全文获取类型
收费全文 | 47360篇 |
免费 | 2735篇 |
国内免费 | 186篇 |
专业分类
耳鼻咽喉 | 629篇 |
儿科学 | 1207篇 |
妇产科学 | 953篇 |
基础医学 | 6269篇 |
口腔科学 | 2439篇 |
临床医学 | 3482篇 |
内科学 | 11879篇 |
皮肤病学 | 1172篇 |
神经病学 | 4045篇 |
特种医学 | 1078篇 |
外国民族医学 | 1篇 |
外科学 | 6947篇 |
综合类 | 280篇 |
一般理论 | 14篇 |
预防医学 | 3516篇 |
眼科学 | 819篇 |
药学 | 2709篇 |
中国医学 | 154篇 |
肿瘤学 | 2688篇 |
出版年
2023年 | 318篇 |
2022年 | 735篇 |
2021年 | 1614篇 |
2020年 | 878篇 |
2019年 | 1317篇 |
2018年 | 1564篇 |
2017年 | 1037篇 |
2016年 | 1150篇 |
2015年 | 1290篇 |
2014年 | 1867篇 |
2013年 | 2316篇 |
2012年 | 3668篇 |
2011年 | 3782篇 |
2010年 | 2184篇 |
2009年 | 1811篇 |
2008年 | 3053篇 |
2007年 | 3071篇 |
2006年 | 3009篇 |
2005年 | 2876篇 |
2004年 | 2491篇 |
2003年 | 2218篇 |
2002年 | 2020篇 |
2001年 | 504篇 |
2000年 | 442篇 |
1999年 | 469篇 |
1998年 | 379篇 |
1997年 | 317篇 |
1996年 | 279篇 |
1995年 | 280篇 |
1994年 | 211篇 |
1993年 | 158篇 |
1992年 | 307篇 |
1991年 | 260篇 |
1990年 | 214篇 |
1989年 | 202篇 |
1988年 | 192篇 |
1987年 | 152篇 |
1986年 | 150篇 |
1985年 | 155篇 |
1984年 | 145篇 |
1983年 | 110篇 |
1982年 | 81篇 |
1981年 | 78篇 |
1980年 | 94篇 |
1979年 | 92篇 |
1978年 | 68篇 |
1977年 | 73篇 |
1976年 | 56篇 |
1974年 | 60篇 |
1973年 | 53篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Prospective study of antigenemia,plasma viremia and lymphocytic viremia in HIV-infected hemophiliacs
S. Melón Garcia M. de Oña Navarro C. Rodriguez Pinto M. Fernández Urgellés A. Martinez Gutierrez P. de la Iglesia F. J. Mendez García 《European journal of clinical microbiology & infectious diseases》1995,14(5):400-405
A total of 186 blood samples from 24 HIV-1 seropositive hemophiliac patients, monitored every four months for 29 months, were investigated for the presence of viral antigen in plasma. In addition, peripheral blood mononuclear cells (PBMC) were cultured for HIV-1, using normal PBMC as a target for replication. Antigenemia was detected in 51 % of the patients and from PBMC in 87.5 % of the patients. The incidence of HIV isolation in asymptomatic patients (42.8 %) was similar to that found in symptomatic patients (51.4 %). Patients with opportunistic infections had a higher incidence of lymphocytic viremia (p<0.05). Plasma viremia was closely associated (p<0.05) with low CD4+ counts and infection progression. The persistence of antigenemia was also a marker of a poor clinical course. In treated patients, plasma viremia was the marker that better correlated with the clinical course, and it did not appear during the first nine months of therapy. Zidovudine doses of >500 mg/day significantly lowered the appearance of antigenemia and lymphocytic viremia (p<0.05). 相似文献
12.
13.
14.
Human cataract lens proteins can be bleached by exposure to sodium borohydride (NaBH4), sodium cyanoborohydride (NaCNBH3), or hydrogen peroxide (H2O2). The decolouration resulting from these treatments could be monitored by a change in absorbance at 350 nm. At pH 12 the magnitude of the absorbance change increased in proportion with the severity of the nuclear cataract in the case of NaBH4 and H2O2 treatments, but not in the case of NaCNBH3 treatment. The rate of change in absorbance at 350 nm following exposure to the different reagents was used to evaluate three model systems for senile nuclear cataract. These model systems utilized calf lens proteins which had been tanned by exposure either to 3-hydroxyanthranilic acid, dopa/tyrosinase, or ultraviolet light. 相似文献
15.
