全文获取类型
收费全文 | 918篇 |
免费 | 68篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 26篇 |
妇产科学 | 15篇 |
基础医学 | 74篇 |
口腔科学 | 29篇 |
临床医学 | 98篇 |
内科学 | 183篇 |
皮肤病学 | 12篇 |
神经病学 | 44篇 |
特种医学 | 112篇 |
外科学 | 112篇 |
综合类 | 80篇 |
一般理论 | 2篇 |
预防医学 | 47篇 |
眼科学 | 32篇 |
药学 | 53篇 |
中国医学 | 8篇 |
肿瘤学 | 59篇 |
出版年
2023年 | 7篇 |
2022年 | 10篇 |
2021年 | 24篇 |
2020年 | 19篇 |
2019年 | 22篇 |
2018年 | 43篇 |
2017年 | 22篇 |
2016年 | 21篇 |
2015年 | 32篇 |
2014年 | 42篇 |
2013年 | 55篇 |
2012年 | 57篇 |
2011年 | 52篇 |
2010年 | 68篇 |
2009年 | 45篇 |
2008年 | 32篇 |
2007年 | 43篇 |
2006年 | 49篇 |
2005年 | 30篇 |
2004年 | 14篇 |
2003年 | 16篇 |
2002年 | 9篇 |
2001年 | 9篇 |
2000年 | 23篇 |
1999年 | 11篇 |
1998年 | 15篇 |
1997年 | 17篇 |
1996年 | 18篇 |
1995年 | 17篇 |
1994年 | 16篇 |
1993年 | 19篇 |
1992年 | 10篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 16篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 2篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1965年 | 1篇 |
排序方式: 共有996条查询结果,搜索用时 93 毫秒
81.
Cornelia FA van Wesenbeeck Michiel A Keyzer Maarten Nubé 《International journal of health geographics》2009,8(1):1-18
Background
Agricultural science can address a population's vitamin, amino acid and mineral malnutrition through biofortification - agronomy, plant breeding and biotechnology to develop crops with high nutrient contents. Biofortified crop varieties should be grown in areas with populations at risk of nutrient deficiency and in areas where the same crop is already grown and consumed. Information on the population at risk of nutrient deficiency is rarely available for sub-national administrative units, such as provinces, districts, and municipalities. Nor is this type of information commonly analyzed with data on agricultural production. This project developed a method to identify populations at risk of nutrient deficiency in zones with high crop production, places where biofortification interventions could be targeted.Results
Nutrient deficiency risk data were combined with crop production and socioeconomic data to assess the suitability of establishing an intervention. Our analysis developed maps of candidate sites for biofortification interventions for nine countries in Latin America and the Caribbean. Results for Colombia, Nicaragua, and Bolivia are presented in this paper. Interventions in northern Colombia appear promising for all crops, while sites for bean biofortification are widely scattered throughout the country. The most promising sites in Nicaragua are found in the center-north region. Candidate sites for biofortification in Bolivia are found in the central part of the country, in the Andes Mountains. The availability and resolution of data limits the analysis. Some areas show opportunities for biofortification of several crops, taking advantage of their spatial coincidence. Results from this analysis should be confirmed by experts or through field visits.Conclusion
This study demonstrates a method for identifying candidate sites for biofortification interventions. The method evaluates populations at risk of nutrient deficiencies for sub-national administrative regions, and provides a reasonable alternative to more costly, information-intensive approaches. 相似文献82.
Billakanty SR Kligman MD Kanjwal YM Kosinski DJ Maly GT Karabin B Grubb BP 《Pacing and clinical electrophysiology : PACE》2008,31(7):884-888
Background: As bariatric surgery has become an increasingly popular treatment for obesity, we have seen an increasing number of patients present after bariatric surgery with new-onset syncope, near-syncope, and lightheadedness.
Methods: We retrospectively reviewed patients who had had bariatric surgery referred to our institution for evaluation of orthostatic intolerance. We reviewed history, physical examination, type of bariatric surgery procedure, and tilt table test results in these patients. There were 14 women and one man with mean age 42 ± 6 years, preoperative body mass index was 49.3 ± 6.0 kg/m2 , and mean postoperative weight loss was 55.9 kg. Mean onset of symptoms was 5.2 ± 3.9 months after surgery. Presenting symptoms were lightheadedness in 15 (100%), near-syncope in 11 (73%), and syncope in nine (60%). All but one patient had a positive tilt table test with eight (53%) having a neurocardiogenic response, three (20%) having a dysautonomic response, and (20%) having a postural tachycardia response. The likely mechanism of orthostatic intolerance is autonomic insufficiency in combination with reverse course of obesity-related hypertension. The majority of the patients (12 out of 15) responded to standard therapy for autonomic insufficiency.
