全文获取类型
收费全文 | 5910篇 |
免费 | 604篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 106篇 |
儿科学 | 228篇 |
妇产科学 | 57篇 |
基础医学 | 786篇 |
口腔科学 | 128篇 |
临床医学 | 723篇 |
内科学 | 1406篇 |
皮肤病学 | 71篇 |
神经病学 | 527篇 |
特种医学 | 513篇 |
外科学 | 690篇 |
综合类 | 80篇 |
一般理论 | 3篇 |
预防医学 | 402篇 |
眼科学 | 66篇 |
药学 | 424篇 |
1篇 | |
中国医学 | 2篇 |
肿瘤学 | 331篇 |
出版年
2021年 | 55篇 |
2019年 | 63篇 |
2018年 | 73篇 |
2017年 | 57篇 |
2016年 | 77篇 |
2015年 | 90篇 |
2014年 | 107篇 |
2013年 | 187篇 |
2012年 | 202篇 |
2011年 | 196篇 |
2010年 | 146篇 |
2009年 | 179篇 |
2008年 | 170篇 |
2007年 | 211篇 |
2006年 | 226篇 |
2005年 | 240篇 |
2004年 | 217篇 |
2003年 | 232篇 |
2002年 | 186篇 |
2001年 | 223篇 |
2000年 | 213篇 |
1999年 | 200篇 |
1998年 | 156篇 |
1997年 | 169篇 |
1996年 | 161篇 |
1995年 | 141篇 |
1994年 | 133篇 |
1993年 | 127篇 |
1992年 | 147篇 |
1991年 | 129篇 |
1990年 | 132篇 |
1989年 | 144篇 |
1988年 | 139篇 |
1987年 | 127篇 |
1986年 | 112篇 |
1985年 | 120篇 |
1984年 | 73篇 |
1983年 | 77篇 |
1982年 | 57篇 |
1981年 | 74篇 |
1980年 | 65篇 |
1979年 | 51篇 |
1978年 | 67篇 |
1977年 | 65篇 |
1976年 | 53篇 |
1975年 | 39篇 |
1974年 | 40篇 |
1973年 | 51篇 |
1972年 | 35篇 |
1967年 | 39篇 |
排序方式: 共有6544条查询结果,搜索用时 337 毫秒
1.
Megan L. Robbins Robert C. Wright Ana María López Karen Weihs 《Journal of psychosocial oncology》2019,37(2):160-177
AbstractObjectives: This study examined word use as an indicator of interpersonal positive reframing in daily conversations of couples coping with breast cancer and as a predictor of stress.Design: The Electronically Activated Recorder (EAR) and Linguistic Inquiry and Word Count (LIWC) were used to examine naturally occurring word use conceptually linked to positive reframing (positive emotion, negative emotion, and cognitive processing words).Sample: Fifty-two couples coping with breast cancer.Methods: Couples wore the EAR, a device participants wear, that audio-recorded over one weekend (>16,000 sound files), and completed self-reports of positive reframing (COPE) and stress (Perceived Stress Scale). LIWC, a software program, measured word use.Findings: Both partners’ word use (i.e., positive emotion and cognitive processing words) was associated with their own reported positive reframing, and spouses’ word use was also indicative of patients’ positive reframing. Results also revealed that, in general, words indicating positive reframing predicted lower levels of stress.Conclusions: Findings supported the hypothesis that partners—and particularly spouses of breast cancer patients—may assist each other’s coping by positively reframing the cancer experience and other negative experiences in conversation. 相似文献
2.
Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight. 相似文献
3.
Angela Bryan Reuben N Robbins Monica S Ruiz Dennis O'Neill 《Health education & behavior》2006,33(2):154-177
Prisons and prison inmates present important targets for HIV/AIDS prevention interventions. Inmates often have histories of high-risk behavior that place them in danger of contracting HIV/AIDS, and rates of HIV/AIDS tend to be much higher in this population. The goal of this study was to assess the effectiveness of a prison-based HIV/AIDS intervention to change attitudes toward HIV prevention, norms supporting HIV prevention, perceived behavioral control (i.e., self-efficacy) for HIV prevention behaviors, and intentions to engage in HIV prevention behaviors postrelease. The intervention also had the goal of encouraging inmates to become HIV/AIDS peer educators. The intervention appeared most successful at influencing beliefs and behaviors related to peer education and somewhat successful at influencing beliefs and intentions related to condom use. Analyses also showed some significant differences in effectiveness by race/ethnicity. Results are discussed from the perspectives of both research and practice with regard to prison-based HIV prevention efforts. 相似文献
4.
5.
