全文获取类型
收费全文 | 17790篇 |
免费 | 730篇 |
国内免费 | 2篇 |
出版年
2021年 | 258篇 |
2020年 | 214篇 |
2019年 | 250篇 |
2018年 | 423篇 |
2017年 | 342篇 |
2016年 | 524篇 |
2015年 | 678篇 |
2014年 | 749篇 |
2013年 | 989篇 |
2012年 | 1036篇 |
2011年 | 1037篇 |
2010年 | 601篇 |
2009年 | 503篇 |
2008年 | 662篇 |
2007年 | 677篇 |
2006年 | 632篇 |
2005年 | 578篇 |
2004年 | 491篇 |
2003年 | 499篇 |
2002年 | 485篇 |
2001年 | 320篇 |
2000年 | 248篇 |
1999年 | 214篇 |
1998年 | 135篇 |
1992年 | 256篇 |
1991年 | 235篇 |
1990年 | 191篇 |
1989年 | 224篇 |
1988年 | 241篇 |
1987年 | 248篇 |
1986年 | 218篇 |
1985年 | 247篇 |
1984年 | 206篇 |
1983年 | 166篇 |
1980年 | 94篇 |
1979年 | 237篇 |
1978年 | 157篇 |
1977年 | 143篇 |
1976年 | 139篇 |
1975年 | 168篇 |
1974年 | 267篇 |
1973年 | 272篇 |
1972年 | 252篇 |
1971年 | 243篇 |
1970年 | 258篇 |
1969年 | 246篇 |
1968年 | 185篇 |
1967年 | 185篇 |
1966年 | 169篇 |
1965年 | 124篇 |
排序方式: 共有10000条查询结果,搜索用时 281 毫秒
1.
Iteng Ng-Choi ngel Oliveras Lidia Feliu Marta Planas 《International journal of peptide research and therapeutics》2020,26(2):695-707
The feasibility of the solid-phase intramolecular 4(5)-arylation of a histidine residue to obtain biaryl cyclic peptides bearing a His-Phe linkage was esta 相似文献
2.
Sacramento Doralice Rodrigues Coelho Rosalie Reed Rodrigues Wigg Márcia Dutra Toledo Luna Linhares Luiz Fernando de Matos dos Santos Marta Gonçalves Azevedo Soares Semêdo Luzia Teixeira de Ribeiro da Silva Antonio Jorge 《World journal of microbiology & biotechnology》2004,20(3):225-229
A promising producer of bioactive compounds isolated from a Brazilian tropical soil was tested for its range of antimicrobial
activities. Strain 606, classified as Streptomyces sp., could not be identified up to species level, suggesting a possible new taxon. The supernatant and 10 extracts and fractions,
obtained by extraction and chromatographic techniques, presented antimicrobial activity using antibiograms. The methanolic
fraction was highly active against pathogenic bacteria, phytopathogenic fungi and the human pathogenic yeast Candida albicans. It also possessed high antiviral activity inhibiting the propagation of an acyclovir-resistant herpes simplex virus type
1 strain on HEp-2 cells at non-cytotoxic concentration. The strong cytotoxic effect suggests an antitumour action.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
4.
5.
A new simple enzymatic method for measuring AMP content in freeze-clamped rat heart is presented. The method is based on the ammonia estimation after the deamination of 5'-AMP by muscle 5'-adenylic acid deaminase. The minimum detectable amount of AMP was about 1.5 nmol. The recovery of AMP added to the tissue homogenate was 94%. The variance coefficient evaluated by assaying five samples from one tissue extract was equal to 5%. AMP content of rat heart (0.28 mumol/g wet tissue) is comparable with the values reported by others. 相似文献
6.
7.
Josep C. Jiménez-Chillarón Rubén Díaz Débora Martínez Thais Pentinat Marta Ramón-Krauel Sílvia Ribó Torsten Plösch 《Biochimie》2012
Nutrition plays a key role in many aspects of health and dietary imbalances are major determinants of chronic diseases including cardiovascular disease, obesity, diabetes and cancer. Adequate nutrition is particularly essential during critical periods in early life (both pre- and postnatal). In this regard, there is extensive epidemiologic and experimental data showing that early sub-optimal nutrition can have health consequences several decades later. 相似文献
8.
9.
10.
M. Filek J. Biesaga-Kościelniak I. Marcińska M. Cvikrová I. Macháčková J. Krekule 《Biologia Plantarum》2010,54(3):483-487
The contents of endogenous free and conjugated polyamines, putrescine (Put) and spermidine (Spd), were determined during 9
week of vernalization (at 5 °C) in winter wheat seedlings cultivated on Murashige and Skoog media without (MS0) and with 2
mg dm−3 zearalenone (MSZEN). At the 4th week of chilling treatment, which is sufficient to induce generative development in 30 % of plants, the marked increase in
free and conjugated forms of Put and free Spd were observed. The presence of ZEN in medium significantly accelerated the vernalization.
About 20 % of plants treated with ZEN flowered already after 2 weeks and 40 % after 3 weeks of chilling. Significantly higher
content of free Put was determined in roots grown on MSZEN compared with MS0 during the first 5 weeks of vernalization with
maximum at the 4th week. After germination, a marked decrease in free Spd content was observed both in plants grown on MS0 and MSZEN. Application
of ZEN significantly slowed down the Spd decline in leaves and roots during the first and second week of vernalization. The
content of Spd and its conjugates decreased in vernalized plants after 1 week of cultivation at 20 °C. 相似文献