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   86352篇
  免费   10322篇
  国内免费   4835篇
耳鼻咽喉   904篇
儿科学   1507篇
妇产科学   720篇
基础医学   4848篇
口腔科学   1906篇
临床医学   11672篇
内科学   8561篇
皮肤病学   1183篇
神经病学   2312篇
特种医学   3696篇
外科学   7519篇
综合类   22061篇
现状与发展   13篇
预防医学   11352篇
眼科学   1032篇
药学   9150篇
  116篇
中国医学   8594篇
肿瘤学   4363篇
  2024年   379篇
  2023年   1386篇
  2022年   2727篇
  2021年   3478篇
  2020年   3169篇
  2019年   1658篇
  2018年   2132篇
  2017年   2756篇
  2016年   2231篇
  2015年   3826篇
  2014年   4739篇
  2013年   6161篇
  2012年   7620篇
  2011年   8018篇
  2010年   7472篇
  2009年   6831篇
  2008年   6471篇
  2007年   6187篇
  2006年   5455篇
  2005年   4255篇
  2004年   2955篇
  2003年   2378篇
  2002年   1888篇
  2001年   1796篇
  2000年   1208篇
  1999年   589篇
  1998年   402篇
  1997年   415篇
  1996年   405篇
  1995年   331篇
  1994年   265篇
  1993年   249篇
  1992年   157篇
  1991年   126篇
  1990年   118篇
  1989年   142篇
  1988年   125篇
  1987年   106篇
  1986年   109篇
  1985年   98篇
  1984年   79篇
  1983年   81篇
  1982年   64篇
  1981年   67篇
  1980年   45篇
  1979年   24篇
  1978年   25篇
  1977年   36篇
  1976年   32篇
  1954年   20篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
981.
目的 比较常规疗法伍用增免灵与单用常规疗法对活动性肺结核的疗效及外周血T 淋巴细胞亚群的影响。方法 抽取常规化疗组(61 例)、常规化疗加增免灵组(72 例) 及健康对照组(35 例) 患者外周血,用APAAP法测定外周血淋巴细胞亚群。结果 活动性肺结核患者外周血CD+3 及CD+4 百分率及CD+4 /CD+8 比值显著低于健康对照组( P< 0.05) ,CD+8 高于健康对照组。结论 短程化疗伍用增免灵可显著改善活动性肺结核的疗效及细胞免疫状况。  相似文献   
982.
尾部悬吊及恢复过程中大鼠动脉血管收缩反应的变化   总被引:2,自引:2,他引:0  
目的 探讨模拟失重下动脉收缩反应变化的时程特征及其可逆性。方法 采用尾部悬吊大鼠模型模拟失重,利用离休动脉环测定血管收缩反应的变化。结果 尾部悬吊2wk后,大鼠的腹主动脉、肠系膜动脉和股动脉收缩反应明显降低,而颈总动脉无明显改变;悬吊4wk后,肠系膜动脉和股动脉的收缩反应与悬吊2wk相比有进一步的降低;悬吊8wk大鼠的动脉血管收缩反应性与悬吊4wk相比无明显差异;4wk尾部悬吊大鼠解除悬吊后5wk  相似文献   
983.
模拟失重大鼠比目鱼肌小动脉风各级血管内径的变化   总被引:1,自引:1,他引:0  
目的 探讨模拟失重是否可引起后肢肌肉小动脉网各级血管内径发生改变及其可逆性。方法 采用墨汁灌注法观察尾部悬吊4wk(SUS-4),悬吊4wk后恢复1wk(REC-1)、恢复5wk(REC-5),以及对照(CON)大鼠比目鱼肌小动脉网各组血管内径的变化。结果 在SUS-4组,比目鱼肌的营养动脉、弓状小动脉及V、Ⅱ级模行小动脉的内径,较CON组分别减小了31%、29%、28%及41%(均为P〈0.01  相似文献   
984.
目的 观察轻、中度缺氧对脑事件相关电位(ERP)的影响,比较不同刺激模式发的ERP对缺氧的敏感性,方法12名受试者在地面、2500m和4300m匠心同度(吸放低氧混合气)分别进行视觉Ocddball、Sternberg记忆量(MSET)为1 和MSET为3的任务测试,记录ERP的P3潜伏期、波幅和反应时(RT)及反应错误率(ER)。结果 4300m高度缺氧时P3潜伏期显著延长,任务难度较大时ER增  相似文献   
985.
Background: Patients who receive a combination of a benzodiazepine and an opioid for conscious sedation are at risk for developing respiratory depression. While flumazenil effectively antagonizes the respiratory depression associated with a benzodiazepine alone, its efficacy in the presence of both a benzodiazepine and an opioid has not been established. This study was designed to determine whether flumazenil can reverse benzodiazepine-induced depression of ventilatory drive in the presence of an opioid.

Methods: Twelve healthy volunteers completed this randomized, double-blind, crossover study. Ventilatory responses to carbon dioxide and to isocapnic hypoxia were determined during four treatment phases: (1) baseline, (2) alfentanil infusion; (3) combined midazolam and alfentanil infusions, and (4) combined alfentanil, midazolam, and "study drug" (consisting of either flumazenil or flumazenil vehicle) infusions. Subjects returned 2-6 weeks later to receive the alternate study drug.

