全文获取类型
收费全文 | 2601315篇 |
免费 | 185803篇 |
国内免费 | 7589篇 |
专业分类
耳鼻咽喉 | 34554篇 |
儿科学 | 85610篇 |
妇产科学 | 71810篇 |
基础医学 | 365641篇 |
口腔科学 | 69986篇 |
临床医学 | 235745篇 |
内科学 | 517976篇 |
皮肤病学 | 62715篇 |
神经病学 | 214805篇 |
特种医学 | 100511篇 |
外国民族医学 | 744篇 |
外科学 | 388454篇 |
综合类 | 50530篇 |
现状与发展 | 5篇 |
一般理论 | 972篇 |
预防医学 | 197293篇 |
眼科学 | 57221篇 |
药学 | 188885篇 |
8篇 | |
中国医学 | 5354篇 |
肿瘤学 | 145888篇 |
出版年
2021年 | 20200篇 |
2019年 | 20803篇 |
2018年 | 29484篇 |
2017年 | 22739篇 |
2016年 | 26384篇 |
2015年 | 29730篇 |
2014年 | 40715篇 |
2013年 | 60847篇 |
2012年 | 80824篇 |
2011年 | 85095篇 |
2010年 | 51394篇 |
2009年 | 49489篇 |
2008年 | 79611篇 |
2007年 | 84478篇 |
2006年 | 86148篇 |
2005年 | 82306篇 |
2004年 | 79276篇 |
2003年 | 76536篇 |
2002年 | 73854篇 |
2001年 | 128778篇 |
2000年 | 131690篇 |
1999年 | 110833篇 |
1998年 | 31415篇 |
1997年 | 28072篇 |
1996年 | 28333篇 |
1995年 | 27496篇 |
1994年 | 25167篇 |
1993年 | 23497篇 |
1992年 | 85383篇 |
1991年 | 81805篇 |
1990年 | 79005篇 |
1989年 | 76280篇 |
1988年 | 69701篇 |
1987年 | 68170篇 |
1986年 | 63720篇 |
1985年 | 60696篇 |
1984年 | 45102篇 |
1983年 | 38047篇 |
1982年 | 22554篇 |
1981年 | 20071篇 |
1979年 | 39109篇 |
1978年 | 27551篇 |
1977年 | 23355篇 |
1976年 | 21584篇 |
1975年 | 22919篇 |
1974年 | 26906篇 |
1973年 | 25483篇 |
1972年 | 23861篇 |
1971年 | 22047篇 |
1970年 | 20281篇 |
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
991.
H. Fjeldsøe-Nielsen M. Unemo H. Fredlund S. V. Hjorth L. M. Berthelsen H. M. Palmer A. Friis-Møller 《European journal of clinical microbiology & infectious diseases》2005,24(4):280-283
In the study presented here 26 recent Danish clinical isolates of prolyliminopeptidase (PIP)-negative Neisseria gonorrhoeae were phenotypically and genotypically characterized to investigate whether one or more PIP-negative strains are circulating in the Danish community. The profiles of these isolates were compared with those of three isolates from a recent outbreak of PIP-negative N. gonorrhoeae infection in the UK. Twenty-five of the Danish isolates and all three UK isolates had similar antibiograms and were designated serovar IB-4. Genotypic characterization by pulsed-field gel electrophoresis, porB1b gene sequencing, and opa-typing revealed that these isolates were indistinguishable or closely related. The results indicate that at least one PIP-negative N. gonorrhoeae strain is currently circulating in the Danish community, and this strain is indistinguishable from the one that caused an outbreak in the UK.An erratum to this article can be found at 相似文献
992.
T. Pinzer M. Reiß H. Bourquain K. G. Krishnan G. Schackert 《Acta neurochirurgica》2006,148(10):1085-1090
Summary Aspergillosis belongs to the group of mycotic diseases of paranasal sinuses. The invasive forms, and particularly the fulminant
forms, are potentially fatal. Isolated aspergillosis of the sphenoid sinus or the clivus is a difficult diagnosis, since the
often misleading clinical manifestations of this rare disease develop late. These patients become apparent by neurological
signs such as cavernous sinus syndrome, pseudotumor of the pituitary or the orbit. Diagnosis is often made intra-operatively
or on histological examination.
We report a case of invasive aspergillosis uniquely involving the sellar area revealed by clinical features suggesting a pseudotumor
of the pituitary. Although such lesions are almost always seen in immune suppressed subjects, in our case, the patient was
immune competent and had no past history of sinusitis.
The question of whether, and when to perform limited or extensive surgery remains an issue for discussion, owing to the rarity
of this disease honed by lack of experience. It depends on several factors: the kind of disease, the immunity, the subtype
of invasive fungal sinusitis and the degree of tissue invasion. 相似文献
993.
