全文获取类型
收费全文 | 1445篇 |
免费 | 70篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 18篇 |
2020年 | 12篇 |
2019年 | 17篇 |
2018年 | 20篇 |
2017年 | 15篇 |
2016年 | 40篇 |
2015年 | 47篇 |
2014年 | 51篇 |
2013年 | 78篇 |
2012年 | 99篇 |
2011年 | 83篇 |
2010年 | 65篇 |
2009年 | 57篇 |
2008年 | 92篇 |
2007年 | 114篇 |
2006年 | 76篇 |
2005年 | 121篇 |
2004年 | 100篇 |
2003年 | 90篇 |
2002年 | 84篇 |
2001年 | 15篇 |
2000年 | 10篇 |
1999年 | 13篇 |
1998年 | 22篇 |
1997年 | 17篇 |
1996年 | 20篇 |
1995年 | 15篇 |
1994年 | 19篇 |
1993年 | 14篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 10篇 |
1988年 | 4篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1971年 | 3篇 |
排序方式: 共有1515条查询结果,搜索用时 187 毫秒
101.
Jayasinghe L Mallika Kumarihamy BM Suranga Arundathie BG Dissanayake L Hara N Fujimoto Y 《Steroids》2003,68(5):447-450
Chemical investigation of ethyl acetate extract of the fruits of Diploclisia glaucescens of the family Menispermaceae furnished a new ecdysteroid 2-deoxy-5beta,20-dihydroxyecdysone, together with 20-hydroxyecdysone, 3-deoxy-1beta,20-dihydroxyecdysone, 2-deoxy-20-hydroxyecdysone, 24-ethyl-20-hydroxyecdysone (makisterone C). Latter two ecdysteroids are reported first time from the family Menispermaceae. 相似文献
102.
Tokunaga N Yamazaki T Akiyama T Mori H 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2003,798(1):163-166
A high-performance liquid chromatography with electrochemical detection (HPLC-ED) method is described for determination of 3-methoxy-4-hydroxyphenylglycol (MHPG) in microdialysate from the skeletal muscle interstitial space. Using a microdialysis technique, we sampled 30 microl dialysate from the skeletal muscle interstitial space and injected dialysate directly into HPLC-ED system. The control MHPG concentration of dialysate was 213+/-18 pg/ml. The MHPG concentrations were reduced by entacapone (catechol-O-methyltransferase inhibitor, COMT), augmented by local infusion of dihydroxyphenylglycol. This system offers a new possibility for simple, rapid monitoring of MHPG as an index of COMT activity in skeletal muscle. 相似文献
103.
Yamamoto S Nakanishi O Matsui T Shinohara N Kinoshita H Lambert C Ishikawa T 《Cellular and molecular neurobiology》2003,23(2):175-185
The analgesia effects of intrathecal adenosine A1 receptor agonist, R-PIA, on the hyperalgesia and CSF-glutamate release after formalin injection into the rat paw were evaluated. R-PIA significantly and dose-dependently attenuated increases in flinching behavior, and this attenuating effect was reversed by the adenosine A1 receptor antagonist, aminophylline. Morphine blocked flinchs, however MK-801 partially abolished. The increase in CSF-glutamate release evoked by formalin stimulation was inhibited by morphine but not by either R-PIA or MK-801. These findings suggest that the intrathecal adenosine A1 receptor agonist provokes analgesic effect via the postsynaptic action independent of an effect upon spinal glutamate release. 相似文献
104.
