全文获取类型
收费全文 | 1984篇 |
免费 | 121篇 |
国内免费 | 1篇 |
专业分类
2106篇 |
出版年
2022年 | 9篇 |
2021年 | 20篇 |
2020年 | 17篇 |
2019年 | 24篇 |
2018年 | 16篇 |
2017年 | 26篇 |
2016年 | 44篇 |
2015年 | 71篇 |
2014年 | 80篇 |
2013年 | 118篇 |
2012年 | 135篇 |
2011年 | 132篇 |
2010年 | 72篇 |
2009年 | 88篇 |
2008年 | 124篇 |
2007年 | 136篇 |
2006年 | 113篇 |
2005年 | 113篇 |
2004年 | 111篇 |
2003年 | 143篇 |
2002年 | 118篇 |
2001年 | 16篇 |
2000年 | 17篇 |
1999年 | 20篇 |
1998年 | 28篇 |
1997年 | 19篇 |
1996年 | 16篇 |
1995年 | 20篇 |
1994年 | 15篇 |
1993年 | 15篇 |
1992年 | 13篇 |
1991年 | 9篇 |
1990年 | 10篇 |
1989年 | 8篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 10篇 |
1978年 | 15篇 |
1977年 | 9篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1973年 | 10篇 |
1972年 | 7篇 |
1971年 | 10篇 |
排序方式: 共有2106条查询结果,搜索用时 15 毫秒
91.
92.
Thirty-six bacteria that degraded long-chain hydrocarbons were isolated from natural environments using long-chain hydrocarbons (waste car engine oil, base oil or the c-alkane fraction of base oil) as the sole carbon and energy source. A phylogenetic tree of the isolates constructed using their 16S rDNA sequences revealed that the isolates were divided into six genera plus one family (Acinetobacter, Rhodococcus, Gordonia, Pseudomonas, Ralstonia, Bacillus and Alcaligenaceae, respectively). Furthermore, most of the isolates (27 of 36) were classified into the genera Acinetobacter, Rhodococcus or Gordonia. The hydrocarbon-degradation similarity in each strain was confirmed by the 2,6-dichlorophenol indophenol (2,6-DCPIP) assay. Isolates belonging to the genus Acinetobacter degraded long-chain normal alkanes (n-alkanes) but did not degrade short-chain n-alkanes or cyclic alkanes (c-alkanes), while isolates belonging to the genera Rhodococcus and Gordonia degraded both long-chain n-alkanes and c-alkanes. 相似文献
93.
Attempt at cloning high-quality goldfish breed 'Ranchu' by fin-cultured cell nuclear transplantation
The viability of ornamental fish culture relies on the maintenance of high-quality breeds. To improve the profitability of culture operations we attempted to produce cloned fish from the somatic nucleus of the high-quality Japanese goldfish (Carassius auratus auratus) breed 'Ranchu'. We transplanted the nucleus of a cultured fin-cell from an adult Ranchu into the non-enucleated egg of the original goldfish breed 'Wakin'. Of the 2323 eggs we treated, 802 underwent cleavage, 321 reached the blastula stage, and 51 reached the gastrula stage. Two of the gastrulas developed until the hatching stage. A considerable number of nuclear transplants retained only the donor nucleus. Some of these had only a 2n nucleus derived from the same donor fish. Our results provide insights into the process of somatic cell nuclear transplantation in teleosts, and the cloning of Ranchu. 相似文献
94.
95.
96.
Kohno T Ichikawa H Totoki Y Yasuda K Hiramoto M Nammo T Sakamoto H Tsuta K Furuta K Shimada Y Iwakawa R Ogiwara H Oike T Enari M Schetter AJ Okayama H Haugen A Skaug V Chiku S Yamanaka I Arai Y Watanabe S Sekine I Ogawa S Harris CC Tsuda H Yoshida T Yokota J Shibata T 《Nature medicine》2012,18(3):375-377
97.
