收费全文 | 30508篇 |
免费 | 2234篇 |
国内免费 | 2427篇 |
耳鼻咽喉 | 90篇 |
儿科学 | 322篇 |
妇产科学 | 1240篇 |
基础医学 | 1769篇 |
口腔科学 | 619篇 |
临床医学 | 2684篇 |
内科学 | 7863篇 |
皮肤病学 | 1361篇 |
神经病学 | 4063篇 |
特种医学 | 878篇 |
外科学 | 7039篇 |
综合类 | 293篇 |
预防医学 | 4826篇 |
眼科学 | 159篇 |
药学 | 839篇 |
中国医学 | 9篇 |
肿瘤学 | 1115篇 |
2018年 | 277篇 |
2017年 | 420篇 |
2016年 | 1057篇 |
2015年 | 1034篇 |
2014年 | 1287篇 |
2013年 | 2173篇 |
2012年 | 479篇 |
2011年 | 620篇 |
2010年 | 1031篇 |
2009年 | 1480篇 |
2008年 | 590篇 |
2007年 | 571篇 |
2006年 | 1095篇 |
2005年 | 920篇 |
2004年 | 733篇 |
2003年 | 844篇 |
2002年 | 826篇 |
2001年 | 955篇 |
2000年 | 714篇 |
1999年 | 821篇 |
1998年 | 826篇 |
1997年 | 816篇 |
1996年 | 1002篇 |
1995年 | 1145篇 |
1994年 | 963篇 |
1993年 | 843篇 |
1992年 | 874篇 |
1991年 | 776篇 |
1990年 | 642篇 |
1989年 | 617篇 |
1988年 | 585篇 |
1987年 | 629篇 |
1986年 | 506篇 |
1985年 | 614篇 |
1984年 | 538篇 |
1983年 | 453篇 |
1982年 | 463篇 |
1981年 | 430篇 |
1980年 | 405篇 |
1979年 | 387篇 |
1978年 | 355篇 |
1977年 | 348篇 |
1976年 | 276篇 |
1975年 | 229篇 |
1974年 | 217篇 |
1973年 | 182篇 |
1972年 | 147篇 |
1968年 | 151篇 |
1967年 | 164篇 |
1966年 | 131篇 |
Methods: Five hundred twenty-six patients were enrolled. They received a single dose of vecuronium, rocuronium, or atracurium to facilitate tracheal intubation and received no more relaxant thereafter. Neuromuscular blockade was not reversed at the end of the procedure. On arrival in the postanesthesia care unit, the TOF ratio was measured at the adductor pollicis, using acceleromyography. Head lift, tongue depressor test, and manual assessment of TOF and DBS fade were also performed. The time delay between the injection of muscle relaxant and quantitative measurement of neuromuscular blockade was calculated from computerized anesthetic records.
Results: The TOF ratios less than 0.7 and 0.9 were observed in 16% and 45% of the patients, respectively. Two hundred thirty-nine patients were tested 2 h or more after the administration of the muscle relaxant. Ten percent of these patients had a TOF ratio less than 0.7, and 37% had a TOF ratio less than 0.9. Clinical tests (head lift and tongue depressor) and manual assessment of fade showed a poor sensitivity (11-14%) to detect residual blockade (TOF < 0.9). 相似文献
Methods: The authors surveyed spontaneous afferent discharge in rats with hind paw inflammation evoked by complete Freund adjuvant over the entire 14 days of the inflammatory pain condition, as determined in parallel experiments assessing allodynia and hyperalgesia.
Results: Inflammation-evoked heat hyperalgesia, mechanoallodynia, and mechanohyperalgesia began within hours, persisted until at least day 7, and resolved by day 14. A large percentage (23%) of A fibers had spontaneous discharge 2 days after inflammation, but the incidence was much reduced (to 7-9%) by 7 and 14 days. At all times, the A-fiber discharge frequency was low (<3.0 Hz) or very low (<0.3 Hz). A large percentage (24%) of C fibers had spontaneous discharge 2 and 7 days after inflammation, but this also declined to near control levels by day 14; C-fiber discharge frequency was also always low (most at 0.3-1.0 Hz). 相似文献
Methods: The authors prospectively studied 122 chest tubes percutaneously inserted in 75 consecutive critically ill patients. For clinical reasons independent of the study, thoracic computed tomography scanning was performed in 63 patients, allowing direct visualization of 106 chest tubes. Based on these findings, chest tube position was classified as intrapleural, intrafissural, or intraparenchymal. Factors predicting chest tube malposition were analyzed by univariate and multivariate analysis.
Results: The mean delay between chest tube placement and thoracic scan was 3.5 +/- 2.9 days. Twenty-two chest tubes were diagnosed as being intrafissural (21%), and 10 were diagnosed as being intraparenchymal (9%). The only predicting factor associated with the risk of malposition was the use of a trocar for the percutaneous insertion of the chest tube (P = 0.032). 相似文献
Methods: Rats (n = 30) were injected with varying doses (0.625, 2.5, and 10 U) of botulinum toxin into the tibialis muscle. Control animals (n = 9) received an equivalent volume of saline. At 128 days after injection, neuromuscular function, pharmacodynamics of atracurium, and nAChRs were evaluated.
Results: Nerve-evoked tensions, including tetanic tension and muscle mass, were decreased on the toxin-injected side in a dose-dependent manner relative to saline-injected controls as well as the contralateral side. Specific muscle tension and specific tetanic muscle tension (tensions/muscle mass) were not reduced. The ED10 of atracurium was reduced, the ED50 was unchanged, and the ED90 was increased in the highest (10-U) dose of toxin group. The atracurium plasma concentration to maintain a steady state 50% paralysis was significantly reduced in the 10-U toxin group. The nAChR concentrations in the tibialis muscle were significantly increased in a dose-dependent manner in all experimental groups. 相似文献
Methods: Gabapentin was administered orally and intracerebroventricularly to rats on the day after paw incision, and withdrawal threshold to paw pressure was measured. The authors also measured cerebrospinal fluid concentration of norepinephrine and postoperative morphine use after surgery in patients who received oral placebo or gabapentin.
Results: Both oral and intracerebroventricular gabapentin attenuated postoperative hypersensitivity in rats in a dose-dependent manner. This effect of gabapentin was blocked by intrathecal administration of the [alpha]2-adrenergic receptor antagonist idazoxan and the G protein-coupled inwardly rectifying potassium channel antagonist tertiapin-Q, but not by atropine. In humans, preoperative gabapentin, 1,200 mg, significantly increased norepinephrine concentration in cerebrospinal fluid and decreased morphine requirements. 相似文献