全文获取类型
收费全文 | 12332篇 |
免费 | 1019篇 |
国内免费 | 361篇 |
出版年
2024年 | 14篇 |
2023年 | 139篇 |
2022年 | 279篇 |
2021年 | 578篇 |
2020年 | 325篇 |
2019年 | 435篇 |
2018年 | 416篇 |
2017年 | 365篇 |
2016年 | 521篇 |
2015年 | 867篇 |
2014年 | 944篇 |
2013年 | 1059篇 |
2012年 | 1276篇 |
2011年 | 1094篇 |
2010年 | 648篇 |
2009年 | 568篇 |
2008年 | 663篇 |
2007年 | 617篇 |
2006年 | 543篇 |
2005年 | 495篇 |
2004年 | 377篇 |
2003年 | 272篇 |
2002年 | 256篇 |
2001年 | 145篇 |
2000年 | 100篇 |
1999年 | 136篇 |
1998年 | 60篇 |
1997年 | 76篇 |
1996年 | 58篇 |
1995年 | 34篇 |
1994年 | 40篇 |
1993年 | 33篇 |
1992年 | 44篇 |
1991年 | 40篇 |
1990年 | 30篇 |
1989年 | 26篇 |
1988年 | 22篇 |
1987年 | 13篇 |
1986年 | 19篇 |
1985年 | 15篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1982年 | 9篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1974年 | 3篇 |
1971年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
71.
Arpana Agrawal Sarah J. Brislin Kathleen K. Bucholz Danielle Dick Ronald P. Hart Emma C. Johnson Jacquelyn Meyers Jessica Salvatore Paul Slesinger COGA Collaborators Laura Almasy Tatiana Foroud Alison Goate Victor Hesselbrock John Kramer Samuel Kuperman Alison K. Merikangas John I. Nurnberger Jay Tischfield Howard J. Edenberg Bernice Porjesz 《Genes, Brain & Behavior》2023,22(5):e12864
72.
João Ricardo Sato Claudinei Eduardo Biazoli Ana Paula Arantes Bueno Arthur Caye Pedro Mario Pan Marcos Santoro Jessica Honorato-Mauer Giovanni Abrahão Salum Marcelo Queiroz Hoexter Rodrigo Affonseca Bressan Andrea Parolin Jackowski Euripedes Constantino Miguel Sintia Belangero Luis Augusto Rohde 《Genes, Brain & Behavior》2023,22(2):e12838
73.
74.
The gene (alyVI) encoding an alginate lyase of marine bacterium Vibrio sp. QY101, which was isolated from a decaying thallus of Laminaria, was cloned using a strategy of combined degenerate PCR and long range-inverse PCR (LR-IPCR), then sequenced and expressed in Escherichia coli. Gene alyVI was composed of a 1014 bp open reading frame (ORF) encoding 338 amino acid residues. The calculated molecular mass of alyVI product is 38.4 kDa, but a signal peptide is cleaved off, leaving a mature protein of 34 kDa. AlyVI was purified from culture supernatants to electrophoretic homogeneity using affinity chromatography. AlyVI was most active at pH 7.5 and 40 degrees C in the presence of 1 mM ZnCl2. A nine-amino-acid consensus region (YXRESLREM), which was only found in polyguluronate lyases, was also observed in the amino-terminal region of AlyVI. However, AlyVI could degrade both M block and G block. These results indicate that a novel alginate lyase-encoding gene has been cloned. 相似文献
75.
本文对高原冻伤中血液循环障碍作形态计量,旨在探讨血循环障碍在冻伤过程中的变化及高原冻伤发病机理中所起的作用。实验选用Wistar雄性大鼠40只,随机分为平原冻伤组、急性低氧冻伤组和低氧习服冻伤组。习服组动物于低压舱内模拟海拔6000m缺氧每日4h,连续两周。其余动物常规饲养。习服期满次日习服组与低氧组一同进入舱内模拟海拔6000m低氧4h,再行冷冻。冻后继续低氧4h。冻后48h取材。对各组动物冻后48h冻肢皮下血管的病变作图象分析。结果发现,平原组血管淤滞、血栓绝对数及其百分比均为最低,习服组最高,低氧组居中。但低氧组与平原组的血栓/淤滞百分比无明显差别。骨骼肌坏死的面积百分比习服组显著高于低氧组与平原组,而后两组间无差别。血栓/淤滞百分比与骨骼肌坏死面积百分比之间的有高度相关关系。冻融是直接引起血管内皮损伤的原发因素,局部血液循环障碍是造成严重的继发损伤的主要原因。 相似文献
76.
77.
78.
核糖核酸(RNA)与稀土铽离子在pH5.0~6.5条件下能形成具有较强荧光的络合物,其激发峰在288nm处,发射峰为494nm及545nm处.RNA在0.1~10mg/L范围内与其荧光强度呈线性关系,其检出限为6.0×10 ̄(-8)mol/L.腺苷酸,尿苷酸,胞苷酸对RNA的干扰比较小,因此可在其存在下选择性地测定RNA. 相似文献
79.
Cell signaling and heat shock protein expression 总被引:5,自引:0,他引:5
Exposure of cells and organs to heat shock is associated with numerous changes in various cellular metabolic parameters and overexpression of proteins collectively known as heat shock proteins (HSP). In this communication we review the cell-signaling events that are altered in response to heat shock as they relate to the subsequent induction of HSP 70 kd (HSP-70) expression. We also review the mechanisms by which HSP-70 is involved in conferring cytoprotective effects. The possibility of altering HSP expression through manipulations of the cell-signal process has clinical importance.The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the Department of the Army or Department of Defense. 相似文献
80.
This study addresses the ability of DNA fragments from various sources to mediate autonomous DNA replication in cultured Drosophila melanogaster cells. We created a series of plasmids containing genomic DNA fragments from the Ultrabithorax gene of Drosophila and tested them for autonomous replication after transfection into Schneider line 2 cells. We found that all plasmids containing Drosophila DNA fragments were able to replicate autonomously, as were plasmids containing random human and Escherichia coli genomic DNA fragments. Most of the plasmids were detectable 18 days after transfection in the absence of selection, suggesting that transfected DNA is maintained in Drosophila cells without rapid loss or degradation. The finding that all plasmids containing Drosophila, human, or bacterial DNA replicate autonomously in Drosophila cells suggests that the signals that direct autonomous replication in Drosophila contain a low degree of sequence specificity. A two-dimensional gel analysis of initiation on one of the plasmids was consistent with many dispersed initiation sites. Low sequence specificity and dispersed initiation sites also characterize autonomous replication in human cells and Senopus eggs and may be general properties of autonomous replication in animal cells. 相似文献