全文获取类型
收费全文 | 1235篇 |
免费 | 81篇 |
国内免费 | 3篇 |
出版年
2022年 | 6篇 |
2021年 | 9篇 |
2020年 | 6篇 |
2019年 | 8篇 |
2018年 | 11篇 |
2016年 | 21篇 |
2015年 | 18篇 |
2014年 | 25篇 |
2013年 | 63篇 |
2012年 | 61篇 |
2011年 | 62篇 |
2010年 | 46篇 |
2009年 | 38篇 |
2008年 | 55篇 |
2007年 | 50篇 |
2006年 | 50篇 |
2005年 | 54篇 |
2004年 | 64篇 |
2003年 | 64篇 |
2002年 | 68篇 |
2001年 | 47篇 |
2000年 | 44篇 |
1999年 | 39篇 |
1998年 | 10篇 |
1997年 | 18篇 |
1996年 | 8篇 |
1995年 | 9篇 |
1994年 | 9篇 |
1993年 | 8篇 |
1992年 | 28篇 |
1991年 | 32篇 |
1990年 | 23篇 |
1989年 | 26篇 |
1988年 | 27篇 |
1987年 | 16篇 |
1986年 | 24篇 |
1985年 | 12篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 11篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 14篇 |
1978年 | 11篇 |
1977年 | 9篇 |
1976年 | 13篇 |
1974年 | 8篇 |
1972年 | 6篇 |
1971年 | 12篇 |
1969年 | 10篇 |
排序方式: 共有1319条查询结果,搜索用时 15 毫秒
131.
132.
Yuko Matsuura-Hachiya Yuji Nakai Keiko Abe Toshio Nishiyama Koji Y. Arai 《Biochemistry and Biophysics Reports》2015
The renin–angiotensin system is known to be involved in skin remodeling and inflammation. Previously, we reported that ultraviolet B (UVB) irradiation enhanced angiotensin-converting enzyme (ACE) expression and angiotensin II levels in hairless mouse skin, and an ACE inhibitor, enalapril maleate (EM), accelerated repair of UVB-induced wrinkles. In this study, we analyzed gene expression profiles by DNA microarray and protein distribution patterns using an immunofluorescence method to clarify the process of EM-accelerated wrinkle repair in UVB-irradiated hairless mouse skin. In the microarray analysis, we detected EM-induced up-regulation of various extracellular matrix (ECM)-related genes in the UVB-irradiated skin. In the immunofluorescence, we confirmed that type I collagen α1 chain, fibrillin 1, elastin and dystroglycan 1 in the skin decreased after repeated UVB irradiation but staining for these proteins was improved by EM treatment. In addition, ADAMTS2 and MMP-14 also increased in the EM-treated skin. Although the relationship between these molecules and wrinkle formation is not clear yet, our present data suggest that the molecules are involved in the repair of UVB-induced wrinkles. 相似文献
133.
The objective of this study was to elucidate how temperature affects the reproduction and development of Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), an emerging major pest of blueberry in Japan. Although extensive studies of the biology of this pest have been carried out, the effects of temperature on its reproduction and development remain unknown. We found that when adults mated at 31 °C for 4 days, none of the eggs hatched. Female oviposition and egg hatching rate were also reduced as temperature increased during the oviposition period. When D. suzukii larvae developed above 31 °C, pupation and adult eclosion were abolished. According to field observations, adult D. suzukii ceased to appear from the end of July 2010, when the average temperature exceeded 28 °C or when the temperature within a day exceeded 33 °C for 8 h or more. Experiments in which the mating temperature fluctuated within a day revealed that both the number of eggs oviposited and their hatch rate were significantly suppressed when the daily temperature regime during mating was either 31 °C for 12 h/25 °C for 12 h or 33 °C for 8 h/25 °C for 16 h, relative to the values at 25 °C for 24 h. 相似文献
134.
Stress responses in Salix gracilistyla cuttings subjected to repetitive alternate flooding and drought 总被引:2,自引:0,他引:2
To determine the tolerance of Salix gracilistyla to repetitive alternate flooding and drought, we measured leaf stomatal conductance, pre-dawn water potential, osmotic adjustment,
and biomass production under greenhouse conditions. We used a control and nine crossed treatments (F1-D1–F3-D3) in which we
combined 1-, 2-, or 3-week floodings (F) and droughts (D). Leaf stomatal conductance was lowest in 3 weeks of flooding or
drought when the preceding event (flood or drought) was also of a 3-week duration. Leaf pre-dawn water potential was reduced
in 3 weeks of drought when preceded by 2 or 3 weeks of flooding. Cuttings had slight osmotic adjustments in repetitions of
long floodings and droughts. During longer durations of drought in crossed experiments, plants had low root and shoot mass,
few hypertrophic lenticels, and reduced leaf mass; when flooding duration increased in crossed experiments, root mass was
reduced, there were more hypertrophic lenticels, and the leaf area was reduced. Cuttings achieved stress tolerance by inhibition
of transpiration, osmotic adjustment, reduction of transpiration area, and development of hypertrophic lenticels. Stress tolerance
was weak when repetitive 2- or 3-week floodings were combined with 3-week droughts. The duration of flooding and drought periods
under which S. gracilistyla achieves stress tolerance may be critical in determining distributions along riverbanks. 相似文献
135.
