全文获取类型
收费全文 | 6918篇 |
免费 | 470篇 |
国内免费 | 62篇 |
专业分类
耳鼻咽喉 | 43篇 |
儿科学 | 161篇 |
妇产科学 | 140篇 |
基础医学 | 1141篇 |
口腔科学 | 123篇 |
临床医学 | 563篇 |
内科学 | 1897篇 |
皮肤病学 | 187篇 |
神经病学 | 636篇 |
特种医学 | 95篇 |
外科学 | 620篇 |
综合类 | 31篇 |
一般理论 | 3篇 |
预防医学 | 520篇 |
眼科学 | 150篇 |
药学 | 649篇 |
中国医学 | 21篇 |
肿瘤学 | 470篇 |
出版年
2024年 | 10篇 |
2023年 | 109篇 |
2022年 | 272篇 |
2021年 | 421篇 |
2020年 | 199篇 |
2019年 | 285篇 |
2018年 | 306篇 |
2017年 | 206篇 |
2016年 | 234篇 |
2015年 | 250篇 |
2014年 | 340篇 |
2013年 | 391篇 |
2012年 | 564篇 |
2011年 | 598篇 |
2010年 | 298篇 |
2009年 | 260篇 |
2008年 | 431篇 |
2007年 | 414篇 |
2006年 | 368篇 |
2005年 | 356篇 |
2004年 | 275篇 |
2003年 | 260篇 |
2002年 | 237篇 |
2001年 | 38篇 |
2000年 | 43篇 |
1999年 | 67篇 |
1998年 | 36篇 |
1997年 | 31篇 |
1996年 | 18篇 |
1995年 | 12篇 |
1994年 | 3篇 |
1993年 | 9篇 |
1992年 | 16篇 |
1991年 | 14篇 |
1990年 | 12篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1898年 | 2篇 |
排序方式: 共有7450条查询结果,搜索用时 15 毫秒
991.
992.
Christos Skevas Toam Katz Lars Wagenfeld Gisbert Richard Stephan Linke 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2013,251(4):1175-1183
Introduction
Laser in situ keratomileusis (LASIK) is superior to surface ablation techniques (SAT) such as alcohol photorefractive keratectomy (APRK) or Epi-LASIK (EpiK) in terms of visual recovery and postoperative pain. This study compares subjective symptoms and visual recovery of two different SATs with LASIK.Materials and Methods
One hundred and twenty seven patients were operated using one of the three techniques. Patients filled out a questionnaire describing symptoms assessing subjective visual recovery on a linear scale from ‘not functioning’ to ‘full visual function’ and pain on a linear scale from ‘no pain’ to ‘severe daily pain’. Subjective symptoms such as halos, double vision, low night vision, reduced contrast and dry eyes were also evaluated.Results
Visual recovery was faster and discomfort symptoms less pronounced with the LASIK than with surface ablation procedures. More pain was reported after APRK than after EpiK (flap-off technique) in the early postoperative period, with a maximum of pain on postoperative days 3–4. Subjective visual recovery showed no statistically significant difference between the two surface ablation procedures. Halos, double vision, low night vision, reduced contrast and dry eyes were more extensively reported by the EpiK than the APRK group and were less pronounced in the LASIK than in the SAT group.Discussion and conclusions
Our study does not uniformly support the previously published favourable results of EpiK compared to APRK with regard to subjective recovery of vision and postoperative pain. 相似文献993.
Lars Wagenfeld Friederike von Domarus Sonja Weiss Maren Klemm Gisbert Richard Oliver Zeitz 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2013,251(10):2339-2344
Background
Reactive oxygen species (ROS) play an important role in the pathogenesis of various ocular diseases. ROS can induce vasodilation or vasoconstriction depending on the species, the tested vessel bed, and the condition of the vessel. This study investigates the effect of different dosages of ROS on the tone of rat ophthalmic arteries.Methods
Freshly dissected rat ophthalmic arteries were pressurized in a perfusion setup in steps of 10 mmHg to 180 mmHg in three consecutive cycles. The first cycle was run under mostly physiological conditions, the second cycle was run after ROS treatment, and the third cycle as passive dilation after all Ca2+ was removed from the solution. ROS-induced dilation or constriction was calculated in relation to the passive dilation. All experiments were performed with or without endothelium.Results
For vessels with endothelium, dilation in control experiments was 20.0?±?0.1 %; after 5 s of ROS dilation was 74.4?±?0.6 %, and after 20 s 87.4?±?0.3 %. ANOVA revealed significant differences between these groups (P?=?0.048). For vessels without endothelium, a slight dilation was seen in control experiments (14.5?±?0.4 %), which was also present after 5 s of ROS treatment (15.4?±?0.4 %). Treatment with ROS for 20 s led to a constriction of the vessel preparations (?16.6?±?0.5 %; P?=?0.831).Conclusions
ROS led to a vasodilation in vessels with endothelium that was not seen in vessels without endothelium. Endothelial function seems to determine the effect of ROS on the vessel tone in isolated rat ophthalmic arteries. 相似文献994.
