全文获取类型
收费全文 | 5443篇 |
免费 | 172篇 |
国内免费 | 6篇 |
学科分类
工业技术 | 5621篇 |
出版年
2022年 | 62篇 |
2021年 | 86篇 |
2020年 | 47篇 |
2019年 | 63篇 |
2018年 | 86篇 |
2017年 | 104篇 |
2016年 | 126篇 |
2015年 | 92篇 |
2014年 | 119篇 |
2013年 | 264篇 |
2012年 | 220篇 |
2011年 | 276篇 |
2010年 | 219篇 |
2009年 | 239篇 |
2008年 | 224篇 |
2007年 | 243篇 |
2006年 | 240篇 |
2005年 | 171篇 |
2004年 | 182篇 |
2003年 | 149篇 |
2002年 | 153篇 |
2001年 | 119篇 |
2000年 | 112篇 |
1999年 | 92篇 |
1998年 | 224篇 |
1997年 | 172篇 |
1996年 | 142篇 |
1995年 | 121篇 |
1994年 | 117篇 |
1993年 | 97篇 |
1992年 | 59篇 |
1991年 | 46篇 |
1990年 | 57篇 |
1989年 | 48篇 |
1988年 | 51篇 |
1987年 | 48篇 |
1986年 | 30篇 |
1985年 | 80篇 |
1984年 | 60篇 |
1983年 | 57篇 |
1982年 | 47篇 |
1981年 | 82篇 |
1980年 | 48篇 |
1979年 | 52篇 |
1978年 | 18篇 |
1977年 | 40篇 |
1976年 | 53篇 |
1975年 | 43篇 |
1974年 | 32篇 |
1973年 | 26篇 |
排序方式: 共有5621条查询结果,搜索用时 15 毫秒
1.
Christian Ligoure Michel Cloitre Christille Le Chatelier Fabrice Monti 《Polymer》2005,46(17):6402-6410
A remarkable correlation exists between the degree of expansion of polyurethane foams and the structure of the reacting premixes. Polyurethane foams obtained from reacting premixes containing microemulsions are highly expanded. The expansion rate is proportional to the volume fraction of microemulsion in the premix. The stability of premixes with and without microemulsion is completely different suggesting distinct creaming mechanisms. We apply this idea to synthesize polyurethane foams from microemulsions successfully. This approach can be used to rationalize the design of polyurethane formulations leading to highly expanded foams. 相似文献
2.
3.
Mirna Suárez-Quiroz Béatrice De Louise Oscar Gonzalez-Rios Michel Barel Bernard Guyot Sabine Schorr-Galindo & Joseph-Pierre Guiraud 《International Journal of Food Science & Technology》2005,40(6):605-611
Roasting coffee led to a drop in the ochratoxin A (OTA) concentration, as measured by the reference method, especially for dark type roasts. The way the beverage was prepared also affected the OTA content, which could paradoxically be higher than that of the initial roasted coffee. Assays on the thermal stability of pure OTA showed that it ought to be found in larger quantities in roasted coffee. This suggested that OTA was masked by reactions with the substrate during roasting. The absence of OTA in green coffee is therefore the best guarantee of safety. 相似文献
4.
5.
6.
7.
Abrial A. Bouvier J. Fournier J.-M. Senn P. 《Solid-State Circuits, IEEE Journal of》1993,28(7):725-729
A half-flash, subranging, 8-b, 13.5-MHz, video ADC (analog-to-digital converter) using overlapped architecture that combines the advantages of both flash and half-flash converters is described. Its conversion rate is that of a flash, without any multiplexing and with a low number of comparators. Its low power consumption and the small silicon area required for its implementation enable it to be integrated in mixed digital/analog circuits such as a video acquisition circuit devoted to visiophony applications. It has been manufactured using a CMOS 1-μm technology with two polysilicon and two metallization layers 相似文献
8.
9.
The high cost of mental health surveys of the general population has sparked interest in less costly research methods. Two low-cost mental health survey strategies (mail and telephone) were compared in terms of cost, response rate and quality of data obtained. A total of 1,074 persons agreed to participate in the study as a sample, one-half by telephone and the other half by mail. They completed the Diagnostic Interview Schedule Self-Administered, a questionnaire designed to be self-administered, which was used to assess specific mental disorders and to evaluate risk factors. In addition, 239 respondents who were selected according to the presence or absence of specific diagnoses were reinterviewed face-to-face using the Diagnostic Interview Schedule as an external criterion. The telephone method yielded a better response rate (15% higher) and better control over answers (for example, less missing data). The mail strategy was less expensive and appeared to yield data of slightly better quality, particularly for respondents suffering from anxiety disorders. 相似文献
10.
Michel Gangnet Burton Rosenberg 《Annals of Mathematics and Artificial Intelligence》1993,8(3-4):271-284
Aconstraint system includes a set of variables and a set of relations among these variables, calledconstraints. The solution of a constraint system is an assignment of values to variables so that all, or many, of the relations are made true. A simple and efficient method for constraint resolution has been proposed in the work of B.N. Freeman-Benson, J. Maloney, and A. Borning. We show how their method is related to the classical problem of graph matching, and from this connection we derive new resolution algorithms. 相似文献