全文获取类型
收费全文 | 1785篇 |
免费 | 140篇 |
国内免费 | 61篇 |
专业分类
化学 | 965篇 |
力学 | 184篇 |
综合类 | 25篇 |
数学 | 102篇 |
物理学 | 397篇 |
无线电 | 313篇 |
出版年
2024年 | 8篇 |
2023年 | 33篇 |
2022年 | 88篇 |
2021年 | 84篇 |
2020年 | 64篇 |
2019年 | 51篇 |
2018年 | 53篇 |
2017年 | 52篇 |
2016年 | 62篇 |
2015年 | 81篇 |
2014年 | 82篇 |
2013年 | 122篇 |
2012年 | 127篇 |
2011年 | 80篇 |
2010年 | 86篇 |
2009年 | 92篇 |
2008年 | 67篇 |
2007年 | 77篇 |
2006年 | 88篇 |
2005年 | 80篇 |
2004年 | 51篇 |
2003年 | 74篇 |
2002年 | 45篇 |
2001年 | 54篇 |
2000年 | 39篇 |
1999年 | 23篇 |
1998年 | 22篇 |
1997年 | 33篇 |
1996年 | 27篇 |
1995年 | 23篇 |
1994年 | 16篇 |
1993年 | 24篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1976年 | 2篇 |
排序方式: 共有1986条查询结果,搜索用时 0 毫秒
11.
Isaac Zamora-Bello Eduardo Rivadeneyra-Domínguez Juan Francisco Rodríguez-Landa 《Molecules (Basel, Switzerland)》2022,27(12)
Epilepsy is a chronic neurological disorder that lacks a cure. The use of plant-derived antioxidant molecules such as those contained in turmeric powder and resveratrol may produce short-term anticonvulsant effects. A total of 42 three-month-old male Wistar rats were divided into six groups (n = 7 in each group): Vehicle (purified water), turmeric (150 and 300 mg/kg, respectively), and resveratrol (30 and 60 mg/kg, respectively), administered per os (p.o.) every 24 h for 35 days. Carbamazepine (300 mg/kg/5 days) was used as a pharmacological control for anticonvulsant activity. At the end of the treatment, status epilepticus was induced using the lithium–pilocarpine model [3 mEq/kg, intraperitoneally (i.p.) and 30 mg/kg subcutaneously (s.c.), respectively]. Seizures were evaluated using the Racine scale. The 300 mg/kg of turmeric and 60 mg/kg of resveratrol groups had an increased latency to the first generalized seizure. The groups treated with 150 and 300 mg/kg of turmeric and 60 mg/kg of resveratrol also had an increased latency to status epilepticus and a decreased number of generalized seizures compared to the vehicle group. The chronic administration of turmeric and resveratrol exerts anticonvulsant effects without producing kidney or liver damage. This suggests that both of these natural products of plant origin could work as adjuvants in the treatment of epilepsy. 相似文献
12.
13.
14.
3 GPa熔融盐固体介质三轴高温压力容器的轴压摩擦力标定 总被引:1,自引:0,他引:1
在温度标定和围压标定的基础上,采用轴压循环方法,对3 GPa固体介质三轴高温高压实验系统的轴压摩擦力进行了标定,分析了围压、温度、轴向位移速率、装样方式(盐套类型)等实验条件对轴压摩擦力的影响。结果表明:静摩擦力、挤压摩擦力和滑动摩擦力3种轴压摩擦力对轴向应力的影响不同,其中静摩擦力和挤压摩擦力对轴向应力的影响很小,影响应力精度的主要是滑动摩擦力。静摩擦力及滑动摩擦力与围压正相关;静摩擦力与轴向位移速率正相关,但受其影响较小,滑动摩擦力不受其影响;静摩擦力和滑动摩擦力与温度负相关,并且受其影响较显著;盐套类型对轴压摩擦力的影响较大,当实验条件接近盐套熔点时,轴压摩擦力显著降低,当样品周围的盐套处于熔融状态时,轴压摩擦力最小。基于此,确定了标定轴压摩擦力的具体步骤,并对角闪岩的应力-应变曲线进行了轴压摩擦力标定。对比轴压摩擦力校正前、后的应力-应变曲线发现,经过轴压摩擦力校正的应力-应变曲线能更好地反映样品的实际变形情况。 相似文献
15.
16.
