全文获取类型
收费全文 | 522965篇 |
免费 | 41158篇 |
国内免费 | 12047篇 |
专业分类
耳鼻咽喉 | 6778篇 |
儿科学 | 12705篇 |
妇产科学 | 8808篇 |
基础医学 | 42278篇 |
口腔科学 | 13672篇 |
临床医学 | 54735篇 |
内科学 | 59044篇 |
皮肤病学 | 6736篇 |
神经病学 | 28016篇 |
特种医学 | 13457篇 |
外国民族医学 | 40篇 |
外科学 | 53363篇 |
综合类 | 80424篇 |
现状与发展 | 21篇 |
一般理论 | 52篇 |
预防医学 | 61727篇 |
眼科学 | 6889篇 |
药学 | 50082篇 |
684篇 | |
中国医学 | 54884篇 |
肿瘤学 | 21775篇 |
出版年
2024年 | 6562篇 |
2023年 | 10799篇 |
2022年 | 17538篇 |
2021年 | 22896篇 |
2020年 | 21933篇 |
2019年 | 25886篇 |
2018年 | 23060篇 |
2017年 | 19928篇 |
2016年 | 17315篇 |
2015年 | 16327篇 |
2014年 | 32325篇 |
2013年 | 34056篇 |
2012年 | 29120篇 |
2011年 | 31447篇 |
2010年 | 25343篇 |
2009年 | 22969篇 |
2008年 | 22026篇 |
2007年 | 22281篇 |
2006年 | 19438篇 |
2005年 | 16648篇 |
2004年 | 13693篇 |
2003年 | 11995篇 |
2002年 | 9411篇 |
2001年 | 8283篇 |
2000年 | 6944篇 |
1999年 | 5891篇 |
1998年 | 4851篇 |
1997年 | 4512篇 |
1996年 | 3879篇 |
1995年 | 3691篇 |
1994年 | 3502篇 |
1993年 | 2872篇 |
1992年 | 2836篇 |
1991年 | 2469篇 |
1990年 | 2187篇 |
1989年 | 1991篇 |
1988年 | 1884篇 |
1987年 | 1646篇 |
1985年 | 4765篇 |
1984年 | 5792篇 |
1983年 | 4087篇 |
1982年 | 4793篇 |
1981年 | 4158篇 |
1980年 | 3692篇 |
1979年 | 3391篇 |
1978年 | 2905篇 |
1977年 | 2207篇 |
1976年 | 2506篇 |
1975年 | 1845篇 |
1974年 | 1618篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Pathophysiological aspects of brain edema 总被引:16,自引:0,他引:16
Igor Klatzo 《Acta neuropathologica》1987,72(3):236-239
Summary Two mayor types of brain edema, related to two different pathomechanisms, can be recognized: 1)cytotoxic type-where the main feature is the swelling of cellular elements of brain parenchyma and 2)vasogenic type-where an increased vascular permeability leading to accumulation of edema fluid inthe extracellular spaces plays the principal role. In this type of edema, there is a close interrelationship between extravasation of serum proteins and retention of water in the brain tissue. In theischemic brain edema both cytotoxic and vasogenic mechanisms are involved. A biphasic opening of the blood-brain barrier, associated with vasogenic edema, is observed following release of major cerebral artery occlusion. The first opening of the barrier is related to a reactive hyperemia which follows promptly recirculation. The second opening, recognizable after a delay, is associated with a severe ischemic brain tissue injury.Dedicated to Prof. F. Seitelberger on the occasion of his seventieth birthday 相似文献
32.
33.
34.
Massimo Porena Sauro Biscotto Elisabetta Costantini Ettore Mearini Livio Verdini 《Neurourology and urodynamics》2003,22(3):206-222
AIMS: The aim of this study is to compare PUMA curves with different pathologic conditions causing bladder dysfunction in 158 men and 83 women. METHODS: PUMA results in terms of bladder outlet obstruction and detrusor contractility were compared in 92 men with benign prostatic hypertrophy (BPH) and p(ves) congruent with p(det) (i.e., p(abd) congruent with 0) with the results of the urodynamics operator's opinion, the provisional International Continence Society method, Abrams and Griffith's diagram, urethral resistence factor (URA), Sch?fer's diagram, and Watt factor. PUMA curves correlated reliably with different pathologic conditions such as obstructive BPH, orthotopic bladder, cystocele, the neurological bladder, and bladder diverticulum. Statistical analysis indicated excellent agreement between PUMA and URA; agreement with other methods was good in cases of obstruction and nonobstruction. In doubtful cases, as diagnosed by standard methods, PUMA agreed only with the Abrams and Griffith's diagram. PUMA and Wmax were in good agreement on detrusor con traction force. Agreement between PUMA and Sch?fer's diagram was excellent for patients with detrusor hypercontractility and good for patients with detrusor hypocontractility and normocontractility. PUMA is the only method applicable to women. It is easy to perform. When integrated with other diagnostic tests, it provides realistic data for diagnosis, medical or surgical therapy, and outcome. 相似文献
35.
