全文获取类型
收费全文 | 1004篇 |
免费 | 53篇 |
国内免费 | 93篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 27篇 |
妇产科学 | 244篇 |
基础医学 | 101篇 |
口腔科学 | 23篇 |
临床医学 | 137篇 |
内科学 | 170篇 |
皮肤病学 | 19篇 |
神经病学 | 55篇 |
特种医学 | 38篇 |
外科学 | 57篇 |
综合类 | 39篇 |
预防医学 | 28篇 |
眼科学 | 15篇 |
药学 | 143篇 |
中国医学 | 3篇 |
肿瘤学 | 45篇 |
出版年
2023年 | 2篇 |
2022年 | 9篇 |
2021年 | 32篇 |
2020年 | 12篇 |
2019年 | 15篇 |
2018年 | 27篇 |
2017年 | 35篇 |
2016年 | 13篇 |
2015年 | 19篇 |
2014年 | 23篇 |
2013年 | 56篇 |
2012年 | 62篇 |
2011年 | 71篇 |
2010年 | 46篇 |
2009年 | 40篇 |
2008年 | 36篇 |
2007年 | 98篇 |
2006年 | 43篇 |
2005年 | 52篇 |
2004年 | 23篇 |
2003年 | 31篇 |
2002年 | 30篇 |
2001年 | 33篇 |
2000年 | 31篇 |
1999年 | 37篇 |
1998年 | 31篇 |
1997年 | 18篇 |
1996年 | 19篇 |
1995年 | 23篇 |
1994年 | 28篇 |
1993年 | 15篇 |
1992年 | 17篇 |
1991年 | 22篇 |
1990年 | 16篇 |
1989年 | 13篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1980年 | 3篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1944年 | 2篇 |
1943年 | 2篇 |
排序方式: 共有1150条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
Alterations in the conjunctival bacterial flora following a single dose of azithromycin in a trachoma endemic area 下载免费PDF全文
Chern KC Shrestha SK Cevallos V Dhami HL Tiwari P Chern L Whitcher JP Lietman TM 《The British journal of ophthalmology》1999,83(12):1332-1335
BACKGROUND/AIMS: The World Health Organisation has recommended repeated mass treatment of children in trachoma endemic areas with oral azithromycin. While chlamydia, the causative agent of trachoma, remains universally sensitive to azithromycin, there is concern that large scale programmes may alter the bacterial flora and induce resistance in streptococcal species. In this study the effect of a single dose of azithromcyin on the prevalence, species distribution, and resistance of conjunctival bacterial flora was determined. METHODS: Baseline and 14 day follow up bacterial cultures were taken from the conjunctivae of 121 children who reside in a trachoma endemic area of Nepal. 91 children were treated with azithromycin at baseline and 31 children received deferred treatment at the 14 day follow up. RESULTS: Although the prevalence of bacterial pathogens decreased significantly with azithromycin treatment, a significant change in the distribution of specific bacterial pathogens could not be demonstrated. Streptococcal resistance to azithromycin was found significantly more frequently after treatment. No change in the prevalence, distribution, or resistance pattern was found in the untreated control group. CONCLUSION: Repeated mass treatment of trachoma endemic areas with oral azithromycin will have an effect on bacterial flora. However, further work needs to be done to determine if this will have any clinical relevance. 相似文献
105.
Guiqing Wang Tiangui Huang Pavan Kumar Makam Surendraiah Kemeng Wang Rashida Komal Jian Zhuge Chian-Ru Chern Alexander A. Kryszuk Cassidy King Gary P. Wormser 《Emerging infectious diseases》2013,19(11):1803-1810
CTX-M extended-spectrum β-lactamase (ESBL)–producing Klebsiella pneumoniae isolates are infrequently reported in the United States. In this study, we analyzed nonduplicate ESBL-producing K. pneumoniae and Escherichia coli clinical isolates collected during 2005–2012 at a tertiary care medical center in suburban New York City, USA, for the presence of blaCTX-M, blaSHV, blaTEM, and blaKPC genes. Despite a high prevalence of blaCTX-M genes in ESBL-producing E. coli since 2005, blaCTX-M genes were not detected in K. pneumoniae until 2009. The prevalence of CTX-M–producing K. pneumoniae increased significantly over time from 1.7% during 2005–2009 to 26.4% during 2010–2012 (p<0.0001). CTX-M-15 was the dominant CTX-M genotype. Pulsed-field gel electrophoresis and multilocus sequence typing revealed high genetic heterogeneities in CTX-M–producing K. pneumoniae isolates. This study demonstrates the recent emergence and polyclonal spread of multidrug resistant CTX-M–producing K. pneumoniae isolates among patients in a hospital setting in the United States. 相似文献
106.
