全文获取类型
收费全文 | 753篇 |
免费 | 28篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 31篇 |
妇产科学 | 12篇 |
基础医学 | 77篇 |
口腔科学 | 16篇 |
临床医学 | 75篇 |
内科学 | 103篇 |
皮肤病学 | 15篇 |
神经病学 | 13篇 |
特种医学 | 160篇 |
外科学 | 59篇 |
综合类 | 123篇 |
预防医学 | 34篇 |
药学 | 56篇 |
1篇 | |
肿瘤学 | 32篇 |
出版年
2023年 | 6篇 |
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 31篇 |
2012年 | 26篇 |
2011年 | 18篇 |
2010年 | 27篇 |
2009年 | 37篇 |
2008年 | 26篇 |
2007年 | 37篇 |
2006年 | 24篇 |
2005年 | 16篇 |
2004年 | 20篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2001年 | 13篇 |
2000年 | 12篇 |
1999年 | 16篇 |
1998年 | 42篇 |
1997年 | 38篇 |
1996年 | 41篇 |
1995年 | 24篇 |
1994年 | 21篇 |
1993年 | 25篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 11篇 |
1989年 | 25篇 |
1988年 | 19篇 |
1987年 | 16篇 |
1986年 | 23篇 |
1985年 | 18篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 17篇 |
1981年 | 9篇 |
1980年 | 12篇 |
1979年 | 3篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1975年 | 7篇 |
1953年 | 2篇 |
1945年 | 2篇 |
排序方式: 共有809条查询结果,搜索用时 0 毫秒
21.
背景和目的:最近的研究结果表明,对其他一线药物和注射类药物(如卡那霉素、卷曲霉素)等耐药是影响耐多药结核病(MDR-TB)患者治疗效果的独立危险因素.本研究旨在明确耐其他一线药物和注射类药物对韩国不合并人免疫缺陷病毒(HIV)感染的MDR-TB患者临床疗效的影响.方法:采用回顾性队列研究分析1996年1月至2005年12月首尔国家大学附属医院治疗的211例MDR-TB患者治疗效果,排除7例丢失和7例迁出,对197例患者进行了最终分析. 相似文献
22.
23.
24.
Human marrow erythropoiesis in culture. I. Characterization of methylcellulose colony assay 总被引:11,自引:0,他引:11
We examined the morphological and functional characteristics of human marrow erythrocytes cultured with a recently developed methylcellulose colony assay technique. Erythrocytic cells in various stages of development were observed, and a significant degree of maturational synchrony within individual colonies was noted. By light microscopy, colonies consisting of late normoblasts appeared compact, had an orange hue attributable to their hemoglobin, and demonstrated pseudoperoxidase activity, whereas colonies composed of early erythroblasts grew less compact or in clusters of smaller cell aggregates and showed no reddish tinge. Colonies possessing intermediate features were also observed. Maturational synchrony of individual colonies was confirmed using ransmission and scanning electron microscopy. The ultrastructure and cytochemistry of most immature cells were normal. The mature erythrocytes, however, were severely microcytic and hypochromic and contained one to several Heinz bodies. These defects in the cytoplasmic maturation of erythrocytes corresponded with impaired granulocytic maturation in culture, which we observed previously, and suggest environmental or nutritional defects in culture. Linearity of the method was confirmed using five normal bone marrows. Erythropoietin dose-responses observed in ten normal marrows were comparable to the previously reported results and revealed significant variation in individual plating efficiencies. 相似文献
25.
ABM Kharsany N Hancock JA Frohlich HR Humphries SS Abdool Karim Q Abdool Karim 《HIV medicine》2010,11(10):661-665
Objectives
The aim of this study was to evaluate the HIV‐1 RNA pooled nucleic acid amplification testing (NAAT) strategy to screen pregnant women in the ‘window period’ of acute HIV infection (AHI) in rural South Africa.Methods
In 2007 and 2008, 750 consecutive pregnant women on their first antenatal care visit to a primary health care clinic were tested anonymously for HIV infection. HIV‐1 RNA pooled NAAT was performed on HIV antibody‐negative samples. All positive pools were tested individually and positive samples were classified as incident cases to calculate HIV incidence.Results
The overall HIV prevalence was 37.3% [95% confidence interval (CI) 34.3–41.3]. Of the 467 HIV antibody‐negative samples, four (0.9%) were HIV‐1 RNA‐positive. The mean viral load in the four samples was 386 260 HIV‐1 RNA copies/mL (range 64 200–1 228 130). The HIV incidence was 11.2% per year (95% CI 0.3–22.1) and all women with AHI were ≤21 years of age.Conclusions
Identifying AHI in pregnancy is important for health interventions to reduce perinatal and heterosexual transmission of HIV, and to estimate HIV incidence for epidemiological surveillance. 相似文献26.
Lund SS Tamow L Stehouwer CD 《药品评价》2008,5(8):380-380
在2型糖尿病患者中,反映炎症和内皮功能障碍的生物标志已经与心血管疾病和代谢调节联系起来。二甲双胍和促胰岛素分泌剂被证明有相同的抗高血糖作用。此研究比较了二甲双胍和促胰岛素分泌剂瑞格列奈在非肥胖的2型糖尿病患者的心血管疾病生物标志上的效能。 相似文献
27.
