全文获取类型
收费全文 | 592篇 |
免费 | 50篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 45篇 |
妇产科学 | 7篇 |
基础医学 | 56篇 |
口腔科学 | 28篇 |
临床医学 | 53篇 |
内科学 | 109篇 |
皮肤病学 | 24篇 |
神经病学 | 29篇 |
特种医学 | 121篇 |
外科学 | 23篇 |
综合类 | 13篇 |
预防医学 | 45篇 |
眼科学 | 4篇 |
药学 | 33篇 |
中国医学 | 2篇 |
肿瘤学 | 66篇 |
出版年
2022年 | 3篇 |
2020年 | 3篇 |
2019年 | 15篇 |
2018年 | 13篇 |
2017年 | 12篇 |
2016年 | 12篇 |
2015年 | 13篇 |
2014年 | 8篇 |
2013年 | 30篇 |
2012年 | 8篇 |
2011年 | 11篇 |
2010年 | 28篇 |
2009年 | 31篇 |
2008年 | 14篇 |
2007年 | 21篇 |
2006年 | 12篇 |
2005年 | 14篇 |
2004年 | 16篇 |
2003年 | 12篇 |
2002年 | 11篇 |
2001年 | 9篇 |
2000年 | 15篇 |
1999年 | 10篇 |
1998年 | 31篇 |
1997年 | 32篇 |
1996年 | 29篇 |
1995年 | 24篇 |
1994年 | 26篇 |
1993年 | 19篇 |
1992年 | 9篇 |
1991年 | 8篇 |
1990年 | 8篇 |
1989年 | 16篇 |
1988年 | 16篇 |
1987年 | 13篇 |
1986年 | 19篇 |
1985年 | 15篇 |
1984年 | 9篇 |
1983年 | 7篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 7篇 |
1973年 | 2篇 |
1969年 | 2篇 |
1968年 | 3篇 |
排序方式: 共有661条查询结果,搜索用时 0 毫秒
31.
Passive intestinal permeability in 33 newborn babies was studied using feeds containing lactulose and mannitol. Each marker is thought to pass across the gut wall by a different route; lactulose by a paracellular and mannitol by a transcellular pathway. Neither is metabolised and both are wholly and solely excreted by the kidney; urinary recovery is a measure of the intestinal uptake. Babies born before 34 weeks' gestation exhibited a higher intestinal permeability to lactulose than more mature babies, and all preterm babies showed an appreciable decline in lactulose absorption during the first week of oral feeds. Babies of 34 to 37 weeks' gestation achieved a 'mature' intestinal permeability to lactulose within four days of starting oral feeds. These findings may reflect the immaturity of the gut of the preterm baby rather than a process essential to adaptation to enteral nutrition. 相似文献
32.
Ki-ras mutations are an early event and correlate with tumor stage in transplacentally-induced murine lung tumors 总被引:2,自引:2,他引:2
Leone-Kabler S; Wessner LL; McEntee MF; D'Agostino RB Jr; Miller MS 《Carcinogenesis》1997,18(6):1163-1168
A previous study from this laboratory demonstrated that treatment of
pregnant mice with 3-methylcholanthrene (MC) caused lung tumors in the
offspring at 1 year after birth, the incidence of which correlated with
fetal inducibility of Cyp1a1. Analysis by PCR amplification and allele-
specific hybridization (ASO) of paraffin-embedded tumors generated from
that study revealed the presence of point mutations in exon 1 of the Ki-
ras gene. This work has now been expanded by PCR amplification and ASO
analysis of 31 additional lesions. Point mutations were found in 37 of the
47 (79%) lesions analyzed in this and the previous study, the majority of
which were G-->T transversions in the first or second base of codon 12.
