全文获取类型
收费全文 | 565篇 |
免费 | 31篇 |
国内免费 | 15篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 17篇 |
妇产科学 | 11篇 |
基础医学 | 84篇 |
口腔科学 | 10篇 |
临床医学 | 44篇 |
内科学 | 140篇 |
皮肤病学 | 9篇 |
神经病学 | 19篇 |
特种医学 | 127篇 |
外科学 | 27篇 |
综合类 | 12篇 |
预防医学 | 75篇 |
眼科学 | 3篇 |
药学 | 23篇 |
中国医学 | 1篇 |
肿瘤学 | 8篇 |
出版年
2021年 | 3篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 9篇 |
2012年 | 11篇 |
2011年 | 22篇 |
2010年 | 10篇 |
2009年 | 18篇 |
2008年 | 14篇 |
2007年 | 10篇 |
2006年 | 14篇 |
2005年 | 9篇 |
2004年 | 10篇 |
2003年 | 6篇 |
2002年 | 4篇 |
2001年 | 12篇 |
2000年 | 12篇 |
1999年 | 12篇 |
1998年 | 20篇 |
1997年 | 28篇 |
1996年 | 28篇 |
1995年 | 13篇 |
1994年 | 19篇 |
1993年 | 12篇 |
1992年 | 13篇 |
1991年 | 8篇 |
1990年 | 11篇 |
1989年 | 20篇 |
1988年 | 23篇 |
1987年 | 23篇 |
1986年 | 19篇 |
1985年 | 24篇 |
1984年 | 19篇 |
1983年 | 22篇 |
1982年 | 23篇 |
1981年 | 18篇 |
1980年 | 13篇 |
1979年 | 7篇 |
1978年 | 12篇 |
1977年 | 11篇 |
1976年 | 11篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有611条查询结果,搜索用时 15 毫秒
11.
Dohle GR; Ramos L; Pieters MH; Braat DD; Weber RF 《Human reproduction (Oxford, England)》1998,13(3):620-623
Male genital tract obstructions may result from infections, previous
inguinal and scrotal surgery (vasectomy) and congenital bilateral absence
of the vas deferens (CBAVD). Microsurgery can sometimes be successful in
treating the obstruction. In other cases and in cases of failed surgical
intervention, the patient can be treated by microsurgical or percutaneous
epididymal sperm aspiration (MESA, PESA) or testicular sperm extraction
(TESE) and intracytoplasmic sperm injection (ICSI). We present the results
of 39 ICSI procedures for obstructive azoospermia in 24 couples. The
aetiology of the obstruction was failed microsurgery in 11 patients, CBAVD
in nine and genital infections in four. Sperm retrieval was accomplished
via MESA in four cases, PESA in 18 cases and via TESE in 11 cases. TESE was
only applied when PESA failed to produce enough spermatozoa for
simultaneous ICSI. In six patients, the ICSI procedure was performed with
cryopreserved spermatozoa after an initial PESA procedure. Fertilization
occurred in 47% of the metaphase II oocytes; embryo transfer was performed
in 92% of procedures and resulted in a clinical pregnancy in 13/39
procedures. Ongoing pregnancy was achieved in 10/39 procedures. One
pregnancy was terminated early after prenatal investigation showed a
cytogenetic abnormality (47,XX+18, Edwards syndrome). The other nine
pregnancies resulted in the live birth of 10 children, without any
congenital abnormalities. Epididymal and testicular retrieved spermatozoa
were successfully used for ICSI to treat obstructive azoospermia, and
resulted in an ongoing pregnancy in 10 of 24 couples (41.6%) after 39 ICSI
procedures, a success rate of 25.6% per treatment cycle and of 27.7% per
embryo transfer.
相似文献
12.
13.
