全文获取类型
收费全文 | 1378篇 |
免费 | 103篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 16篇 |
儿科学 | 48篇 |
妇产科学 | 13篇 |
基础医学 | 147篇 |
口腔科学 | 15篇 |
临床医学 | 157篇 |
内科学 | 230篇 |
皮肤病学 | 67篇 |
神经病学 | 91篇 |
特种医学 | 198篇 |
外科学 | 158篇 |
综合类 | 21篇 |
一般理论 | 1篇 |
预防医学 | 125篇 |
眼科学 | 20篇 |
药学 | 106篇 |
肿瘤学 | 92篇 |
出版年
2021年 | 17篇 |
2020年 | 13篇 |
2019年 | 15篇 |
2018年 | 20篇 |
2017年 | 14篇 |
2016年 | 14篇 |
2015年 | 10篇 |
2014年 | 36篇 |
2013年 | 43篇 |
2012年 | 49篇 |
2011年 | 43篇 |
2010年 | 36篇 |
2009年 | 31篇 |
2008年 | 44篇 |
2007年 | 52篇 |
2006年 | 49篇 |
2005年 | 83篇 |
2004年 | 48篇 |
2003年 | 43篇 |
2002年 | 40篇 |
2001年 | 33篇 |
2000年 | 42篇 |
1999年 | 33篇 |
1998年 | 40篇 |
1997年 | 33篇 |
1996年 | 43篇 |
1995年 | 30篇 |
1994年 | 24篇 |
1993年 | 36篇 |
1992年 | 29篇 |
1991年 | 21篇 |
1990年 | 22篇 |
1989年 | 35篇 |
1988年 | 36篇 |
1987年 | 46篇 |
1986年 | 26篇 |
1985年 | 32篇 |
1984年 | 25篇 |
1983年 | 31篇 |
1982年 | 31篇 |
1981年 | 19篇 |
1980年 | 18篇 |
1979年 | 16篇 |
1978年 | 11篇 |
1977年 | 16篇 |
1976年 | 20篇 |
1975年 | 14篇 |
1973年 | 6篇 |
1972年 | 4篇 |
1967年 | 4篇 |
排序方式: 共有1505条查询结果,搜索用时 15 毫秒
1.
S J Harwood R G Carroll M Anderson B I Friedman L M Zangara A K Brunette R Kline 《Clinical nuclear medicine》1987,12(9):694-702
Thirty gallium scans, using currently acceptable dosage levels (5-6 mCi) and a conventional rotating gamma camera, were performed on 20 patients with lymphoma or infection. Compared to planar scans, SPECT increased sensitivity and lesion detection from 48% to 89% in lymphoma, and from 50% to 80% in infection. The predictive value of a negative site was 81% in lymphoma and 67% in infection. Gallium utility is markedly increased by SPECT imaging. A normal gallium SPECT scan is highly accurate in ruling out disease. 相似文献
2.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence. 相似文献
3.
Sean Ekins Dayna C Mankowski Dennis J Hoover Michael P Lawton Judith L Treadway H James Harwood 《Drug metabolism and disposition》2007,35(3):493-500
CYP51 fulfills an essential requirement for all cells, by catalyzing three sequential mono-oxidations within the cholesterol biosynthesis cascade. Inhibition of fungal CYP51 is used as a therapy for treating fungal infections, whereas inhibition of human CYP51 has been considered as a pharmacological approach to treat dyslipidemia and some forms of cancer. To predict the interaction of inhibitors with the active site of human CYP51, a three-dimensional quantitative structure-activity relationship model was constructed. This pharmacophore model of the common structural features of CYP51 inhibitors was built using the program Catalyst from multiple inhibitors (n = 26) of recombinant human CYP51-mediated lanosterol 14alpha-demethylation. The pharmacophore, which consisted of one hydrophobe, one hydrogen bond acceptor, and two ring aromatic features, demonstrated a high correlation between observed and predicted IC(50) values (r = 0.92). Validation of this pharmacophore was performed by predicting the IC(50) of a test set of commercially available (n = 19) and CP-320626-related (n = 48) CYP51 inhibitors. Using predictions below 10 microM as a cutoff indicative of active inhibitors, 16 of 19 commercially available inhibitors (84%) and 38 of 48 CP-320626-related inhibitors (79.2%) were predicted correctly. To better understand how inhibitors fit into the enzyme, potent CYP51 inhibitors were used to build a Cerius(2) receptor surface model representing the volume of the active site. This study has demonstrated the potential for ligand-based computational pharmacophore modeling of human CYP51 and enables a high-throughput screening system for drug discovery and data base mining. 相似文献
4.
5.
Paul G. Egland Dale A. Pelletier Marilyn Dispensa Jane Gibson Caroline S. Harwood 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(12):6484-6489
A reductive benzoate pathway is the central conduit for the anaerobic biodegradation of aromatic pollutants and lignin monomers. Benzene ring reduction requires a large input of energy and this metabolic capability has, so far, been reported only in bacteria. To determine the molecular basis for this environmentally important process, we cloned and analyzed genes required for the anaerobic degradation of benzoate and related compounds from the phototrophic bacterium, Rhodopseudomonas palustris. A cluster of 24 genes was identified that includes twelve genes likely to be involved in anaerobic benzoate degradation and additional genes that convert the related compounds 4-hydroxybenzoate and cyclohexanecarboxylate to benzoyl-CoA. Genes encoding benzoyl-CoA reductase, a novel enzyme able to overcome the resonance stability of the aromatic ring, were identified by directed mutagenesis. The gene encoding the ring-cleavage enzyme, 2-ketocyclohexanecarboxyl-CoA hydrolase, was identified by assaying the enzymatic activity of the protein expressed in Escherichia coli. Physiological data and DNA sequence analyses indicate that the benzoate pathway consists of unusual enzymes for ring reduction and cleavage interposed among enzymes homologous to those catalyzing fatty acid degradation. The cloned genes should be useful as probes to identify benzoate degradation genes from other metabolically distinct groups of anaerobic bacteria, such as denitrifying bacteria and sulfate-reducing bacteria. 相似文献
6.
7.
This study assessed the impact of family history of alcoholism and antisocial behavior on problem drinking among male first-time DWI offenders. A sample of 123 men in DWI classes were assessed on demographic factors, antisocial behavior and family history of alcoholism. Also, measures of current and past drinking problems were assessed, including scales of perceived ability to control consumption, degree of physical dependence, occurrence of alcohol-related problems and preoccupation with alcohol. The results indicated that while family history of alcohol and antisocial behavior were not significantly related to quantity/frequency of alcohol consumption or alcohol-related problems, family history was related to drink duration. Main effects of family history and antisocial behavior were found for preoccupation with alcohol and physical dependence. There was a significant interaction with respect to perceived ability to control drinking. Results are discussed with regard to the implication that family history of alcoholism and antisocial behavior may influence the development of important precursors to alcoholism. 相似文献
8.
9.
10.