Noriyuki?OsadaEmail author Shinji?Sugiura Koji?Kawamura Michiko?Cho Hiroshi?Takeda 《Ecological Research》2003,18(6):711-723
We investigated the flowering phenology, pollinator visitation, and fruit set of 25 animal-pollinated woody species in a warm temperate secondary forest in Japan. Various species flowered sequentially from February to October. The principal pollinators were bumblebees, honey-bees, flies and/or beetles and birds; bumblebees and flies/beetles pollinated most trees. The duration of flowering was shorter for species that bloomed in the middle of the season than it was for species that bloomed earlier or later in the season. The timing of flowering was more synchronous within species that had a shorter flowering duration; this was also detected when phylogenetically independent contrasts were calculated. This could be important for the effective pollination of species with a short flowering duration because such species bloom sequentially over a short period of less than 1month around May. Fruit set was related not to pollinator type, sex expression, flowering sequence (in order of the date of peak flowering) or flowering duration, but to the relative abundance of the species in the forest. This correlation was detected for fly- and beetle-pollinated species but not for bumblebee-pollinated species. Thus, relatively rare plant species with opportunistic pollinators might experience limited fruit set because of insufficient pollinator services. Bagging experiments conducted on eight hermaphrodite species revealed that the fruit set of bagged flowers was nearly zero, lower than that of control flowers. These results indicate the importance of pollinators for successful reproduction and thus for the coexistence of plants in this secondary forest. 相似文献
105.
Isolation of Paenibacillus illinoisensis that produces cyclodextrin glucanotransferase resistant to organic solvents 总被引:1,自引:0,他引:1
A bacterium that secreted cyclodextrin glucanotransferase (CGTase) in a medium overlaid with n-hexane was isolated and identified as Paenibacillus illinoisensis strain ST-12 K. The CGTase of the strain was purified from the culture supernatant. The molecular mass was 70 kDa. The enzyme was stable at pH 6 to 10 and active at pH 5.0 to 8.0. The optimum temperature at pH 7.0 was 65 degrees C in the presence of 5 mM CaCl2. The enzyme produced mainly beta-cyclodextrin. The total yield of alpha-, beta-, and gamma- cyclodextrins was increased 1.4-fold by the addition of ethanol. In particular, the yield of beta-cyclodextrins in the presence of 10% (vol/vol) ethanol was 1.6-fold that without ethanol. The CGTase was stable and active in the presence of large amounts of various organic solvents. 相似文献
106.
Kajiura-Kobayashi H Yoshida N Sagata N Yamashita M Nagahama Y 《Development genes and evolution》2000,210(8-9):416-425
Mos plays a crucial role in meiotic cell division in vertebrates. In Xenopus, Mos is involved in the initiation of oocyte maturation as an initiator and in the arrest at the metaphase II stage (MII)
as a component of the cytostatic factor (CSF). The function of Mos is mediated by MAP kinase (MAPK). We investigated the function
of the Mos/MAPK pathway during goldfish oocyte maturation induced by 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-DP), a natural
maturation-inducing hormone in fishes. Mos was absent in immature goldfish oocytes. It appeared before the onset of germinal
vesicle breakdown (GVBD), increased to a maximum in mature oocytes arrested at MII and disappeared after fertilization. MAPK
was activated after Mos synthesis but before maturation-promoting factor (MPF) activation, and its activity reached maximum
at MII. Injection of either Xenopus or goldfish c-mos mRNA into one blastomere of 2-cell-stage Xenopus and goldfish embryos induced metaphase arrest, suggesting that goldfish Mos has a CSF activity. Injection of constitutively
active Xenopus c-mos mRNA into immature goldfish oocytes induced MAPK activation, but neither MPF activation nor GVBD occurred. Conversely, the
injection of goldfish c-mos antisense RNA inhibited both Mos synthesis and MAPK activation in the 17α,20β-DP-treated oocytes, but these oocytes underwent
GVBD. These results indicate that the Mos/MAPK pathway is not essential for initiating goldfish oocyte maturation despite
its general function as a CSF. We discuss the general role of Mos/MAPK during oocyte maturation, with reference to the difference
in contents of inactive MPF (pre-MPF) stored in immature oocytes.
Received: 10 February 2000 / Accepted: 25 April 2000 相似文献
107.
Shinrin-yoku (forest-air bathing and walking) effectively decreases blood glucose levels in diabetic patients 总被引:6,自引:0,他引:6
Y. Ohtsuka Noriyuki Yabunaka Shigeru Takayama 《International journal of biometeorology》1998,41(3):125-127
The influence of ”shinrin-yoku” (forest-air bathing and walking) on blood glucose levels in diabetic patients was examined.