ME BURGE AM JOSHUA CM McNEIL R HUI MJ BOYER R ABRAHAM 《Asia-Pacific Journal of Clinical Oncology》2005,1(1):47-52
Background: Pemetrexed and cisplatin have recently been shown to significantly improve survival compared with cisplatin alone. However, there are only limited data reflecting teaching hospital experience outside a clinical trial. Pemetrexed has only been available in Australia on a restricted basis since 2002. We reviewed our experience of patients treated on the Australian ‘Special Access Scheme’ at three major thoracic oncology units. Methods: Charts were reviewed for all patients enrolled on the scheme. Data was extracted on age, World Health Organization (WHO) performance status, histology, prior therapy, time from diagnosis to starting pemetrexed, chemotherapy (pemetrexed alone or with a platinum), cycle number, response rate, actuarial progression‐free and overall survival. Doses were cisplatin 75 mg/m2 or carboplatin AUC = 5 and pemetrexed 500 mg/m2 every 21 days. Results: 52 patients (32 male and 20 female) were reviewed. Median age was 58 years and 88% were WHO 0–1. Histology included 54% epithelial, 17% biphasic (epithelial and sarcomatoid) and 21% undefined. The median time from diagnosis to administration of pemetrexed was 145 days. Sixty‐five percent had minimal surgical intervention with video assisted thoracoscopy, pleurodesis and biopsy, while 19% had received prior palliative radiation. Seventy‐one percent were chemotherapy naïve, the remaining 29% having received previous platinum and/or gemcitabine regimens. Twenty‐three percent had pemetrexed alone, 35% in combination with carboplatin and 42% with cisplatin. The median number of cycles was 4 (range 1–13). The response rate was 33%. No toxicity was observed in 20% grade 3–4 toxicity in 10% (majority nausea/vomiting). The median progression‐free and overall survival times from starting pemetrexed were 184 days and 298 days, respectively. Conclusions: Pemetrexed‐based regimens are safe and effective in a community setting in malignant mesothelioma. 相似文献
6.
Effects of iontophoretically applied dopamine and its receptor antagonists on physiologically identified retinal ganglion cells were studied in the optically intact eye of pentobarbitone anaesthetised kittens (7-9 weeks of age) and the results were compared with the effects obtained from adult cats (18-22 weeks of age). In both the adult and the kitten, dopamine had an inhibitory effect on visually evoked and spontaneous activity of the retinal ganglion cells, irrespective of cell type. However, unlike in the adult, the effects of dopamine in kittens were variable and not dependent on retinal eccentricity. In adult cells, only L-sulpiride (a potent D2 receptor antagonist) reduced the inhibitory effect of exogenous dopamine, whereas in kitten cells, both alpha-flupenthixol (a potent D1 receptor antagonist) and L-sulpiride did so. When applied alone, neither alpha-flupenthixol nor affected the activity of ganglion cells in adults, but in kittens both antagonists produced an excitatory effect in some cells. Physiologically active dopaminergic innervation seemed, therefore, to be present on the immature ganglion cells, but was subsequently 'eliminated' during the course of postnatal development. Furthermore, in immature cells, both D1 and D2 type receptors are present but only D2 receptors remain in adult. Therefore, there is a mismatch between dopamine receptors and dopamine in the adult retina and this mismatch may be the consequence of a developmental event. 相似文献
7.
Dissociable roles of the ventral, medial and lateral striatum on the acquisition and performance of a complex visual stimulus-response habit. 总被引:3,自引:0,他引:3
The effects of discrete bilateral ibotenic acid lesions to 3 areas of striatum were examined on a conditional visual discrimination task involving temporal frequency (SLOW vs FAST flashes) that had previously been shown to be sensitive to the effects of dorsal striatal dopamine depletion. Two of the groups, namely, those with nucleus accumbens (ACC) and lateral caudate-putamen (LCP) lesions, were very disrupted in the acquisition of the task. The nature of the respective impairments of the 2 groups was dissociable, however. The performance of the ACC group could be improved either by manipulations of stimulus duration or inter-stimulus interval, implying an attentional deficit. In contrast, the rats with lesions of the LCP were not significantly improved by any of the behavioural challenges. Their performance was characterised by a bias to respond to the SLOW discriminandum. Under conditions of non-reward, the LCP group extinguished their responding at a similar rate to control rats whereas the ACC group were very much more persistent. Lesions of the medial caudate-putamen failed to affect any index of performance significantly. These data suggest that the LCP is necessary for the acquisition of arbitrary stimulus-response rules and that damage to an equivalent area in humans, such as in Huntington's disease, may explain deficits of procedural memory. The second part of the experiment investigated the effects of ACC lesions on established performance of the schedule. The lesioned group behaved identically to the ACC group that had been lesioned prior to acquisition, both in terms of accuracy and degree of persistence in extinction, further implying the role of attentional factors and inflexibility in the lesion-induced deficit. 相似文献
8.
Hisako Ikeda Jonathan Robbins 《Documenta ophthalmologica. Advances in ophthalmology》1988,69(2):175-186
Anatomical and physiological segregation of neurons into ON (brightening detector) and OFF (darkening detector) channels in the retina and subsequent visual system ensure the high sensitivity required for contrast detection and spatial discrimination. This segregation is finest at the visual axis. Neurochemically, ON and OFF ganglion cells at the visual axis seem to be distinguished by different inhibitory transmitters but not excitatory transmitters. Microiontophoretic studies of inhibitory transmitters on the retinal ganglion cells in kittens and adult cats suggest that this neurochemical distinction is poor in immature ganglion cells at the visual axis. Initially both ON and OFF cells seem to be supplied by GABAergic, glycinergic, and catecholaminergic amacrine cells, but in adults, ON cells remain supplied only by GABAergic amacrines, while OFF cells are supplied by glycinergic amacrines. Postnatal elimination of multiple inputs and strengthening of the appropriate inputs, as seen in the central nervous system, also seem to occur at the retinal neurotransmitter synapses during development. 相似文献
9.
CM Reid M. Nelson P. Beckinsale P. Ryan LMH Wing LJ Beilin MA Brown GLR Jennings CI Johnston J. Marley JJ McNeil TO Morgan J. Shaw ID Steven MJ West 《Clinical and experimental pharmacology & physiology》1997,24(5):370-373
1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial. 相似文献
10.
A new OSHA: the tasks for the first 100 days 总被引:1,自引:0,他引:1