Conclusion: Some patients may develop significant orthostatic intolerance due to autonomic insufficiency following bariatric surgery, and awareness of the potential association between bariatric surgery and new orthostatic intolerance is important for providing timely care. 相似文献
Methods: We retrospectively reviewed patients who had had bariatric surgery referred to our institution for evaluation of orthostatic intolerance. We reviewed history, physical examination, type of bariatric surgery procedure, and tilt table test results in these patients. There were 14 women and one man with mean age 42 ± 6 years, preoperative body mass index was 49.3 ± 6.0 kg/m
Conclusion: Some patients may develop significant orthostatic intolerance due to autonomic insufficiency following bariatric surgery, and awareness of the potential association between bariatric surgery and new orthostatic intolerance is important for providing timely care. 相似文献
83.
我省长学制医学教育的回顾与思考 总被引:1,自引:0,他引:1
我省七年制医学教育开办了近20年,为社会培养了一批深受欢迎、质量较好和具有较高综合素质的高层次医学人才。建立与我省经济发展水平相适应的以五年制为主体、重点发展八年制的医学教育学制体系,是我省高等医学教育发展的必然趋势。 相似文献
84.
85.
Jung Nathalie Namjoshi Sarika Mohammed Yousuf Grice Jeffrey E. Benson Heather A. E. Raney Sam G. Roberts Michael S. Windbergs Maike 《Pharmaceutical research》2022,39(5):935-948
Pharmaceutical Research - The quality testing and approval procedure for most pharmaceutical products is a streamlined process with standardized procedures for the determination of critical quality... 相似文献
86.
87.
88.
Single-locus DNA probes for tandem repeat sequences are now used in conjunction with particular endonucleases to characterize heritable restriction fragment lengths in parentage tests. Southern blots of this type, however, demonstrate only two attributes of an allele: its length and the presence of nucleotide sequences that are complementary to the probe. Not all restriction fragments of the same apparent length that react with the same probe are identical. Differences between comigrating fragments can be detected by the selection of a restriction enzyme that recognizes sites in a subset of the repeat sequences, and the information content of these loci is therefore increased. This report describes a paternity case in which two brothers appeared, after DNA phenotyping using Hinf I, to be the father. A second phenotyping using Hae III excluded one of the brothers. 相似文献
89.
125I粒子对Hela细胞杀伤作用的实验研究 总被引:2,自引:0,他引:2
目的观察体外Hela细胞在^125I粒子照射下细胞凋亡和增殖的规律,探讨^125I粒子对肿瘤的杀伤作用。方法用^125I粒子照射Hela细胞,用不同的方法观察不同剂量和时间点细胞的增殖反应及形态变化。结果受照射细胞发生凋亡,于Ⅱb期出现凋亡小体;细胞凋亡率随累积剂量的增加而增加,于5Gy时出现凋亡率峰值;细胞克隆形成率显著下降,与凋亡形成呈反向关系。并有反剂量率效应。结论^125I粒子对肿瘤的治疗作用可能为早期抑制肿瘤细胞增殖,晚期使肿瘤细胞大量凋亡。 相似文献
90.
Trabecular bone architecture in female renal allograft recipients-- assessed by computed tomography 总被引:1,自引:0,他引:1
Grotz WH; Mundinger FA; Muller CB; Rasenack J; Schulte-Monting J; Langer MF; Schollmeyer PJ 《Nephrology, dialysis, transplantation》1997,12(3):564-569
BACKGROUND: Osteopenia with decreased bone mineral density (BMD) is a
frequent finding in renal allograft recipients. Data concerning the bone
architecture in these patients do not exist, however. METHODS: We compared
the bone architecture of 33 randomly assigned women (age 49 +/- 12 years),
who had received renal allografts 5.6 +/- 5.3 years before the
investigation, with 74 women (age 50 +/- 14 years) who were admitted for
osteodensitometry. All patients underwent single-energy computed tomography
(SEQCT) and a midvertebral high-resolution tomography with
computer-assisted analysis of the trabecular vertebral body architecture.
RESULTS: Progressive alteration of bone architecture was associated with
increasing vertebral height loss of the vertebral body. Height reduction of
a vertebral body of more than 15% was associated with a significantly lower
BMD (-2.3 +/- 0.8 versus -1.1 +/- 1.1 standard deviations below normal
BMD), a lower trabecular bone area (13 +/- 8% versus 42 +/- 22%) and a
lower trabecular diameter (1.4 +/- 0.5 mm versus 2.2 +/- 0.8 mm) compared
to recipients without height reduction. In comparison to a matched group of
patients with similarly reduced BMD (1.1 +/- 1.2 versus 1.2 +/- 1.1 SD
below normal BMD), renal allograft recipients showed a lower number of
trabecular plates (5.6 +/- 3.1 versus 7.0 +/- 3.7) and a smaller
intertrabecular surface (54 +/- 116 mm versus 75 +/- 138 mm). CONCLUSIONS:
Alterations of bone architecture in renal allograft recipients were
associated with progressive vertebral height loss. Despite similar bone
mineral density, differences of bone architecture could be observed between
renal allograft recipients and patients with osteoporosis.
相似文献