J Thomas W B Neser B Knuckles K Semenya D J Thomas R F Gillum 《Journal of the National Medical Association》1988,80(11):1185-1188
As part of a longitudinal study of precursors for hypertension and atherosclerosis in a cohort of 315 black physicians, the predictive values of cold pressor reactivity were assessed. At initial evaluation, cold pressor tests were performed on all members of the cohort. At the 23- to 30- year follow-up, the participants were again examined and tho cumulative incidence of hypertension was analyzed by the Kaplan-Meier curves in relationship to cold pressor reactivity. The relationship between follow-up hypertension status and baseline cold pressor reactivity was also examined in a logistic regression analysis in which other potential confounders were controlled. 相似文献
14.
L1 knockout mice show dilated ventricles, vermis hypoplasia and impaired exploration patterns 总被引:8,自引:3,他引:8
Fransen E; D'Hooge R; Van Camp G; Verhoye M; Sijbers J; Reyniers E; Soriano P; Kamiguchi H; Willemsen R; Koekkoek SK; De Zeeuw CI; De Deyn PP; Van der Linden A; Lemmon V; Kooy RF; Willems PJ 《Human molecular genetics》1998,7(6):999-1009
L1 is a neural cell adhesion molecule mainly involved in axon guidance and
neuronal migration during brain development. Mutations in the human L1 gene
give rise to a complex clinical picture, with mental retardation,
neurologic abnormalities and a variable degree of hydrocephalus. Recently,
a transgenic mouse model with a targeted null mutation in the L1 gene was
generated. These knockout (KO) mice show hypoplasia of the corticospinal
tract. Here we have performed further studies of these KO mice including
magnetic resonance imaging of the brain, neuropathological analysis and
behavioral testing. The ventricular system was shown to be abnormal with
dilatation of the lateral ventricles and the 4th ventricle, and an altered
shape of the Sylvius aqueduct. Additionally, the cerebellar vermis of the
KO mice is hypoplastic. Their exploratory behavior is characterized by
stereotype peripheral circling reminiscent of that of rodents with induced
cerebellar lesions.
相似文献
15.
Consumption of 'low-yield' cigarettes: its frequency and relationship to serum thiocyanate. 下载免费PDF全文
A R Folsom T F Pechacek R de Gaudemaris R V Luepker D R Jacobs Jr R F Gillum 《American journal of public health》1984,74(6):564-568
To determine the use and possible health risks of low-yield cigarettes, we ascertained the cigarette brands and serum thiocyanate (SCN) levels of 2,561 adult smokers (age 25-74) in population-based samples of seven upper Midwestern communities during 1980-82. Brands were coded according to December 1981 Federal Trade Commission (FTC) ratings for "tar", nicotine, and carbon monoxide (CO). Compared to 1980 data from the National Center for Health Statistics for the United States as a whole, a greater proportion of smokers in these communities smoked low-yield brands. More people with higher education than lesser and more women than men smoked low-yield cigarettes. Greater proportions of older people (65-75 years) than younger people (less than 65 years) smoked cigarettes in the highest and lowest brand yield categories. SCN, adjusted for number of cigarettes smoked and for sex, was only weakly associated with brand ratings for "tar" (r = +.12), nicotine (R = +.11), and CO (r = +.15). Furthermore, the gradient in SCN between lowest and highest quintiles of brand strength was less than 16 per cent--much lower than the 300-500 per cent gradient in smoke components implied by FTC ratings. These data add to the evidence that smoking low-yield cigarettes may not be significantly less hazardous than smoking high-yield brands. 相似文献
16.
目的: 研究1,25-二羟维生素D3 对结肠癌细胞系Caco-2 细胞中报告基因表达的作用,并探讨在报告载体pGL2 序列中存在潜在的抑制性维生素D应答元件(VDRE)的可能性。方法: 采用磷酸钙沉淀法将报告载体转染入Caco-2 细胞。Caco-2细胞经不同浓度1,25-二羟维生素D3 处理后测定细胞裂解液中表达的荧光素酶活性。结果: 应用pGL2 报告载体时,当用pSG5-VDR表达载体共转染后,1,25-二羟维生素D3显著地抑制Caco-2 细胞荧光素酶的表达(P< 0.05);而未使用该表达载体共转染则无抑制作用(P> 0.05)。应用pGL3 报告载体时,不同浓度的1,25-二羟维生素D3 对pLG3转染后Caco-2 细胞表达的荧光素酶活性均无显著抑制作用(P> 0.05),该作用不依赖是否存在有pSG5-VDR表达载体共转染。结论:1,25-二羟维生素D3 对报告载体PGL2 荧光素酶表达具有抑制作用,而对pGL3 则否;类似人类PTH基因中的潜在抑制性VDRE存在于报告载体pGL2,在pGL3 中该VDRE业已改变。 相似文献
17.
