全文获取类型
收费全文 | 4800篇 |
免费 | 51篇 |
国内免费 | 5篇 |
学科分类
工业技术 | 4856篇 |
出版年
2023年 | 12篇 |
2022年 | 16篇 |
2021年 | 21篇 |
2020年 | 10篇 |
2019年 | 18篇 |
2018年 | 25篇 |
2017年 | 27篇 |
2016年 | 37篇 |
2015年 | 30篇 |
2014年 | 23篇 |
2013年 | 80篇 |
2012年 | 51篇 |
2011年 | 101篇 |
2010年 | 65篇 |
2009年 | 68篇 |
2008年 | 90篇 |
2007年 | 93篇 |
2006年 | 97篇 |
2005年 | 76篇 |
2004年 | 59篇 |
2003年 | 58篇 |
2002年 | 69篇 |
2001年 | 63篇 |
2000年 | 35篇 |
1999年 | 146篇 |
1998年 | 982篇 |
1997年 | 616篇 |
1996年 | 380篇 |
1995年 | 229篇 |
1994年 | 177篇 |
1993年 | 224篇 |
1992年 | 59篇 |
1991年 | 50篇 |
1990年 | 57篇 |
1989年 | 55篇 |
1988年 | 40篇 |
1987年 | 46篇 |
1986年 | 40篇 |
1985年 | 36篇 |
1984年 | 26篇 |
1983年 | 23篇 |
1982年 | 34篇 |
1981年 | 21篇 |
1980年 | 40篇 |
1979年 | 13篇 |
1978年 | 17篇 |
1977年 | 82篇 |
1976年 | 160篇 |
1975年 | 12篇 |
1973年 | 10篇 |
排序方式: 共有4856条查询结果,搜索用时 15 毫秒
1.
In this study, the effect and side-effect of epidural injection with lappaconitine compound for post-operative analgesia was observed. One hundred and twenty patients were randomly divided into 4 groups. Lappaconitine compound (LB) consisted of 12 mg of lappaconitine and 22.5 mg of bupivacaine, was given to group A (the group of observation), and lappaconitine 12 mg, bupivacaine 22.5 mg and morphine 2 mg to group B, C and D respectively for control. All were given by epidural injection with single blind method during post-operative pain of incision operation. Result showed that the initiating of analgesia was quicker in group A and C than that in group B and D, and the efficacy was group D > A > C > B. There was significant difference between group A and B in the above two parameters, P < 0.01 and P < 0.05. The analgisia maintenence time of single injection was D > A > B > C, that of group D was significantly longer than that of group A (P < 0.01). It indicated that the epidural injection with LB was more rapid and potent than that with lappaconitine alone in post-operative analgesia, and the former had no side-effect, it was safer than morphine. 相似文献
2.
We report new measurements of the effective thermal conductivity Keff and relaxation time τ in dilute mixtures of3He in superfluid4He, with molar concentrationsX≤10−3. The temperature range extended fromT≈1.4 K toT
λ. Both Kcff and τ are found to agree with theoretical predictions, in contrast to previous experiments where significant differences
were observed. A new thermal conductivity cell design was used which almost completely eliminates extraneous volumes and surfaces,
and the earlier results are explained in relation to these design changes. 相似文献
3.
4.
5.
6.
7.
Computerized analysis of lung sounds can play a very important role in management of patients with a variety of medical conditions, particularly those who are seriously ill. While single-channel devices can play an important role in making auscultation more objective, multi-channel instruments greatly improve the efficiency of data collection. This has a particular advantage in the rapid assessments of patients who are in acute distress from cardiopulmonary conditions. As noted, it has the distinct advantage of being noninvasive. This is a particular advantage in the case of children and pregnant women. A number of other groups are currently working with multichannel devices, but have not yet reported their findings. The future will likely see improved acoustic instruments useful in diagnosis and management of medical conditions 相似文献
8.
9.
MG Newman 《Canadian Metallurgical Quarterly》1997,2(1):180-198
The design and implementation of clinical trials (CTs) carried out to evaluate antimicrobial and anti-infective drugs and devices are one of the most difficult challenges in contemporary periodontal research and product development. The overwhelming amount of evidence which has established a microbial etiology for periodontitis is the basis for developing and testing antimicrobial treatments. Well-designed antimicrobial CTs start with a carefully crafted hypothesis and a protocol which explicitly integrates the requirements of the patient, the clinician, the sponsor, and regulatory authorities. Surrogate variables for effectiveness must be clinically relevant, scientifically sound, and statistically valid. Currently, clinical attachment level measurements and alveolar bone assessments are accepted as proof of effectiveness. Indication and claim support of the antimicrobial product guide the design and implementation of the CT. Adverse microbiologic consequences, such as lack of antimicrobial susceptibility, wrong spectrum, incorrect dosage, non-compliance, and drug interference, must be monitored. Successful CTs balance a large group of variables used to screen, randomize, and assign subjects to experimental and control groups to ensure that prognostic and risk factors are properly accounted for. 相似文献
10.