全文获取类型
收费全文 | 594篇 |
免费 | 45篇 |
专业分类
639篇 |
出版年
2022年 | 3篇 |
2021年 | 12篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 6篇 |
2015年 | 22篇 |
2014年 | 24篇 |
2013年 | 27篇 |
2012年 | 49篇 |
2011年 | 34篇 |
2010年 | 23篇 |
2009年 | 20篇 |
2008年 | 34篇 |
2007年 | 33篇 |
2006年 | 28篇 |
2005年 | 34篇 |
2004年 | 37篇 |
2003年 | 24篇 |
2002年 | 24篇 |
2001年 | 15篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 11篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 3篇 |
1987年 | 12篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 8篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1969年 | 2篇 |
1967年 | 2篇 |
1966年 | 4篇 |
1963年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有639条查询结果,搜索用时 0 毫秒
631.
632.
Bas Brouwers Edson Mendes de Oliveira Maria Marti-Solano Fabiola B.F. Monteiro Suli-Anne Laurin Julia M. Keogh Elana Henning Rebecca Bounds Carole A. Daly Shane Houston Vikram Ayinampudi Natalia Wasiluk David Clarke Bianca Plouffe Michel Bouvier M. Madan Babu I. Sadaf Farooqi Jacek Mokrosiński 《Cell reports》2021,34(12):108862
633.
In 131 patients treated exclusively by selective denervation during the past 10 years, all or almost all the abnormal movements of spasmodic torticollis were suppressed in 115 (88%) while preserving posture and mobility. This approach was also used in certain forms of adult-onset dystonia. An appreciable amount of abnormal movements remained in the other patients, either due to residual innervation or because of limitation of denervation necessary to preserve normal movements (laterocollis) or neck stability (retrocollis). A medio-lateral approach to the posterior cervical region in the sitting position using stimulation under light anaesthesia is recommended. 相似文献
634.
635.
636.
Hiroyuki Kobayashi Koji Ogawa Rong Yao Olivier Lichtarge Michel Bouvier 《Traffic (Copenhagen, Denmark)》2009,10(8):1019-1033
Site-directed mutagenesis guided by evolutionary trace analysis revealed that substitution of V179 and W183 within a cluster of evolutionarily important residues on the surface of the fourth transmembrane domain of the β1 -adrenergic receptor (β1 AR) significantly reduced the propensity of the receptor to self-assemble into homodimers as assessed by bioluminescence resonance energy transfer in living cells. These results suggest that mutation of V179 and W183 result in conformational changes that reduce homodimerization either directly by interfering with the dimerization interface or indirectly by causing local misfolding that result in reduced self-assembly. However, the mutations did not cause a general misfolding of the β1 AR as they did not prevent heterodimerization with the β2 AR. The homodimerization-compromised mutants were significantly retained in the endoplasmic reticulum (ER) and could not be properly matured and trafficked to the cell surface. Lipophilic β-adrenergic ligands acted as pharmacological chaperones by restoring both dimerization and plasma membrane trafficking of the ER-retained dimerization-compromised β1 AR mutants. These results clearly indicate that homodimerization occurs early in the biosynthetic process in the ER and that pharmacological chaperones can promote both dimerization and cell surface targeting, most likely by stabilizing receptor conformations compatible with the two processes. 相似文献
637.
Ximena Tabares Heike Zimmermann Elisabeth Dietze Gregor Ratzmann Lukas Belz Andrea Vieth‐Hillebrand Lydie Dupont Heinz Wilkes Benjamin Mapani Ulrike Herzschuh 《Ecology and evolution》2020,10(2):962-979
- Shrub encroachment has far‐reaching ecological and economic consequences in many ecosystems worldwide. Yet, compositional changes associated with shrub encroachment are often overlooked despite having important effects on ecosystem functioning.
- We document the compositional change and potential drivers for a northern Namibian Combretum woodland transitioning into a Terminalia shrubland. We use a multiproxy record (pollen, sedimentary ancient DNA, biomarkers, compound‐specific carbon (δ13C) and deuterium (δD) isotopes, bulk carbon isotopes (δ13Corg), grain size, geochemical properties) from Lake Otjikoto at high taxonomical and temporal resolution.
- We provide evidence that state changes in semiarid environments may occur on a scale of one century and that transitions between stable states can span around 80 years and are characterized by a unique vegetation composition. We demonstrate that the current grass/woody ratio is exceptional for the last 170 years, as supported by n‐alkane distributions and the δ13C and δ13Corg records. Comparing vegetation records to environmental proxy data and census data, we infer a complex network of global and local drivers of vegetation change. While our δD record suggests physiological adaptations of woody species to higher atmospheric pCO2 concentration and drought, our vegetation records reflect the impact of broad‐scale logging for the mining industry, and the macrocharcoal record suggests a decrease in fire activity associated with the intensification of farming. Impact of selective grazing is reflected by changes in abundance and taxonomical composition of grasses and by an increase of nonpalatable and trampling‐resistant taxa. In addition, grain‐size and spore records suggest changes in the erodibility of soils because of reduced grass cover.
- Synthesis. We conclude that transitions to an encroached savanna state are supported by gradual environmental changes induced by management strategies, which affected the resilience of savanna ecosystems. In addition, feedback mechanisms that reflect the interplay between management legacies and climate change maintain the encroached state.
638.
Mechanisms involved in adrenergic receptor desensitization 总被引:1,自引:0,他引:1
S Collins M Bouvier M J Lohse J L Benovic M G Caron R J Lefkowitz 《Biochemical Society transactions》1990,18(4):541-544
639.
Effects of space environment on embryonic growth up to hatching of salamander eggs fertilized and developed during orbital flights. 总被引:1,自引:0,他引:1
Lydie Gualandris-Parisot David Husson Alain Bautz Danielle Durand Paulette Kan Christian Aimar Herve Membre Anne-Marie Duprat Christian Dournon 《Biological Sciences in Space》2002,16(1):3-11
In vertebrates, only few experiments have been performed in microgravity to study the embryonic development from fertilization. To date, these concern only amphibian and fish. We report here a study on the embryonic development of Pleurodeles waltl (urodele amphibian) eggs oviposited in microgravity. The experiment was performed twice on board the Mir space station and the data obtained included video recording and morphological, histological and immunocytological analyses. The data confirm that the microgravity conditions have effects during the embryonic period, particularly during cleavage and neurulation, inducing irregular segmentation and abnormal closure of the neural tube. Moreover, we observed several abnormalities hither to undescribed corresponding to cortical cytoplasm movements, a decrease of cell adhesion and a loss of cells. These abnormalities were temporary and subsequently reversible. The young larvae that hatched during the flight displayed normal morphology and swimming behavior after landing. The results obtained in the urodele Pleurodeles waltl are in accordance with those observed earlier in the anuran Xenopus laevis and in the fish Oryzias latipes. 相似文献