Scharer K 《Issues in mental health nursing》2000,21(8):723-744
The admission of a child to a psychiatric unit is difficult for parents. While many articles about admissions can be discovered in the literature, few address the process of admission. A grounded theory study was undertaken to describe and explain the relationships that develop between parents and nurses in child psychiatric units. The crucial nature of the admission process was discovered and is the focus of this article. Theoretical sampling was used. Data were collected by interviewing parents and the nursing staff working with the parents. In addition, participant observation was used. Data were analyzed using the constant comparative method. Parents often came to the unit expecting to be blamed for their child's problems. When nurses responded with reassurance and caring, the parents' engagement was enhanced. During admission, expectations of parents and nurses influenced the relationship. In addition, the study discovered ways that nursing routines influence the relationship during the admission period. 相似文献
28.
DC Wilson MJ Cunningham MMcC Reid SS Johnston TF Fannin 《Acta paediatrica (Oslo, Norway : 1992)》1992,81(1):84-85
A baby with unilateral cleft lip, midline cleft palate and hypertelorism developed meningitis in the first 48 h of life. Examination of the nasopharynx showed a soft tissue mass, which was confirmed as a basal encephalocele by computed tomography. There was also congenital hydrocephalus and the corpus callosum was absent. Surgical treatment included repair of the anterior basal skull defect, repair of the lip and palate, and ventriculo-peritoneal shunt. There is currently evidence of developmental delay and right-sided visual impairment due to Morning Glory syndrome. This case demonstrates that basal encephalocele should be considered in any baby with midline facial deformity who develops meningitis. 相似文献
29.
Evidence for endogenous formation of tobacco-specific nitrosamines in rats treated with tobacco alkaloids and sodium nitrite 总被引:2,自引:0,他引:2
Carcinogenic tobacco-specific nitrosamines are present in tobacco products
and are believed to play a significant role in human cancers associated
with tobacco use. Additional amounts of tobacco-specific nitrosamines could
be formed endogenously. We tested this hypothesis by treating rats with
nicotine and sodium nitrite and analyzing their urine. Initially, we
treated groups of rats with (S)-nicotine (60 micromol/kg) and NaNO2 (180
micromol/kg), (S)-nicotine alone, NaNO2 alone or
4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK, 12 nmol/kg) by gavage
twice daily for 4 days. We collected urine and analyzed for two metabolites
of NNK; 4-(methylnitrosamino)-1-(3- pyridyl)-1-butanol and its glucuronide.
We did not detect these metabolites in the urine of rats treated with
nicotine alone or nicotine plus NaNO2, indicating that endogenous
conversion of nicotine to NNK did not occur. However, the urine did contain
N'- nitrosonornicotine (NNN), N'-nitrosoanabasine (NAB) and N'-
nitrosoanatabine (NAT). Analysis of the (S)-nicotine used in this
experiment demonstrated that it contained trace amounts of nornicotine,
anabasine and anatabine. In a second experiment, we used an identical
protocol to compare the endogenous nitrosation of this (S)-nicotine with
that of synthetic (R,S)-nicotine, which did not contain detectable amounts
of nornicotine, anabasine or anatabine. NNN (0.53 x 10(-3)% of nicotine
dose), NAB (0.68%) and NAT (2.1%) were detected in the urine of the rats
treated with the (S)-nicotine and NaNO2. NNN (0.47 x 10(- 3)% of dose), but
not NAB or NAT, was present in the urine of the rats treated with synthetic
(R,S)-nicotine and NaNO2. NNN probably formed via nitrosation of
metabolically formed nornicotine. These results demonstrate for the first
time that endogenous formation of tobacco- specific nitrosamines occurs in
rats treated with tobacco alkaloids and NaNO2. The potential significance
of the results with respect to nitrosamine formation in people who use
tobacco products or nicotine replacement therapy is discussed.
相似文献
30.
Expression of differential nitric oxide synthase isoforms in human normal gastric mucosa and gastric cancer tissue 总被引:10,自引:2,他引:10
The present study investigated the expression and distribution of three
isoforms of nitric oxide synthase (NOS) in different anatomical regions of
the human stomach and in gastric neoplastic tissues by immunohistochemistry
using specific antibodies. Intracellular localization of individual
isoenzymes of NOS was detected in normal gastric mucosa. Gastric cancer
tissues had a marked reduction of all three NOS isoforms expression. The
expression of the endothelial NOS, neuronal NOS and inducible NOS in the
tumor tissue was significantly lower than in normal gastric mucosa (P =
0.01, P = 0.02, P < 0.01, respectively). In the tumor tissue the
expression of inducible NOS was significantly lower than the expression of
both constitutive forms of NOS (P < 0.01). There was a tendency to
higher expression of both constitutive forms of NOS in earlier stages T2 of
the tumor compared to advanced T4 tumor. In contrast, the expression of
inducible NOS was higher than in the advanced T4 tumor than in the earlier
stages T2 of the tumor. The mapping of the expression of endothelial NOS,
neuronal NOS and inducible NOS in human stomach showed higher expression of
NOS isoforms in the distal third than in the proximal third of the stomach
(P = 0.03, P = 0.04, P = 0.01, respectively). We conclude that there is
greater expression of NOS in the stomach corpus and in antrum than in the
proximal third of the normal human stomach mirroring the anatomical
predilection of common pathological changes in this part of the human
stomach. Furthermore, there was loss of the expression of individual
isoenzymes in gastric neoplasms.
相似文献