全文获取类型
收费全文 | 7526篇 |
免费 | 140篇 |
国内免费 | 2篇 |
学科分类
工业技术 | 7668篇 |
出版年
2021年 | 40篇 |
2020年 | 45篇 |
2019年 | 50篇 |
2018年 | 56篇 |
2017年 | 61篇 |
2016年 | 76篇 |
2015年 | 49篇 |
2014年 | 64篇 |
2013年 | 248篇 |
2012年 | 108篇 |
2011年 | 170篇 |
2010年 | 122篇 |
2009年 | 135篇 |
2008年 | 158篇 |
2007年 | 156篇 |
2006年 | 135篇 |
2005年 | 119篇 |
2004年 | 157篇 |
2003年 | 153篇 |
2002年 | 125篇 |
2001年 | 125篇 |
2000年 | 113篇 |
1999年 | 205篇 |
1998年 | 1146篇 |
1997年 | 620篇 |
1996年 | 425篇 |
1995年 | 253篇 |
1994年 | 276篇 |
1993年 | 275篇 |
1992年 | 108篇 |
1991年 | 108篇 |
1990年 | 119篇 |
1989年 | 104篇 |
1988年 | 96篇 |
1987年 | 99篇 |
1986年 | 92篇 |
1985年 | 96篇 |
1984年 | 65篇 |
1983年 | 77篇 |
1982年 | 81篇 |
1981年 | 75篇 |
1980年 | 71篇 |
1979年 | 55篇 |
1978年 | 56篇 |
1977年 | 111篇 |
1976年 | 224篇 |
1975年 | 46篇 |
1974年 | 42篇 |
1973年 | 36篇 |
1970年 | 25篇 |
排序方式: 共有7668条查询结果,搜索用时 437 毫秒
11.
12.
LJ Huang K Durick JA Weiner J Chun SS Taylor 《Canadian Metallurgical Quarterly》1997,94(21):11184-11189
Subcellular localization directed by specific A kinase anchoring proteins (AKAPs) is a mechanism for compartmentalization of cAMP-dependent protein kinase (PKA). Using a two-hybrid screen, a novel AKAP was isolated. Because it interacts with both the type I and type II regulatory subunits, it was defined as a dual specific AKAP or D-AKAP1. Here we report the cloning and characterization of another novel cDNA isolated from that screen. This new member of the D-AKAP family, D-AKAP2, also binds both types of regulatory subunits. A message of 5 kb pairs was detected for D-AKAP2 in all embryonic stages and in all adult tissues tested. In brain, skeletal muscle, kidney, and testis, a 10-kb mRNA was identified. In testis, several small mRNAs were observed. Therefore, D-AKAP2 represents a novel family of proteins. cDNA cloning from a mouse testis library identified the full length D-AKAP2. It is composed of 372 amino acids which includes the R binding fragment, residues 333-372, at its C-terminus. Based on coprecipitation assays, the R binding domain interacts with the N-terminal dimerization domain of RIalpha and RIIalpha. A putative RGS domain was identified near the N-terminal region of D-AKAP2. The presence of this domain raises the intriguing possibility that D-AKAP2 may interact with a Galpha protein thus providing a link between the signaling machinery at the plasma membrane and the downstream kinase. 相似文献
13.
Rolandic discharge (RD), noted in the electroencephalography (EEG) of patients with benign epilepsy in childhood with centrotemporal spikes (BECCT) has several unique features. One feature is that the amount or frequency of RDs does not correlate well with the incidence of seizures in BECCT although it is a key finding in the diagnosis of this epileptic syndrome. In this study, we examined the efficacy of antiepileptic drugs focusing on the disappearance of RDs in relationship with seizure control. Forty patients with BECCT who were not medically treated prior to this study were randomly sorted into three groups. Twenty patients were assigned for clonazepam (CZP) treatment, 10 patients for valproate (VPA) and the remaining 10 patients for carbamazepine (CBZ). Each drug was administered for 4 consecutive weeks. EEGs were recorded twice during the study, before and 4 weeks after the medication trial. The effects of each treatment on RDs were assessed. RDs disappeared in 15 of the 20 cases treated with CZP (75%) within 4 weeks while the same was observed in only one of the 10 cases treated with VPA (10%). CBZ failed to demonstrate any effect on RD. In the group treated with CZP, there were no differences in seizure incidence, seizure type and blood concentration of CZP between the patients whose RDs disappeared and those whose RDs remained. 相似文献
14.
15.
The case of a 36-year-old man who sought treatment of right facial myokymia and spastic paretic facial contracture is reported. Computed tomography and magnetic resonance imaging revealed a tumor located in the right cerebellar peduncle and the right dorsal pons bulging into the fourth ventricle. After microsurgical partial resection of the mass, which was verified histologically as an anaplastic glioma, facial myokymia initially ceased. The vermicular rippling movements were less intense upon recurrence and could be controlled by low-dose dexamethasone in the further course, when magnetic resonance imaging showed an interstitial pontine edema after percutaneous radiation therapy. It is assumed that facial myokymia and spastic paretic facial contracture were generated by ectopic activity due to alterations in the microenvironment at the intrapontine portion of the axons of the seventh nerve caused by the compressive effect of the tumor and later by edema. 相似文献
16.
The aim of this study was to compare the sensitivities of commercial monoclonal antibody pools to be used as an initial rapid screen for detection of viral antigens in respiratory secretions. The availability of commercial monoclonal antibodies has dramatically improved the detection of viruses by immunofluorescence techniques in exfoliated cells obtained from respiratory secretions. Several companies have recently introduced monoclonal antibody pools to detect the presence of respiratory viruses in a single preparation. Ninety-four stored slide preparations that had previously been examined by individual monoclonal antibodies were tested using three commercial monoclonal antibody pools produced by Sanofi (UK), Dako (UK), and Quadratech (UK). These monoclonal antibody pools had a sensitivity of 79.6%, 90.9%, and 100%, respectively, when compared with the original results. The overall intensity of immunofluorescence was also examined. 相似文献
17.
Patrick R. Taylor Ph.D. Milton Manrique Ph.D. 《JOM Journal of the Minerals, Metals and Materials Society》1996,48(6):43-45
Due to several inherent advantages, plasma processing technology may become a very useful tool in the production of new materials. An increasing research effort based on experimental as well as theoretical investigations has been invested in this area for the synthesis of advanced materials. In describing the thermal-plasma processing technique, this article employs examples from research at the Plasma Processing Laboratory at the University of Idaho. 相似文献
18.
19.
对于今天的织物,易护理性是一项基本要求。然而,理想的易护理效果不可能仅通过Tencel纤维本身的性能来获得,合适的织物组织结构、恰当的前处理,以及最佳的高级整理加工可以提高Tencel织物的易护理性能,并超过其他纤维素纤维。关于织物组织结构的影响已经在其他杂志上有过讨论。本文将说明如何采用不同的前处理、后整理加工,获得高档最终产品的方法。 相似文献
20.