全文获取类型
收费全文 | 1338篇 |
免费 | 79篇 |
国内免费 | 3篇 |
出版年
2023年 | 7篇 |
2022年 | 19篇 |
2021年 | 30篇 |
2020年 | 15篇 |
2019年 | 23篇 |
2018年 | 35篇 |
2017年 | 27篇 |
2016年 | 51篇 |
2015年 | 47篇 |
2014年 | 58篇 |
2013年 | 70篇 |
2012年 | 113篇 |
2011年 | 112篇 |
2010年 | 77篇 |
2009年 | 59篇 |
2008年 | 90篇 |
2007年 | 71篇 |
2006年 | 92篇 |
2005年 | 69篇 |
2004年 | 48篇 |
2003年 | 47篇 |
2002年 | 39篇 |
2001年 | 12篇 |
2000年 | 7篇 |
1999年 | 12篇 |
1998年 | 11篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1994年 | 11篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 6篇 |
1989年 | 11篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1984年 | 4篇 |
1982年 | 3篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1977年 | 3篇 |
1975年 | 4篇 |
1974年 | 7篇 |
1967年 | 4篇 |
1965年 | 5篇 |
1963年 | 4篇 |
1958年 | 6篇 |
1957年 | 6篇 |
1955年 | 3篇 |
排序方式: 共有1420条查询结果,搜索用时 15 毫秒
21.
22.
Our experiments showed that the activity of -glutamyltransferase (-GT) did not remarkably change in homogenates of mouse, rat, and bovine brains during the first four days post mortem. In the course of that period, the brain microvessels also retained their -GT activity. -GT of microvessels from bovine brain cortex, solubilized with sodium deoxycholate, was eluted in the void volume Vo when chromatographed on a Sephadex G-200 column with the detergent Triton X-100. In human post mortem brains, the specific activity of -GT in choroid plexi was found to be about five times higher than that in the cerebral cortex, white matter, basal ganglia, pons, and cerebellum but about four times lower than that in the microvessels obtained from the studied brain regions. Our findings suggest that it is possible to study the components of the blood-brain barrier on material from deceased subjects. 相似文献
23.
24.
Using natural spawning and artificial fertilization, the entire process of development from eggs to juveniles was observed in the sea-star, Asterina batheri Goto.
The breeding season of this animal in Tsukumo Bay and Toyama Bay is estimated to be late summer. The spawned eggs are approximately 430 μm in diameter and float near the surface of sea water. They develop, through a wrinkled blastula stage by holoblastic. radial cleavage, into a pear-shaped brachiolaria bearing 3 blunt brachiolar arms. Metamorphosis takes place while the brachiolariae are swimming. Ten days after fertilization, metamorphosis is complete; the resulting juveniles are about 800 μm in diameter and colored pale brown with a green tint. They bear 2 pairs of tube-feet and a terminal tentacle in each arm.
Development of this species is thus of the direct type, and very similar in every respect to that of Asterina coronata japonica , which is closely related to the present species. 相似文献
The breeding season of this animal in Tsukumo Bay and Toyama Bay is estimated to be late summer. The spawned eggs are approximately 430 μm in diameter and float near the surface of sea water. They develop, through a wrinkled blastula stage by holoblastic. radial cleavage, into a pear-shaped brachiolaria bearing 3 blunt brachiolar arms. Metamorphosis takes place while the brachiolariae are swimming. Ten days after fertilization, metamorphosis is complete; the resulting juveniles are about 800 μm in diameter and colored pale brown with a green tint. They bear 2 pairs of tube-feet and a terminal tentacle in each arm.
Development of this species is thus of the direct type, and very similar in every respect to that of Asterina coronata japonica , which is closely related to the present species. 相似文献
25.
Antisera (B10.129×A)F1 anti-P and (B10×A)F1 anti-B10.P contain antibodies that define, in the PVP hemagglutination test, an antigen originally described as G or H-2.7. Of the independentH-2 haplotypes, the H-2.7 antigen is present inf, j, k, p, ands. In addition, the antisera also contain a weak cytotoxic antibody, distinct from anti-H-2.7. The cytotoxic antibody reacts with antigens controlled by theK orI regions. The hemagglutinating H-2.7 antibody does not have cytotoxic activity. The genetic determinant coding for antigen H-2.7 can be mapped into the chromosomal segment between theS andD regions. The H-2.7 antigen thus serves as a marker for a new region of theH-2 complex. The locus coding for antigen H-2.7 is designatedH-2 G and the correspondingH-2 regionG. The H-2.7 antigen has a tissue distribution distinct from that of the H-2 antigens controlled by theK orD regions. So far it could be detected primarily on erythrocytes. 相似文献
26.
Antoaneta Trendafilova Victoria Ivanova Miroslav Rangelov Milka Todorova Gulmira Ozek Suleyman Yur Temel Ozek Ina Aneva Ralitza Veleva Veselina Moskova‐Doumanova Jordan Doumanov Tanya Topouzova‐Hristova 《化学与生物多样性》2020,17(4)
Chlorogenic (5‐CQA), 1,5‐, 3,5‐, 4,5‐ and 3,4‐dicaffeoylquinic (DCQA) acids were identified and quantified in the methanol extracts of Inula oculus‐christi L., I. bifrons L., I. aschersoniana Janka var. aschersoniana, I. ensifolia L., I. conyza (Griess .) DC. and I. germanica L. by HPLC analysis. The amount of 5‐CQA varied from 5.48 to 28.44 mg/g DE and the highest content was detected in I. ensifolia. 1,5‐DCQA (4.05–55.25 mg/g DE) was the most abundant dicaffeoyl ester of quinic acid followed by 3,5‐DCQA, 4,5‐DCQA and 3,4‐DCQA. The extract of I. ensifolia showed the highest total phenolic content (119.92±0.95 mg GAE/g DE) and exhibited the strongest DPPH radical scavenging activity (69.41±0.55 %). I. bifrons extract was found to be the most active sample against ABTS.+ (TEAC 0.257±0.012 mg/mL) and the best tyrosinase inhibitor. The studied extracts demonstrated a low inhibitory effect towards acetylcholinesterase and possessed low cytotoxicity in concentration range from 10 to 300 μg/mL toward non‐cancer (MDCK II) and cancer (A 549) cells. 相似文献
27.
Milosavljevic Isidora Jakovljevic Vladimir Petrovic Dejan Draginic Nevena Jeremic Jovana Mitrovic Miroslav Zivkovic Vladimir Srejovic Ivan Stojic Vladislava Bolevich Sergey Andjelkovic Nebojsa 《Molecular and cellular biochemistry》2021,476(11):4167-4175
Molecular and Cellular Biochemistry - The aim of our study was to investigate the effects of one-month consumption of polyphenol-rich standardized Aronia melanocarpa extract (SAE) on redox status... 相似文献
28.
29.
30.
Miroslav Bobek Pittaya Tuntiwachwuttikul M. Mohsen Ismail Thomas J. Bardos 《Nucleosides, nucleotides & nucleic acids》2013,32(8):1657-1665
Abstract N-Aminopyrazine analogues of cytidine and 2′-deoxycytidine were prepared from 1-(β-D-ribofuranosyl)-1,2-dihydro-2-oxopyrazine and 1-(2-deoxy-β-D-ribofuranosyl)-1,2-dihydro-2-oxopyrazine, respectively, by amination with O-mesitylenesulfonylhydroxylamine. 相似文献