全文获取类型
收费全文 | 2694篇 |
免费 | 192篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 119篇 |
妇产科学 | 67篇 |
基础医学 | 247篇 |
口腔科学 | 113篇 |
临床医学 | 290篇 |
内科学 | 468篇 |
皮肤病学 | 252篇 |
神经病学 | 162篇 |
特种医学 | 189篇 |
外科学 | 366篇 |
综合类 | 40篇 |
一般理论 | 1篇 |
预防医学 | 129篇 |
眼科学 | 89篇 |
药学 | 163篇 |
中国医学 | 24篇 |
肿瘤学 | 133篇 |
出版年
2023年 | 21篇 |
2022年 | 24篇 |
2021年 | 61篇 |
2020年 | 48篇 |
2019年 | 71篇 |
2018年 | 93篇 |
2017年 | 72篇 |
2016年 | 67篇 |
2015年 | 87篇 |
2014年 | 94篇 |
2013年 | 136篇 |
2012年 | 152篇 |
2011年 | 186篇 |
2010年 | 100篇 |
2009年 | 66篇 |
2008年 | 105篇 |
2007年 | 138篇 |
2006年 | 109篇 |
2005年 | 114篇 |
2004年 | 113篇 |
2003年 | 95篇 |
2002年 | 113篇 |
2001年 | 80篇 |
2000年 | 70篇 |
1999年 | 56篇 |
1998年 | 46篇 |
1997年 | 39篇 |
1996年 | 46篇 |
1995年 | 32篇 |
1994年 | 33篇 |
1993年 | 18篇 |
1992年 | 21篇 |
1991年 | 39篇 |
1990年 | 17篇 |
1989年 | 35篇 |
1988年 | 37篇 |
1987年 | 32篇 |
1986年 | 32篇 |
1985年 | 28篇 |
1984年 | 17篇 |
1982年 | 14篇 |
1981年 | 9篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 10篇 |
1974年 | 7篇 |
1966年 | 10篇 |
排序方式: 共有2910条查询结果,搜索用时 15 毫秒
1.
2.
Quang Ngoc Nguyen Linh Dieu Vuong Van-Long Truong To Van Ta Nam Trung Nguyen Hung Phi Nguyen Ha Hoang Chu 《Pathology, research and practice》2019,215(5):885-892
Genetic and epigenetic alterations importantly contribute to the pathogenesis of lung cancer. In the study, we measured the frequency and distribution of molecular abnormalities of EGFR as well as the aberrant promoter methylations of BRCA1, MGMT, MLH1, and RASSF1A in Vietnamese lung adenocarcinomas. We investigated the association between genetic and epigenetic alteration, and between each abnormality with clinicopathologic parameters. Somatic EGFR mutation that was found in 49/139 (35.3%) lung adenocarcinomas showed a significant association with young age, female gender, and non-smokers. EGFR overexpression was identified in 82 tumors (59.0%) and statistical relationships with EGFR or BRCA1 methylation but not EGFR mutation. In addition, EGFR, BRCA1, MGMT, MLH1, and RASSF1A methylations were found in 33 (23.7%), 41 (29.5%), 46 (33.1%), 28 (20.1%), and 41 (29.5%) cases of a total of 139 lung adenocarcinomas, respectively. The RASSF1A methylation was found to be linked to the smoking habit. Methylations in MGMT and RASSF1A were also found to correlate with metastasis status. Furthermore, the distribution of EGFR mutation and that of BRCA1, MGMT or RASSF1A methylation were significantly exclusive in lung adenocarcinomas. The main finding of our study demonstrate that epigenetic abnormalities might play a critical role for the lung tumorigenesis in patients with smoking history and metastasis, and partly affect the predictive value of EGFR mutations through blocking expression due to promoter EGFR hypermethylation. Mutually exclusive distribution of genetic and epigenetic alterations reflects differently biological characteristics in the etiology of lung adenocarcinomas. 相似文献
3.
Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight. 相似文献
4.
Stoma Adjustable Silicone Gastric Banding versus Vertical Banded Gastroplasty for the Treatment of Morbid Obesity 总被引:1,自引:0,他引:1
Background: Among gastric restrictive operations, the procedure of choice is still controversial. The aim of this study is
to compare the results of two different gastric restrictive procedures: vertical banded gastroplasty (VBG) and stoma adjustable
silicone gastric banding (ASGB). Methods: Between 1991 and 1996, 51 patients were treated surgically for morbid obesity: 27
underwent VBG and 24 underwent ASGB. Preoperative body weight (BW), body mass index (BMI) and percentage of ideal body weight
(% IBW) were (mean ± SD): 145.7 ± 45.3 kg; 53.9 ± 15.9 kg/m2; 249.1 ± 73.5% respectively in the VBG group. Corresponding figures for the ASBG group were 132.5 ± 22.7 kg; 46.9 ± 7.8 kg/m2 and 207.2 ± 35.0%. Results: In the VBG group, the median follow-up period was 26 months (range: 7-47). Eighteen months after
the operation BW, BMI, % IBW and percentage of excess weight loss (% EWL) were 85.5 ± 26.8 kg, 31.9 ± 9.8 kg/m2, 145.4 ± 43.9% and 74 ± 1% respectively. Complications included incisional hernia (n = 1), and bowel obstruction (n = 1).