Tushar M Ranchod Daynia E Ballot Alma M Martinez Barbara J Cory Victor A Davies J Colin Partridge 《Suid-Afrikaanse tydskrif vir geneeskunde》2004,94(11):913-916
BACKGROUND: Little is known about parental experience and decision making with regard to premature infants requiring intensive care in developing countries. We undertook this study to characterise parents' experience of physician counselling and their role in making life-support decisions for very low-birth-weight (VLBW) (birth weight < 1 501 g) infants born in South Africa's public-sector neonatal intensive care units (NICUs). METHODS: Parents of surviving VLBW infants treated in three Johannesburg-area public hospitals and attending follow-up clinics in August 2001 were interviewed regarding their experience of perinatal counselling on outcomes (pain, survival, disability), perception of actual and optimal decision making, and satisfaction with NICU communication. RESULTS: Parents of 51 infants were interviewed. Seventy-five per cent of parents reported antenatal counselling by physicians on at least one perinatal topic (severe disability, pain, death, finances or religious/moral considerations). The majority of parents (> 60%) who received counselling thought that these topics had been discussed adequately. Most parents reported that doctors had the primary decision-making role, either without consulting them (41%) or after consulting them (37%). Joint decision making was rare (14%). Parents wanted more input in life-support decisions than they reported being given. CONCLUSION: Counselling is not consistently provided in public-sector hospitals in Johannesburg. Parents of premature infants want a larger share in NICU decision making than they currently experience. Most parents were satisfied with communication later during their infant's hospitalisation. South Africa presents a unique opportunity to study the use of advanced medical technologies in a nation with marked disparities in access to care. 相似文献
16.
17.
James Edward Paul Elizabeth Ling Carlos Lalonde Lehana Thabane 《Journal canadien d'anesthésie》2007,54(10):799-810
PURPOSE: To determine if deliberate hypotension decreases blood loss and transfusion requirements in patients undergoing orthopedic surgery, a systematic review of all randomized trials addressing this issue was undertaken. METHODS: Electronic databases, citations lists and review articles were searched for potential articles. Relevant articles met the following inclusion criteria: English language, humans undergoing orthopedic surgery, deliberate hypotension used by any method, intraoperative blood loss measured as an outcome, and the trial methodology being randomized and controlled. Four outcomes were analyzed, including estimated blood loss, blood transfused, surgery duration, and quality of the surgical field. For all analyses, the random-effects model was used. RESULTS: Seventeen articles met the inclusion criteria. The surgeries studied included total hip arthroplasty (seven), orthognathic surgery (eight), total knee arthroplasty (one) and spinal fusion (one). A total of 636 patients were randomized across all studies. For blood loss, the overall weighted mean difference favoured treatment, with a savings of about 287 mL of blood [95% confidence interval (CI): -447, -127]. The mean differences also showed a statistically significant benefit for deliberate hypotension in reducing transfusion requirements (-667 mL of blood transfused; 95% CI: -963, -370). Deliberate hypotension was not shown to reduce the duration of surgery (-1.9 min of surgery; 95% CI: -7.2, 3.5) or improve surgical conditions (surgical field quality rating -0.5; 95% CI: -1.1, 0.2). CONCLUSION: This review provides some support for the use of deliberate hypotension in reducing blood loss and transfusion requirements in orthopedic surgery, but these results are tempered by the small sample sizes and poor methodological quality of published studies. 相似文献
18.
Carlos Cotrim Otília Sim?es M J Loureiro Pedro Cordeiro Rita Miranda Cecília Silva Teresa Avillez Manuel Carrageta 《Revista portuguesa de cardiologia》2006,25(5):529-533
We describe the case of a pregnant woman with idiopathic pulmonary arterial hypertension, a responder in right heart catheterization, followed since the first trimester in outpatient consultations, admitted to hospital at 23 weeks gestation. She was treated with inhaled iloprost until delivery (at 34 weeks gestation) and continuous infusion of iloprost throughout the perioperative period and following days. This line of therapy has proved efficacious in previous cases. The authors present echocardiographic images that document acute changes in ventricular synchrony during inhalation of iloprost. 相似文献
19.
Francisco J. Romero Juan Segura-Aguilar Elena Monsalve Carlos Hermenegildo Eberhard Nies Francisco J. Puertas Joaquí n Rom 《Neurotoxicology and teratology》1990,12(6):603-605
The present work tries to establish the antioxidant capacity of the peripheral nervous tissue of the rat, in terms of the enzymatic activities present in this tissue that either prevent the formation of activated species as the semiquinone radical (DT-diaphorase), protect against activated oxygen species (superoxide dismutase, glutathione peroxidase), conjugate natural toxic products or xenobiotics (glutathione S-transferases, especially the activity conjugating 4-hydroxy-nonenal), or complete the glutathione system metabolism (glutathione disulfide reductase, γ-glutamyl transpeptidase). All the activities studied are lower in this tissue than they are in liver, except for γ-glutamyl transpeptidase. The relevance of the results obtained and its possible relationship with different neuropathies is discussed. It is concluded that the peripheral nervous tissue is by far less protected than the liver against oxidative damage. 相似文献
20.
Tim Elliott Marc Bonneville Juan Carlos Zúiga-Pflücker Paul R. Walker David Essayan Nicolas Glaichenhaus Anna Vyakarnam Jean-Laurent Casanova Yang Liu Hugh Auchincloss Jr Gerry Waneck Christian LeGuern Cezmi Akdis Allison Green 《Current opinion in immunology》2002,14(6):673
A selection of interesting papers that were published in the two months before our press date in major journals most likely to report significant results in immunology. 相似文献