Results: Alfentanil decreased the slope of the carbon dioxide response curve from 2.14 +/- 0.40 to 1.43 +/- 0.19 l [dot] min sup -1 [dot] mmHg sup -1 (x +/- SE, P < 0.05), and decreased the minute ventilation at PET CO2 = 50 mmHg (V with dotE 50) from 19.7 +/- 1.2 to 14.8 +/- 0.9 l [dot] min sup -1 (P < 0.05). Midazolam further reduced these variables to 0.87 +/- 0.17 l [dot] min sup -1 [dot] mmHg sup -1 (P < 0.05) and 11.7 +/- 0.8 l [dot] min sup -1 (P <0.05), respectively. With addition of flumazenil, slope and V with dot sub E 50 increased to 1.47 +/- 0.37 l [dot] min sup -1 [dot] mmHg sup -1 (P < 0.05) and 16.4 +/- 2.0 l [dot] min sup -1 (P < 0.05); after placebo, the respective values of 1.02 +/- 0.19 l [dot] min sup -1 [dot] mmHg sup -1 and 12.5 +/- 1.2 l [dot] min sup -1 did not differ significantly from their values during combined alfentanil and midazolam administration. The effect of flumazenil differed significantly from that of placebo (P < 0.05). Both the slope and the displacement of the hypoxic ventilatory response, measured at PET CO2 = 46 +/- 1 mmHg, were affected similarly, with flumazenil showing a significant improvement compared to placebo.  相似文献   

986.
The European Renaissance was a time of enormous change and rapid progress in the arts, sciences, and medicine. A glimpse of wound care in the last phase of the European Renaissance is provided by the analysis of work by Wilhelm Fabry, the "father of German surgery," as provided in his book De Combustionibus ("Burns") which details his range of treatments for the burn wound, as well as his approach to the later problems of scarring and contracture. We describe some of the historic events which may have stimulated Fabry's writings, in particular, the influences passed down from the medical school of Padua which thereby advanced the cause of wound care and surgery. Finally, we briefly explore the potential of such an approach to the works of our medical forefathers.  相似文献   
987.
Objective. To describe factors related to compliance diagnostic follow‐up among minority women of low socioeconomic status with abnormal screening mammograms.

Methods. A retrospective cross‐sectional survey using a structured telephone interview. Three cancer screening clinics at an urban inner‐city public hospital. All women with abnormal screening mammograms between September 1990 and January 1992 were eligible; women were interviewed in August 1992. Abnormal mammograms were those requiring specific, non‐routine clinical follow‐up; non‐compliance was defined as delayed follow‐up (four to six months after the date of the mammogram), or no follow‐up at the time of interview (more than 6 months after abnormal).

Results. Sixty‐two of 442 screened women had abnormal results; the overall rate of non‐compliance with follow‐up was 50%. Among the 42 (68%) women who agreed to be interviewed, non‐compliers were less likely to state that they had been told to receive follow‐up than compilers (65% versus 100%; p = 0.008). Non‐compliant women were less likely to have suspicious mammography interpretations (p = 0.05), and more likely to report barriers to follow‐up, such as cost of lost wages and medical care, system barriers, or fears, than compliant women (61.9% versus 9%, p = 0.01). There were no differences between the two groups for age, education, insurance, source of care, family history, knowledge or attitudes.

Conclusions. These preliminary results suggest that follow‐up of low income, minority women with abnormal screening mammograms could be enhanced by improved communication of results. Future studies should extend these findings with larger samples and in other settings and populations.  相似文献   

988.
Effects of pentagastrin, histamine, PGI2, and vasopressin on gastric mucosal blood flow (GMBF) in innervated stomachs of anesthetized dogs were measured by means of the hydrogen clearance method, using a contact electrode. The results were compared with findings obtained with the aminopyrine (AP) clearance method in Heidenhain pouch preparations. Pentagastrin at 2 and 8 g/kg/hr had no effects on GMBF, as measured by the hydrogen clearance method, but there was a marked increase in GMBF when the AP clearance method was used. Histamine at 40 or 160 g/kg/hr tended to reduce or significantly reduced GMBF when measured with the hydrogen clearance method, but there was a significant increase in GMBF with the AP clearance method. Both PGI2 (3 or 30 g/kg/hr) and vasopressin (0.06 or 0.25 units/kg/hr) reduced GMBF as determined by both methods. These results indicate that the hydrogen clearance method is advantageous for detecting regional GMBF but is disadvantageous when attempting to detect the effects of agents which increase GMBF.The Editor wishes to express publicly his regrets to the authors that the editorial planned to highlight this paper will not appear until next month. He particularly apologizes for the long delay in publishing after the paper had been accepted in anticipation of the editorial to appear in the same issue.  相似文献   
989.
The purpose of this study was to examine reading, demographic, social and psychological factors related to pre-adolescent smoking and non-smoking behaviors and attitudes. The school-home humanistic education program was implemented in a large, urban public school system. It stressed responsible decision-making, increased self-esteem and the inter-relationships among the acquisition of knowledge of the consequences of smoking, personal feelings, family relationships and behavior. The results showed that family involvement was necessary to affect smoking attitudes and behaviors. Of all the variables studied, reading had a most pervasive relationship. Peer influence and self-esteem also were related to smoking knowledge, smoking attitude, future smoking intentions and the "purchase" of cigarettes. Two of several conclusions drawn from the results are: 1. Family involvement is necessary to affect attitudes and behaviors. 2. Health education research that does not investigate the relationship between program outcomes and reading achievement may be misleading.  相似文献   
990.
目的:研究冰醋酸涂剂的稳定性。方法:采用酸碱中和分析法和气相色谱法分别对醋酸与其不稳定产物乙酸乙酯运行定量测定。结果:在放置过程中醋酸含量下降,而乙酸乙酯含量增加。结论:《中国医院制剂规范》第2版收载的冰醋酸涂剂不稳定。  相似文献   
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