全文获取类型
收费全文 | 2330篇 |
免费 | 204篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 40篇 |
儿科学 | 77篇 |
妇产科学 | 94篇 |
基础医学 | 364篇 |
口腔科学 | 102篇 |
临床医学 | 170篇 |
内科学 | 331篇 |
皮肤病学 | 42篇 |
神经病学 | 110篇 |
特种医学 | 253篇 |
外科学 | 200篇 |
综合类 | 62篇 |
一般理论 | 1篇 |
预防医学 | 280篇 |
眼科学 | 28篇 |
药学 | 116篇 |
中国医学 | 1篇 |
肿瘤学 | 285篇 |
出版年
2021年 | 17篇 |
2020年 | 18篇 |
2019年 | 25篇 |
2018年 | 26篇 |
2017年 | 21篇 |
2016年 | 28篇 |
2015年 | 26篇 |
2014年 | 37篇 |
2013年 | 46篇 |
2012年 | 55篇 |
2011年 | 71篇 |
2010年 | 42篇 |
2009年 | 54篇 |
2008年 | 71篇 |
2007年 | 94篇 |
2006年 | 98篇 |
2005年 | 70篇 |
2004年 | 71篇 |
2003年 | 72篇 |
2002年 | 47篇 |
2001年 | 61篇 |
2000年 | 75篇 |
1999年 | 59篇 |
1998年 | 58篇 |
1997年 | 60篇 |
1996年 | 56篇 |
1995年 | 57篇 |
1994年 | 42篇 |
1993年 | 49篇 |
1992年 | 83篇 |
1991年 | 68篇 |
1990年 | 69篇 |
1989年 | 86篇 |
1988年 | 74篇 |
1987年 | 89篇 |
1986年 | 77篇 |
1985年 | 54篇 |
1984年 | 39篇 |
1983年 | 46篇 |
1982年 | 22篇 |
1981年 | 32篇 |
1980年 | 29篇 |
1979年 | 37篇 |
1978年 | 22篇 |
1977年 | 28篇 |
1976年 | 38篇 |
1975年 | 24篇 |
1971年 | 10篇 |
1970年 | 9篇 |
1966年 | 9篇 |
排序方式: 共有2556条查询结果,搜索用时 0 毫秒
1.
Cancer risk after evaluation for infertility 总被引:3,自引:0,他引:3
L A Brinton L J Melton G D Malkasian A Bond R Hoover 《American journal of epidemiology》1989,129(4):712-722
To evaluate cancer risk by various causes of infertility, the authors conducted a retrospective cohort study among 2,335 women evaluated for infertility at the Mayo Clinic between 1935 and 1964. Most cancers occurred at expected frequencies, with the exception of cancers of the thyroid (standardized incidence ratio (SIR) = 2.6) and other endocrine glands (SIR = 6.7), although analyses were based on small numbers. Patients with progesterone deficiencies (31 per cent of the study subjects) had a 20 per cent higher cancer risk than did those with other causes of infertility, with excesses deriving primarily from cancers of the lung, cervix, ovary, and thyroid and from melanoma. Breast cancer risk, however, was not elevated in either patients with progesterone deficiencies (SIR = 0.9) or patients with other causes of infertility (SIR = 1.0). Examination of other parameters of infertility, including age at evaluation, type of infertility (primary vs. secondary), and years of attempted conception, showed no elevated risks of breast cancer in any subgroup. These results fail to support previous studies that have linked progesterone deficiencies among infertile women to elevated breast cancer risk. However, the data suggest a possible involvement of a progesterone deficiency in the etiology of other cancers, particularly thyroid cancer and melanoma. 相似文献
2.
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
3.
D J Castro L Hoover R B Lufkin D J Castro T S Fu 《Archives of pathology & laboratory medicine》1987,111(9):867-869
This is an unusual case presentation of a young woman with a clinical history and course simulating juvenile hyaline fibromatosis, but without hyalinization in the stroma. Because of the age of onset, the apparent familial inheritance, the nonaggressive and nonregressive tumor traits, the disease cannot be classified as multicentric fibromatosis. Therefore, we are referring to this case as multicentric fibromatosis with familial inheritance, a previously unreported entity to our knowledge. 相似文献
4.
Effect of ciprofibrate, bezafibrate, and LY171883 on peroxisomal beta-oxidation in cultured rat, dog, and rhesus monkey hepatocytes 总被引:3,自引:0,他引:3
P S Foxworthy S L White D M Hoover P I Eacho 《Toxicology and applied pharmacology》1990,104(3):386-394
Cultured rat hepatocytes have been used extensively to study the mechanisms of chemically induced peroxisome proliferation. Hepatocytes from nonrodent species have been used on a limited scale to study interspecies differences in the response. Because of their importance in pharmaceutical safety assessment, we have developed a model to study the response of beagle dog and rhesus monkey hepatocytes to peroxisome proliferators. Treatment of the hepatocytes with peroxisome proliferators was begun after 20 hr in culture and continued for 72 hr. Untreated rat, dog, and monkey hepatocytes retained 62, 42, and 43% of their initial (20 hr) peroxisomal beta-oxidation activity throughout 92 hr of culture. Ciprofibrate, bezafibrate, and LY171883 caused a dose-related increase in beta-oxidation in rat hepatocytes to a maximum of 10-, 8-, and 5-fold, respectively. In dog and monkey hepatocytes the increases in beta-oxidation were less than 2-fold. Peroxisome morphology in dog and monkey hepatocytes appeared to be unchanged by the drugs. Morphometric analysis in monkey hepatocytes showed no increase in peroxisome volume fraction in response to the chemicals. Treatment of dog and monkey hepatocytes with dexamethasone and glucagon during the final 24 hr in culture caused a 4- to 6-fold increase in tyrosine aminotransferase activity. This induction is characteristic of the in vivo response. The small increase in beta-oxidation reflects the relative insensitivity of the dog and monkey liver to peroxisome proliferators in vivo rather than a loss of sensitivity during culture. Cultured hepatocytes from beagle dog and rhesus monkey may provide a model for studying the mechanisms underlying the interspecies differences. Such information would help clarify the relevance of rodent data in human risk assessment. 相似文献
5.
6.
Edited by Lauren Dundes. Walnut Creek (CA): Altamira Press, 2003. 239 pages. $27.95, paperback, $75.00, hardback. 相似文献
7.
Cytochrome P450IIE1 genetic polymorphisms, racial variation, and lung cancer risk. 总被引:10,自引:0,他引:10
S Kato P G Shields N E Caporaso R N Hoover B F Trump H Sugimura A Weston C C Harris 《Cancer research》1992,52(23):6712-6715
8.
9.
Ralls PW; Johnson MB; Kanel G; Dobalian DM; Colletti PM; Boswell WD Jr; Radin DR; Halls JM 《Radiology》1986,161(2):451-454
FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease. 相似文献
10.