Masaki Asada Tetsuo Obitsu Atsushi Kinoshita Yoshihiko Nakai Toshihiko Nagase Isamu Sugimoto Motoyuki Tanaka Hiroya Takizawa Ken Yoshikawa Kazutoyo Sato Masami Narita Shuichi Ohuchida Hisao Nakai Masaaki Toda 《Bioorganic & medicinal chemistry letters》2010,20(8):2639-2643
A series of novel N-acylsulfonamide analogs were synthesized and evaluated for their binding affinity and antagonist activity for the EP3 receptor subtype. Representative compounds were also evaluated for their inhibitory effect on PGE2-induced uterine contraction in pregnant rats. Among those tested, a series of N-acylbenzenesulfonamide analogs were found to be more potent than the corresponding carboxylic acid analogs in both the in vitro and in vivo evaluations. The structure activity relationships (SAR) are also discussed. 相似文献
136.
Hidenori Takahashi Testuhito Shinkawa Shinjiro Nakai Yasunori Inoue 《Plant Growth Regulation》2010,62(2):137-149
Root hair formation is induced in lettuce seedlings when the seedlings are transferred from a liquid medium at pH 6.0 to one
at pH 4.0. Auxin, ethylene, and light are also required for the induction of root hair formation. To investigate the mechanism
by which ethylene production is regulated during root hair formation, we isolated three 1-aminocyclopropane-1-carboxylic acid
(ACC) oxidase genes (Ls-ACO1, 2, and 3) from lettuce, each of which exists as a single copy in the genome. Analysis of the deduced amino acid sequences of the three
ACO proteins as well as a phylogenetic analysis revealed that Ls-ACO3 was the most divergent among the ACO family. Northern
hybridization analyses revealed that the mRNA levels of Ls-ACO2, but not Ls-ACO1 and Ls-ACO3, increased in the primary root after the transfer to a pH 4.0 medium. Addition of ACC or indole-3-acetic acid (IAA) to the
pH 6.0 medium induced root hair formation, and a concomitant accumulation of Ls-ACO2 mRNA was observed. In contrast, the mRNA levels of Ls-ACO1 and Ls-ACO3 were unaffected by either ACC or IAA treatment. Furthermore, white light irradiation of dark-grown seedlings following the
transfer to pH 4.0 medium induced the accumulation of all three ACO mRNAs. However, accumulation of Ls-ACO2 mRNA was also observed in non-irradiated seedlings, suggesting that the expression of Ls-ACO2 was induced not by light but by low pH. These results suggest that among the differentially regulated ACO genes, Ls-ACO2 plays a key role in ethylene production during low-pH-induced root hair formation in lettuce. 相似文献
137.
138.
Emi Kamiyama Daisuke Nakai Tsuyoshi Mikkaichi Noriko Okudaira Osamu Okazaki 《Life sciences》2010,86(1-2):52-58
AimsThe inhibitory effect of angiotensin II type 1 receptor blockers (ARBs) on P-glycoprotein (P-gp) was examined to evaluate their clinical drug–drug interaction (DDI) potential.Main methodsWe performed an inhibition study on the vectorial transport of digoxin, a typical substrate for P-gp, using a human colonic adenocarcinoma cell line, Caco-2 cells, and verapamil-stimulated ATPase activity using human multidrug resistance 1 (hMDR1)-expressing membrane.Key findingsThe vectorial transport of digoxin was inhibited by candesartan cilexetil, irbesartan and telmisartan with the IC50 values of 14.7, 34.0 and 2.19 µM, respectively. Those values were 7.4–426-fold higher than their theoretical clinical gastrointestinal concentration [I] at doses in clinical DDI studies. Other ARBs failed to show interaction with P-gp.SignificanceIt was demonstrated that candesartan cilexetil, irbesartan and telmisartan had the potential to inhibit the transport of various drugs via P-gp. Telmisartan, which caused an increase in the serum digoxin concentration in humans, had a sufficiently high [I]/IC50 value, suggesting that DDI between digoxin and telmisartan was caused by the inhibition of digoxin efflux via intestinal P-gp. 相似文献
139.
140.
Design and synthesis of new potent dipeptidyl peptidase IV inhibitors with enhanced ex vivo duration
Kondo T Nekado T Sugimoto I Ochi K Takai S Kinoshita A Tajima Y Yamamoto S Kawabata K Nakai H Toda M 《Bioorganic & medicinal chemistry》2007,15(7):2631-2650
A series of 5beta-methylprolyl-2-cyanopyrrolidine analogs were synthesized and evaluated as DPP-IV inhibitors, and the duration of their ex vivo activity was assessed. Comparison of their potency and duration of action was done among three different species. The mode of binding was investigated, and the effect on the plasma glucose level was evaluated. Structure-activity relationships are also presented. 相似文献