《Comptes Rendus Physique》2013,14(6):447-450
One of the major emerging fields of research of the beginning of this century concerns living fluids. By “living fluids”, we mean two major categories of complex fluids: (i) fluids which are essential to life, like blood, and (ii) active fluids made of particles that are able to propel themselves in the suspending fluid by converting a form of their energy into mechanical motion. Studies on active fluids have known a considerable interest since the last decade. Blood might be viewed as an old topic, but the progresses in experimental techniques, analytical concepts and numerics, have contributed nowadays to a dramatic renewal of the interest in this field, with a great potential towards understanding physical and mechanical factors in cardiovascular diseases. These fields have considerably strengthened interdisciplinary research. The series of reviews of this dossier focus on the tremendous recent progress achieved in research on living fluids both from the experimental and theoretical points of views. These reviews present also the major open issues, making of this dossier a unique guide for future research in these fields. This project grew up thanks to the international summer school that we organized on the topic “living fluids” at the IES (Institut dʼétudes scientifiques) of Cargèse (Corsica) in 2012. 相似文献
17.
眼科临床上所使用的简易头托限定医生与受试者的距离不能超过一臂之长,因此无法用于较为庞大的眼底自适应成像系统。为了达到眼底自适应成像系统与受试者瞳孔快速对准、稳定定位的要求,设计了一种可长距离控制的二自由度的头托。采用具有自锁能力的梯形丝杠驱动头托垂直运动,采用传动效率高的滚珠丝杠驱动头托水平运动,以步进电机提供动力。基于PIC16F877单片机,完成了头托移动控制的软硬件设计,并在MPLAB与Proteus环境下进行了联合仿真实验。仿真结果表明,所设计的头托可在竖直方向和水平方向以20μm的精准度定位,能够实现长距离、快速准确的瞳孔对准和左右瞳孔切换过程,是眼底自适应成像系统的良好辅助工具。 相似文献
18.
Remotely Controlled Red Blood Cell Carriers for Cancer Targeting and Near‐Infrared Light‐Triggered Drug Release in Combined Photothermal–Chemotherapy 下载免费PDF全文
Xiaoqi Sun Chao Wang Min Gao Aiyan Hu Zhuang Liu 《Advanced functional materials》2015,25(16):2386-2394
Red blood cells (RBCs), the “innate carriers” in blood vessels, are gifted with many unique advantages in drug transportation over synthetic drug delivery systems (DDSs). Herein, a tumor angiogenesis targeting, light stimulus‐responsive, RBC‐based DDS is developed by incorporating various functional components within the RBC platform. An albumin bound near‐infrared (NIR) dye, together with a chemotherapy drug doxorubicin, is encapsulated inside RBCs, the surfaces of which are modified with a targeting peptide to allow cancer targeting. Under stimulation by an external NIR laser, the membrane of the RBCs would be destroyed by the light‐induced photothermal heating, resulting in effective drug release. As a proof of principle, RBC‐based cancer cell targeted drug delivery and light‐controlled drug release is demonstrated in vitro, achieving a marked synergistic therapeutic effect through the combined photothermal–chemotherapy. This work presents a novel design of smart RBC carriers, which are inherently biocompatible, promising for targeted combination therapy of cancer. 相似文献
19.
This study investigates the recovery of electric resistivity in pure iron, Fe–0.6Ni and Fe–1.5Mn as related to isochronal annealing following 1 MeV proton irradiation at lower temperature than 70 K, focusing on the relationship between solute atoms and irradiation defects. Both nickel and manganese prevent stage ID recovery, which corresponds to correlated recombination. Stage II recovery is also changed by the addition of a solute, which corresponds to the migration of small interstitial clusters. In both pure iron and Fe–0.6Ni, no evident difference was observed in the stage III region, which corresponds to the migration of vacancies. In contrast, two substages appeared in the Fe–1.5Mn at a higher temperature than stage IIIB appeared in pure iron. These substages are considered to represent the release of irradiation-induced defects, which was trapped by manganese. 相似文献
20.
动态光谱法对提高近红外无创血液成份检测精度的理论分析 总被引:6,自引:0,他引:6
近红外光谱无创血液成分检测因测量方法具有优越性,已经成为生物医学领域的研究热点之一.但除血氧以外,目前还没有进入临床应用的报道,其原因在于个体差异和测量条件对检测精度的影响.研究了一种不同于传统的新检测方法-动态光谱法可使测量精度提高.先从检测原理出发,研究了传统的近红外无创血液成分测量过程中产生误差、造成测量精度较低的因素;再分析了动态光谱法对这些因素的抑制或克服.从理论上得到了动态光谱法可以大大提高血液成分无创检测精度的结论,为基于光谱法的无创血液成分检测的临床应用提供了条件. 相似文献