全文获取类型
收费全文 | 8428篇 |
免费 | 552篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 298篇 |
妇产科学 | 237篇 |
基础医学 | 1514篇 |
口腔科学 | 238篇 |
临床医学 | 786篇 |
内科学 | 1743篇 |
皮肤病学 | 129篇 |
神经病学 | 738篇 |
特种医学 | 312篇 |
外国民族医学 | 1篇 |
外科学 | 956篇 |
综合类 | 57篇 |
一般理论 | 3篇 |
预防医学 | 560篇 |
眼科学 | 163篇 |
药学 | 632篇 |
中国医学 | 7篇 |
肿瘤学 | 590篇 |
出版年
2021年 | 112篇 |
2020年 | 82篇 |
2019年 | 110篇 |
2018年 | 126篇 |
2017年 | 102篇 |
2016年 | 124篇 |
2015年 | 164篇 |
2014年 | 219篇 |
2013年 | 317篇 |
2012年 | 403篇 |
2011年 | 412篇 |
2010年 | 262篇 |
2009年 | 234篇 |
2008年 | 387篇 |
2007年 | 418篇 |
2006年 | 413篇 |
2005年 | 382篇 |
2004年 | 324篇 |
2003年 | 363篇 |
2002年 | 327篇 |
2001年 | 180篇 |
2000年 | 215篇 |
1999年 | 211篇 |
1998年 | 109篇 |
1997年 | 98篇 |
1996年 | 92篇 |
1995年 | 76篇 |
1994年 | 82篇 |
1993年 | 71篇 |
1992年 | 132篇 |
1991年 | 126篇 |
1990年 | 144篇 |
1989年 | 131篇 |
1988年 | 121篇 |
1987年 | 110篇 |
1986年 | 123篇 |
1985年 | 128篇 |
1984年 | 69篇 |
1983年 | 58篇 |
1981年 | 65篇 |
1979年 | 86篇 |
1978年 | 66篇 |
1977年 | 54篇 |
1975年 | 72篇 |
1973年 | 59篇 |
1972年 | 60篇 |
1971年 | 57篇 |
1970年 | 57篇 |
1969年 | 66篇 |
1968年 | 53篇 |
排序方式: 共有9013条查询结果,搜索用时 31 毫秒
31.
PURPOSE: Research in the field of brain injury rehabilitation has tended to regard return to work as a measure of outcome. Researchers have not paid particular attention to the experiences of people living with a brain injury. The aim of the phenomenological study reported here was to identify and describe what characterizes the meaning of work to those with acquired brain injury. METHODS: Ten participants of working age were interviewed about the meaning of work 1-5 years after being inflicted with a brain injury. Data were analyzed and interpreted using the Empirical Phenomenological Psychological method. RESULTS: The findings revealed a meaning structure consisting of four main characteristics. Work was no longer experienced as the primary event in life and the social dimension had become more important. The perceived competence and work identity were threatened after the injury. A common theme across all interviews was the struggle to return to a state of normality, and working was considered to be evidence of success. CONCLUSION: The findings described the altered meaning of work 1-5 years after brain injury. This knowledge should lead to an increased understanding among occupational therapists engaged in work rehabilitation after brain injury and can serve as a basis for individualized intervention strategies. 相似文献
32.
A model was developed which estimates the costs of osteoporosis risk evaluation and treatment, and the resulting savings in terms of reduced fracture frequency, for the adult female population of the United States. In the absence of treatment, the model predicts 1.44 million fractures will occur annually from non-violent causes. Treatment of all women beginning at age 50 with an agent that slows bone loss by 50% would reduce the number of these fractures by 0.59 million. Selective treatment of the 47% of women at the greatest fracture risk would reduce the number of fractures by 0.45 million, but would only cost 47% as much as treating all women. Additional data are required before the model can be used to evaluate specific treatment regimens. However, it appears that selective treatment of those at highest risk would yield the greatest benefit to cost ratio, if only benefits related to reduced fracture frequency are considered. 相似文献
33.
