全文获取类型
收费全文 | 23331篇 |
免费 | 1738篇 |
国内免费 | 295篇 |
专业分类
耳鼻咽喉 | 419篇 |
儿科学 | 416篇 |
妇产科学 | 623篇 |
基础医学 | 3422篇 |
口腔科学 | 419篇 |
临床医学 | 2049篇 |
内科学 | 4888篇 |
皮肤病学 | 794篇 |
神经病学 | 1720篇 |
特种医学 | 1234篇 |
外科学 | 3317篇 |
综合类 | 250篇 |
现状与发展 | 1篇 |
一般理论 | 3篇 |
预防医学 | 913篇 |
眼科学 | 613篇 |
药学 | 1817篇 |
中国医学 | 270篇 |
肿瘤学 | 2196篇 |
出版年
2023年 | 196篇 |
2022年 | 571篇 |
2021年 | 830篇 |
2020年 | 482篇 |
2019年 | 760篇 |
2018年 | 840篇 |
2017年 | 669篇 |
2016年 | 894篇 |
2015年 | 1202篇 |
2014年 | 1402篇 |
2013年 | 1546篇 |
2012年 | 2145篇 |
2011年 | 2067篇 |
2010年 | 1341篇 |
2009年 | 1096篇 |
2008年 | 1330篇 |
2007年 | 1280篇 |
2006年 | 1167篇 |
2005年 | 1097篇 |
2004年 | 867篇 |
2003年 | 745篇 |
2002年 | 720篇 |
2001年 | 330篇 |
2000年 | 271篇 |
1999年 | 230篇 |
1998年 | 98篇 |
1997年 | 96篇 |
1996年 | 62篇 |
1995年 | 63篇 |
1994年 | 49篇 |
1993年 | 32篇 |
1992年 | 109篇 |
1991年 | 92篇 |
1990年 | 88篇 |
1989年 | 77篇 |
1988年 | 62篇 |
1987年 | 43篇 |
1986年 | 40篇 |
1985年 | 47篇 |
1984年 | 40篇 |
1983年 | 29篇 |
1982年 | 21篇 |
1981年 | 32篇 |
1980年 | 15篇 |
1979年 | 21篇 |
1978年 | 17篇 |
1977年 | 17篇 |
1975年 | 14篇 |
1973年 | 18篇 |
1972年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Jia-You Fang Yann-Lii Leu Tsong-Long Hwang Hsiao-Chin Cheng Chi-Feng Hung 《European journal of pharmaceutical sciences》2003,19(4):253-262
To improve the drug permeation into and/or across the skin, essential oils extracted from Alpinia oxyphylla (AO) were evaluated using in vitro and in vivo permeation techniques with Wistar rats as the animal model. Hydrocarbons and oxygenated sesquiterpenes were the major components in the lower-polarity fraction (AO-1) and higher-polarity fraction (AO-2), respectively. Permeation of indomethacin was significantly enhanced after treatment with AO-1 and AO-2 in the in vitro and in vivo studies. AO-2 generally showed a higher ability to promote drug permeation compared to AO-1. The increment of skin/vehicle partitioning may be the predominant mechanism for this enhancing activity. Both transepidermal water loss (TEWL) and colorimetric evaluation showed limited irritation to skin by AO essential oils at the macroscopic level. Human skin fibroblasts were used to investigate the in vitro screening of skin toxicity. AO-1 slightly increased prostaglandin E(2) (PGE(2)) formation from skin fibroblasts. A striking result was observed with AO-2, which greatly inhibited the release of PGE(2). Moreover, both AO essential oils had no statistically significant effect on PGE(2) release by human lung epithelial cells. The results of this study indicate that skin disruption and inflammation do not necessary correspond to the enhancing efficiency of the enhancers tested. 相似文献
52.
S H Jee S Y Won J E Yun J E Lee J S Park S S Ji 《International journal of gynaecology and obstetrics》2004,85(3):301-308
OBJECTIVES: Although some studies have reported that the arginine isoform on codon 72 of p53 increases the susceptibility to invasive cervical cancer, such data remain controversial. The objective of this study was to quantitatively summarize the evidence for such a relationship. METHODS: Our data sources consisted of a MEDLINE search of the literature published before December 2002, bibliography review, and expert consultation. Thirty-seven studies met the inclusion criteria. Information on sample size, study design, Hardy-Weinberg equilibrium, and method of genotype determination was abstracted by two reviewers using a standardized protocol. The overall odds ratio (OR) of the p53 gene on invasive cervical cancer was estimated using the Mantel-Haenzel method. RESULTS: The overall OR (95% confidence interval) for cervical cancer among those with the homozygous mutant (Arg/Arg) was 1.2 (1.1-1.3, P=0.001) compared with those with the heterozygous mutant (Arg/Pro). By a cellular type of cervical cancer, the overall OR among those with Arg/Arg was statistically significant in adenocarcinomas (1.7, 1.1-2.6, P=0.024), but not in squamous cell carcinomas (1.1, 0.9-1.2, P=0.960), compared with Pro/Pro. Compared with Arg/Pro, the OR among those with Arg/Arg was statistically significant in HPV types 16 (1,5, 1.2-2.0, P=0.002). CONCLUSIONS: Overall, the p53 gene was associated with increased risk for invasive cervical cancer. However, the risk varied by country, cellular, and HPV type. 相似文献
53.
54.
Jae Sue Choi Han Suk Young Jong Cheol Park Jin-Ho Choi Won Sick Woo 《Archives of pharmacal research》1986,9(4):233-236
The flavonoids isolated from the leaves ofRhododendron brachycarpum, were identified as quercetin, avicularin, quercitrin and hyperin. 相似文献
55.