Akihiro Inagaki Soichiro Yamaguchi Hiromi Takahashi-Iwanaga Toshihiko Iwanaga Toru Ishikawa 《The Journal of membrane biology》2010,235(1):27-41
ClC-2, a member of the voltage-gated Cl− channel family, is expressed in the distal colonic surface epithelial cells of various species, but its functional significance
remains unclear. Here, by means of electrophysiological and molecular biological techniques, we have identified and characterized
a ClC-2-like conductance naturally expressed by surface epithelial cells acutely dissociated from rectal colon of rats fed
a standard diet. Whole-cell patch-clamp experiments showed that the surface cells, whether an amiloride-sensitive Na+ conductance was present or not, displayed a strong hyperpolarization-activated, inwardly rectifying Cl− current. Analysis both by in situ hybridization and immunohistochemistry confirmed the expression of ClC-2 in the rectal
surface epithelium. The native Cl− current shared common electrophysiological properties including voltage-dependent activation, anion selectivity sequence,
and Zn2+ sensitivity with that recorded from HEK293 cells transfected with ClC-2 cloned from rat rectal colon (rClC-2). Cell-attached
patch recordings on the surface cells revealed that native ClC-2-like currents activated only at potentials at least 40 mV
more negative than resting membrane potentials. In Ussing chamber experiments with rat rectal mucosa, either basolateral or
apical application of Zn2+ (0.1 mM), which inhibited both native ClC-2-like currents and recombinant rClC-2 currents, had little, if any, effects on
basal amiloride-sensitive short-circuit current. Collectively, these results not only demonstrate that a functional ClC-2-type
Cl− channel is expressed in rat rectal surface epithelium, but also suggest that the channel activity may be negligible and thus
nonessential for controlling electrogenic Na+ transport in this surface epithelium under basal physiological conditions. 相似文献
98.
Shengyu Lv Hongrui Liu Jian Cui Tomoka Hasegawa Hiromi Hongo Wei Feng Juan Li Bao Sun Akira Kudo Norio Amizuka Minqi Li 《Journal of molecular histology》2014,45(3):303-309
The purpose of this study was to investigate immunolocalization of collagenolytic enzymes including cathepsin K, matrix metalloproteinase (MMP) 1 and 2 in the compressed periodontal ligament (PDL) during orthodontic tooth movement using a periostin deficient (Pn-/-) mouse model. Twelve-week-old male mice homozygous for the disrupted periostin gene and their wild type (WT) littermates were used in these experiments. The tooth movement was performed according to Waldo’s method, in which elastic bands of 0.5 mm thickness were inserted between the first and second upper molars of mice under anesthesia. At 1 and 3 days after orthodontic force application, mice were fixed with transcardial perfusion of 4 % paraformaldehyde in 0.1 M phosphate buffer (pH 7.4), and the first molars and peripheral alveolar bones were extracted for histochemical analyses. Compared with WT mice, immunolocalization of cathepsin K, MMP1 and MMP2 was significantly decreased at 1 and 3 days after orthodontic tooth movement in the compressed PDL of Pn-/- mice, although MMP1-reactivity and MMP2-reactivity decreased at different amounts. Very little cathepsin K-immunoreactivity was observed in the assessed regions of Pn-/- mice, both before and after orthodontic force application. Furthermore, Pn-/- mice showed a much wider residual PDL than WT mice. Taken together, we concluded that periostin plays an essential role in the function of collagenolytic enzymes like cathepsin K, MMP1 and MMP2 in the compressed PDL after orthodontic force application. 相似文献
99.
H Nakatogawa S Ohbayashi M Sakoh-Nakatogawa S Kakuta SW Suzuki H Kirisako C Kondo-Kakuta NN Noda H Yamamoto Y Ohsumi 《The Journal of biological chemistry》2012,287(34):28503-28507
In autophagy, a cup-shaped membrane called the isolation membrane is formed, expanded, and sealed to complete a double membrane-bound vesicle called the autophagosome that encapsulates cellular constituents to be transported to and degraded in the lysosome/vacuole. The formation of the autophagosome requires autophagy-related (Atg) proteins. Atg8 is a ubiquitin-like protein that localizes to the isolation membrane; a subpopulation of this protein remains inside the autophagosome and is transported to the lysosome/vacuole. In the budding yeast Saccharomyces cerevisiae, Atg1 is a serine/threonine kinase that functions in the initial step of autophagosome formation and is also efficiently transported to the vacuole via autophagy. Here, we explore the mechanism and significance of this autophagic transport of Atg1. In selective types of autophagy, receptor proteins recognize degradation targets and also interact with Atg8, via the Atg8 family interacting motif (AIM), to link the targets to the isolation membrane. We find that Atg1 contains an AIM and directly interacts with Atg8. Mutations in the AIM disrupt this interaction and abolish vacuolar transport of Atg1. These results suggest that Atg1 associates with the isolation membrane by binding to Atg8, resulting in its incorporation into the autophagosome. We also show that mutations in the Atg1 AIM cause a significant defect in autophagy, without affecting the functions of Atg1 implicated in triggering autophagosome formation. We propose that in addition to its essential function in the initial stage, Atg1 also associates with the isolation membrane to promote its maturation into the autophagosome. 相似文献
100.