收费全文 | 25439篇 |
免费 | 2274篇 |
国内免费 | 62篇 |
医药卫生 | 27775篇 |
2023年 | 224篇 |
2022年 | 272篇 |
2021年 | 505篇 |
2020年 | 383篇 |
2019年 | 589篇 |
2018年 | 646篇 |
2017年 | 508篇 |
2016年 | 524篇 |
2015年 | 575篇 |
2014年 | 855篇 |
2013年 | 1207篇 |
2012年 | 1791篇 |
2011年 | 1856篇 |
2010年 | 971篇 |
2009年 | 980篇 |
2008年 | 1576篇 |
2007年 | 1711篇 |
2006年 | 1697篇 |
2005年 | 1592篇 |
2004年 | 1574篇 |
2003年 | 1430篇 |
2002年 | 1292篇 |
2001年 | 310篇 |
2000年 | 269篇 |
1999年 | 267篇 |
1998年 | 278篇 |
1997年 | 228篇 |
1996年 | 186篇 |
1995年 | 175篇 |
1994年 | 168篇 |
1993年 | 178篇 |
1992年 | 180篇 |
1991年 | 153篇 |
1990年 | 159篇 |
1989年 | 158篇 |
1988年 | 151篇 |
1987年 | 132篇 |
1986年 | 109篇 |
1985年 | 138篇 |
1984年 | 108篇 |
1983年 | 117篇 |
1982年 | 103篇 |
1981年 | 97篇 |
1980年 | 89篇 |
1979年 | 70篇 |
1978年 | 69篇 |
1977年 | 59篇 |
1976年 | 65篇 |
1974年 | 67篇 |
1973年 | 65篇 |
On physical examination the patient had numerous tender, isolated, and clustered hyperkeratotic, crusted papules, measuring 4–6 mm, on the plantar and periungual surfaces. Several lesions were ulcerated (Figs 1 and 2). The hyperkeratotic masses were debrided with a surgical blade. An intact, white, coiled structure was curetted from each papule, leaving numerous empty crater-like lesions (Fig. 3), which were identified on histologic sections as Tunga penetrans. Microscopic examination of unstained specimens showed branching, thin, translucent tubular structures with numerous eggs. Ring-shaped cross-sections of the organism's respiratory and digestive tracts were seen on hematoxylin and eosin stain (Fig. 4).
The patient received a 10-day course of dicloxacillin and topical bacitracin ointment. All lesions were healed within 1 week of therapy. 相似文献
Methods: The tail flick latency (TFL) test quantified the time in seconds for an animal to move its tail away from a thermal stimulus created by a beam of light. TFL measures were used to evaluate the antinociceptive effects of the adenosine A1 receptor agonist N6-p-sulfophenyladenosine (SPA). Pontine microinjection of SPA (0.1 [mu]g/0.25 [mu]l, 0.88 mm) was followed by TFL measures as a function of time after drug delivery and across the sleep-wake cycle.
Results: Compared with saline (control), pontine administration of the adenosine agonist significantly increased latency to tail withdrawal (P < 0.0001). The increase in antinociceptive behavior evoked by the adenosine agonist SPA was blocked by pretreatment with the adenosine A1 receptor antagonist 8-cyclopentyl-1, 3-dipropylxanthine (DPCPX, 0.75 ng/0.25 [mu]l, 10 [mu]m). 相似文献