Berhooz Rajabalitabar Hung Anh Nguyen Herv Cheradame 《Macromolecular chemistry and physics.》1995,196(11):3597-3604
Polymerizations of 2-methylpropene (MP) initiated by the system 1,4-bis(1-azido-1-methylethyl)benzene (DAMEB)/BCl3 in the presence of DMSO were carried out by “all monomer in” (AMI) technique at ?70°C in CH2Cl2 solution. FT-IR, 1H NMR and SEC analyses of polymers (PMP) showed that the M n versus weight of PMP plot is a straight line without intercept and azide Fn3 and aromatic ring F? functionalities are close to the theoretical values of 2 and 1, respectively. A polymerization of MP initiated by the system α,ω-diazido-PMP/BCl3/DMSO led to a final poly(2-methylpropene) (PMP) with an increase of M n corresponding to the amount of MP introduced and presenting the same functionalities FN3 and F? as the starting PMP. These results indicate that the polymerization system MP/DAMEB/BCl3/DMSO is a “living” one, because in an acceptably large range of molecular weight (M n < 50000) the Mayo plot 1/DP versus 1/DP 0 is a straight line. The intercept gives ktrM/kp = 4 · 10?5, showing the transfer reaction proceeds at very low rate. 相似文献
56.
The hexane extract from Nutmeg, the seed ofMyristica fragrans significantly inhibited hepatic drug-metabolizing enzyme activity. Through systematic fractionation by SiO2 column and vacuum liquid chromatography monitoring by bioassay, three components, myristicin, (I), licarin-B(II) and dehydrodiisoeugenol(III) were isolated as active principles. Compounds II and III, with a single treatment (200 mg/kg, i.p.) showed not only a significant prolongation of hexobarbital-induced sleeping time but also a significant inhibition of aminopyrine N-demethylase and hexobarbital hydroxylase activities in mice. Compounds I and II provoked a sleep episode at a subhypnotic dose of HB, suggesting that they posses CNS-depressant properties. 相似文献
57.
Yang Hee Lee Ihn Rhan Lee Won Sick Won Chung Hee Park 《Archives of pharmacal research》1988,11(3):247-249
58.
Overexpression of S100A4 is closely related to the aggressiveness of gastric cancer 总被引:25,自引:0,他引:25
Cho YG Nam SW Kim TY Kim YS Kim CJ Park JY Lee JH Kim HS Lee JW Park CH Song YH Lee SH Yoo NJ Lee JY Park WS 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2003,111(5):539-545
Elevated levels of the calcium-binding protein S100A4 cause metastasis of benign rat mammary tumor cells. To investigate whether S100A4 plays an important role in the invasion and metastasis of gastric cancers, we examined the gene mutations in the coding regions and expression patterns of the S100A4 in gastric adenocarcinoma in Korea. Moderate to strong expression of S100A4 was found in 53 (68.8%) of the 77 gastric adenocarcinomas, whilst normal gastric epithelium either failed to stain or showed weak staining. Interestingly, S100A4 expression was more frequently observed in gastric cancer patients with advanced gastric cancer (p=0.039), positive lymph node metastasis (p=0.001), and peritoneal dissemination (p=0.022). No gene mutations were found in the analyzed genomic area in 77 gastric adenocarcinomas and 15 gastric cancer cell lines. We found one single nucleotide polymorphism without an amino acid change, A99G, in two cases. These data suggest that the overexpression of S100A4 may be closely related to the aggressiveness of gastric cancer in Korea. 相似文献
59.
Seo JS Lee SY Won KJ Kim DJ Sohn DS Yang KM Cho SH Park JD Lee KH Kim HD 《Journal of Korean medical science》2000,15(6):641-646
We provided a curve-fit equation to predict the normal heart weight (g) in Koreans by examining 422 autopsies (215 males and 207 females, from newborn to age 77 yr) who were relatively in good general condition. Heart weight was well correlated with body surface area (m2), body weight (kg), and body height (cm) but poorly with age in both sex. Heart weight progressively increased from birth to the earlier 3rd and 4th decades in male and female, respectively, and then gradually decreased; mean heart weight of all age group was greater in male than in female and significantly different from birth to 4th decade. In both sex, heart weight exponentially increased in accordance with the increase of body height, body weight, and body surface (in male, heart weight=0.00312 x body height(2.239), r2=0.750, p<0.0001; in female, heart weight=0.00443 x body height(2170), r2=0.781, p<0.0001; in male, heart weight=9.22 x body weight(0.853), r2=0.770, p<0.0001; in female, heart weight=9.00 x body weight0.855, r2=0.820, p<0.0001; in male, heart weight=155.18 x body surface area1.290, r=0.808, p<0.0001; in female, heart weight=124.13 x body surface area1.242, r=0.834, p<0.0001). These results indicate that heart weight is better correlated with body surface area than with body weight; however, body weight should be a better determinant of a predicted heart weight, since body surface area is entirely dependent on body height and body weight. 相似文献
60.
Detection of antibodies to human immunodeficiency virus by latex agglutination with recombinant antigen. 总被引:2,自引:7,他引:2 下载免费PDF全文
C H Riggin G A Beltz C H Hung R M Thorn D J Marciani 《Journal of clinical microbiology》1987,25(9):1772-1773
Recombinant human immunodeficiency virus (HIV) env antigen was attached to polystyrene particles, and these complexes were used to develop the first latex agglutination assay for antibodies to HIV. A total of 95 positive and 116 negative human serum samples were assayed for antibodies to HIV by latex agglutination, and results were compared with those of a commercial enzyme immunoassay. Latex agglutination was also compared with, and found to be completely concordant with, Western blot (immunoblot) analysis with virion antigens. 相似文献