全文获取类型
收费全文 | 398篇 |
免费 | 52篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 36篇 |
妇产科学 | 1篇 |
基础医学 | 23篇 |
口腔科学 | 9篇 |
临床医学 | 39篇 |
内科学 | 65篇 |
皮肤病学 | 9篇 |
神经病学 | 8篇 |
特种医学 | 120篇 |
外科学 | 28篇 |
综合类 | 29篇 |
预防医学 | 15篇 |
眼科学 | 31篇 |
药学 | 32篇 |
肿瘤学 | 26篇 |
出版年
2019年 | 2篇 |
2018年 | 5篇 |
2016年 | 2篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 10篇 |
2012年 | 2篇 |
2011年 | 5篇 |
2010年 | 9篇 |
2009年 | 12篇 |
2008年 | 10篇 |
2007年 | 21篇 |
2006年 | 26篇 |
2005年 | 4篇 |
2004年 | 10篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 17篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 34篇 |
1997年 | 21篇 |
1996年 | 27篇 |
1995年 | 25篇 |
1994年 | 22篇 |
1993年 | 23篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 12篇 |
1985年 | 12篇 |
1984年 | 11篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 14篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1972年 | 3篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1964年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有472条查询结果,搜索用时 31 毫秒
41.
42.
Eight patients with the diagnosis of lymphangiomyomatosis were evaluated with computed tomography (CT), chest radiography, and pulmonary function tests to determine the relationship between the extent of disease seen on imaging studies and functional status. Chest radiographic assessment included the subjective determination of disease extent and measurements of lung length and the arc of the right hemidiaphragm. Disease extent on CT scans was scored as a percentage of lung that was abnormal on the basis of visual assessment of the degree of cystic replacement of the lung parenchyma. Significant correlations were observed between CT scores and percentages of predicted forced expiratory volume in 1 second/forced vital capacity (r = -.92, P less than .002) and diffusing capacity of the lungs for carbon monoxide (r = -.80, P less than .017). No significant correlations were observed between subjective chest radiographic scores and pulmonary function tests, although measurements of lung length and percentage of predicted total lung capacity were correlated (r = .76, P less than .045). CT was more accurate than chest radiography in defining the presence and extent of parenchymal cysts and provided for greater morphologic-physiologic correlation. CT, particularly high-resolution CT, may be useful in the diagnosis and longitudinal evaluation of patients with this disease and may be more sensitive than pulmonary function tests in the early stages of lung damage. 相似文献
43.
44.
F Moureau J Wouters DP Vercauteren S Collin G Evrard F Durant F Ducrey JJ Koenig FX Jarreau 《European journal of medicinal chemistry》1992,27(9)
Toloxatone is a reversible MAOA-inhibitor, marketed as antidepressant (Humoryl®), with an original chemical structure. It differs from first generation irreversible MAOIs, known to induce covalent bonds with the enzyme active site. In order to understand the mechanism of the reversible inactivation of the MAO, as a first step, a detailed structural and electronic analysis was undertaken. An X-ray diffraction-crystallographic study showed that toloxatone is a planar molecule and brought to light hydrogen bonds and π-π interactions. MO calculations confirmed the planar structure as energetically favoured. Electronic analysis demonstrated a delocalization of both ring systems. The combined results give evidence for the potential of toloxatone to participate in reversible, long distance interactions with an appropriate partner. 相似文献
45.
46.
Racial/Ethnic differences in smoking, drinking, and illicit drug use among American high school seniors, 1976-89. 总被引:12,自引:11,他引:1
下载免费PDF全文
![点击此处可从《American journal of public health》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J G Bachman J M Wallace Jr P M O''Malley L D Johnston C L Kurth H W Neighbors 《American journal of public health》1991,81(3):372-377
BACKGROUND. This paper reports racial/ethnic differences in the use of licit and illicit drugs by high school seniors in the United States. METHODS. The study uses questionnaire data from annual, nationally representative surveys of seniors from 1976 through 1989. Combined sample sizes were 57,620 for 1976-79; 75,772 for 1980-84; and 73,527 for 1985-89. RESULTS. Native American had the highest prevalence rates for cigarettes, alcohol, and most illicit drugs; White students had the next highest rates for most drugs. Asian Americans had the lowest prevalence rates, and Black students had levels nearly as low except for marijuana. Prevalence rates for the Hispanic groups were mostly in the intermediate ranges except for relatively high cocaine use among the males. Trend patterns for most forms of drug use were similar across subgroups, although cigarette use declined more sharply for Black than White seniors, resulting in greater Black-White differences in recent years. CONCLUSIONS. This study, other school-based studies, and general population surveys all show relatively low levels of drug use by most non-White youth, especially Black Americans and Asian Americans. Multivariate analyses indicate that such subgroup differences in high school seniors' drug use are not primarily attributable to family composition, parents' education, region, or urban-rural distinctions. 相似文献
47.