Eighty-seven (29 male and 58 female) non-insulin-dependent diabetic patients [61 (SEM 1) years old] participated in the present
study. Shinrin-yoku was performed nine times over a period of 6 years. The patients were divided into two parties. They then
walked in the forest for 3 km or 6 km according to their physical ability and/or the existence of diabetic complications.
The mean blood glucose level after forest walking changed from 179 (SEM 4) mg · 100 ml–1 to 108 (SEM 2) mg · 100 ml–1 (P<0.0001). The level of glycated haemoglobin A1c also decreased from 6.9 (SEM 0.2)% (before the first shinrin-yoku) to 6.5 (SEM 0.1)% (after the last shinrin-yoku; P<0.05). Blood glucose values declined by 74 (SEM 9) mg · 100 ml–1 and 70 (SEM 4) mg · 100 ml–1 after short- and long-distance walking respectively. There was no significant difference between these values. Since the
forest environment causes changes in hormonal secretion and autonomic nervous functions, it is presumed that, in addition
to the increased calorie consumption and improved insulin sensitivity, walking in a forest environment has other beneficial
effects in decreasing blood glucose levels.
Received: 9 July 1997/Accepted: 20 October 1997 相似文献
108.
109.
Ogawa Noriyuki; Yabuta Naohiro; Ueno Yoshihisa; Izui Katsura 《Plant & cell physiology》1998,39(10):1010-1019
Phosphoenolpyruvate carboxylase (PEPC) [EC 4.1.1.31
[EC]
] of plantsundergoes regulatory phosphorylation in response to light ornutritional conditions. However, the nature of protein kinase(s)for this phosphorylation has not yet been fully elucidated.We separated a Ca2+-requiring protein kinase from Ca2+-independentone, both of which can phosphorylate maize leaf PEPC and characterizedthe former kinase after partial purification. Several linesof evidence indicated that the kinase is one of the characteristicCa2+-dependent but calmodulin-independent protein kinase (CDPK).Although the Mr, of native CDPK was estimated to be about 100kDa by gel permeation chromatography, in situ phosphorylationassay of CDPK in a SDS-polyacrylamide gel revealed that thesubunit has an Mr of about 50 kDa suggesting dimer formationor association with other protein(s). Several kinetic parameterswere also obtained using PEPC as a substrate. Although the CDPKshowed an ability of regulatory phosphorylation (Ser-15 in maizePEPC), no significant desensitization to feedback inhibitor,malate, could be observed presumably due to low extent of phosphorylation.The kinase was not specific to PEPC but phosphorylated a varietyof synthetic peptides. The possible physiological role of thiskinase was discussed.
1Present address: NEOS Central Research Laboratory, 1-1 Ohike-machi,Kosei-cho, Shiga, 520-3213 Japan.
2Present address: Chugai Pharmaceutical Co., Ltd., 1-135 Komakado,Gotemba, 412-0038 Japan.
4N.O. and N.Y. contributed equally to this work. 相似文献
110.
Ryutaro Kakinuma Noriyuki Moriyama Yukio Muramatsu Shiho Gomi Masahiro Suzuki Hirobumi Nagasawa Masahiko Kusumoto Tomohiko Aso Yoshihisa Muramatsu Takaaki Tsuchida Koji Tsuta Akiko Miyagi Maeshima Naobumi Tochigi Shun-ichi Watanabe Naoki Sugihara Shinsuke Tsukagoshi Yasuo Saito Masahiro Kazama Kazuto Ashizawa Kazuo Awai Osamu Honda Hiroyuki Ishikawa Naoya Koizumi Daisuke Komoto Hiroshi Moriya Seitaro Oda Yasuji Oshiro Masahiro Yanagawa Noriyuki Tomiyama Hisao Asamura 《PloS one》2015,10(12)