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   40167篇
  免费   3711篇
  国内免费   94篇
耳鼻咽喉   404篇
儿科学   1385篇
妇产科学   814篇
基础医学   5418篇
口腔科学   839篇
临床医学   4794篇
内科学   7045篇
皮肤病学   815篇
神经病学   3904篇
特种医学   1263篇
外国民族医学   1篇
外科学   5949篇
综合类   835篇
一般理论   34篇
预防医学   4652篇
眼科学   593篇
药学   2742篇
  2篇
中国医学   47篇
肿瘤学   2436篇
  2023年   283篇
  2022年   404篇
  2021年   966篇
  2020年   567篇
  2019年   938篇
  2018年   1068篇
  2017年   777篇
  2016年   763篇
  2015年   863篇
  2014年   1234篇
  2013年   1768篇
  2012年   2579篇
  2011年   2689篇
  2010年   1481篇
  2009年   1265篇
  2008年   2230篇
  2007年   2192篇
  2006年   2100篇
  2005年   2059篇
  2004年   1901篇
  2003年   1787篇
  2002年   1751篇
  2001年   889篇
  2000年   814篇
  1999年   696篇
  1998年   376篇
  1997年   326篇
  1996年   347篇
  1995年   282篇
  1994年   279篇
  1993年   254篇
  1992年   539篇
  1991年   539篇
  1990年   543篇
  1989年   463篇
  1988年   455篇
  1987年   433篇
  1986年   358篇
  1985年   384篇
  1984年   327篇
  1983年   264篇
  1982年   265篇
  1981年   216篇
  1980年   212篇
  1979年   268篇
  1978年   242篇
  1977年   180篇
  1976年   175篇
  1974年   210篇
  1973年   200篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
We report select outcomes from an evaluation of Project Wall Talk, a community-based, peer-led HIV prevention education program implemented in 36 Texas State prison units. Peer educators completed questionnaires prior to receipt of a 40-hour intensive training (N = 590) and at 9-month follow-up (N = 257). Students (N = 2506) completed questionnaires pre- and post-receipt of peer educator-led HIV education sessions. Peer educators and their students showed significant increases in HIV-related knowledge. Peer educators showed significant increases in assessment of their skills as educators. For both peer educators and students, significant differences in HIV-related knowledge were indicated across categories of prior educational level attained and race/ethnicity; no such differences were indicated at follow-up. Compared with baseline, a significantly greater proportion of peer educators reported ever having had an HIV test. After receiving peer-led education, a significantly smaller proportion of students reported they knew their HIV status and more indicated plans to take an HIV test. Additionally, in months 12 and 18 following program implementation, the numbers of HIV tests at the five units that implemented the peer education program were roughly twice that of five, matched comparison units without the peer education program. Based on peer educator reports, we projected that peer educators (N = 257) may have as many as 84,000 or more annual opportunities to share HIV-related knowledge with other prisoners outside the classroom.  相似文献   
32.
All 253 children receiving neurosurgical intervention for hydrocephalus (HCP) at a single British Neurosurgical Unit over a decade were investigated by retrospective case note review. Referral rates and mean age at presentation remained stable throughout, as did proportions of children presenting due to myelomeningocoele or meningitis. Comparing the first and second halves of the decade, the predominant aetiologies (intraventricular haemorrhage [IVH] at <1 year and brain tumour at 1-16 years) reduced from comprising half (70/129) of all cases to just over one-third (43/124). Other significant changes included a 45% reduction in neonatal IVH and a 179% increase in rare miscellaneous disorders. Outcome after 4 years of follow-up for all patients showed 44.4% without deficit, 11.9% with non-cognitive neurological deficits only, 11.5% with cognitive impairment only, 13.5% with both cognitive and neurological impairments, and 15.5% mortality.  相似文献   
33.
34.
This pilot study examined a behavioral treatment to increase calorie intake in toddlers with cystic fibrosis. Eight toddlers were randomly assigned to behavioral plus nutrition (BEH) or nutrition intervention (NTR) conditions. Calorie intake and weight were measured at pre- and posttreatment. The BEH group showed a trend for changes in calorie intake pre- to posttreatment (p = .07; 40% increase). Results for the BEH and NTR groups did not differ significantly. Most participants achieved weight gains consistent with normal growth. Seventy-five percent had not shown this pattern during the year prior to intervention. These results support the feasibility and potential for behavioral interventions in this age group.  相似文献   
35.
36.
OBJECTIVE: To examine the effects of aging and age-related hearing loss on the perception and neural representation of a time-varying speech cue. METHODS: P1, N1 and P2 cortical responses were recorded from younger and older normal-hearing adults, as well as older adults with age-related hearing loss. Synthetic speech tokens representing 10 ms increments along a /ba/-/pa/ voice-onset-time (VOT) continuum were used to evoke the responses. Each participant's ability to discriminate the speech tokens was also assessed. RESULTS: Compared with younger participants, older adults with and without hearing loss had more difficulty discriminating 10 ms VOT contrasts. In addition, both older groups elicited abnormal neural response patterns. There were no significant age-related findings for P1 latency; however, N1 latencies were prolonged for both older groups in response to stimuli with increased VOT durations. Also, P2 latencies were delayed for both older groups. The presence of age-related hearing loss resulted in a significant increase in N1 amplitude in response to voiceless stimuli. CONCLUSIONS: Aging and age-related hearing loss alter temporal response properties in the central auditory system. Because both older groups had difficulty discriminating these same speech stimuli, we conclude that some of the perceptual difficulties described by older adults might be due to age-related changes regulating excitatory and inhibitory processes. SIGNIFICANCE: Some of the speech understanding difficulties expressed by elderly adults may be related to impaired temporal precision in the aging auditory system. This might explain why older adults frequently complain that wearing a hearing aid makes speech louder, but does not necessarily improve their ability to understand speech.  相似文献   
37.
Abstract: Most individuals concerned about hereditary breast cancer risk will neither order nor benefit from genetic testing at the present time. Many will, however, seek information about their risk and testing. Risk assessment services, in addition to providing information about hereditary risk and genetic testing, need also to include assessment of non-hereditary risks, information about how to evaluate risks, early detection modalities, the etiology of cancer, and assistance in devising follow-up health care plans. Psychosocial factors, particularly those pertaining to the individual's past history with illness and beliefs about causes and prognosis, must be taken into account to provide relevant information that is understood. A case history with examples of some of the types of information that lead to informed consent in a cancer risk assessment setting is provided.  相似文献   
38.
Which nutrients are processed by a poorly perfused gut?   总被引:1,自引:0,他引:1  
  相似文献   
39.
40.
In order to determine the effects of the Fowler-Stephens orchiopexy (FSO) on fertility, young rats underwent simulated FSO, FSO and concurrent contralateral orchiectomy (FSO/OR), unilateral orchiectomy (OR), or sham operation (controls). Twelve weeks after the operation, each male rat was mated to two proven-fertile female rats for 17 days (three ovulatory cycles). Two weeks later, both male and female rats were killed. No pregnancy resulted from the matings of the FSO/OR males. In contrast, pregnancy ensued in 13 of 16 (81%) females in the FSO group, 9 of 14 (64%) in the OR group, and 11 of 12 (92%) in the control group. There were no fertile males in the FSO/OR group. In the FSO group, eight of eight males induced pregnancy in at least one female; in the OR group, six of seven (86%) males were fertile as were all six males in the control group. No differences in litter size or fetal weight were observed between fertile females in various groups.  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