全文获取类型
收费全文 | 1142篇 |
免费 | 67篇 |
出版年
2022年 | 7篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2018年 | 11篇 |
2017年 | 15篇 |
2016年 | 24篇 |
2015年 | 33篇 |
2014年 | 30篇 |
2013年 | 72篇 |
2012年 | 58篇 |
2011年 | 72篇 |
2010年 | 33篇 |
2009年 | 36篇 |
2008年 | 60篇 |
2007年 | 65篇 |
2006年 | 50篇 |
2005年 | 57篇 |
2004年 | 43篇 |
2003年 | 46篇 |
2002年 | 41篇 |
2001年 | 41篇 |
2000年 | 38篇 |
1999年 | 33篇 |
1998年 | 13篇 |
1997年 | 15篇 |
1996年 | 13篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1992年 | 21篇 |
1991年 | 18篇 |
1990年 | 19篇 |
1989年 | 23篇 |
1988年 | 21篇 |
1987年 | 10篇 |
1986年 | 23篇 |
1985年 | 14篇 |
1984年 | 10篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1975年 | 6篇 |
1973年 | 7篇 |
1972年 | 4篇 |
1971年 | 6篇 |
1968年 | 6篇 |
排序方式: 共有1209条查询结果,搜索用时 31 毫秒
41.
Heitaroh Iwata Toshio Matsuda Sadaaki Maeda Akemichi Baba 《Biochimica et Biophysica Acta (BBA)/General Subjects》1979,583(2):159-166
The effect of ascorbic acid on microsomal thiamine diphosphate activity in rat brain was examined. Ascorbic acid at 0.02–0.1 mM increased the thiamine diphosphate activity by 20–600% and produced a significant amount of lipid peroxide, which was measured with thiobarbiturate under the same conditions as the enzyme. A lag period of about 10 min was observed in the process of stimulation of enzyme activity by ascorbic acid. The stimulation of enzyme activity and the lipid peroxidation induced by ascorbic acid were blocked by metal-binding compounds (EDTA, α,α′-dipyridyl, o-phenanthroline) and an antioxidant (N,N′-diphenyl p-phenylenediamine). GSH significantly enhanced the stimulation of enzyme activity and formation of lipid peroxide by 0.02–0.05 mM ascorbic acid. The effect of GSH was due in part to maintenance of the concentration of ascorbic acid in the medium, since GSH could convert dehydroascorbic acid, an oxidized form of ascorbic acid, to ascorbic acid. 相似文献
42.
Sadako Iwata Kunio Tochikubo Keijiro Kato Takanori Hirata Shozo Kotani Kunio Yagi 《Microbiology and immunology》1976,20(2):123-129
Enzyme(s) capable of decomposing N-acetylglucosaminyl ribitol teichoic acid prepared from the cell wall of Staphylococcus aureus FDA 209 P was obtained from the culture supernatant of a gram-negative, rod-shaped, spore-forming soil bacterium. Properties of the bacterium were very similar to those of Bacillus circulans. 相似文献
43.
44.
Limnology - The in-stream processing of nutrients plays an important role in the fluvial nutrient transport from lands to the ocean, but few empirical studies have addressed the temporal dynamics... 相似文献
45.
46.
Shoichi Fujita Issei Chiba Mayumi Ishizuka Hidenobu Hoshi Hisato Iwata Akihito Sakakibara 《Biomarkers》2013,18(1):19-25
The impact of environmental pollution on selected animals was tested by monitoring the hepatic content of cytochromes P450 and their enzyme activities or by calculating TEQ values from the concentration of pollutants in the body. Fish-eating Stellars Sea Eagles, Haliaeetus pelagicus, found dead in the northern part of Hokkaido island accumulated high levels of PCBs and DDT and metabolites. The TEQ values calculated from the PCB concentration in the eagles were high enough to cause a significant toxic effect in other birds living in the same environment. Some of these birds were also contaminated with high concentrations of lead. Spotted seals, Phoca largha, captured along the coast-line of Hokkaido accumulated PCBs in their fat at about 100 million times the concentrations in the surface sea water. The levels of expressions of hepatic microsomal CYP 1A1and related enzyme activities in these seals showed good correlation to the levels of PCBs accumulated in the fat. The fresh water crabs, Eriocheir japonicus, were captured from three different rivers with various degrees of pollution. The P450 content and the related enzyme activities showed good correlation to TEQ values obtained from the concentrations of PCBs and PCDDs in the crabs from the rivers. The wild rodents, Clethrionomys rufocanus, were captured from urban, agricultural, and forest areas in Hokkaido. Those from the forest area had the lowest CYP content and related enzyme activities, comparable to those in laboratory-raised animals. Those from the urban areas, presumably contaminated with PAHs from fuel combustion, showed increased CYP 1A1 content and related enzyme activities. Those from the agricultural areas showed increased levels of CYP 1A1, 2B, 2E1. Rats treated with some of the agrochemicals used in the area resulted in a similar pattern of induction. It is concluded that P450 can be a useful biomarker for assessing the environmental impact of chemical pollutants on wild animals. 相似文献
47.