The mutational spectrum appeared to be dependent on the relative stage of
differentiation of the lesion, as both the incidence of mutation and type
of mutation produced correlated with malignant progression. Mutations
occurred in 60% of the hyperplasias, 80% of the adenomas and 100% of the
adenocarcinomas. In the lesions with mutations, GLY12-->CYS12
transversions occurred in 100% of the hyperplasias, 42% of the adenomas and
14% of the adenocarcinomas. The GLY12-->VAL12 transversions occurred in
none of the hyperplasias, 42% of the adenomas and 57% of the
adenocarcinomas. The remaining mutations, which consisted of ASP12
transitions and ARG13 transversions, occurred only in adenomas (17%) and
adenocarcinomas (29%). Between this study and our previous analyses, the
identity of the mutations obtained by ASO were confirmed by sequence
analysis of eight of the 37 lesions that harbored mutations at the Ki-ras
gene locus. There were no differences in the type or incidence of mutations
relative to the metabolic phenotype or sex of the mice. These data suggest
that mutational activation of the Ki-ras gene locus is an early event in
transplacental lung tumorigenesis, and that the type of mutations produced
by exposure to chemical carcinogens can influence the carcinogenic
potential of the tumor. This may have prognostic significance in
determining the malignant progression of the neoplasm.
相似文献
33.
The prevalence of dyslipidaemia in children with insulin dependent diabetes mellitus (IDDM) and its relation to glycaemic control was studied in a group of 51 diabetic children and a control population of 132 schoolchildren. The prevalence of dyslipidaemia in the fasting state was increased in the diabetic group (39%) compared with control subjects (17%). Serum cholesterol concentration alone was raised in 25% of diabetic subjects while serum cholesterol and triglycerides were raised in 14%, compared with 16% and 0.7% respectively in control subjects. Serum total cholesterol (5.1 v 4.5 mmol/l), low density lipoprotein cholesterol (3.2 v 2.6 mmol/l), non-esterified fatty acids (0.91 v 0.50 mmol/l), and triglycerides (0.94 v 0.76 mmol/l) were higher in diabetic children. Serum total cholesterol, triglycerides, and apolipoprotein (apo)B concentrations increased with worsening control, while serum high density lipoprotein cholesterol and apoA-I concentrations were unaltered. There were also positive correlations between glycated haemoglobin and total cholesterol, triglycerides, and apoB in diabetic children. Thus, abnormalities in circulating lipids are common in young subjects with IDDM but largely disappear if blood glucose concentrations are reasonably controlled. 相似文献
34.
35.
36.
37.
In a patient with primary hyperparathyroidism an attempt was made to ablate a middle mediastinal parathyroid gland by forceful staining with radiographic contrast material. The gland was stained on two separate occasions, two weeks apart. Both times the serum calcium level temporarily fell to the normal range but reverted to abnormal levels. The patient ultimately required surgery for correction of hypercalcemia. The mechanism of staining and possible reasons for failure as well as potential complications are discussed. 相似文献
38.
A retrospective review of the dynamic CT studies performed in our institution on head and neck lesions, excluding the brain, was carried out. Five basic types of density vs. time curves were obtained. Dynamic CT scanning is valuable in the differential diagnosis, management, and followup of such cases; its usefulness as an imaging modality in diagnosis and followup of hemangiomas is stressed. 相似文献
39.
M F Spittle H Bush S E James K Hellmann 《International journal of radiation oncology, biology, physics》1979,5(9):1649-1651
One hundred thirteen patients with inoperable carcinoma of the bronchus were ramdomly allocated to receive either radiotherapy or radiotherapy plus razoxane. They were stratified according to histology and analyzed according to whether they had oat-cell or non oat-cell carcinomas and whether they tolerated only 1 course (3,000 rad) or 2 courses (6,000 rad) of radiotherapy. Of the patients who had 2 courses of radiotherapy, only 7% developed leukopenia and the same percentage developed severe esophagitis; but of those who had the combined treatment, 32% developed leukopenia and the same pecentage developed severe esophagitis.Although the median survival time was greater in those who received the combined treatment in both one treatment and two treatment groups, neither achieved statistical significance. Sixty four percent of patients who had two treatments (i.e. 6,000 rad plus razoxane) survived 12 months; this compares favorably with most other published clinical trials of inoperable carcinoma of the bronchus. 相似文献
40.