全文获取类型
收费全文 | 894篇 |
免费 | 94篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 68篇 |
妇产科学 | 10篇 |
基础医学 | 110篇 |
口腔科学 | 32篇 |
临床医学 | 89篇 |
内科学 | 174篇 |
皮肤病学 | 20篇 |
神经病学 | 44篇 |
特种医学 | 130篇 |
外科学 | 159篇 |
综合类 | 42篇 |
预防医学 | 30篇 |
眼科学 | 29篇 |
药学 | 20篇 |
肿瘤学 | 36篇 |
出版年
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 9篇 |
2018年 | 22篇 |
2017年 | 10篇 |
2016年 | 26篇 |
2015年 | 32篇 |
2014年 | 36篇 |
2013年 | 45篇 |
2012年 | 33篇 |
2011年 | 29篇 |
2010年 | 52篇 |
2009年 | 54篇 |
2008年 | 33篇 |
2007年 | 46篇 |
2006年 | 30篇 |
2005年 | 31篇 |
2004年 | 16篇 |
2003年 | 20篇 |
2002年 | 13篇 |
2001年 | 13篇 |
2000年 | 15篇 |
1999年 | 12篇 |
1998年 | 41篇 |
1997年 | 46篇 |
1996年 | 42篇 |
1995年 | 36篇 |
1994年 | 23篇 |
1993年 | 29篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 22篇 |
1988年 | 16篇 |
1987年 | 12篇 |
1986年 | 13篇 |
1985年 | 15篇 |
1984年 | 7篇 |
1983年 | 12篇 |
1982年 | 5篇 |
1981年 | 13篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 3篇 |
1963年 | 2篇 |
1937年 | 3篇 |
1936年 | 2篇 |
排序方式: 共有996条查询结果,搜索用时 15 毫秒
41.
Genotypic and phenotypic resistance patterns of human immunodeficiency virus type 1 variants with insertions or deletions in the reverse transcriptase (RT): multicenter study of patients treated with RT inhibitors 下载免费PDF全文
42.
Novero V; Camus M; Tournaye H; Smitz J; Verheyen G; Joris H; Derde MP; Van Steirteghem AC; Devroey P 《Human reproduction (Oxford, England)》1997,12(1):59-63
Serum follicle stimulating hormone (FSH) is routinely measured when
evaluating the infertile male for intracytoplasmic sperm injection (ICSI).
However, among the sperm parameters, only its relationship with sperm
concentration is well documented. Few investigations concern the
relationship between FSH and sperm motility and morphology, and the results
of ICSI. A retrospective study of 316 couples who underwent ICSI was
carried out to determine the relationships between serum FSH concentrations
in the male and (i) standard sperm parameters_(concentration, motility and
morphology) and (ii) fertilization, cleavage, pregnancy and implantation
rates after ICSI. There was an inverse correlation with sperm concentration
and total motility but no relationship was found with progressive motility
and sperm morphology. Neither was any relationship found between serum FSH
and fertilization, cleavage, pregnancy and implantation rates, and the
results of ICSI. These findings suggest the need to review the routine
measurement of serum FSH in the infertile male when ICSI is the planned
treatment procedure.
相似文献
43.
AC Winter K Berger JE Buring & T Kurth 《Cephalalgia : an international journal of headache》2009,29(2):269-278
We evaluated the association of body mass index (BMI) with migraine and migraine specifics in a cross-sectional study of 63 467 women aged ≥ 45 years, of whom 12 613 (19.9%) reported any history of migraine and 9195 had active migraine. Compared with women without migraine and a BMI < 23 kg/m2 , women with a BMI ≥ 35 kg/m2 had adjusted odds ratios (ORs) (95% confidence intervals) of 1.03 (0.95, 1.12) for any history of migraine. Findings were similar for active migraineurs. Women with a BMI of ≥ 35 kg/m2 had increased risk for low and high migraine frequency, with the highest estimate for women who reported daily migraine. Compared with women with the lowest associated risk (migraine frequency < 6 times/year; BMI between 27.0 and 29.9 kg/m2 ), women with a BMI ≥ 35 kg/m2 had an OR of daily migraine of 3.11 (1.12, 8.67). Among the women with active migraine, a BMI ≥ 35 kg/m2 was associated with increased risk of phonophobia and photophobia and decreased risk of a unilateral pain characteristic and migraine aura. Our data confirm previous findings that the association between BMI with migraine is limited to migraine frequency and specific migraine features. 相似文献
44.
