全文获取类型
收费全文 | 1130篇 |
免费 | 70篇 |
出版年
2022年 | 2篇 |
2021年 | 11篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 14篇 |
2017年 | 6篇 |
2016年 | 15篇 |
2015年 | 27篇 |
2014年 | 45篇 |
2013年 | 64篇 |
2012年 | 68篇 |
2011年 | 73篇 |
2010年 | 46篇 |
2009年 | 44篇 |
2008年 | 63篇 |
2007年 | 95篇 |
2006年 | 74篇 |
2005年 | 82篇 |
2004年 | 107篇 |
2003年 | 73篇 |
2002年 | 62篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 18篇 |
1997年 | 14篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 9篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 12篇 |
1981年 | 12篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1972年 | 3篇 |
排序方式: 共有1200条查询结果,搜索用时 15 毫秒
171.
The effect of light irradiation on cytoplasmic streaming inVallisneria mesophyll cells was investigated. Red light ( 相似文献
172.
In addition to the known triterpene motiol, hopenol-b (hop-22(29)-en-3β-ol) was isolated from the whole herb of Euphorbia supina. It has not been found previously in nature, though it has been prepared by both synthetic and biosynthetic methods. 相似文献
173.
174.
175.
Cancer chemoprevention, the prevention of cancer by ingestion of chemical agents that reduce the risk of carcinogenesis, is one of the potent ways to reduce morbidity and mortality. We have been searching for cancer chemopreventive agents from the leaves and barks of coniferous trees that have been treated as waste in the forestry industry. We have previously reported the isolation of spiro‐biflavonoids, named as abiesinols, and a neolignan from the MeOH extract of the bark of Abies sachalinensis. These compounds were tested for their inhibitory effects on the activation of (±)‐(E)‐methyl‐2‐[(E)‐hydroxyimino]‐5‐nitro‐6‐methoxyhex‐3‐enamide (NOR 1), a nitric oxide (NO) donor, as a primary screening test for anti‐tumor initiators. All compounds tested exhibited potent inhibitory effects on NOR 1 activation. Furthermore, abiesinol A, bearing a spiro‐biflavonoid skeleton, showed remarkable anti‐tumor‐initiating activity in the in vivo two‐stage mouse skin carcinogenesis test using peroxynitrite (ONOO?; PN) as the initiator and 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) as the promoter. 相似文献
176.
Usui Akira Kitahara Yuichi Matsushita Yutaka Kitajima Miyoko Sakamoto Reiko Watanabe Tsuyoshi Motohashi Nobutaka 《Sleep and biological rhythms》2008,6(1):53-55
Sleep and Biological Rhythms - The patient was a 21-year-old male who complained of daytime sleepiness. His multiple sleep latency test (MSLT) showed multiple sleep onset REM periods (SOREMPs). The... 相似文献
177.
Kanji Takeo Reiko Tanaka Makoto Miyaji Kazuko Nishimura 《FEMS microbiology letters》1995,129(2-3):231-235
Abstract Stationary-phase cells of Cryptococcus neoformans displayed two morphological characteristics: virtually all the cells were unbudded even in the early stationary phase and even when grown in rich media, and average cell size increased from that of exponential-phase cells. DNA contents for small and large stationary-phase cells were determined by quantitative fluorescence microscopy after DNA staining with propidium iodide or DAPI. Small cells contained G, DNA, whereas large unbudded cells had either a G2 or G1 DNA content, indicating that Cr. neoformans can enter into the stationary phase from either the G1 or G2 period. 相似文献
178.
Masakazu Terauchi Tamami Odai Asuka Hirose Kiyoko Kato Mihoko Akiyoshi Mikako Masuda Reiko Tsunoda Hiroaki Fushiki Naoyuki Miyasaka 《BioPsychoSocial medicine》2018,12(1):21
Background
Although dizziness is one of the most common symptoms of menopause, the underlying mechanism is not precisely known. Therefore, this study aimed to investigate the prevalence of, and the factors associated with, dizziness in peri- and postmenopausal women.Methods
We conducted a cross-sectional study in which we analyzed the first-visit records of 471 Japanese women aged 40 to 65?years who enrolled in a health and nutrition education program at a menopause clinic. The prevalence of dizziness was estimated according to the participants’ responses to the Menopausal Health-Related Quality of Life Questionnaire. The background characteristics of age, menopause status, body composition, cardiovascular parameters, basal metabolism, and physical fitness; other menopausal symptoms, including vasomotor, insomnia, depression, and anxiety symptoms; and lifestyle characteristics were assessed for their associations with dizziness.Results
The percentage of women who suffered from dizziness once a week or more frequently was 35.7%. Compared to the women without dizziness, those with the symptom were younger; had a higher body weight, body mass index, body fat percentage, muscle mass, and waist-to-hip ratio; had higher systolic pressure; were slower in reaction time; had higher physical and psychological symptom scores of menopause; exercised less regularly; and consumed less alcohol. A multivariate logistic regression analysis revealed that the anxiety symptom, which was evaluated by the Hospital Anxiety and Depression Scale, was the sole factor that was independently associated with dizziness (adjusted odds ratio 1.14; 95% confidence interval 1.08–1.20).Conclusions
Dizziness is highly prevalent in Japanese peri- and postmenopausal women and it is associated with anxiety. The treatment of anxiety in this population might improve the symptom.179.
Advances in soil microbial ecology and the biodiversity 总被引:3,自引:0,他引:3
Tsutomu Hattori Hisayuki Mitsui Hideki Haga Norio Wakao Shuichi Shikano Krystyna Gorlach Yasuhiro Kasahara Adel El-Beltagy Reiko Hattori 《Antonie van Leeuwenhoek》1997,72(1):21-28
Recent studies on the colony formation of soil bacteria opened the way to categorize soil bacteria into colony forming curve (CFC) groups of different growth rates. A bacterial culture collection comprising organisms from every CFC group is called an ecocollection. Outlines of ECs of paddy soil 1992 and grassland soil 1987 and 1992 were described. Phylogenetic studies by 16S rDNA sequencing showed a great diversity of culture strains of the ecocollections (EC). A set of alternative concepts was proposed; the active and the quiescent forms of bacterial cells in soil. The former is able to be cultivated and thus counted by the plate method, while the latter is not unless it transforms into the former. Based on the results several points required for extensive cataloguing of soil bacteria were noted. 相似文献
180.
A strain ofBullera alba that secretes a killer toxin inhibitory (at pH values ranging from 3 to 7) to many ascomycetous and basidiomycetous yeast-like
fungi was discovered. Its killer phenotype was incurable. The toxin was relatively thermostable and resistant to many proteases,
and it was identified as a microcin. It inhibited the growth of some pathogenic yeasts and was the most active againstCryptococcus neoformans. 相似文献