全文获取类型
收费全文 | 7886篇 |
免费 | 29篇 |
国内免费 | 1篇 |
学科分类
工业技术 | 7916篇 |
出版年
2022年 | 10篇 |
2021年 | 11篇 |
2020年 | 6篇 |
2019年 | 19篇 |
2018年 | 18篇 |
2017年 | 23篇 |
2016年 | 22篇 |
2015年 | 27篇 |
2014年 | 39篇 |
2013年 | 57篇 |
2012年 | 48篇 |
2011年 | 72篇 |
2010年 | 46篇 |
2009年 | 63篇 |
2008年 | 72篇 |
2007年 | 46篇 |
2006年 | 47篇 |
2005年 | 48篇 |
2004年 | 37篇 |
2003年 | 42篇 |
2002年 | 36篇 |
2001年 | 23篇 |
2000年 | 27篇 |
1999年 | 187篇 |
1998年 | 2037篇 |
1997年 | 1218篇 |
1996年 | 799篇 |
1995年 | 429篇 |
1994年 | 374篇 |
1993年 | 421篇 |
1992年 | 71篇 |
1991年 | 118篇 |
1990年 | 116篇 |
1989年 | 100篇 |
1988年 | 106篇 |
1987年 | 98篇 |
1986年 | 87篇 |
1985年 | 73篇 |
1984年 | 14篇 |
1983年 | 24篇 |
1982年 | 41篇 |
1981年 | 60篇 |
1980年 | 64篇 |
1979年 | 8篇 |
1978年 | 33篇 |
1977年 | 185篇 |
1976年 | 370篇 |
1975年 | 12篇 |
1968年 | 5篇 |
1954年 | 5篇 |
排序方式: 共有7916条查询结果,搜索用时 15 毫秒
1.
2.
Assuming that the chemical reactions used to synthesize a combinatorial library member are successful, then knowledge of the specific reaction sequence is equivalent to knowing the member's chemical identity. Because the determination of chemical identity is typically not automatable and requires a substantial amount of material, schemes that encode a member's reaction history onto the reaction platform are of value. The primary benefits of encoding are relational nomenclature (all methods) and automated handling (some methods). Encoding methods evaluated to date are spatial, graphical, chemical, spectrometric, electronic, and physical. 相似文献
3.
OBJECTIVES: To assess that neuromuscular relaxation onset of the adductor pollicis (AP) is related to neuromuscular stimulation rate. To assess that train-of-four (TOF) at 0.05 Hz is a more accurate indicator of optimal tracheal intubation time and conditions, than TOF at 0.08 Hz. STUDY DESIGN: Prospective, comparative, randomized double-blind study. PATIENTS: Forty adults, physical class ASA 1 or 2, undergoing general anaesthesia with tracheal intubation were allocated to two groups (n = 20) according to the sequence of stimulation of the AP: either TOF at 0.05 Hz (test group) or TOF at 0.08 Hz (control group). METHODS: Induction of anaesthesia was achieved with thiopentone, fentanyl and vecuronium (0.1 mg.kg-1). Neuromuscular monitoring was obtained with force displacement transducers attached to each AP. Tracheal intubation was performed once AP muscular response obtained with TOF at 0.05 Hz for test group and TOF at 0.08 Hz for control group was abolished. Results are expressed as mean +/- SEM. Fisher exact test was used for intubation conditions comparison. Curarization time between groups was compared with unpaired Student's t test (P < 0.05 accepted). RESULTS: TOF with 0.05 Hz stimulation significantly increased curarization time: 217 +/- 7 versus 162 +/- 6 s (P < 0.001). Intubation conditions were excellent in 95% and good in 5% of patients in the study group, compared to 15 and 40% in the control group, respectively (P < 0.01) in 45% of the control group patients coughing at intubation occurred. CONCLUSION: Low stimulation rate (TOF at 0.05 Hz) of AP is a reliable technique to determine the appropriate intubation time for patients paralyzed with vecuronium. 相似文献
4.
5.
A set of six coals ranging in rank from lignite to hvA bituminous was swollen with a series of alkyl-substituted pyridines and a smaller set of 4-alkylanilines. The size and branching of the alkyl groups was varied and the effect of this variation on the dissolution of the amines in the coal and the resulting coal swelling was measured volumetrically. In a few cases, substituents which hindered the amine nitrogen were studied. The lignite and subbituminous coal have a much higher tolerance to branched, bulky groups than do the bituminous coals. The presence of tertiary groups in a solute strongly inhibits their dissolution in bituminous coals. Bituminous coals behave as if extensive parallel packing of structures occurs. Often, they can accept very large planar groups but have a low capacity for branched groups. 相似文献
6.
7.
8.
9.
10.