Shtereva N 《Rejuvenation research》2006,9(2):355-357
Oral health is more than healthy teeth. Oral diseases and disorders can affect general health, well-being, and quality of life. The goal of this investigation was to establish oral health related to quality of life of geriatric patients. The study was made for a period of 12 months in a private dental office in Sofia, Bulgaria. It included 53 geriatric patients (36 women and 17 men). The women's average age was 69.5 years old (65 to 87), and men's average age was 70.5 years old (65 to 84). A special questionnaire was made and patients were asked about specific dental problems related to quality of life. Of the respondents, 69.8% were women and only 30.2% were men, which means that women are more likely to visit dental health care offices. Of geriatric patients, 31.5% visit the dental office because of acute pain and 68.4% because of caries. The following are the specific items used to assess geriatric oral health and quality of life: trouble biting or chewing (eating), uncomfortable eating in front of other people, trouble speaking, and limitation of social contacts. Oral health can be an indicator of general health and quality of life in geriatric patients. Oral diseases are progressive and cumulative. They become more complex over time. Improved oral health will allow geriatric patients to improve their self-confidence, have active social contacts, and restore the ability to work at home or on the job. 相似文献
995.
Negrotto S Pacienza N D'Atri LP Pozner RG Malaver E Torres O Lazzari MA Gómez RM Schattner M 《Experimental hematology》2006,34(10):1420-1428
OBJECTIVE: Although cAMP is involved in a number of physiologic functions, its role in hematopoietic cell fate decision remains poorly understood. We have recently demonstrated that in CD34(+)-derived megakaryocytes, cAMP-related agents prevent apoptosis. In this study we addressed the question of whether cAMP also regulates survival of their precursors, CD34(+) cells. METHODS: Apoptosis was evaluated by fluorescence microscopy, and detection of hypodiploid or annexin V(+) cells by flow cytometry. Mitochondrial membrane potential and bcl-xL or caspase-3 expression were assessed by flow cytometry. Colony-forming units were studied by clonogenic assays in methylcellulose. RESULTS: We found that two different cAMP analogs such as Dibutiril-cAMP and sp-5,6-DCl-BIMPS (BIMPS) promoted survival of human umbilical cord-derived CD34(+) cells by suppressing apoptosis induced by either nitric oxide (NO) or serum deprivation. Involvement of PKA and PI3K pathway was demonstrated by the ability of their specific inhibitors Rp-cAMP and Wortmannin or LY294002 respectively to reverse the antiapoptotic effect of BIMPS. Treatment of CD34(+) cell with BIMPS not only restrained the bcl-xL downregulation but also suppressed the loss of mitochondrial membrane potential and caspase-3 activation induced by serum starvation. While thrombopoietin (TPO), granulocyte colony-stimulating factor (G-CSF) or stem cell factor (SCF) were not able to increase cAMP levels, the antiapoptotic activity exerted by these growth factors was blocked by inhibition of the adenylate cyclase and synergized by BIMPS. Cyclic AMP analogs suppressed the decreased colony formation in cells exposed to NO or serum deprivation. CONCLUSION: Altogether, our results strongly suggest that cAMP appears to be not only a key pathway controlling CD34(+) survival, but also a mediator of the TPO-, G-CSF- and SCF-mediated cytoprotection. 相似文献
996.