48.
Benjamin Tiburzy Martin Szyska Hiroaki Iwata Navina Chrobok Upasana Kulkarni Misa Hirose Ralf J. Ludwig Kathrin Kalies Jürgen Westermann David Wong Rudolf Armin Manz 《PloS one》2013,8(12)
Autoantibodies are believed to be maintained by either the continuous generation of short-lived plasma cells in secondary lymphoid tissues or by long-lived plasma cells localized in bone marrow and spleen. Here, we show in a mouse model for the autoimmune blistering skin disease epidermolysis bullosa acquisita (EBA) that chronic autoantibody production can also be maintained in inflamed lymph nodes, by plasma cells exhibiting intermediate lifetimes. After EBA induction by immunization with a mCOL7c-GST-fusion protein, antigen-specific plasma cells and CD4 T cells were analyzed. Plasma cells were maintained for months in stable numbers in the draining lymph nodes, but not in spleen and bone marrow. In contrast, localization of mCOL7c-GST -specific CD4 T cells was not restricted to lymph nodes, indicating that availability of T cell help does not limit plasma cell localization to this site. BrdU-incorporation studies indicated that pathogenic mCOL7c- and non-pathogenic GST-specific plasma cells resemble intermediates between short-and long-lived plasma cells with half-lives of about 7 weeks. Immunization with mCOL7c-GST also yielded considerable numbers of plasma cells neither specific for mCOL7c- nor GST. These bystander-activated plasma cells exhibited much shorter half-lives and higher population turnover, suggesting that plasma cell lifetimes were only partly determined by the lymph node environment but also by the mode of activation. These results indicate that inflamed lymph nodes can harbor pathogenic plasma cells exhibiting distinct properties and hence may resemble a so far neglected site for chronic autoantibody production. 相似文献
49.
Kate M. Scott Karestan C. Koenen Sergio Aguilar-Gaxiola Jordi Alonso Matthias C. Angermeyer Corina Benjet Ronny Bruffaerts Jose Miguel Caldas-de-Almeida Giovanni de Girolamo Silvia Florescu Noboru Iwata Daphna Levinson Carmen C. W. Lim Sam Murphy Johan Ormel Jose Posada-Villa Ronald C. Kessler 《PloS one》2013,8(11)
Background
Associations between lifetime traumatic event (LTE) exposures and subsequent physical ill-health are well established but it has remained unclear whether these are explained by PTSD or other mental disorders. This study examined this question and investigated whether associations varied by type and number of LTEs, across physical condition outcomes, or across countries.Methods
Cross-sectional, face-to-face household surveys of adults (18+) were conducted in 14 countries (n = 38, 051). The Composite International Diagnostic Interview assessed lifetime LTEs and DSM-IV mental disorders. Chronic physical conditions were ascertained by self-report of physician''s diagnosis and year of diagnosis or onset. Survival analyses estimated associations between the number and type of LTEs with the subsequent onset of 11 physical conditions, with and without adjustment for mental disorders.Findings
A dose-response association was found between increasing number of LTEs and odds of any physical condition onset (OR 1.5 [95% CI: 1.4–1.5] for 1 LTE; 2.1 [2.0–2.3] for 5+ LTEs), independent of all mental disorders. Associations did not vary greatly by type of LTE (except for combat and other war experience), nor across countries. A history of 1 LTE was associated with 7/11 of the physical conditions (ORs 1.3 [1.2–1.5] to 1.7 [1.4–2.0]) and a history of 5+ LTEs was associated with 9/11 physical conditions (ORs 1.8 [1.3–2.4] to 3.6 [2.0–6.5]), the exceptions being cancer and stroke.Conclusions
Traumatic events are associated with adverse downstream effects on physical health, independent of PTSD and other mental disorders. Although the associations are modest they have public health implications due to the high prevalence of traumatic events and the range of common physical conditions affected. The effects of traumatic stress are a concern for all medical professionals and researchers, not just mental health specialists. 相似文献50.
Kazuyuki Nakamura Hirofumi Kodera Tenpei Akita Masaaki Shiina Mitsuhiro Kato Hideki Hoshino Hiroshi Terashima Hitoshi Osaka Shinichi Nakamura Jun Tohyama Tatsuro Kumada Tomonori Furukawa Satomi Iwata Takashi Shiihara Masaya Kubota Satoko Miyatake Eriko Koshimizu Kiyomi Nishiyama Mitsuko Nakashima Yoshinori Tsurusaki Noriko Miyake Kiyoshi Hayasaka Kazuhiro Ogata Atsuo Fukuda Naomichi Matsumoto Hirotomo Saitsu 《American journal of human genetics》2013