全文获取类型
收费全文 | 2264篇 |
免费 | 147篇 |
国内免费 | 1篇 |
出版年
2022年 | 10篇 |
2021年 | 27篇 |
2020年 | 14篇 |
2019年 | 15篇 |
2018年 | 33篇 |
2017年 | 23篇 |
2016年 | 45篇 |
2015年 | 60篇 |
2014年 | 66篇 |
2013年 | 169篇 |
2012年 | 119篇 |
2011年 | 136篇 |
2010年 | 85篇 |
2009年 | 68篇 |
2008年 | 104篇 |
2007年 | 116篇 |
2006年 | 114篇 |
2005年 | 117篇 |
2004年 | 121篇 |
2003年 | 111篇 |
2002年 | 117篇 |
2001年 | 61篇 |
2000年 | 62篇 |
1999年 | 67篇 |
1998年 | 34篇 |
1997年 | 23篇 |
1996年 | 19篇 |
1995年 | 23篇 |
1994年 | 18篇 |
1993年 | 12篇 |
1992年 | 29篇 |
1991年 | 29篇 |
1990年 | 35篇 |
1989年 | 30篇 |
1988年 | 34篇 |
1987年 | 29篇 |
1986年 | 29篇 |
1985年 | 20篇 |
1984年 | 15篇 |
1983年 | 10篇 |
1982年 | 19篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 20篇 |
1975年 | 11篇 |
1974年 | 9篇 |
1970年 | 9篇 |
1969年 | 9篇 |
1968年 | 14篇 |
1967年 | 8篇 |
排序方式: 共有2412条查询结果,搜索用时 31 毫秒
61.
Attempts were made to isolate and identify the unit chemical structure essential for manifestation of the immunoadjuvant activities characteristic of bacterial cell walls. The N-acetylmuramyl-peptide subunit monomers, Nalpha-(N-acetylmuramyl-L-alanyl-D-isoglutaminyl)-Nepsilon-(glycylglycyl)-L-lysyl-D-alanine from the cell walls of Staphylococcus aureus (FDA 209P) and N-acetylmuramyl-L-alanyl-D-isoglutaminyl-meso-diaminopimelic acid and/or N-acetylmuramyl-L-alanyl-D-isoglutaminyl-meso-diaminopimelyl-D-alanine from those of Lactobacillus plantarum (ATCC 8014), were shown to be unit chemical entities with definite adjuvant activity both in stimulation of antibody production and in induction of delayed-type hypersensitivity to ovalbumin when administered to guinea-pigs as water-in-oil emulsions. 相似文献
62.
Toshio Miyazaki Toshiro Yadomae Takayoshi Terui Haruki Yamada Terukichi Kikuchi 《Biochimica et Biophysica Acta (BBA)/General Subjects》1975,385(2)
A water-soluble glucuronan “protuberic acid”, [α]d22 −83.6° and purified from Kobayashia Nipponica, and its physicochemical properties were investigated.The purified protuberic acid was homogeneous as shown by zone electrophoresis, gel filtration over Sepharose 4B, and ultracentrifugation. The sedimentation coefficient was 1.8 S and its intrinsic viscosity was 1.1 dl/g. By gel filtration the molecular weight was estimated to be about 170 000. The results of periodate oxidation, methylation analysis, and partial acid hydrolysis indicated that this acidic polysaccharide has a linear structure of mainly 1,4-linkages and containing an acid-labile linkage. Reduced protuberic acid, [α]d22 −44°, is also described. 相似文献
63.
64.
Shizuya Tanaka Toshiro Kato Shigeo Yamamoto Hirosuke Yoshioka 《Bioscience, biotechnology, and biochemistry》2013,77(10):1953-1959
Since S-n-butyl S′-p-tert-butylbenzyl N-3-pyridyldithiocarbonimidate, a potent fungicide to powdery mildew, is known to inhibit ergosterol biosynthesis in Monilinia fructigena, the activities were assessed on 24 compounds having other substituents than the 3-pyridyl and on 24 compounds having a variety of different structures connecting the 3-pyridyl and the p-tert-butylphenyl group from that of the dithiocarbonimidate.In the former group the 3-pyridyl group was essential for the activities and the substitution at the 2- or 6-position resulted, on available data, in inactive compounds. Several other β-N-heterocyclic analogs were also active. In the latter group, a number of modified compounds from the dithiocarbonimidate structure were shown to be active. 相似文献
65.
66.