Cheung AM Tansey CM Tomlinson G Diaz-Granados N Matté A Barr A Mehta S Mazer CD Guest CB Stewart TE Al-Saidi F Cooper AB Cook D Slutsky AS Herridge MS 《American journal of respiratory and critical care medicine》2006,174(5):538-544
RATIONALE: Little is known about the long-term outcomes and costs of survivors of acute respiratory distress syndrome (ARDS). OBJECTIVES: To describe functional and quality of life outcomes, health care use, and costs of survivors of ARDS 2 yr after intensive care unit (ICU) discharge. METHODS: We recruited a cohort of ARDS survivors from four academic tertiary care ICUs in Toronto, Canada, and prospectively monitored them from ICU admission to 2 yr after ICU discharge. MEASUREMENTS: Clinical and functional outcomes, health care use, and direct medical costs. RESULTS: Eighty-five percent of patients with ARDS discharged from the ICU survived to 2 yr; overall 2-yr mortality was 49%. At 2 yr, survivors continued to have exercise limitation although 65% had returned to work. There was no statistically significant improvement in health-related quality of life as measured by Short-Form General Health Survey between 1 and 2 yr, although there was a trend toward better physical role at 2 yr (p = 0.0586). Apart from emotional role and mental health, all other domains remained below that of the normal population. From ICU admission to 2 yr after ICU discharge, the largest portion of health care costs for a survivor of ARDS was the initial hospital stay, with ICU costs accounting for 76% of these costs. After the initial hospital stay, health care costs were related to hospital readmissions and inpatient rehabilitation. CONCLUSIONS: Survivors of ARDS continued to have functional impairment and compromised health-related quality of life 2 yr after discharge from the ICU. Health care use and costs after the initial hospitalization were driven by hospital readmissions and inpatient rehabilitation. 相似文献
997.
Metra M Zani C Covolo L Nodari S Pezzali N Gelatti U Donato F Nardi G Dei Cas L 《European journal of heart failure》2006,8(2):131-135
BACKGROUND: Adrenergic activation has a central role in the development of HF. The function of the beta1- and the alpha2C-adrenergic receptors is influenced by gene polymorphisms: the beta1Arg389 variant is associated with increased beta1-receptor sensitivity and the alpha2C-receptor Del322-325 variant is associated with decreased alpha2C receptor function and increased norepinephrine release. We hypothesised that these polymorphisms could influence the prevalence of heart failure. METHODS: The role of the beta1- and alpha2C-adrenergic receptor gene polymorphisms as risk factors for heart failure (HF) was assessed in an Italian white Caucasian population using a case-control study design. Genomic DNA was analysed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RLFP). RESULTS: We compared 260 Caucasian patients with HF and 230 normal subjects. The beta1Arg389 allele was frequent both in the patients with HF (69%) and in the normal subjects (73%). The alpha2CDel322-325 variant was rare in both groups (9% and 8%, respectively). Patients homozygotes for either the beta1Arg389 or the alpha(2C)Del322-325 alleles had no increased risk of HF (odds ratio [OR], 0.8; 95%CI: 0.5-1.2 and OR, 0.8; 95% CI: 0.4-1.8, respectively). Patients homozygotes for both the beta1Arg389 and the alpha(2C)Del322-325 alleles had no increased risk of HF as well (OR: 0.6; 95% CI: 0.2-2.1). CONCLUSIONS: Beta1-ARs and alpha2C-ARs polymorphisms are not associated with an increased risk of HF in an Italian white Caucasian population. 相似文献
998.
Platt L Bobrova N Rhodes T Uusküla A Parry JV Rüütel K Talu A Abel K Rajaleid K Judd A 《AIDS (London, England)》2006,20(16):2120-2123
We found a high prevalence of HIV among injecting drug users (IDU) 54% in Tallinn and 90% in Kohtla Jarve, Estonia. Risk factors for HIV in Tallinn included use of the drug 'china white', being registered as an IDU at a drug treatment clinic, and sharing injecting equipment with sex partners. Differences existed in risk behaviour between the cities. An urgent scale-up of HIV prevention is needed. It is also important to explore how local 'risk environments' mediate the risk of HIV transmission. 相似文献
999.
1000.
Bobrova N Alcorn R Rhodes T Rughnikov I Neifeld E Power R 《Journal of substance abuse treatment》2007,33(4):373-378
This study explored injection drug users' (IDUs) perceptions of drug abuse treatment and treatment providers in three Russian cities as well as their attitudes toward opiate substitution therapy, which is currently not available in Russia. Data were collected from 121 qualitative interviews with IDUs conducted in 2003–2004. Negative perceptions of available treatments were related to poor treatment outcomes, judgmental service providers, lack of psychologic services, and short lengths of stay in treatment. Positive perceptions were associated with receiving psychosocial care and nonjudgmental attitudes from providers. Most participants had heard about opiate substitution therapy, and some had treated themselves using methadone from the black market. Although respondents had doubts that opiate substitution therapy could work effectively in Russia, most agreed that this type of treatment would help IDUs function better in the society. 相似文献