全文获取类型
收费全文 | 373745篇 |
免费 | 45484篇 |
国内免费 | 3210篇 |
专业分类
耳鼻咽喉 | 7242篇 |
儿科学 | 11065篇 |
妇产科学 | 6658篇 |
基础医学 | 32045篇 |
口腔科学 | 5710篇 |
临床医学 | 49036篇 |
内科学 | 93377篇 |
皮肤病学 | 10427篇 |
神经病学 | 37316篇 |
特种医学 | 15938篇 |
外国民族医学 | 13篇 |
外科学 | 75348篇 |
综合类 | 2753篇 |
现状与发展 | 73篇 |
一般理论 | 177篇 |
预防医学 | 23108篇 |
眼科学 | 8651篇 |
药学 | 16271篇 |
1篇 | |
中国医学 | 325篇 |
肿瘤学 | 26905篇 |
出版年
2024年 | 785篇 |
2023年 | 5806篇 |
2022年 | 3272篇 |
2021年 | 8134篇 |
2020年 | 8642篇 |
2019年 | 7000篇 |
2018年 | 12927篇 |
2017年 | 11269篇 |
2016年 | 12655篇 |
2015年 | 13521篇 |
2014年 | 22833篇 |
2013年 | 25813篇 |
2012年 | 22238篇 |
2011年 | 23010篇 |
2010年 | 19710篇 |
2009年 | 22584篇 |
2008年 | 21195篇 |
2007年 | 20299篇 |
2006年 | 22184篇 |
2005年 | 19472篇 |
2004年 | 17789篇 |
2003年 | 15559篇 |
2002年 | 15063篇 |
2001年 | 5493篇 |
2000年 | 4244篇 |
1999年 | 5028篇 |
1998年 | 6202篇 |
1997年 | 5484篇 |
1996年 | 5079篇 |
1995年 | 4789篇 |
1994年 | 3348篇 |
1993年 | 2963篇 |
1992年 | 2275篇 |
1991年 | 2252篇 |
1990年 | 1792篇 |
1989年 | 1861篇 |
1988年 | 1641篇 |
1987年 | 1421篇 |
1986年 | 1479篇 |
1985年 | 1353篇 |
1984年 | 1421篇 |
1983年 | 1277篇 |
1982年 | 1521篇 |
1981年 | 1347篇 |
1980年 | 1178篇 |
1979年 | 752篇 |
1978年 | 832篇 |
1977年 | 825篇 |
1976年 | 638篇 |
1975年 | 583篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
972.
Objectives Using a novel longitudinal tracking project, this study develops and evaluates the performance of a predictive model and index of rural medical practice intention based on the characteristics of incoming medical students. Methods Medical school entry survey data were obtained from the Medical Schools Outcome Database (MSOD) project implemented in all Australian and New Zealand medical schools and coordinated through Medical Deans Australia and New Zealand, the representative body for the Deans of 18 Australian and two New Zealand medical schools and faculties. The medical school commencement survey collects data on students’ education and family background, including rural upbringing, personal circumstances and scholarships, and on their practice intentions in terms of location and specialty. The MSOD will also allow tracking of medical graduates after graduation. Logistic regression modelling was used to develop a predictive model of rural practice intention. Split‐sample validation was used to gain some insight into the stability of performance of the model. Results Response rates to the MSOD survey exceeded 90% on average. The model findings confirm and extend previous research examining the association of medical student characteristics with intention to take up rural medical practice. The statistically significant independent factors in the model included students’ rural backgrounds, financial arrangements and intentions regarding specialist versus generalist practice upon graduation. Model performance was good, with an area under the receiver‐operator characteristics curve of 0.86, and reproducible, with an area in a validation sample of 0.83. Conclusions The model and related index provide important insights into individual factors associated with rural practice intention among students commencing medical studies. The model can also provide a means for optimising the use of scarce medical programme resources, thereby helping to improve the supply of rural medical practitioners. This study illustrates the power and potential of a robust, consistent, systematic longitudinal tracking project. 相似文献
973.
George K Kouvidis Mark B Sommers Peter V Giannoudis Pavlos G Katonis Michael Bottlang 《Journal of orthopaedic surgery and research》2009,4(1):16-9
Background
Lag screw cut-out failure following fixation of unstable intertrochanteric fractures in osteoporotic bone remains an unsolved challenge. This study tested if resistance to cut-out failure can be improved by using a dual lag screw implant in place of a single lag screw implant. Migration behavior and cut-out resistance of a single and a dual lag screw implant were comparatively evaluated in surrogate specimens using an established laboratory model of hip screw cut-out failure. 相似文献974.
Collagenous colitis is an inflammatory mucosal disorder of the colon with distinctive histopathological features, including a thickened subepithelial collagen layer. The clinical course is usually benign, but serious complications, including death, may occur. In the present report, a 69-year-old woman with watery diarrhea and collagenous colitis developed bloody diarrhea that was refractory to treatment medications, including corticosteroids and azathioprine. Endoscopic and histopathological studies showed a focal neutrophilic inflammatory process that progressed to a diffuse and extensive form of colitis, eventually requiring total proctocolectomy. Careful histological review of the resected colon showed no evidence of persistent collagenous colitis. These findings suggest an important need for continued long-term follow-up of patients with collagenous colitis because superimposed and serious colonic complications may occur, including a severe and extensive pancolitis refractory to medications and necessitating total proctocolectomy. 相似文献
975.
976.
