |
2015年 | 10281篇 |
2014年 | 18623篇 |
2013年 | 20349篇 |
2012年 | 15501篇 |
2011年 | 16874篇 |
2010年 | 13319篇 |
2009年 | 12833篇 |
2008年 | 12823篇 |
2007年 | 12586篇 |
2006年 | 11525篇 |
2005年 | 9539篇 |
2004年 | 8008篇 |
2003年 | 6943篇 |
2002年 | 5917篇 |
2001年 | 5192篇 |
2000年 | 4302篇 |
1999年 | 3679篇 |
1998年 | 3521篇 |
1997年 | 3084篇 |
1996年 | 2782篇 |
1995年 | 2494篇 |
1994年 | 2307篇 |
1993年 | 1950篇 |
1992年 | 1855篇 |
1991年 | 1597篇 |
1990年 | 1308篇 |
1989年 | 1107篇 |
1988年 | 1009篇 |
1987年 | 904篇 |
1986年 | 783篇 |
1985年 | 913篇 |
1984年 | 767篇 |
1983年 | 483篇 |
1982年 | 566篇 |
1981年 | 484篇 |
1980年 | 377篇 |
1979年 | 325篇 |
1978年 | 265篇 |
1977年 | 224篇 |
1976年 | 216篇 |
1975年 | 81篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Secondary prevention of coronary events in coronary artery disease (CAD) patients with aspirin is generally accepted because of ease of administration, predictable safety, and proven efficacy. The use of long-term anticoagulant therapy with heparins, vitamin-K antagonists (VKAs), or thrombin inhibitors is, however, more controversial. During the last 40 years, several trials have been conducted in order to evaluate the role of anticoagulant therapy in patients with CAD as a protection against subsequent death and thrombo-embolic complications. The conducted trials are heterogeneous in many ways, concerning comparative medications, patient populations, endpoints and follow-up, which makes a standardized recommendation on the basis of these studies difficult. This review is an overview of the largest and best studies on this topic and discusses the scientific background for a possible use of VKA or an alternative anticoagulant treatment in CAD patients, looking at both the beneficial effects and the risk of bleeding. 相似文献
42.
K. C. Lødrup Carlsen M. Løvik B. Granum P. Mowinckel K. H. Carlsen 《Pediatric allergy and immunology》2006,17(4):304-312
The endotoxin receptor soluble CD14 (sCD14) has been implicated in the 'hygiene hypothesis' suggesting reduced allergic sensitization with bacterial stimulation. However, the relationship between early life sCD14 and allergic diseases is conflicting. We aimed to investigate whether possible risk factors for allergic diseases were associated with sCD14 levels at 2 yr of age. In the nested case-control study of the birth cohort studies 'Environment and Childhood Asthma study in Oslo' 411 children selected with recurrent bronchial obstruction (rBO) (n=241) and no bronchial obstruction (n=170) by 2 yr were investigated with skin prick test and structured parental interview at age 2 yr. Exposure to tobacco smoke, pets and infections was recorded semi-annually by questionnaires (0-2 yr). The sCD14 was analysed from frozen, stored serum by ELISA technique. Regression analyses were performed in all subjects with complete data (n=406, 180 girls), and in girls and in boys separately. Mean sCD14 (ng/ml) was significantly higher among girls 2035 (1973-2096) vs. 1947 (1890-2004) (boys). The sCD14 was significantly reduced among girls exposed to antenatal maternal smoking and with parental asthma, after adjusting for age, parental rhino-conjunctivitis, pet keeping and childhood infections. Recurrent otitis media (OM) increased and common colds significantly decreased sCD14 levels in girls. Boys with atopic dermatitis and rBO had reduced sCD14. Pet exposure was not significantly associated with sCD14. We report novel gender-related effects of sCD14 in early life and suggest that gender, tobacco smoke exposure, age and middle ear disease in particular should be accounted for when assessing the role of sCD14 in childhood allergic diseases. 相似文献
43.
Hui-Ju Wen Ying-Chu Lin Yung-Ling Lee Yueliang Leon Guo 《Pediatric allergy and immunology》2006,17(7):489-494
High cord blood immunoglobulin E (cbIgE) is known to be associated with increased risks of atopic diseases in childhood. The relationship between genetic polymorphisms and high cbIgE has not been well documented. A cross-sectional study was conducted to assess the association between cbIgE and genetic polymorphisms of interleukin (IL)-4 -590C/T, the beta-subunit of the high-affinity receptor for IgE (FcepsilonRI-beta) E237G, lymphotoxin (LT)-alphaNcoI alleles, and tumor necrosis factor (TNF)-alpha -308G/A. A total of 320 mother-neonate pairs were recruited from four maternity hospitals from different locations of Taiwan. Cord blood was obtained and assayed for cbIgE. Polymerase chain reaction followed by restriction fragment length polymorphism was used to assess the genotypes. Three hundred pairs of mothers and neonates were included in the final analysis. Infants with IL-4 -590 C allele were found to have higher risk of elevated cbIgE (> or =0.35 IU/ml, 24.3%) (p = 0.004). After adjusting for gender, birth order, maternal age, and history of allergic disease in maternal and paternal families, odds ratios for CC and CT genotypes were 4.41 and 3.16 (95% confidence interval 0.78-22.67, and 1.66-6.13), respectively, using TT genotype as reference. The genotypes of FcepsilonRI-beta, LT-alpha, and TNF-alpha were not associated with cbIgE before or after the adjustment. Our finding suggested a significant association of cbIgE with genetic polymorphism of IL-4 -590C/T, but not with the genotypes of FcepsilonRI-beta, LT-alpha, and TNF-alpha. 相似文献
44.