One patient died of acute myocardial infarction on the third postoperative day. In the ASGB group, median follow-up time was
19.7 months (range: 18-26). At 18 months postoperation BW, BMI, % IBW and % EWL values were 86.6 ± 20.6 kg 30.6 ± 6.6 kg/m2
140.6 ± 29.3% and 64 ± 1% respectively. Gastric wall erosion occurred in two patients and the bands had to be removed. These
patients underwent VBG 6 months later. Complications encountered in this group were incisional hernia (n = 1), outlet stenosis
and reflux esophagitis (n = 1), reservoir leakage (n = 1) and gastrointestinal bleeding (n = 1). Two patients died of pulmonary
embolism and acute gastrointestinal bleeding. Conclusions: Weight reduction was not statistically significant between the
two groups. ASGB was easier to perform and less invasive than VBG. 相似文献
5.
6.
P.F. MORSE D.F. HORROBIN M.S. MANKU J.C.M. STEWART R. ALLEN S. LITTLEWOOD S. WRIGHT† J. BURTON† D.J. GOULD‡ P.J. HOLT§ C.T. JANSEN¶ L. MATTILA¶ W. MEIGEL TH. DETTKE D. WEXLER†† L. GUENTHER†† A. BORDONI‡‡ A. PATRIZI‡‡ 《The British journal of dermatology》1989,121(1):75-90
Gamma-linolenic acid in the form of a particular variety of evening primrose oil (Epogam) has been reported of value in the treatment of atopic eczema. Nine controlled trials of evening primrose oil were performed in eight centres. Four of the trials were parallel and five cross-over. Doctors and patients assessed the severity of eczema by scoring measures of inflammation, dryness, scaliness, pruritus and overall skin involvement. Individual symptom scores were combined to give a single global score at each assessment point. In the analysis of the parallel studies, both patient and doctor scores showed a highly significant improvement over baseline (P less than 0.0001) due to Epogam: for both scores the effect of Epogam was significantly better than placebo. Similar results were obtained on analysis of the cross-over trials, but in this case the difference between Epogam and placebo in the doctors' global score, although in favour of Epogam, failed to reach significance. The effects on itch were particularly striking. There was no placebo response to this symptom, whereas there was a substantial and highly significant response to Epogam (P less than 0.0001). When the improvements, or otherwise, in clinical condition were related to changes in plasma levels of dihomogammalinolenic and arachidoni acids, it was found that there was a positive correlation between an improvement in clinical score and a rise in the fatty acid levels. 相似文献
7.
Ittel TH; Steinhausen C; Kislinger G; Kinzel S; Nolte E; Sieberth HG 《Nephrology, dialysis, transplantation》1997,12(7):1369-1375
BACKGROUND: Developments in accelerator mass spectrometry (AMS) now permit
the determination of femtogram amounts of 26Al in blood and in various
tissues with good precision and free of external contamination. METHODS: In
the present study we used trace quantities of 26Al to investigate the
intestinal absorption and compartmentalization of aluminium in rats with
renal failure (Nx, 5/6 nephrectomy) and in pair- fed controls (C). Single
oral doses of 20 ng 26Al were administered to six animals in each group
and, subsequently, 24-h post-load 26Al was analysed in serum, urine, bone,
liver, and spleen by means of AMS. RESULTS: Serum concentrations of 26Al
were significantly lower in uraemic rats compared to controls, whereas
urinary excretion was comparable (Nx, 7.11 +/- 5.78 pg/day vs C, 9.46 +/-
6.10 pg/day), suggesting a higher fraction of ultrafiltrable serum 26Al in
uraemia. The target tissues of cellular transferrin-mediated 26Al uptake,
liver and spleen, tended to show a larger degree of aluminium accumulation
in controls (0.26 +/- 0.31 pg/g vs Nx, 0.14 +/- 0.10 pg/g and 0.37 +/- 0.27
pg/g vs Nx, 0.25 +/- 0.27 pg/g respectively). In contrast, in bone, a site
of extracellular aluminium deposition, 26Al concentrations were more
elevated in uraemia (1.22 +/- 0.59 pg/g vs C: 0.68 +/- 0.30 pg/g).
Estimated total 26Al accumulation in all measured target tissues was
significantly higher in uraemic rats (28.15 +/- 9.90 pg vs C: 17.03 +/-
7.03 pg) and total recovery of 26Al from tissue and urine was 26.58 +/-
6.74 pg in controls and 35.75 +/- 7.03 pg in uraemic animals, suggesting a
fractional absorption of 0.133% and 0.175% respectively. CONCLUSIONS: Our
data suggest that fractional absorption from a dietary level dose of 26Al
is about 0.13%. Compartmentalization occurs in transferrin-dependent target
tissues such as liver and spleen; however, in quantitative terms
extracellular deposition in bone is more important. Uraemia has a
significant effect on the intestinal absorption and compartmentalization of
aluminium. It enhances fractional absorption and increases subsequent
extracellular deposition of aluminium in bone. However, at the same time
uraemia does not increase transferrin-dependent cellular accumulation of
aluminium in liver and spleen.
相似文献
8.
9.
For solid-phase peptide synthesis, 2, 4-dimethoxy-4′ -hydroxybenzhydrol linker was prepared via lithium borohydride reduction of 2, 4-dimethoxy-4′-hydroxybenzophenone. The potassium salt of the linker was coupled to chloromethylpolystyrene. This method proved to be better than use of the cesium salt. This new synthesis gave a polymer with appropriate structure and a good degree of substitution. 相似文献
10.