首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   162723篇
  免费   31908篇
  国内免费   2456篇
耳鼻咽喉   5286篇
儿科学   5559篇
妇产科学   2575篇
基础医学   4721篇
口腔科学   1778篇
临床医学   27700篇
内科学   49769篇
皮肤病学   7606篇
神经病学   16054篇
特种医学   7053篇
外科学   43184篇
综合类   278篇
现状与发展   72篇
一般理论   3篇
预防医学   7568篇
眼科学   3779篇
药学   1608篇
中国医学   19篇
肿瘤学   12475篇
  2024年   688篇
  2023年   4876篇
  2022年   1320篇
  2021年   3356篇
  2020年   6227篇
  2019年   2428篇
  2018年   7678篇
  2017年   7598篇
  2016年   8722篇
  2015年   8757篇
  2014年   15901篇
  2013年   16197篇
  2012年   6372篇
  2011年   6420篇
  2010年   10826篇
  2009年   14684篇
  2008年   6625篇
  2007年   4858篇
  2006年   7279篇
  2005年   4486篇
  2004年   3648篇
  2003年   2593篇
  2002年   2621篇
  2001年   3932篇
  2000年   3109篇
  1999年   3305篇
  1998年   3746篇
  1997年   3563篇
  1996年   3428篇
  1995年   3271篇
  1994年   1998篇
  1993年   1620篇
  1992年   1447篇
  1991年   1482篇
  1990年   1116篇
  1989年   1231篇
  1988年   1068篇
  1987年   904篇
  1986年   921篇
  1985年   762篇
  1984年   577篇
  1983年   569篇
  1982年   548篇
  1981年   433篇
  1980年   384篇
  1979年   342篇
  1978年   358篇
  1977年   418篇
  1975年   298篇
  1972年   320篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
A 33-year-old African woman was evaluated for tender nodules on her feet. Accompanied by her four children, she had recently immigrated from Somalia. Before her immigration, she resided in a Kenyan refugee camp for approximately 1 year, where she walked barefoot in sand and dirt. The patient stated that she and her four children, as well as many people living in the same compound, had similar, tender lesions on their feet. Her children were "treated" by their grandmother, who removed the contents of their lesions with a safety pin.
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   
52.
Background: Molecular theories of general anesthesia often are divided into two categories: (l) Anesthetics may bind specifically to proteins, such as ionic channels, and alter their function directly, and (2) anesthetics may alter the functions of integral membrane proteins indirectly through modification of the physical properties of the membrane. Recent studies have provided evidence that anesthetics can bind to proteins and modify their function directly, bringing into question the role of the membrane in anesthetic interactions. To reexamine the role of membrane lipids in anesthetic interactions, an experimental approach was used in which the membrane lipid composition could be systematically altered and the impact on anesthetic interactions with potential targets examined.

Methods: Sodium channels from human brain cortex were incorporated into planar lipid bilayers with increasing cholesterol content. The anesthetic suppression of these channels by pentobarbital was quantitatively examined by single channel measurements under voltage-clamp conditions.

Results: Changes in cholesterol content had no effect on measured channel properties in the absence of anesthetic. In the presence of pentobarbital, however, cholesterol inhibited anesthetic suppression of channel ionic currents, with 1.9% (weight/weight, corresponding to 3.5 mol%) cholesterol decreasing anesthetic suppression of sodium channels by half.  相似文献   

53.
54.
55.
Summary: This is the first report of the largest study of blood pressure measurement in pregnancy in a New Zealand population using standardized definitions and methodology. Over 3,800 women who delivered in an 8-month period in the Wellington region were included in the study. Blood pressure measurement and the presence of oedema and proteinuria were recorded from booking until delivery and in the puerperium. Only 2.7% of women were unable to be contacted after delivery for details on outcomes. The results established normal ranges for blood pressure throughout pregnancy. The data show that Mood pressure greater than 140/90 until 35 weeks' gestation is outside 2 standard deviations at all gestations and justifies using these measurements as the definition of hypertension in pregnancy. The fall in blood pressure in the 2nd trimester was less than 1 mm Ffg per week in both the systolic and diastolic pressures. This fall was smaller than previously recorded in other studies. Gestational hypertension was the commonest blood pressure abnormality occurring in 15.2% of the population. This represented 69% of the pregnant women with a hypertensive disorder. The overall incidence of both gestational hypertension and preeclampsia was 18.5% which is higher than reported in other parts of the world. In this study obesity was significantly associated with hypertensive disorders in pregnancy. An arm circumference of >33 cm, one of the measurements of obesity, was found in 6.8% of the study population. Even after the effect of arm circumference was taken into account, hypertensive disorders were also more common in Pacific Island women. Ankle oedema was significantly associated with the development of both gestational hypertension and preeclampsia but the incidence of oedema was noted in only 11.9% of the subjects.  相似文献   
56.
The efficacy and safety of ketoprofen and paracetamol were compared for the treatment of acute migraine in a randomized, double-blind study of 64 patients. Thirty-four patients received ketoprofen 100 mg intramuscularly, and 30 patients received paracetamol 500 mg intramuscularly. Partial or complete relief of pain and other symptoms was achieved 15 to 20 minutes after administration in the ketoprofen group and within 35 minutes in the paracetamol group. Complete relief of pain was achieved within 30 to 40 minutes after ketoprofen in 28 patients (82.5%) compared to 5 patients (17.5%) in the paracetamol group. Six of the patients treated with ketoprofen needed a second dose for complete relief of pain during the 4-hour follow-up period. Side effects were rare and minimal. Our findings suggest that ketoprofen produced statistically significant benefit in the treatment of acute migraine.  相似文献   
57.
58.
59.
60.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号