全文获取类型
收费全文 | 3649篇 |
免费 | 18篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 12篇 |
综合类 | 4篇 |
化学工业 | 122篇 |
金属工艺 | 40篇 |
机械仪表 | 11篇 |
建筑科学 | 37篇 |
能源动力 | 17篇 |
轻工业 | 74篇 |
水利工程 | 1篇 |
石油天然气 | 6篇 |
无线电 | 151篇 |
一般工业技术 | 181篇 |
冶金工业 | 2885篇 |
原子能技术 | 7篇 |
自动化技术 | 123篇 |
出版年
2022年 | 8篇 |
2019年 | 8篇 |
2018年 | 11篇 |
2017年 | 13篇 |
2016年 | 10篇 |
2014年 | 9篇 |
2013年 | 42篇 |
2012年 | 18篇 |
2011年 | 33篇 |
2010年 | 33篇 |
2009年 | 31篇 |
2008年 | 37篇 |
2007年 | 36篇 |
2006年 | 43篇 |
2005年 | 35篇 |
2004年 | 31篇 |
2003年 | 24篇 |
2002年 | 34篇 |
2001年 | 17篇 |
2000年 | 22篇 |
1999年 | 108篇 |
1998年 | 837篇 |
1997年 | 533篇 |
1996年 | 322篇 |
1995年 | 216篇 |
1994年 | 155篇 |
1993年 | 196篇 |
1992年 | 38篇 |
1991年 | 38篇 |
1990年 | 56篇 |
1989年 | 42篇 |
1988年 | 35篇 |
1987年 | 40篇 |
1986年 | 45篇 |
1985年 | 38篇 |
1984年 | 23篇 |
1983年 | 16篇 |
1982年 | 23篇 |
1981年 | 33篇 |
1980年 | 39篇 |
1979年 | 11篇 |
1978年 | 18篇 |
1977年 | 70篇 |
1976年 | 132篇 |
1975年 | 8篇 |
1974年 | 7篇 |
1973年 | 9篇 |
1972年 | 7篇 |
1967年 | 10篇 |
1966年 | 9篇 |
排序方式: 共有3671条查询结果,搜索用时 0 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.
3.
4.
5.
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
6.
7.
HJ Lee HK Ha MH Kim YK Jeong PN Kim MG Lee JS Kim DJ Suh SG Lee YI Min YH Auh 《Canadian Metallurgical Quarterly》1997,169(2):517-520
OBJECTIVE: The purpose of this study was to evaluate ERCP and CT findings of ectopic drainage of the common bile duct into the duodenal bulb. CONCLUSION: Although rare, the diagnosis of ectopic drainage of the common bile duct into the duodenal bulb is important to prevent inadvertent damage during biliary tract or gastric surgery and to clarify the cause of chronic peptic ulcers. 相似文献
8.
This is the second in a series of articles provided to the readers of PENNSYLVANIA MEDICINE as an update from researchers and clinicians in this cutting-edge medical field. The series is partially sponsored through a grant from the Pennsylvania Department of Health to the University of Pittsburgh Department of Human Genetics. 相似文献
9.
MG Tucci G Ricotti R Giardino S Carraro G Mattei I Cataldi G Lucarini R Solmi L Tosi G Biagini 《Canadian Metallurgical Quarterly》1997,43(8):1213-1220
Establishing guidelines and experimental models preclinical and clinical evaluations of new agents for treatment, and/or prevention of human diseases has become a task of crucial importance. Psoriasis is such one disease holding great interest for dermatology owing to its high rate of incidence and complexity of treatment. However the absence of psoriatic lesions in animals and the inability to induce them, calls for experimental techniques both in vitro and in vivo. The purpose of this study was to evaluate experimentally the effects of tacalcitol on cell proliferation and differentiation process. Thereafter a human pilot study on psoriatic patients has been developed. 相似文献
10.
SM Kornblau E Estey T Madden HT Tran S Zhao U Consoli V Snell G Sanchez-Williams H Kantarjian M Keating RA Newman M Andreeff 《Canadian Metallurgical Quarterly》1997,15(5):1796-1802
PURPOSE: Expression of the multidrug resistance gene (MDR1) p170 protein is frequent in leukemic blasts from patients with relapsed acute myelogenous leukemia (AML). A phase I study using the nonimmunosuppressive MDR1 blocker SDZ PSC-833 (PSC) in combination with mitoxantrone (MITO) and etoposide (VP) was performed. PATIENTS AND METHODS: Starting doses (LVL0) of MITO (3.25 mg/m2/d on days 1 and 3 to 6) and VP (210 mg/m2/d on days 1 and 3 to 5) were 40% of the maximal-tolerated dose (MTD) from a prior study. A 1.5-mg/kg loading dose of PSC was followed by a 120-hour continuous infusion of 10 mg/kg/d on days 2 to 6. Blood samples for PSC, MITO, and VP pharmacokinetics (PK) were taken on days 1 and 3, and samples for MDR1 expression were taken on day 0. RESULTS: Severe mucositis developed in all patients at LVL0; therefore, MITO and VP doses were reduced to 2.5 and 170 mg/m2 (LVL-1) for the next seven patients, and this dose proved to be MTD. All LVL0 and three LVL-1 patients had transient elevations in the serum bilirubin level to > or = 4 mg/dL. Serum creatinine level increased to greater than 2 mg/dL in one case. There were no other grade 3 or 4 nonhematologic toxicities observed. The peripheral blood was cleared of leukemia in three LVL0 and four LVL-1 patients. The marrow was cleared of leukemic cells in one LVL0 and five LVL-1 patients, and a significant reduction in marrow leukemic infiltrate was observed in eight of 10. No patient achieved complete remission (CR), and all died of progressive disease (n = 8) or infection (n = 2). MDR1 expression was detected by fluorescent-activated cell sorter (FACS) analysis in five of seven cases. An elevated MDR1 mRNA level was detected by quantitative polymerase chain reaction (Q-PCR) in six of eight cases studied. Clearing of leukemia cells from the marrow occurred in four of six MDR1-positive and one of three MDR1-negative patients. Despite the fact that LVL0 doses had to be reduced due to toxicity, coadministration of PSC did not produce a consistent effect on MITO PK; however, it did repeatedly lead to increased levels of VP in the serum. CONCLUSION: We conclude that PSC-MITO-VP is a tolerable regimen with antileukemic activity. Addition of PSC necessitated a 66% reduction in MITO and VP doses from a prior study without PSC. 相似文献