全文获取类型
收费全文 | 663篇 |
免费 | 78篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 66篇 |
妇产科学 | 6篇 |
基础医学 | 94篇 |
口腔科学 | 30篇 |
临床医学 | 71篇 |
内科学 | 137篇 |
皮肤病学 | 19篇 |
神经病学 | 23篇 |
特种医学 | 128篇 |
外科学 | 40篇 |
综合类 | 42篇 |
预防医学 | 24篇 |
眼科学 | 29篇 |
药学 | 12篇 |
肿瘤学 | 25篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 19篇 |
2017年 | 7篇 |
2016年 | 21篇 |
2015年 | 22篇 |
2014年 | 26篇 |
2013年 | 40篇 |
2012年 | 19篇 |
2011年 | 12篇 |
2010年 | 42篇 |
2009年 | 44篇 |
2008年 | 15篇 |
2007年 | 26篇 |
2006年 | 12篇 |
2005年 | 17篇 |
2004年 | 7篇 |
2003年 | 11篇 |
2002年 | 5篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 40篇 |
1997年 | 42篇 |
1996年 | 42篇 |
1995年 | 36篇 |
1994年 | 22篇 |
1993年 | 28篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 18篇 |
1988年 | 15篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 12篇 |
1982年 | 5篇 |
1981年 | 13篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 2篇 |
1884年 | 1篇 |
排序方式: 共有749条查询结果,搜索用时 15 毫秒
41.
NJ Hoogenraad JD Mitchell NA Don TM Sutherland AC Mc Leay 《Archives of disease in childhood》1980,55(4):292-295
The activity of urea cycle enzymes was assayed in duodenal biopsy specimens obtained from a female infant who presented with neonatal hyperammonaemia. All enzyme levels were normal except N-acetyl glutamate-dependent carbamyl phosphate synthetase 1 (CPS1) which was half the mean activity in normal control specimens. A similar deficiency of CPS1 was also shown in duodenal specimens from the patient's mother who became slightly symptomatic after relatively high protein meals and during pregnancy, and had spontaneously modified her diet to one with protein restriction. The patient is growing normally on a dietary regimen similar to that spontaneously adopted by her mother. Urea cycle enzyme activity in the duodenal biopsy material from the controls was similar to that found in the normal human liver and appears to have distinct advantages as a means of assaying for urea cycle defects in patients with hyperammonaemia and their relatives. 相似文献
42.
Viability of partially damaged human embryos after cryopreservation 总被引:10,自引:13,他引:10
Van den Abbeel E; Camus M; Van Waesberghe L; Devroey P; Van Steirteghem AC 《Human reproduction (Oxford, England)》1997,12(9):2006-2010
In our centre, embryos are judged to have survived cryopreservation if at
least half of the initial number of blastomeres remain intact. Therefore
both fully intact and partially damaged embryos are transferred. The aim of
this study was to investigate the viability of partially damaged human
embryos after cryopreservation. We retrospectively analysed the
implantation and in-vivo development of embryos which were either fully
intact or had lost some blastomeres after cryopreservation. Oocytes were
collected following stimulation with the gonadotrophin-releasing hormone
(GnRH)-agonist Buserelin and human menopausal gonadotrophin. Supernumerary
multicellular embryos with not more than 20% of their volume filled with
anucleate fragments were frozen on day 2 or day 3 of the cycle using a slow
cooling procedure with dimethylsulphoxide as the cryoprotectant. Following
slow thawing, 431 fully intact embryos were transferred in 314 embryo
transfer procedures and 488 partially damaged embryos were transferred in
327 such procedures. The percentage of gestational sacs with fetal
heartbeat obtained after transfer of fully intact embryos was almost three
times higher than that after transfer of partially damaged embryos (11.4
versus 3.5%). Forty-five children (birth rate 10% per embryo transfer) were
born after transfer of fully intact embryos and 14 after transfer of
embryos from which some blastomeres had been lost following
cryopreservation. In conclusion, although children have been delivered
after transfer of partially damaged embryos, the aim of a cryopreservation
programme must be to obtain fully intact embryos after thawing.
相似文献
43.