18.
Richard F. Gillum William B. Stason Milton C. Weinstein 《Journal of community health》1978,4(1):67-72
A strategy for the control of hypertension in communities is presented as a staged program. Stage I consists of the evaluation and improvement of hypertension management in health care facilities. State II entails case-finding in health care facilities. Finally, Stage III involves targeted screening in the community. While isolated screening programs have been justly labeled irrational, such a sequential strategy represents a highly rational approach to the community control of hypertension.Dr. Gillum is with the Laboratory of Physiological Hygiene, University of Minnesota School of Public Health, Minneapolis, Minnesota 55455. Dr. Stason is with the Center for the Analysis of Health Practices, Harvard School of Public Health, Boston, Massachusetts 02115. Dr. Weinstein is with the John F. Kennedy School of Government, Harvard University, Cambridge, Massachusetts 02138. This work was supported in part by grant F32HL5018 from the National Institutes of Health. The Hypertension Screening Group of the 1974–75 Harvard School of Public Health Faculty Seminar on the Analysis of Health and Medical Practices provided an ongoing forum for the development of this work. 相似文献
19.
RF Lamont 《BJOG : an international journal of obstetrics and gynaecology》2006,113(S3):96-99
Over the past 15 years, the use of β-agonists has declined worldwide. Following the Royal College of Obstetricians and Gynaecologists guidelines in 2002, clinicians in the UK and beyond were faced with the dilemma of continuing to use β-agonists, desist from using tocolytic therapy completely or choosing to change to atosiban or calcium channel blockers (CCBs). While grade A level 1 evidence exists to show that atosiban is significantly more efficacious than placebo and significantly safer than β-agonists for the treatment of spontaneous preterm labour, the evidence for CCBs, such as nifedipine, is much less robust and no placebo-controlled trials have been performed. Published studies on nifedipine are largely investigator-led studies of small sample size, which lack sufficient power. As a result, most of the evidence has been based on meta-analyses of these studies, which look retrospectively at pooled data and are only as good as the quality of the studies included. In light of this, a tool was developed to produce a systematic review of studies on tocolytic effectiveness, which can and should be applied to all tocolytics and which considered both method- and topic-specific markers of quality. In the process of applying this tool to nifedipine, an extensive literature search identified 31 studies for a systematic review of the quality of nifedipine studies assessed by eight paired reviewers with wide experience in the subject of spontaneous preterm labour and preterm birth. Forty topic- and method-specific items of quality were assessed. The paucity of good quality studies of nifedipine used for the treatment of spontaneous preterm labour should be highlighted in meta-analyses or systematic reviews, which measure efficacy and should limit and influence the degree to which recommendations and guidelines are made on the basis of such studies. 相似文献
20.
Shalu Gillum 《Journal of consumer health on the Internet》2017,21(4):417-429
Many library-subscribed clinical databases contain educational materials for physicians and librarians to share with patients. These materials are typically written in layperson language meant to be understood by the average, nonclinician person. However, the materials found in these online databases vary widely, and some are better than others. This article uses the Patient Education Materials Assessment Tool (PEMAT) to evaluate the patient education content of several popular clinical databases, including Access Medicine, Clinical Key, DynaMed Plus, Epocrates, and UpToDate. These databases are also evaluated on other, more basic criteria, including findability, content, printing to PDF, customizability, and available languages. 相似文献