AIMS: In normotensive women with Type 1 diabetes and microalbuminuria we previously found preterm delivery (< 34 weeks) in 23% of the pregnancies. Antihypertensive treatment was initiated in late pregnancy when preeclampsia was diagnosed and diastolic blood pressure > 90 mmHg. From April 2000 our routine was changed and early antihypertensive treatment with methyldopa was initiated if antihypertensive treatment was given prior to pregnancy, if urinary albumin excretion (UAE) was > 2 g/24 h, or blood pressure > 140/90 mmHg. The present study describes the impact of this more aggressive antiypertensive treatment in the prevalence of preterm delivery. METHODS: The old cohort (1995-1999) consisted of 26 and the new cohort (2000-2003) of 20 pregnant women with Type 1 diabetes and microalbuminuria. All were referred before gestational week 17. RESULTS: The cohorts were comparable with regard to age, diabetes duration, prepregnancy body mass index, HbA1c, blood pressure 121 (13)/71 (8) vs. 121 (14)/73 (8) mmHg [mean (sd)] and early UAE 69 (16-278) vs. 74 (30-287) mg/24 h (geometric mean and range). Antihypertensive treatment was initiated in the old cohort at 29 (20-33) weeks, n = 9, and in the new at 13 (0-34) weeks, n = 10. The prevalence of preterm delivery before 34 weeks was reduced from 23% to zero (P = 0.02), preterm delivery before 37 weeks from 62% to 40% (P = 0.15) and preeclampsia from 42% to 20% (P = 0.11). Perinatal mortality occurred in 4% vs. 0%. Birth weight was 3124 (767) g vs. 3279 (663) g. CONCLUSION: Introduction of early antihypertensive treatment with methyldopa in normotensive pregnant women with Type 1 diabetes and microalbuminuria resulted in a significant reduction in preterm delivery before gestational week 34. 相似文献
994.
995.
The absolute activities of the pure beta-emitters 89Sr and 90Y have been determined by a direct method, namely the triple-to-double coincidence ratio (TDCR) efficiency calculation technique. This undertaking has extended further the number of radionuclides that have been standardized by this non-extrapolation liquid scintillation (LS) method. Both measurements were carried out within the framework of international key comparisons under the auspices of the International Bureau of Weights and Measures (BIPM). The TDCR results agreed well with those of other participating national laboratories, most using alternative (tracer) methods. 相似文献
996.
997.
Effects of pegfilgrastim on normal biodistribution of 18F-FDG: preclinical and clinical studies. 总被引:1,自引:0,他引:1
Heather A Jacene Takayoshi Ishimori James M Engles Sophie Leboulleux Vered Stearns Richard L Wahl 《Journal of nuclear medicine》2006,47(6):950-956
The purpose of this study was to evaluate the effects of pegfilgrastim, a long-acting granulocyte colony-stimulating factor, on the normal biodistribution of (18)F-FDG in an animal model and in humans. METHODS: Two groups of 12 rats received a single subcutaneous injection of either normal saline or pegfilgrastim. One, 7, 14, and 21 d after injection, biodistribution studies were performed 1 h after (18)F-FDG injection. Sixteen breast cancer patients underwent baseline (18)F-FDG PET/CT and, approximately 1 wk after receiving 1 dose of docetaxel and adjunctive pegfilgrastim, follow-up (18)F-FDG PET/CT (scan 2). Standardized uptake values corrected for lean body mass (SUL) were determined for several normal organs before and after therapy. RESULTS: In rats, bone marrow (18)F-FDG uptake (standardized uptake value) was higher in the pegfilgrastim group 1 d after injection (mean +/- SD, 8.3 +/- 4.1 vs. 2.5 +/- 0.2, P < 0.05), whereas (18)F-FDG uptake in blood was lower (0.41 +/- 0.06 vs. 0.49 +/- 0.01, P < 0.05). In patients, mean SUL was higher in bone marrow (4.49 +/- 1.50 vs. 1.33 +/- 0.22, P < 0.0001), spleen (3.29 +/- 0.83 vs. 1.23 +/- 0.23, P < 0.0001), and liver (1.45 +/- 0.25 vs. 1.31 +/- 0.23, P = 0.01) but lower in brain (4.18 +/- 0.76 vs. 5.14 +/- 1.44, P < 0.01) on scan 2 than on the baseline scan. CONCLUSION: In both the animal model and humans, pegfilgrastim markedly increased bone marrow uptake of (18)F-FDG and reduced (18)F-FDG uptake in some normal tissues. These profound alterations in (18)F-FDG biodistribution induced by pegfilgrastim must be considered when one is evaluating quantitative (18)F-FDG PET scans for tumor response to therapy. 相似文献
998.
999.
1000.