JKS Parihar SM DP Vats SM VSM RP Gupta TR Bera R Phooken A Singh 《Medical Journal Armed Forces India》2007,63(1):19-22
Background
Phaconit or ultra micro incision phacoemulsification cataract surgery involves phacoemulsification through a 0.9 millimetre sleeveless phaco tip and irrigating chopper followed by implantation of a rollable intraocular lens. The procedure leads to negligible astigmatism and faster visual recovery as compared to phacoemulsification with a foldable intraocular lens.Methods
This prospective study analysed 80 cases of sub millimetre phaconit surgery with implantation of rollable intraocular lenses(IOL) in 40 cases and acrylic foldable IOL in the remaining 40 cases. Evaluation of efficacy and adaptability of procedure, equipment settings, operative constraints, postoperative complications, keratometric and topographic evaluation of induced astigmatism with visual outcome and patient''s rehabilitation were studied.Results
The intraoperative complications were surge/ chamber collapse in 16 (20%), iris chaffing in one and corneal burns in two cases. All cases had an induced astigmatism of less than or equal to ± 0.25 D in four to six weeks after rollable IOL and ± 0.5 D to ± 0.75 D after acrylic IOL implantation. All patients had best-corrected visual acuity of 6/6 by third post operative day.Conclusion
Phaconit with rollable IOL is a perfect blend of surgical skill, application of technology and ultra thin IOL.Key Words: Phaconit, Ultra micro phaco, Submillimetre incision, Rollable IOL implantation 相似文献48.
目的:间充质干细胞具有强大的增殖能力和多向分化潜能,文章对其主要的来源途径予以综述。资料来源:应用计算机检索Medline1991-01/2006-01期间的相关文章,检索词为“mesenchyma stem cells,origin,research progress”,并限定文章语言种类为English。同时计算机检索中国期刊全文数据库1998-01/2006-10期间的相关文章,检索词为“间充质干细胞,来源,研究进展”,并限定文章语言种类为中文。资料选择:对资料进行初审,并查看每篇文献后的引文。纳入标准:①间充质干细胞的起源。②间充质干细胞研究进展、干细胞的分离及鉴定。排除标准:重复研究、个案报告或Meta分析类文章。资料提炼:共收集到96篇相关文献,40篇文献符合纳入标准,排除的56篇文献为内容陈旧或重复。符合纳入标准的40篇文献中,分别涉及骨髓、肌肉、脐血、胎盘、外周血、脂肪组织、血管及其他来源的间充质干细胞。资料综合:间充质干细胞是属于中胚层的一类多能干细胞,具有强大的增殖能力和多向分化潜能,动物模型试验和临床应用研究也取得了一定的效果。间充质干细胞来源广泛,易于获得,临床上为神经损伤及其他系统的损伤修复提供了更为广泛的途径。结论:间充质干细胞主要来源于骨髓、肌肉、脐血、外周血、胎盘等组织,具有广阔的应用前景。 相似文献
49.
Rapid mobilization of hematopoietic progenitor cells in rhesus monkeys by a single intravenous injection of interleukin-8 总被引:13,自引:6,他引:13
Laterveer L; Lindley IJ; Heemskerk DP; Camps JA; Pauwels EK; Willemze R; Fibbe WE 《Blood》1996,87(2):781-788
Interleukin-8 (IL-8) is a chemoattractant cytokine involved in chemotaxis and activation of neutrophils. Because in vivo administration of IL-8 induces mobilization of hematopoietic stem cells in mice, we assessed the mobilizing properties of IL-8 in rhesus monkeys. Recombinant human IL-8 was administered as a single intravenous injection at doses of 10, 30, and 100 micrograms/kg to rhesus monkeys (age, 2 to 3 years; weight, 2.5 to 4.5 kg). Venous blood samples were obtained at time intervals ranging from 1 to 480 minutes after IL-8 administration. Cell counts, colony-forming unit-Mix assays, and fluorescence-activated cell sorter analysis were performed. Plasma was harvested to assess IL-8 levels. A time-controlled bolus intravenous injection of 100 micrograms IL-8 per kilogram of body weight resulted in peak IL-8 plasma levels up to 5 micrograms/mL. The calculated half-time life of free IL-8 was 9.9 +/- 2.2 minutes. IL-8 injection resulted in instant neutropenia that was due to pulmonary sequestration, as shown using 99mTc-labeled leukocytes. Within 30 minutes after IL-8 injection, neutrophilia developed with counts up to 10-fold greater than baseline levels. The numbers of hematopoietic progenitor cells (HPCs) increased from 45 +/- 48/mL to 1,382 +/- 599/mL of blood at 30 minutes after injection of 100 micrograms IL-8 per kilogram of bodyweight (mean +/- SD, n = 8). Individual animals showed 10- to 100-fold increase in numbers of circulating HPCs that returned to almost pretreatment values (92 +/- 52 CFU/mL) at 240 minutes after the injection of IL-8. Immunophenotyping showed no significant changes in lymphocyte (sub)populations. A second bolus injection of IL-8 with an interval of 72 hours resulted in similar numbers of mobilized stem cells as observed after the first injection, showing that no tachyphylaxis had occurred. We conclude that IL-8 induces mobilization of HPCs from the bone marrow of rhesus monkeys in a rapid and reproducible fashion. Therefore, IL-8 may be a potentially useful cytokine in the setting of blood stem cell transplantation. 相似文献
50.