Y. F. He P. D. Ross J. W. Davis R. S. Epstein J. M. Vogel R. D. Wasnich 《Calcified tissue international》1994,55(4):243-248
We calculated how long to wait before repeating bone mineral density (BMD) measurements to reassess fracture risk. Correlation results from serial measurements of 495 postmenopausal Japanese-American women were used to estimate 95% confidence intervals (CI) for future BMD. After 7 years of follow-up, BMD correlations with the initial measurement ranged between 0.81 and 0.94, depending on age group and measurement site. In this analysis, the period between measurements was defined as the time required for the lower 95% CI to fall below the BMD value corresponding to doubling of fracture risk. Progressive bone loss causes fracture risk to double after 10 years, on average. However, the 95% CIs indicate that a second BMD measurement will detect risk doubling after only 2 or 3 years for some women. For untreated, early postmenopausal women, the period between measurements was approximately 2–5 years for the radius and 4–6 years for the calcaneus, depending on the initial BMD level. The period was approximately 1 year longer for women age 60 and older. Treatments that halve the bone loss rate would increase the period by 1–3 years. In the absence of a second measurement of BMD, the CI will continue to expand with time, corresponding to a wider range in risk between individuals, and a greater proportion of women will be at increased fracture risk. Obtaining a second BMD measurement pinpoints the patient's status within the precision of the measurement. We conclude that repeated BMD measurements will provide a more accurate estimate of fracture risk than a single, baseline measurement. 相似文献
34.
Ulla Christensen Lone Schmidt Charlotte ?rsted Hougaard Margit Kriegbaum Bj?rn Evald Holstein 《Journal of rehabilitation medicine》2006,38(5):316-321
OBJECTIVE: To examine the association between socioeconomic position and coping strategies in musculoskeletal pain. DESIGN AND SUBJECTS: Cross-sectional study of a random sample of 40- and 50-year-old Danes, participation rate 69%, n=7,125. The study included 1,287 persons who reported functional limitations due to musculoskeletal pain. METHODS: Data was collected by postal questionnaires and scales were developed on problem-solving coping and avoidant coping, based on a range of preliminary studies. Multivariate logistic regression analyses was used to study the correlation with socioeconomic position, measured by occupational social class. RESULTS: Among women, there was no correlation between social class and avoidant coping, but a significant decrease in the use of problem-solving coping by decreasing social class, adjusted odds ratio (OR) = 2.64 (95% confidence interval (CI) 1.31-5.32) in social class V vs social classes I + II. Among men, there was no correlation between social class and problem-solving coping, but a significant increase in the use of avoidant coping with decreasing social class, adjusted OR = 3.31 (95% CI 1.75-6.25) in V vs I + II. CONCLUSION: It is important for clinicians who advise and support patients in their response to musculoskeletal pain to be aware of socioeconomic differences in coping strategies. Gender differences in the association between socioeconomic factors and coping should be further investigated. 相似文献
35.
M Jütte S Klein D Katenkamp W Vogel W G?tz R Woytinas 《Klinische Monatsbl?tter für Augenheilkunde》1992,200(6):674-677
The results with two new enucleation prothesis made of Bioverit are presented. After unilateral enucleation 14 rabbits received bioreactive, 14 rabbits biocompatible and 9 rabbits nylon prostheses. Implantation periods: 1-13 months. The tissue surrounding of the prostheses was studied histologically, the ceramic electron microscopically. Of 28 ceramic prostheses, 26 were adapted very well. Bioverit ist excellently suited as orbital prosthetic material, even half-open implants are possible. 相似文献
36.
Christina Frennesson Peter Jakobsson Ulla L. Nilsson 《Documenta ophthalmologica. Advances in ophthalmology》1995,91(1):9-16
A new approach designed to establish the most suitable area for eccentric viewing and to teach and train patients with severe age-related macular degeneration (AMD) to use the eccentric viewing technique is described. Using a computer and video display based system, as well as software written specifically for this purpose, we investigated and trained ten consecutive patients with AMD. The patients were 80.1 ± 5.6 years old, on average. All of them had an absolute central scotoma. Mean visual acuity was 0.035 ± 0.016. After 30 min of testing, instruction and reading on the screen, followed by 2.6 ± 0.69 one-hour training sessions, on average, with the low vision therapist, reading newspaper and book texts with the aid of hyperoculars or aplanatic systems and a very short reading distance, the patients achieved a reading speed of 58.9 ± 19.7 words/min, significantly (p<0.001) higher than the initial speed when reading on the screen, 11.5 ± 4.5 words/min. 相似文献
37.
38.