Accurate pregnancy dating is vital to obstetric management. However, first trimester fetal charts commonly used in Australia rely on data reported more than three decades ago. This study reports first trimester dating and growth charts for crown‐rump length between 5 and 14 weeks of gestation and biparietal diameter between 9 and 14 weeks of gestation on an Australia population using modern real‐time ultrasound equipment. All consenting eligible women attending a large Sydney clinic for first trimester ultrasound between March 2005 and December 2006 were recruited. Measurements were carried out to Australasian Society for Ultrasound in Medicine standard protocols. Statistical analyses were undertaken using polynomial regression models and thorough diagnostic checks made. Overall 396 eligible women consented to the study, with 268 between 9 and 14 weeks of gestation. The average participant age was 34 years (range 22–45 years), 371 and all yielded valid biometry measurements. Equations, means and 90% reference intervals for crown‐rump length measurements and biparietal diameter measurements were derived using polynomial regression models. Thorough residual and diagnostic checks were made. Once validated by others, we believe they will warrant consideration for use by Australasian Society for Ultrasound in Medicine. 相似文献
45.
AM Boot J Nauta AC Hokken-Koelega HA Pols MA de Ridder SM de Muinck Keizer-Schrama 《Archives of disease in childhood》1995,72(6):502-506
A cross sectional study assessed the bone mineral density (BMD) of 20 young adult patients who received a renal transplantation in childhood. The BMD of the lumbar spine, mainly trabecular bone, and of the total body, mainly cortical bone, were measured and expressed as an SD score. Fourteen patients (70%) had a BMD SD score of the lumbar spine below -1, of whom six patients were below -2. Fifteen patients (75%) had a BMD SD score of the total body below -1, of whom seven patients were below -2, Both trabecular and cortical bone appeared to be involved in the osteopenic process. The cumulative dose of prednisone was inversely correlated to both lumbar spine and total body BMD SD score. In a multiple regression analysis the cumulative dose of prednisone appeared to be the only factor with a significant effect on BMD SD score. Most young adult patients who had received a renal transplantation in childhood had moderate to severe osteopenia. Corticosteroid treatment played a major part in the development of osteopenia in these patients. 相似文献
46.
The aim of this study is to review the literature regarding reduction pneumoplasty (RP) or lung volume reduction surgery in order to assess the state of the art of this topic. Reduction pneumoplasty is a palliative surgical therapy that is offered to selected patients with severe non-bullous emphysema not responding to maximized medical therapy. The use of staple excision or plication of the most destroyed target areas of the lung appeared to be more effective than laser ablation. Currently, a one-stage bilateral procedure is the standard of care although a unilateral reduction can be preferable in patients with asymmetric emphysema and/or if a staged bilateral treatment strategy is planned. Randomized studies have suggested that RP is superior to medical therapy including respiratory rehabilitation for improving subjective dyspnea, exercise capacity, respiratory function and quality of life for up to 1 year. In addition, few long-term studies have suggested that the improvements obtained with RP can be maintained for several years in properly selected patients. Although several issues still await a definitive answer, the available literature data and our current experience have clearly indicated that RP works well and is a safe and effective procedure for palliating symptoms and improving respiratory function in severely disabled emphysematous patients. 相似文献
47.
M Cole L Parker AW Craft S Bell G Dale AC McGill JA Seviour J Smith 《Archives of disease in childhood》1993,68(3):376-378
The relationship between homovanillic acid (HVA), vanillylmandelic acid (VMA), and creatinine in the urine of 6 month old babies has been studied and reference ranges in the form of centiles constructed for HVA and VMA against creatinine. Over 10,000 urine samples were collected from babies in four health districts in the north of England. HVA and VMA concentration, either independently or when divided by creatinine concentration, were dependent upon the absolute concentration of creatinine in the sample. After adjustment for creatinine significant differences in the mean concentration of HVA were found between sexes. No such differences were found for VMA. HVA and VMA were also found to be age dependent. Centiles were constructed using a procedure which makes no distributional assumptions about the data. The net effect of utilising these centiles was to increase the predictive value of a positive screening test from 20% to 40% without any increase in the false negative rate. 相似文献
48.
49.
Buccione R Baldassarre M Trapani V Catalano C Pompeo A Brancaccio A Giavazzi R Luini A Corda D 《European journal of cancer (Oxford, England : 1990)》2005,41(3):470-476
The naturally occurring phosphoinositide metabolite, glycerophosphoinositol 4-phosphate, has recently been shown to induce rearrangements in the actin cytoskeleton through modulation of the small GTPases, Rac and Rho. Since this is directly linked to cell spreading and remodelling, we have evaluated the potential role of glycerophosphoinositol 4-phosphate and related metabolites in tumour cell invasion. The biological effects of these compounds were tested in a number of cellular activities related to cell spreading, including cell migration and cell invasion. We find that unlike other inositol-containing molecules, such as the inositol phosphates, glycerophosphoinositol and glycerophosphoinositol 4-phosphate prevent the invasion of epithelium-derived MDA-MB-231 breast carcinoma and A375MM melanoma cell lines through the extracellular matrix; this is due to a decreased ability to degrade matrix components. These data identify a specific activity of the glycerophosphoinositols that can be exploited for their development as novel anti-invasive drugs. 相似文献
50.
GS Chopra PK Gupta AC Anand PP Varma V Nair Ramji Rai 《Medical Journal Armed Forces India》2005,61(3):234-237