Takimoto Yuki Monkawa Akira Nagata Kohki Kobayashi Masahiro Kinoshita Mariko Gessei Tomoko Mori Toshiya Kagi Hiroyuki 《Plasmonics (Norwell, Mass.)》2020,15(3):805-811
Plasmonics - Detection and monitoring of SO2 is important because it is a representative toxic gas in the atmospheric environment that is emitted from industrial and natural processes. Localized... 相似文献
67.
Kinoshita Kodzue Indo Yoriko Tajima Tomoyuki Kuze Noko Miyakawa Etsuko Kobayashi Toshio Nakamura Tomoyuki Ogata Mitsuaki Okumura Fumihiko Hayakawa Takashi Morimura Naruki Mori Yusuke Okamoto Munehiro Ozaki Yasuhiko Hirata Satoshi 《Primates; journal of primatology》2021,62(3):475-475
Primates - In the original publication of the article, the coauthor “Takashi Hayakawa” was wrongly assigned as co-corresponding author. 相似文献
68.
Masaaki Umeda Momoko Ikeuchi Masaki Ishikawa Toshiro Ito Ryuichi Nishihama Junko Kyozuka Keiko U. Torii Akiko Satake Gohta Goshima Hitoshi Sakakibara 《The Plant journal : for cell and molecular biology》2021,106(2):326-335
Plant stem cells have several extraordinary features: they are generated de novo during development and regeneration, maintain their pluripotency, and produce another stem cell niche in an orderly manner. This enables plants to survive for an extended period and to continuously make new organs, representing a clear difference in their developmental program from animals. To uncover regulatory principles governing plant stem cell characteristics, our research project ‘Principles of pluripotent stem cells underlying plant vitality’ was launched in 2017, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Japanese government. Through a collaboration involving 28 research groups, we aim to identify key factors that trigger epigenetic reprogramming and global changes in gene networks, and thereby contribute to stem cell generation. Pluripotent stem cells in the shoot apical meristem are controlled by cytokinin and auxin, which also play a crucial role in terminating stem cell activity in the floral meristem; therefore, we are focusing on biosynthesis, metabolism, transport, perception, and signaling of these hormones. Besides, we are uncovering the mechanisms of asymmetric cell division and of stem cell death and replenishment under DNA stress, which will illuminate plant-specific features in preserving stemness. Our technology support groups expand single-cell omics to describe stem cell behavior in a spatiotemporal context, and provide correlative light and electron microscopic technology to enable live imaging of cell and subcellular dynamics at high spatiotemporal resolution. In this perspective, we discuss future directions of our ongoing projects and related research fields. 相似文献
69.
Kenji Kinoshita Satoshi Yaginuma Mitsuo Hayashi Kazumi Nakatsu 《Nucleosides, nucleotides & nucleic acids》2013,32(5):661-668
Abstract The molecular and crystal structure of neplanocin C(3), C11H13N5O4 M.W. = 279.26, has been determined by X-ray anlys?s. The space group is P21 with a=16.381(2), b=8.210(1), c=9.127(1) Å, β=105.31(1)° and z=4. The structure was solved by direct method, and least-squares refinement using 2093 reflections with |Fo|>3σ(F) led to the final R value of 0.0772. The sugar puckering of the two crystal-lographically independent molecules is C(2′)-exo-C(3′)-endo, and the torsion angles about the N(9)-C(1′) bond are 22.8(6) and 28.7(6)°, respectively (anti conformation). 相似文献
70.
Kayo Kobayashi Yasuhiro Kamei Masato Kinoshita Thomas Czerny Minoru Tanaka 《Genesis (New York, N.Y. : 2000)》2013,51(1):59-67
We established three lines of transgenic medaka, a heat‐shock element (HSE) monitor line (hse‐GFP line), heat‐inducible driver lines (hse‐cre lines), and effector lines (gapdh‐loxP[DsRed]‐GFP lines). We employed these to comprehensively analyze gene induction at different time points in various tissues. These analyses demonstrate a good response of synthetic HSEs by heat treatment during embryogenesis and the mosaic gene induction by cre/loxP‐mediated recombination, thus providing practical information regarding the feasibility of a heat‐inducible cre/loxP‐mediated system in medaka. We also activated recombination by local heat‐treatment using a metal probe and an infrared laser. Our results collectively indicate that these lines allow us to perform lineage tracing and mosaic analysis and provide the platform to investigate gene functions at later developmental stage and adult. genesis 51:59–67, 2013. © 2012 Wiley Periodicals, Inc. 相似文献