R Vogel R P Crick K B Mills P M Reynolds W Sass C M Clineschmidt R Tipping 《Ophthalmology》1992,99(10):1505-1511
BACKGROUND: Relatively few studies have been conducted linking decreasing intraocular pressure (IOP) to preservation of visual field. This investigation was conducted to determine if this link could be made and to compare the long-term effect of two ocular hypotensive agents on preservation of visual field. METHODS: In an observer-masked study, 189 patients with primary open-angle glaucoma received either timolol or pilocarpine by random allocation. The dose of antiglaucoma agent was increased from 0.25% to 0.5% twice daily for timolol or from 2% to 4% four times daily for pilocarpine if the initial IOP response was inadequate. After an on-treatment baseline, visual fields were followed every 4 months for 2 years using the Octopus program 32. RESULTS: Compared with timolol, significantly more patients receiving pilocarpine discontinued use because of inadequate IOP control (P < or = 0.01). By comparing the mean visual field scores, it can be seen that the pilocarpine group had a significantly worse score at all timepoints from month 4 to month 24. The pilocarpine group also had a greater mean number of test loci with decreased sensitivity of 5 or more decibels (dB) at all timepoints. The mean within-patient regression slope for timolol was 0.01 dB/month and for pilocarpine was -0.06 dB/month (P < 0.01). The study has shown that over a 2-year period, patients treated with pilocarpine 2% or 4% four times daily experienced a significantly greater visual field deterioration than that seen in patients receiving either 0.25% or 0.5% timolol twice daily. CONCLUSION: Although these data do not support a link between lowering of IOP and visual field preservation, treatment with timolol was associated with significantly less visual field loss than treatment with pilocarpine. 相似文献
39.
A. Tchelet T. Vogel D. Helman R. Guy C. Neospouolus V. Goffin J. Djiane A. Gertler 《Molecular and cellular endocrinology》1997,130(1-2):141-152
A new analogue of recombinant human growth hormone (hGH), hGH des(1–6,14) was expressed in Escherichia coli, refolded and purified to homogeneity. The mutation decreased the hormone's ability to bind lactogenic and somatogenic receptors through its site 1, and almost completely abolished its ability to bind these receptors through site 2, as evidenced by both binding and gel-filtration experiments. More specifically, the binding to prolactin receptors (PRLRs) from various species or their soluble recombinant extracellular domains (ECDs) was decreased 1.5–4-fold, whereas the binding to hGH receptor (hGHR) was decreased 10–85-fold. These changes caused an almost total loss of hormone agonistic activity in several in vitro bioassays and subsequently, the hGH des(1–6,14) analogue acquired antagonistic properties. This antagonistic activity was dependent upon modification of site 1. In those cases in which the binding was reduced only slightly, e.g. binding to rabbit PRLRs, hGH des(1–6,14) acted as a strong antagonist, whereas in others in which the binding of site 1 was reduced to a higher degree, such as other PRLRs and, in particular, hGHR, the antagonistic activity was correspondingly weaker. Circular dichroism spectra of the analogue suggested that these changes do not result from a decrease in overall -helix content, but rather from minor local structural modifications at the N-terminus. 相似文献
40.
Norbert Rilinger Johannes Görich Reinhard Scharrer-Pamler Jochen Vogel Reinhard Tomczak Elmar Merkle Roman Sokiranski Hans-Jürgen Brambs 《Cardiovascular and interventional radiology》1997,20(4):263-267
Purpose To evaluate the clinical results of percutaneous transluminal rotational atherectomy in the treatment of peripheral vascular
disease.
Methods Rotational atherectomy was performed in 39 patients aged 39–87 years (mean 66.6 years). A total of 71 lesions (43 stenoses
and 28 occlusions) were treated in 40 limbs. Additional balloon angioplasty was required in 54% of lesions. Fifteen patients
(37.5%) presented in Fontaine stage II, 10 patients (25%) in Fontaine stage III and 15 patients (37.5%) in Fontaine stage
IV. Rotational atherectomy at 750 rpm was carried out over a 0.014-inch guidewire with continuous aspiration into a vacuum,
bottle. Follow-up angiography and color flow Doppler examinations were performed in 22 patients (23 limbs) after a mean period
of 6 months (range 2–14 months)
Results There was one primary technical failure. In 36 of 40 lesions there was a good angiographic result with residual stenoses in
less than 30%. In 70 lesions treated by rotational atherectomy, however, 54% showed residual stenoses of 30%–50% and these
cases required additional balloon angioplasty. The mean ankle-brachial index improved significantly (p<0.001), from 0.49 before the procedure to 1.01 after the procedure. A single distal embolus, related to primary recanalization,
occurred and there were two large inguinal hematomas. Cumulative clinical patency after 6 months was 83.8% and cumulative
angiographic patency after 6 months was 79.1%.
Conclusion Percutaneous rotational atherectomy is a promising approach for the treatment of chronic peripheral vascular disease. Further
prospective, randomized studies are necessary to compare percutaneous transluminal angioplasty with this new technical approach. 相似文献