全文获取类型
收费全文 | 822篇 |
免费 | 16篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 21篇 |
妇产科学 | 2篇 |
基础医学 | 71篇 |
口腔科学 | 8篇 |
临床医学 | 71篇 |
内科学 | 330篇 |
皮肤病学 | 5篇 |
神经病学 | 8篇 |
特种医学 | 22篇 |
外科学 | 51篇 |
综合类 | 9篇 |
预防医学 | 130篇 |
眼科学 | 39篇 |
药学 | 21篇 |
肿瘤学 | 47篇 |
出版年
2021年 | 8篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2014年 | 6篇 |
2013年 | 11篇 |
2012年 | 13篇 |
2011年 | 26篇 |
2010年 | 22篇 |
2009年 | 10篇 |
2008年 | 22篇 |
2007年 | 29篇 |
2006年 | 29篇 |
2005年 | 32篇 |
2004年 | 28篇 |
2003年 | 27篇 |
2002年 | 38篇 |
2001年 | 10篇 |
2000年 | 11篇 |
1999年 | 22篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1993年 | 6篇 |
1992年 | 19篇 |
1991年 | 24篇 |
1990年 | 30篇 |
1989年 | 26篇 |
1988年 | 33篇 |
1987年 | 27篇 |
1986年 | 25篇 |
1985年 | 30篇 |
1984年 | 20篇 |
1983年 | 17篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1979年 | 19篇 |
1978年 | 15篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1975年 | 13篇 |
1974年 | 18篇 |
1973年 | 14篇 |
1972年 | 10篇 |
1971年 | 11篇 |
1970年 | 9篇 |
1969年 | 9篇 |
1968年 | 9篇 |
1967年 | 7篇 |
1966年 | 9篇 |
1965年 | 6篇 |
排序方式: 共有839条查询结果,搜索用时 31 毫秒
1.
2.
3.
The modulation of drug metabolising enzymes by Masheri extract (ME) and Benzo(a)Pyrene [B(a)P] was studied in male Sprague Dawley rats fed different dietary protein levels. Two groups of 21 days old male Sprague Dawley rats were put on a high protein diet (SHP) with 20% Casein, and a low protein diet (SLP) with 3% Casein semisynthetic based diets for 12 weeks. The SLP fed animals showed lower basal levels of the Phase I activating enzymes viz. Cytochrome P450, Benzo(a)Pyrene hydroxylase, Benzphetamine demethylase and Phase II glutathione detoxification system viz. Glutathione (GSH) and Glutathione-S-transferase. ME and B(a)P treatment significantly depleted the glutathione detoxification system in the SLP group whereas an opposite effect was observed in the SHP group. Interstingly, ME and B(a)P treated rats in the SLP group showed a higher percent increase in the hepatic and pulmonary Phase I enzyme activities than those observed in the treated ME/B(a)P treated SHP rats. Furthermore, both ME and B(a)P significantly decreased the hepatic pool of vitamin A while a concomittant increase in that of vitamin C was observed. 相似文献
4.
Classical and anaplastic seminoma: difference in survival 总被引:1,自引:0,他引:1
Classical and anaplastic seminoma are traditionally treated with radiation therapy and are said to have the same prognosis. A retrospective study was undertaken of 90 seminoma patients treated with radiation therapy between 1961 and 1985. The classical group consisted of 71 patients of whom 50 had stage I and 21 had stage II disease. The anaplastic group consisted of 19 patients of whom ten had stage I and nine had stage II disease. The median follow-up time was 64 months for the entire group. The 10-year relapse-free survival rate for the classical group was 94% and for the anaplastic group was 70% (P less than .05). For patients with classical stage I disease, the relapse-free actuarial survival rate was 98%; for patients with anaplastic stage I disease, it was 64% (P less than .02). For the classical stage II disease group, the relapse-free actuarial survival rate was 84% and for the anaplastic stage II disease group, 75% (P less than .70). Four patients in the classical group (6%) had relapses; of these, one patient had local recurrence of tumor, and three had distant metastases. In the anaplastic group, four patients (21%) had relapses; two patients had local recurrence of tumor, and two had distant metastases. Therefore the data suggest a difference in survival and relapse rates between classical and anaplastic seminoma. 相似文献
5.
E V Sidorenko S S Iamnikova T A Ignatenko L A Smogorzhevski? D K L'vov 《Voprosy virusologii》1991,36(2):108-111
Using monoclonal antibodies to hemagglutinin and nucleoprotein of various influenza virus strains, the populations of long-passaged strain A/Hong Kong/1/68 and of recently isolated strain A/sparrow/Ukraine/83 belonging to the H3N2 serovariant were shown to have subpopulations of virions differing in the structure of antigenic sites of hemagglutinin and in nucleoprotein domain which correlated with the degree of electrostatic interaction of virions with an ion-exchanger. The results of the study indicate a possibility of separation in the course of stepwise ion-exchange chromatography on DEAE-Sephadex A-50 of antigenic variants of influenza virus strains which is very important for the understanding of the mechanisms of population variability as well as for investigation of individual epitopes of hemagglutinin and nucleoprotein domains of influenza virus in evaluation of antigenic relationships of virions belonging to the same strain of a certain serotype. 相似文献
6.