Chih-Ping Chen Ming Chen Liang-Kai Wang Schu-Rern Chern Peih-Shan Wu Gwo-Chin Ma Shun-Ping Chang Shin-Wen Chen Fang-Tzu Wu Chen-Chi Lee Yun-Yi Chen Wayseen Wang 《Taiwanese journal of obstetrics & gynecology》2021,60(2):345-349
ObjectiveWe present low-level mosaicism for trisomy 16 at amniocentesis in a pregnancy associated with intrauterine growth restriction (IUGR) and a favorable outcome.Case reportA 31-year-old woman underwent amniocentesis at 24 weeks of gestation because of IUGR. Amniocentesis revealed a karyotype of 47,XX,+16 [3]/46,XX [22]. Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed gene dosage increase in chromosome 16 consistent with 28% mosaicism for trisomy 16. Uniparental disomy (UPD) 7 and UPD 11 were excluded. She underwent repeat amniocentesis at 27 weeks of gestation. Repeat amniocentesis revealed a karyotype of 47,XX,+16 [1]/46,XX [24]. Simultaneous aCGH analysis on the DNA extracted from uncultured amniocytes revealed 25%–35% (log2 ratio = 0.17–0.25) mosaicism for trisomy 16. Interphase fluorescence in situ hybridization (FISH) analysis detected trisomy 16 signals in 28/100 (28%) uncultured amniocytes. Polymorphic DNA marker analysis excluded UPD 16. Level II ultrasound revealed no fetal abnormalities except symmetric IUGR. The pregnancy was continued to 37 weeks of gestation, and a 2306-g phenotypically normal baby was delivered. The cord blood had a karyotype of 46, XX in 50/50 lymphocytes. The umbilical cord had a karyotype of 47,XX,+16 [14]/46,XX [36]. Interphase FISH analysis on buccal mucosal cells and urinary cells at age three days revealed trisomy 16 signals in 3.8% (4/106) buccal mucosal cells and 6.5% (7/107) urinary cells, compared with 1% in the normal control. Polymorphic DNA marker analysis on placenta confirmed trisomy 16 in the placenta and a maternal origin of the extra chromosome 16.ConclusionCytogenetic discrepancy between cultured amniocytes and uncultured amniocytes may present in mosaic trisomy 16 at amniocentesis. Low-level mosaicism for trisomy 16 at amniocentesis without maternal UPD 16 can be associated with a favorable outcome despite the presence of IUGR. 相似文献
107.
108.
109.
110.
P Boucrot C Bobin-Dubigeon L Elkihel Y Letourneux M Jugé G Gandemer and JY Petit 《Fundamental & clinical pharmacology》1998,12(4):433-441
Summary— Compounds able to inhibit phospholipases A2 can be considered as potential anti-inflammatory drugs. In this respect, the inhibitory effect of the phospholipid analogue 1-decyl 2-octyl-rac-glycero-3-phosphocholine (decyloctyl-GPC) added to the culture medium of rat peritoneal macrophages stimulated with ionophore A23187 was determined, (a) The substrate of phospholipase A2 1-octadecanoyl 2-[14C]eicosatetraenoyl-sn-glycero-3-phosphocholine ([14C]20:4-GPC) was added to the culture medium. In macrophages + extracellular fluids, its hydrolysis at the 2-position, produced [14C]non-phosphorous lipids which reached 12% of the dose at 0.14 μM, 73% at 0.9 and > 90% at 1.6 μM; in experiments where macrophages and extracellular fluids were analyzed separately, decyloctyl-GPC initially added at 4 μM, significantly inhibited the release of [14C]fatty acids and the eicosanoid synthesis, demonstrating its ability to inhibit secreted and/or intracellular phospholipases A2. (b) Extracellular fluids were separated from the macrophages and incubated with [14C]20:4-GPC: 48% of the dose was hydrolyzed by extracellular fluid-associated secreted phospholipase A2 and decyloctyl-GPC at 3 μM, reduced this hydrolysis by 50%. (c) [3H]arachidonic acid ([3H]20:4) was added to the culture medium and was esterified in the macrophage membrane phospholipids. Activation of intracellular phospholipase A2 induced the release of [3H] fatty acids and eicosanoid synthesis. These releases were inhibited by 50% with decyloctyl-GPC added at 4 μM. (d) [3H]20:4 and [14C]20:4-GPC were added to the culture medium of the macrophages. [3H] and [14C] fatty acids and eicosanoids were released in macrophages or extracellular fluids. They were significantly reduced by the phospholipid analogue added at 4 μM. It is concluded that secreted and intracellular phospholipases A2 were both inhibited by decyloctyl-GPC which extensively reduced the 20:4 release from exogenous and membrane phospholipids and therefore eicosanoid synthesis. 相似文献