L. C. Scott G. K. Wright G. S. Rai A. N. Exton-Smith J. M. Gardiner 《International journal of geriatric psychiatry》1991,6(8):583-588
Memory performance of elderly patients in the early stages of Alzheimer's disease (DAT) was compared with that of elderly control subjects. In explicit tests of recognition memory, which involve conscious recollection, the DAT patients were grossly impaired. In implicit tests of anagram solution and wordstem completion, which do not require conscious recollection, the DAT patients were not impaired. These findings further support the idea that a separate memory system, episodic memory, underlies conscious recollection, that it is this system which is most commonly damaged in amnesia, and that memory systems not involving conscious recollection may be spared in the early stages of Alzheimer's disease. 相似文献
45.
To study the pathological and histochemical characteristics of lesions in piglet livers infected with Taenia saginata asiatica (T. saginata asiatica) throughout the different stages, piglets were fed with eggs of T. saginata asiatica and raised in isolation in an animal center to establish the T. saginata asiatica infection model with normal piglets as control. The pathological changes in the piglet livers were observed after the infection
using liver sections stained with hematoxylin and eosin. Histochemical methods were used to check the changes in lipid, glycogen
and protein content in the liver. The data collected by image analysis were analyzed statistically with Statistical Package
for the Social Science. The results show that T. saginata asiatica-exposed piglets were indeed infected. Inflammatory reactions began on the fourth day and progressed rapidly. Kupffer cell
hyperplasia, hepatic hydropic degeneration and ballooning degeneration were found in the 10th–20th days after infection. Hepatic
central veins and hepatic sinusoids were dilated and congested. Spotty necrosis occurred in some local liver tissues. In the
40th–60th days, granulomatous reactions and mild hepatocirrhosis were the main lesions. In the 70th–80th days, hepatocirrhosis
and bile duct proliferation were observed in the liver. In the different stages, lipid drops were increased while glycogen
and protein levels were decreased to some degree. There was a significant difference in metabolism between the infected group
and the control group (P < 0.01). It is concluded that pigs are the favorable intermediate host of T. saginata asiatica and its infection can result in serious pathological and histochemical lesions in host organs.
Translated from Journal of Guiyang Medical College, 2006, 31(4): 296–300 [译自: 贵阳医学院学报] 相似文献
46.
Borras Merce; Valdivielso Jose M.; Egido Ramon; Vicente de Vera Pilar; Bordalba Josep Ramon; Fernandez Elvira 《Nephrology, dialysis, transplantation》2006,21(3):789-791
47.
48.
The goal of the present study is to develop a technique for laparoscopic aortobifemoral bypass.Piglets weighing between 60 and 78 kg were anesthetized with halothane. The lateral retroperitoneal approach was preferred to the more familiar anterior transperitoneal approach and was successfully completed in 19 piglets. The piglets were placed in the right lateral decubitus position. The first port (2 cm) was inserted halfway between the tip of the 12th rib and the iliac crest. Four other trocars were placed in the retroperitoneum after balloon inflation had allowed creation of a space which permitted visualization of the aorta from the left renal artery down to the aorto-iliac junction. After evacuation of the retropneumoperitoneum, the cavity was maintained using an abdominal lift device and a retractor.Using this approach, we performed four aortobifemoral bypasses (end-to-end aortic anastomosis) after conventional intravenous heparinization (100 IU/kg) in less than 4 h. Blood loss did not exceed 250 ml and the hematocrit remained stable. Postmortem evaluation of the grafts revealed they were positioned as in a conventional bypass, their limbs having followed in the created retroperitoneal tunnels along the path of the native arteries. No mortality occurred before sacrifice of the animals. We believe that this first performed series of totally retroperitoneal laparoscopic aortobifemoral bypasses in the porcine model is useful in preparation for human application due to the anatomical similarities in the periaortic region. 相似文献
49.
H. S. Markus A. M. Tomkins G. M. Stern 《Journal of neural transmission (Vienna, Austria : 1996)》1993,5(2):117-125
Summary An anthropometric study was performed in 95 subjects (53 male, 42 female) with Parkinson's disease. Weight, height, triceps and biceps skin-fold thicknesses, and mid-arm circumference were recorded. A high incidence of undernutrition was found (23.6% of males and 22.5% of females, as defined by recent British guidelines). A subgroup of severely disabled patients with Parkinson's disease had a significantly lower mean body mass index than a similarly disabled control group with chronic pyramidal upper motor neuron lesions (males 20.6v 23.2 kg/m2 p<0.05; females 20.6v 26.6 kg/m2 p<0.01), suggesting that the undernutrition is not due to chronic illness or immobility alone. Correlation between anthropometric indices and clinical features of disease demonstrated that the presence of moderate or severe dyskinetic movements was the clinical parameter most strongly related to undernutrition. The reduction in anthropometric indices was most marked for skin fold thickness (related to percentage body fat) and least for arm muscle circumference (related to lean body mass); therefore the weight loss seen in Parkinson's disease is primarily due to fat loss rather than muscle loss. 相似文献
50.