全文获取类型
收费全文 | 53224篇 |
免费 | 4717篇 |
国内免费 | 38篇 |
专业分类
57979篇 |
出版年
2023年 | 377篇 |
2022年 | 589篇 |
2021年 | 1292篇 |
2020年 | 823篇 |
2019年 | 1000篇 |
2018年 | 1480篇 |
2017年 | 1239篇 |
2016年 | 1712篇 |
2015年 | 2412篇 |
2014年 | 2669篇 |
2013年 | 3159篇 |
2012年 | 4468篇 |
2011年 | 4303篇 |
2010年 | 2616篇 |
2009年 | 2121篇 |
2008年 | 3344篇 |
2007年 | 3212篇 |
2006年 | 2978篇 |
2005年 | 2664篇 |
2004年 | 2533篇 |
2003年 | 2380篇 |
2002年 | 2188篇 |
2001年 | 769篇 |
2000年 | 782篇 |
1999年 | 615篇 |
1998年 | 558篇 |
1997年 | 375篇 |
1996年 | 343篇 |
1995年 | 291篇 |
1994年 | 295篇 |
1993年 | 300篇 |
1992年 | 306篇 |
1991年 | 289篇 |
1990年 | 244篇 |
1989年 | 205篇 |
1988年 | 220篇 |
1987年 | 213篇 |
1986年 | 153篇 |
1985年 | 179篇 |
1984年 | 195篇 |
1983年 | 152篇 |
1982年 | 188篇 |
1981年 | 169篇 |
1980年 | 156篇 |
1979年 | 131篇 |
1978年 | 136篇 |
1977年 | 117篇 |
1976年 | 100篇 |
1974年 | 91篇 |
1973年 | 102篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
Gorman Daniel Pucci Marinella Soares Lucy S. H. Turra Alexander Schlacher Thomas A. 《Ecosystems》2019,22(4):796-804
Ecosystems - Land–ocean coupling in the form of riverine inputs of terrestrial matter can constitute an energetic subsidy to food webs in nearshore coastal areas. In regions with distinctly... 相似文献
982.
Santini Nadia S. Lovelock Catherine E. Hua Quan Zawadzki Atun Mazumder Debashish Mercer Tim R. Muñoz-Rojas Miriam Hardwick Simon A. Madala Bindu Swapna Cornwell William Thomas Torsten Marzinelli Ezequiel M. Adam Paul Paul Swapan Vergés Adriana 《Ecosystems》2019,22(8):1803-1822
Ecosystems - Saltmarshes provide many valuable ecosystem services including storage of a large amount of ‘blue carbon’ within their soils. To date, up to 50% of the world’s... 相似文献
983.
Birong Zhang James R. Kiefer Robert A. Blake Jae H. Chang Steven Hartman Ellen Rei Ingalla Tracy Kleinheinz Vidhi Mody Michelle Nannini Daniel F. Ortwine Yingqing Ran Amy Sambrone Deepak Sampath Maia Vinogradova Yu Zhong Jerome C. Nwachukwu Kendall W. Nettles Tommy Lai Jun Liang 《Bioorganic & medicinal chemistry letters》2019,29(7):905-911
Despite tremendous progress made in the understanding of the ERα signaling pathway and the approval of many therapeutic agents, ER+?breast cancer continues to be a leading cause of cancer death in women. We set out to discover compounds with a dual mechanism of action in which they not only compete with estradiol for binding with ERα, but also can induce the degradation of the ERα protein itself. We were attracted to the constrained chromenes containing a tetracyclic benzopyranobenzoxepine scaffold, which were reported as potent selective estrogen receptor modulators (SERMs). Incorporation of a fluoromethyl azetidine side chain yielded highly potent and efficacious selective estrogen receptor degraders (SERDs), such as 16aa and surprisingly, also its enantiomeric pair 16ab. Co-crystal structures of the enantiomeric pair 16aa and 16ab in complex with ERα revealed default (mimics the A-D rings of endogenous ligand estradiol) and core-flipped binding modes, rationalizing the equivalent potency observed for these enantiomers in the ERα degradation and MCF-7 anti-proliferation assays. 相似文献
984.
George Nicolae Daniel Ion George Mihai Nitulescu Costin Ioan Popescu 《Bioorganic & medicinal chemistry letters》2019,29(18):2527-2534
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), also known as Apo2L, has been investigated in the past decade for its promising anticancer activity due to its ability to selectively induce apoptosis in tumoral cells by binding to TRAIL receptors (TRAIL-R). Macromolecules such as agonistic monoclonal antibodies and recombinant TRAIL have not proven efficacious in clinical studies, therefore several small molecules acting as TRAIL-R agonists are emerging in the scientific literature. In this work we focus on systemizing these drug molecules described in the past years, in order to better understand and predict the requirements for a novel anti-tumoral therapy based on the TRAIL-R-induced apoptotic mechanism. 相似文献
985.
986.
Simon Nimpf Gregory Charles Nordmann Daniel Kagerbauer Erich Pascal Malkemper Lukas Landler Artemis Papadaki-Anastasopoulou Lyubov Ushakova Andrea Wenninger-Weinzierl Maria Novatchkova Peter Vincent Thomas Lendl Martin Colombini Matthew J. Mason David Anthony Keays 《Current biology : CB》2019,29(23):4052-4059.e4
987.
988.
Barragán-Ocaña Alejandro Reyes-Ruiz Gerardo Olmos-Peña Samuel Gómez-Viquez Hortensia 《Transgenic research》2019,28(3-4):391-399
Transgenic Research - Transgenic crops have been the recipient of strong support as well as vigorously opposed opinions since their appearance. In any case, their growth throughout the world has... 相似文献
989.
Jilmar A. Murillo Juan F. Gil Yulieth A. Upegui Adriana M. Restrepo Sara M. Robledo Winston Quiñones Fernando Echeverri Aurelio San Martin Horacio F. Olivo Gustavo Escobar 《Bioorganic & medicinal chemistry》2019,27(1):153-160
We describe the in vitro activity of two natural isomeric ent-beyerene diterpenes, several derivatives and synthetic intermediates. Beyerenols 1 and 2 showed EC50 of 4.6?±?9.4 and 5.3?±?9.4?μg/mL against amastigotes of L. (V) brazilensis, with SI of 5.1 and 7.7, respectively. Beyerenol 1 was synthesized from stevioside. In vivo experiments with bereyenols showed cure in 50% of hamsters infected with L. (V) brazilensis topically applied as Cream I (beyerenol 1, 0.81%, w/w) and Cream III (beyerenol 2, 1.96%, w/w). These results suggest that beyerenols are potential candidates for cutaneous leishmaniasis chemotherapy by topical application. In vitro assays of amastigotes of L. (V) brazilensis showed EC50 of 1.1?±?0.1 and 1.3?±?0.04?μg/mL, with SI of 3.1 and 3.5 for hydrazone intermediates 10 and 11, respectively. 相似文献
990.
Ezquerra Francisco Javier Cañas Ignacio Oria-de-Rueda Juan Andrés Rubiales Juan Manuel 《Vegetation History and Archaeobotany》2019,28(1):35-50
Vegetation History and Archaeobotany - The management of the forests of Pinus sylvestris L. in north-western Iberia has been subjected to intense debate as the tree has been long considered an... 相似文献