目的:应用酵母双杂交方法筛选BRCA2相互作用蛋白编码基因,验证其相互作用并研究其功能联系。方法:以BRCA2基因3′端片段构建酵母双杂交质粒,筛选正常人乳腺上皮细胞cDNA库,获得编码相互作用蛋白的基因,采用免疫共沉淀、哺乳细胞双杂交和荧光酶测定等方法进一步验证蛋白间相互作用和功能联系.结果:采用酵母双杂交系统筛选,获得了多个编码BRCA2相互作用蛋白的基因,其中包括已知的FHL2蛋白;免疫共沉淀和哺乳动物细胞双杂交试验显示BRCA2和FHL2在体内特异性结合,并证实FHL2在体内形成同源二聚体;转录活性分析发现BRCA2与FHL2有协同转录激活作用。结论:发现BRCA2与FHL2蛋白间相互作用和功能联系,为BRCA2功能研究提供了新的方向。 相似文献
7.
Mutation spectrum and genotype-phenotype analyses in Cowden disease and Bannayan-Zonana syndrome, two hamartoma syndromes with germline PTEN mutation 总被引:22,自引:1,他引:22
Marsh DJ; Coulon V; Lunetta KL; Rocca-Serra P; Dahia PL; Zheng Z; Liaw D; Caron S; Duboue B; Lin AY; Richardson AL; Bonnetblanc JM; Bressieux JM; Cabarrot-Moreau A; Chompret A; Demange L; Eeles RA; Yahanda AM; Fearon ER; Fricker JP; Gorlin RJ; Hodgson SV; Huson S; Lacombe D; Eng C 《Human molecular genetics》1998,7(3):507-515
The tumour suppressor gene PTEN , which maps to 10q23.3 and encodes a 403
amino acid dual specificity phosphatase (protein tyrosine phosphatase;
PTPase), was shown recently to play a broad role in human malignancy.
Somatic PTEN deletions and mutations were observed in sporadic breast,
brain, prostate and kidney cancer cell lines and in several primary tumours
such as endometrial carcinomas, malignant melanoma and thyroid tumours. In
addition, PTEN was identified as the susceptibility gene for two hamartoma
syndromes: Cowden disease (CD; MIM 158350) and Bannayan-Zonana (BZS) or
Ruvalcaba-Riley-Smith syndrome (MIM 153480). Constitutive DNA from 37 CD
families and seven BZS families was screened for germline PTEN mutations.
PTEN mutations were identified in 30 of 37 (81%) CD families, including
missense and nonsense point mutations, deletions, insertions, a
deletion/insertion and splice site mutations. These mutations were
scattered over the entire length of PTEN , with the exception of the first,
fourth and last exons. A 'hot spot' for PTEN mutation in CD was identified
in exon 5 that contains the PTPase core motif, with 13 of 30 (43%) CD
mutations identified in this exon. Seven of 30 (23%) were within the core
motif, the majority (five of seven) of which were missense mutations,
possibly pointing to the functional significance of this region. Germline
PTEN mutations were identified in four of seven (57%) BZS families studied.
Interestingly, none of these mutations was observed in the PTPase core
motif. It is also worthy of note that a single nonsense point mutation,
R233X, was observed in the germline DNA from two unrelated CD families and
one BZS family. Genotype-phenotype studies were not performed on this small
group of BZS families. However, genotype-phenotype analysis inthe group of
CD families revealed two possible associations worthy of follow-up in
independent analyses. The first was an association noted in the group of CD
families with breast disease. A correlation was observed between the
presence/absence of a PTEN mutation and the type of breast involvement
(unaffected versus benign versus malignant). Specifically and more
directly, an association was also observed between the presence of a PTEN
mutation and malignant breast disease. Secondly, there appeared to be an
interdependent association between mutations upstream and within the PTPase
core motif, the core motif containing the majority of missense mutations,
and the involvement of all major organ systems (central nervous system,
thyroid, breast, skin and gastrointestinal tract). However, these
observations would need to be confirmed by studying a larger number of CD
families.
相似文献
8.
MW Lieberman R Barrios G Kala SV Kala ED Lykissa CN Ou 《Environmental health perspectives》1999,107(9):A444-A445
Respond on comments on Lieberman's article: Cyclosiloxanes Produce Fatal Liver and Lung Damage in Mice. Environ Health Perspect 107:161-165 相似文献
9.
10.
Sidorenko SV Rezvan SP Tikchonova AS Krotova LA Ansolis LE Tzvigun EA 《International journal of antimicrobial agents》1996,7(2):109-117
Methodological differences makes it difficult to compare results of antimicrobial susceptibility testing obtained in Russia and in other regions. During the period from October 1993 to May 1994 susceptibility of 1296 isolates of bacteria was investigated according to NCCLS standards by the broth microdilution method. The order of activity of antibiotics against Gram-negative bacteria based on percent of susceptible strains from common hospitals were: amikacin (98%) > ciprofloxacin (93%) = imipenem (93%) > cefoperazone/sulbactam (92%) > ceftazidime (89%) > ceftriaxone (81%) > cefotaxime (80%) > cefoperazone (77%) > gentamicin (71%) > ampicillin/sulbactam (51%) > cefazoline (45%) > ampicillin (25%). The order of activity against strains from teaching hospitals was similar but the percent of susceptible strains was 10-20% less for the majority of antibiotics. The susceptibility level of Gram-negative isolates from Moscow teaching hospitals is lower than from Northern America and Europe. Ampicillln/sulbactam and cefoperazone/sulbactam, as well as other cephalosporins, demonstrated high activity against methicillin-susceptible staphylococci and penicillin-susceptible pneumococci. B-lactams/beta-lactamase inhibitor combinations were active against 100% strains of anaerobic bacteria. 相似文献