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   28587篇
  免费   2561篇
  国内免费   85篇
耳鼻咽喉   304篇
儿科学   1107篇
妇产科学   586篇
基础医学   3633篇
口腔科学   440篇
临床医学   3569篇
内科学   4895篇
皮肤病学   504篇
神经病学   2808篇
特种医学   962篇
外国民族医学   1篇
外科学   3992篇
综合类   634篇
一般理论   23篇
预防医学   3437篇
眼科学   431篇
药学   2090篇
中国医学   45篇
肿瘤学   1772篇
  2023年   235篇
  2022年   335篇
  2021年   788篇
  2020年   435篇
  2019年   755篇
  2018年   882篇
  2017年   616篇
  2016年   599篇
  2015年   692篇
  2014年   944篇
  2013年   1333篇
  2012年   1895篇
  2011年   1955篇
  2010年   1084篇
  2009年   957篇
  2008年   1525篇
  2007年   1548篇
  2006年   1469篇
  2005年   1447篇
  2004年   1291篇
  2003年   1229篇
  2002年   1180篇
  2001年   650篇
  2000年   575篇
  1999年   496篇
  1998年   270篇
  1997年   228篇
  1996年   267篇
  1995年   204篇
  1994年   217篇
  1993年   171篇
  1992年   360篇
  1991年   354篇
  1990年   373篇
  1989年   358篇
  1988年   298篇
  1987年   315篇
  1986年   240篇
  1985年   265篇
  1984年   220篇
  1983年   168篇
  1982年   145篇
  1981年   113篇
  1980年   125篇
  1979年   170篇
  1978年   144篇
  1977年   110篇
  1976年   105篇
  1974年   128篇
  1973年   110篇
排序方式: 共有10000条查询结果,搜索用时 0 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.
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   
34.
T R Kelly  D S Wagner 《Surgery》1988,104(4):600-605
The correct timing of surgery in cases of gallstone pancreatitis is debatable. To delineate more clearly the influence of the timing of surgery in the treatment of the disease, a prospective randomized clinical study of early surgery (less than 48 hours after admission) and delayed surgery (more than 48 hours after admission) was conducted in 165 patients. Ranson's prognostic signs of severity of disease were used to classify the patients into two risk groups: mild pancreatitis (three or fewer positive signs) and severe pancreatitis (more than three positive signs). In patients with three or fewer positive Ranson's signs, the time of surgery appeared to have little effect on the outcome, whereas in patients with more than three positive signs, early surgery resulted in a significant increase in rates of morbidity and mortality. Controlled randomization showed that in patients with gallstone pancreatitis, edematous or hemorrhagic necrotizing pancreatitis can develop, with or without impacted stones, early or late in the progression of the disease, during early or delayed surgery. These findings suggest that (1) although a gallstone initiates a bout of pancreatitis, it does not cause the progression of the disease; (2) the fate of the progression of pancreatitis is decided early by the amount of digestive enzymes being activated; (3) early removal of an impacted stone does not ameliorate the progression of pancreatitis; and (4) surgery should be performed during the initial hospital admission after the pancreatitis has subsided.  相似文献   
35.
Prolactin and growth hormone receptors   总被引:2,自引:0,他引:2  
  相似文献   
36.
Human ehrlichiosis is a recently recognized rickettsial disease. It is caused byEhrlichia chaffeensis, an intraleucocytic Gram-negative, obligate intracellular bacterium, grouped within the genusEhrlichiae. Most human cases of ehrlichiosis have been diagnosed in the USA. Two cases have been reported outside of the USA, one in Europe and one in Africa. From 1 January to 30 June 1992, 765 sera from blood donors or other asymptomatic subjects in 8 African countries, including Ivory Coast, Burkina Faso, Mali, Central African Republic, Angola, Zimbabwe, Mozambique and Commores Islands, were tested by indirect immunofluorescence for the presence ofE. chaffeensis antibodies. Positive sera were confirmed by Western immunoblotting. Only two of 765 sera tested were positive. One serum obtained from Burkina Faso had an IgG titer of 1:200 and one from Mozambique had an IgG titer of 1:80. Human ehrlichiosis seems to occur infrequently in Africa, although many more sera from additional African countries need to be evaluated.  相似文献   
37.
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   
38.
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   
39.
Which nutrients are processed by a poorly perfused gut?   总被引:1,自引:0,他引:1  
  相似文献   
40.
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