Teng-Yi Huang Hsiao-Wen Chung Fu-Nien Wang Cheng-Wen Ko Cheng-Yu Chen 《Magnetic resonance in medicine》2004,51(2):243-247
In this work the feasibility of separating fat and water signals using the balanced steady-state free precession (SSFP) technique is demonstrated. The technique is based on the observation (Scheffler and Hennig, Magnetic Resonance in Medicine 2003;49:395-397) that at the nominal values of TE = TR/2 in SSFP imaging, phase coherence can be achieved at essentially only two orientations (0 degrees and 180 degrees ) relative to the RF pulses in the rotating frame, under the assumption of TR < T2, and independently of the SSFP angle. This property allows in-phase and out-of-phase SSFP images to be obtained by proper choices of the center frequency offset, and thus allows the Dixon subtraction method to be utilized for effective fat-water separation. The TR and frequency offset for optimal fat-water separation are derived from theories. Experimental results from healthy subjects, using a 3.0 Tesla system, show that nearly complete fat suppression can be accomplished. 相似文献
36.
PROBLEM: Recent developments in providing care to children with emotional and behavioral disorders, especially those with serious emotional disturbance, have included the establishment of systems of care. Guided by a set of principles and values, these systems of care have organized and delivered services to children and families with complex needs. To date, nurses have not had a salient role in systems of care. RESULTS: It is estimated that 20% of American children and adolescents have an emotional or mental disorder. As many as two thirds of these children are not receiving services. Systems of care have been funded to provide services for these children, particularly for the most severely affected. To date, nursing has not had a prominent role in these systems of care. CONCLUSIONS: Based on their knowledge, skills, and holistic approach to care, nurses could better integrate nursing care into systems of care. Possible roles as case managers, primary therapists, in-home interventionists, and in educational programs are suggested. 相似文献
37.
Assessment of quality of life in children with peanut allergy 总被引:5,自引:0,他引:5
Natalie J. Avery Rosemary M. King Susan Knight Jonathan O'B. Hourihane 《Pediatric allergy and immunology》2003,14(5):378-382
Children with a peanut allergy (PA) are faced with food and social restrictions due to the potentially life-threatening nature of their disease, for which there is no cure or treatment. This inevitably impacts upon their quality of life (QoL). QoL of 20 children with PA and 20 children with insulin-dependent diabetes mellitus (IDDM) was measured using two disease-specific QoL questionnaires (higher scores correspond to a poorer QoL). One questionnaire was designed by us and the other was adapted from the Vespid Allergy QoL questionnaire. We gave subjects cameras to record how their QoL is affected over a 24-h period. Response rates for both questionnaires were 100%. Mean ages were 9.0 and 10.4 years for PA and IDDM subjects, respectively. Children with a PA reported a poorer quality of life than children with IDDM: mean scores were 54.85 for PA subjects and 46.40 for diabetics (p = 0.004) in questionnaire 1 and 54.30 and 34.50 (p≤0.001) in questionnaire 2. PA children reported more fear of an adverse event and more anxiety about eating, especially when eating away from home. Photographs fell into seven common categories: food, management, environment, away from home, physical activities, restaurant and people. Most photographs related to food and management issues and revealed difficulties for both groups regarding food restrictions. PA subjects felt more threatened by potential hazards within their environment, felt more restricted by their PA regarding physical activities, and worried more about being away from home. However, they felt safe when carrying epinephrine kits and were positive about eating at familiar restaurants. The QoL in children with PA is more impaired than in children with IDDM. Their anxiety may be considered useful in some situations, promoting better adherence to allergen avoidance advice and rescue plans. 相似文献
38.
Hiromitsu Nakaya Shuichi Kawashiri Akira Tanaka Natsuyo Noguchi Koroku Kato Takashi Hase Etsuhide Yamamoto 《Journal of oral pathology & medicine》2005,34(2):87-92
BACKGROUND: Although it is clear that dissemination via the blood system involves angiogenesis, it is uncertain whether tumors also induce lymphangiogenesis or simply invade existing peritumoral vessels. The purpose of this study was to elucidate changes in tumor blood and lymph vessels in cases involving the invasion of squamous cell carcinoma in the oral cavity, and its significance. Blood and lymph vessels densities in tongue carcinomas induced in hamsters were investigated. METHODS: Tongue cancer was induced by abrading the right margin of the tongue of each hamster with an endodontic barbed broach and subsequently applying 1.0% 9,10-dimenthl-1,2-benzanthracene (DMBA) dissolved in acetone, three times a week, at the same site. Fresh frozen sections were prepared and blood vessels stained blue by perfusion with Coomassie Brilliant Blue and lymph vessels stained brown for 5'-nucleotidase. The effects on the blood vessels and lymph vessels were observed. RESULTS: The results showed that blood and lymph vessel densities were greater in the advanced carcinoma tissues than in normal tissue. These were compared in terms of the mode of cancer invasion. As tumor invasion progressed, the blood vessel density decreased but lymph vessel density tended to be higher in high-degree tumor invasion than in low-degree tumor invasion. The expression of vascular endothelial growth factor-C was seen more frequently as tumor invasion progressed. CONCLUSIONS: The present findings indicated that angiogenesis and lymphangiogenesis are affected by cancerous invasion. 相似文献
39.
LESLEY BOULTON MB CHB FRACO DO Ophthalmologist 《Clinical & experimental ophthalmology》1986,14(4):365-371
The Low Vision Clinic at the Palmerston North Hospital has now been oerating for 70 years. Over the course of these ten years a number of factors have emerged which can be as readily applied to general ophthalmological practice as to low vision practice. The philosophy of low vision care is one of which all ophthalmologists should be aware and includes factors to be taken into account when dealing with children, people in the workplace, and everyday factors involved in daily living activities, all of which are equally relevant in routine ophthalmological practice. This paper endeavours to share some thoughts on these factors and also discusses means by which the visually handicapped can be helped in areas where specialist low vision services are not readily available. 相似文献
40.
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