Osteoporosis in men is recognised worldwide as an important and increasing public health problem. The causes are more heterogeneous than those in women. About 50% are diagnosed as secondary cases. In some secondary forms of osteoporosis the specific diagnosis results in additional therapeutic options (e.g. androgen therapy in proven hypogonadism). The basic therapy for osteoporosis in men is no different to that in postmenopausal women, namely recommendations for counteracting modifiable risk factors, especially with regard to diet, physical exercise, and calcium and vitamin D supplementation. Concerning specific drug medications, however, even today there is still a therapeutic dilemma in male osteoporosis. While older substances (e.g. calcitonin, fluoride, alfacalcidol) are approved for both sexes, all newer medications have primarily been approved for the treatment of postmenopausal osteoporosis. Health authorities request studies in purely male populations. For new drugs, fracture data are necessary while for new substances within a class (e.g. bisphosphonates), at the very least consistent effects on bone mineral density (BMD) and bone turnover markers are requested. Due to these regulatory rules, ibandronate, teriparatide and strontium ranelate are not approved in the European Union. Some years ago, alendronate was the first bisphosphonate that was approved for the treatment of men with osteoporosis, based on consistent results from two independent male studies using a daily 10 mg dosage. Very recently risedronate was approved by the FDA and EMEA. A randomised, placebo-controlled multicentre trial of 285 male patients showed, after 2 years, a 5.8% increase in lumbar spine BMD in the risedronate 35 mg once weekly group vs 1.2% in the placebo group. In a prospective controlled study on 316 men with primary or secondary osteoporosis we found, after 12 months, a lumbar spine BMD of +4.7% vs +1.0% in controls. The number of patients with one or more new vertebral fractures was 8 in the risedronate group and 20 in the placebo group (a fracture reduction of 60%). Furthermore, we found a significantly smaller decrease in height and a steeper decrease in back pain in the risedronate group. Risedronate is the first oral bisphosphonate available for men with the more comfortable once weekly dosage. 相似文献
977.
Margaret Hogg Maxine Braithwaite Michael Bailey Tom Kotsimbos John W Wilson 《Journal of cystic fibrosis》2007,6(3):223-227
With increasing numbers of cystic fibrosis (CF) patients surviving to adulthood, issues related to vocation inevitably arise and warrant specific attention. We examined the percentage of participants with CF currently working and explored risk factors for work disability among adults with CF. METHOD: We recruited 50 consecutive patients from an adult cystic fibrosis service. Demographic, employment history, illness severity indicators and CF-attributed work disability factors were evaluated. Demographic risk factors for work disability using the illness severity measures of FEV(1), S-K score, CRDQ, and recent hospitalisation as independent variables were determined. RESULTS: Factorial analysis of a disability index (DI) indicated no dependency on FEV(1) or S-K score, but dependency on quality of life indices (p<0.05), age (p<0.05) and hospital admission rate (p<0.05). Hours worked per week were dependent on quality of life (p<0.01) (mastery of disease domain), fewer hospital admissions (p<0.01) and age (p<0.05). Sixty-eight percent of the sample reported that CF resulted in significant impediments to employment. However, few had sought vocational guidance (6%). CONCLUSION: Determinants of workforce participation shows that hours worked and perceived disability are more dependent on mastery of disease, age, and time in hospital, than on clinical severity scores. Health professionals may assist productivity through career counselling or tailored programs. 相似文献
978.
979.
PURPOSE: The present status of intensity-modulated radiation therapy (IMRT) for treatment of localized prostate cancer is discussed. METHODS: The technological basis of IMRT and the rationale for the use in treatment of prostate cancer are described. Clinical results from the literature are presented and treatment strategies for further reduction of safety margins are outlined. RESULTS AND DISCUSSION: Multiple planning studies demonstrated the dosimetric advantage of IMRT compared to three-dimensional conformal radiotherapy. Though randomized studies are missing, retrospective studies indicate that improved dose distributions of IMRT transfer into improved rates of local control and/or lower rates of rectal toxicity. However, with standard safety margins the benefit of IMRT seems to be limited. Image guidance is considered to be essential to reduce errors of patient setup and internal motion of the prostate. 相似文献
980.
Jason P. Glover DPM Christopher F. Hyer DPM Gregory C. Berlet MD Thomas H. Lee MD 《The Journal of foot and ankle surgery》2008,47(3):237-242
In our retrospective study, we report the objective results of the Mau osteotomy in the treatment of hallux valgus. We reviewed the results of 24 cases of moderate to severe hallux valgus deformities corrected with the Mau osteotomy of the first metatarsal combined with a distal soft-tissue procedure. Follow-up was possible in 24 cases. Preoperatively the mean hallux valgus and first intermetatarsal angles were 31.3 degrees and 16.6 degrees respectively, and were corrected postoperatively to an average of 13.00 degrees+/-7.15 degrees and 9.80 degrees+/-2.43 degrees respectively (P< .001). In the sagittal plane, the first metatarsal was shortened by an average of 2.00 mm. Two (8.3%) cases had dorsal elevation of the osteotomy fragment. Complications included 3 recurrences of the deformity, 1 frank nonunion, 8 dorsal cortical nonunions, 5 cases of undercorrection, and 1 case of broken hardware that was present in the nonunion that went on to revision. There were no superficial or deep infections, and no cases of transfer metatarsalgia were noted. In this series, the use of an oblique first metatarsal osteotomy with a dorsal shelf resulted in reliable and powerful correction of the first intermetatarsal angle in patients with moderate to severe hallux valgus. Particular attention should be paid to severe IM angles and the possibility of undercorrections. Despite ambulation postoperatively, the Mau osteotomy minimized dorsal malunion and the incidence of transfer metatarsalgia. LEVEL OF CLINICAL EVIDENCE: 4. 相似文献