Gill ten Hoor Christian JPA Hoebe Jan EAM van Bergen Elfi EHG Brouwers Robert AC Ruiter Gerjo Kok 《Journal of medical Internet research》2014,16(1)
Background
In the Netherlands, screening for chlamydia (the most prevalent sexually transmitted infection worldwide) is a relatively simple and free procedure. Via an invitation letter sent by the public health services (PHS), people are asked to visit a website to request a test kit. They can then do a chlamydia test at home, send it anonymously to a laboratory, and, within two weeks, they can review their test results online and be treated by their general practitioner or the PHS. Unfortunately, the participation rates are low and the process is believed to be not (cost-) effective.Objective
The objective of this study was to assess whether the low participation rate of screening for chlamydia at home, via an invitation letter asking to visit a website and request a test kit, could be improved by optimizing the invitation letter through systematically applied behavior change theories and evidence.Methods
The original letter and a revised letter were randomly sent out to 13,551 citizens, 16 to 29 years old, in a Dutch municipality. Using behavior change theories, the revised letter sought to increase motivation to conduct chlamydia screening tests. The revised letter was tailored to beliefs that were found in earlier studies: risk perception, advantages and disadvantages (attitude), moral norm, social influence, and response- and self-efficacy. Revisions to the new letter also sought to avoid possible unwanted resistance caused when people feel pressured, and included prompts to trigger the desired behavior.Results
No significant differences in test package requests were found between the two letters. There were also no differences between the original and revised letters in the rates of returned tests (11.80%, 581/4922 vs 11.07%, 549/4961) or positive test results (4.8%, 23/484 vs 4.1%, 19/460). It is evident that the new letter did not improve participation compared to the original letter.Conclusions
It is clear that the approach of inviting the target population through a letter does not lead to higher participation rates for chlamydia screening. Other approaches have to be developed and pilot tested. 相似文献44.
目的探讨高脂血症性急性胰腺炎(HAP)和非高脂血症性急性胰腺炎的特点及临床救治效果。方法回顾分析我院在2013年1月至2013年12月收治的99例急性胰腺炎的临床资料,根据患者有无高脂血症将其分为HAP组(高脂血症患者)和对照组(无高脂血症的AP患者);患者均接受标准化临床治疗,比较2组患者病情、血浆生化指标、治疗转归、住院时间与费用、复发等情况。结果 HAP组重度胰腺炎比例(13.6%)明显高于对照组(7.8%),HAP组血糖和尿酸均显著高于对照组,其中HAP组血糖平均值达到对照组的171%,而HAP组的血淀粉酶却仅为对照组的44.5%;HAP组1年内的复发率(13.6%)显著高对于照组(2.6%),P0.01差异有统计学意义。结论高血脂对急性胰腺炎的病情、表现和治疗结果均有明显影响,应引起高度重视。 相似文献
45.
由于治疗方法的进步,近80%的儿童和青少年癌症患者能够长期生存。在美国,约有270000例儿童癌症的幸存者,即每640名20至39岁成年人中就有一名幸存者。大量的幸存者有利于儿童癌症治疗后长期健康结果的研究。现在可以明确的是,化疗和放疗所致的儿童各器官系统损害在临床上可能潜伏多年。为了全面了解治疗儿童癌症而继发的健康问题,重要的是衡量三项长期结果:健康状况、死亡率和患病率。这三项中,关于前两项已有相当好的研究报道。在一项对20227例癌症5年生存者的回顾性分析中,Mertens等发现以下原因导致的超额死亡率具有统计学意义:继发癌症(… 相似文献
46.
47.
48.
49.
50.
Obesity in children may cause overt clinical disease in childhood. The complex endocrine and metabolic changes of obesity and insulin resistance in adolescents result in hyperinsulinemia, dyslipidemia, hypertension, steatohepatitis, glucose intolerance, type 2 diabetes, acanthosis nigricans and ovarian hyperandrogenemia, commonly known as polycystic ovarian syndrome (PCOS). Type 2 diabetes and PCOS in adolescents are new endocrine diseases in this age group that require unique approaches to diagnosis and treatment. The direct correlation between duration of disease and control of the disease, and subsequent long term complications of these two diseases, predict serious morbidity in young adult life for the affected adolescents. Pediatricians have an important role in the prevention, diagnosis and treatment of obesity, insulin resistance syndrome, type 2 diabetes and PCOS. 相似文献