全文获取类型
收费全文 | 1601710篇 |
免费 | 131506篇 |
国内免费 | 2581篇 |
专业分类
耳鼻咽喉 | 21656篇 |
儿科学 | 52932篇 |
妇产科学 | 46226篇 |
基础医学 | 227767篇 |
口腔科学 | 47201篇 |
临床医学 | 140908篇 |
内科学 | 314767篇 |
皮肤病学 | 34090篇 |
神经病学 | 130114篇 |
特种医学 | 64724篇 |
外国民族医学 | 474篇 |
外科学 | 243793篇 |
综合类 | 39717篇 |
现状与发展 | 3篇 |
一般理论 | 549篇 |
预防医学 | 122867篇 |
眼科学 | 36470篇 |
药学 | 121274篇 |
3篇 | |
中国医学 | 2974篇 |
肿瘤学 | 87288篇 |
出版年
2018年 | 14766篇 |
2016年 | 12900篇 |
2015年 | 15028篇 |
2014年 | 20646篇 |
2013年 | 31352篇 |
2012年 | 42547篇 |
2011年 | 44751篇 |
2010年 | 26338篇 |
2009年 | 25304篇 |
2008年 | 43003篇 |
2007年 | 45246篇 |
2006年 | 46058篇 |
2005年 | 44673篇 |
2004年 | 44092篇 |
2003年 | 42180篇 |
2002年 | 41293篇 |
2001年 | 75683篇 |
2000年 | 78325篇 |
1999年 | 66388篇 |
1998年 | 17731篇 |
1997年 | 16335篇 |
1996年 | 16314篇 |
1995年 | 16020篇 |
1994年 | 15070篇 |
1993年 | 14217篇 |
1992年 | 55427篇 |
1991年 | 53776篇 |
1990年 | 52566篇 |
1989年 | 50832篇 |
1988年 | 47224篇 |
1987年 | 46561篇 |
1986年 | 44284篇 |
1985年 | 42844篇 |
1984年 | 32035篇 |
1983年 | 27565篇 |
1982年 | 16144篇 |
1981年 | 14436篇 |
1980年 | 13564篇 |
1979年 | 30462篇 |
1978年 | 21068篇 |
1977年 | 17764篇 |
1976年 | 16697篇 |
1975年 | 17575篇 |
1974年 | 21487篇 |
1973年 | 20672篇 |
1972年 | 18854篇 |
1971年 | 17770篇 |
1970年 | 16289篇 |
1969年 | 15269篇 |
1968年 | 13950篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
S Chinn S H Downs J M Anto M W Gerbase B Leynaert R de Marco C Janson D Jarvis N Künzli J Sunyer C Svanes E Zemp U Ackermann-Liebrich P Burney 《The European respiratory journal》2006,28(4):763-771
The incidence of asthma has been reported to be associated with obesity. An alternative analysis, of net change in prevalence, does not require exclusion of those with asthma at baseline. Follow-up data were obtained from 9,552 participants in the European Community Respiratory Health Survey and the Swiss cohort Study on Air Pollution and Lung Disease in Adults. Incidence of asthma was analysed by proportional hazards regression, and net changes in symptoms and asthma status by generalised estimating equations, by obesity group. Incidence and net change in ever having had asthma were greater in females than in males, and in participants who remained obese compared with those who were never obese (hazard ratio 2.00, 95% confidence interval 1.25-3.20; excess net change 2.8%, 0.4-5.3% per 10 yrs). The effect of being obese on net change in diagnosed asthma was greater in females than in males, but for net change in wheeze without a cold it was greater in males. The present results are consistent with asthma being more frequently diagnosed in females, especially obese females. These findings may help to explain the reports of a stronger association between asthma and obesity in females than in males. 相似文献
132.
133.
134.
Sonographic features of benign thyroid nodules: interobserver reliability and overlap with malignancy. 总被引:4,自引:0,他引:4
Jeffrey R Wienke Wui K Chong Julia R Fielding Kelly H Zou Carol A Mittelstaedt 《Journal of ultrasound in medicine》2003,22(10):1027-1031
OBJECTIVE: To prospectively determine the sonographic findings of nodular hyperplasia of the thyroid, to compare these with reported findings associated with malignancy, and to assess interobserver reliability. METHODS: Seventy thyroid nodules were scanned, and then biopsies of the nodules were performed under sonographic guidance with fine-needle cytologic analysis; in all cases images were reviewed by 2 experienced radiologists without knowledge of clinical outcome. Findings reported associated with malignancy were specifically assessed. Interobserver agreement between the expert and secondary readers for each finding was calculated by the kappa or weighted kappa statistic and the Fisher exact test of independence. RESULTS: There were 68 benign and 2 malignant nodules in a population of 63 female and 7 male patients. The mean benign nodule size was 2.9 cm; 60% were solid; 54% were hypoechoic; 59% were microlobulated or macrolobulated; 47% had central vascularity; 24% contained calcifications; and 82% were elliptical in shape. There was very good interobserver reliability for the presence of calcium (kappa = 0.91) and good agreement for the presence and location of vascularity (kappa = 0.75) and the amount of cystic components (kappa = 0.62; all P < .01). CONCLUSIONS: Sixty-nine percent of benign nodules had at least 1 finding reported previously as associated with malignancy. The interobserver reliability of the sonographic findings was good to very good for 3 of the 5 findings assessed. 相似文献
135.
136.
A R Molina H Brasch S T Tan 《Journal of plastic, reconstructive & aesthetic surgery》2006,59(12):1458-1462
One serious complication of neurofibromatosis type 1 (NF1) is the development of malignant peripheral nerve sheath tumours (MPNSTs). These malignancies often develop within pre-existing plexiform neurofibromas and their development is now thought to be associated with both tumour suppressor gene mutations and dysregulated growth factor signalling. Recent work demonstrates that the lifetime risk of malignant transformation is significantly greater than previously thought. Ionising radiation, a long-standing disease, particularly the presence of a large number of plexiform neurofibromas from an early age, are suggested risk factors. We present an NF1 patient who developed an MPNST of the cervical vagus nerve which was successfully treated with surgery. Close monitoring of patients with NF and a high level of suspicion towards rapidly enlarging and painful swellings is merited as these features may signify malignant transformation. Whether a positive history of MPNST in other affected family members predisposes the individual to a higher risk of malignant transformation is unclear. 相似文献
137.
138.
139.
In the last 20 years, cases of human cryptococcosis, have increased in immunocompromised patients. In several instances, the cases have been associated with the exposure of the patients to bird droppings. In order to investigate birds of prey as potential carriers and spreaders of Cryptococcus neoformans and other yeasts of importance in human infections, 182 swab samples were collected from the cloacae of several species of birds of prey (Group I) and 32 faecal samples from aviaries in which the birds were housed (Group II). Samples were also taken from digestive tract of 60 dead birds (Group III). A total of 454 samples were cultured from which 215 colonies of yeastlike fungi were recovered and identified. Cryptococcusneoformans var. grubii was isolated from three cloacae samples (4.8%) collected from Falco tinnunculus and from one sample (3.1%) obtained from Buteo buteo, as well as from samples collected at the aviaries in which these birds were kept. Overall, 18 samples (9.9%) from Group I, 13 (40.6%) from Group II, 12 crops (20%), three proventriculi (5%) and 12 cloacae (20%) from Group III yielded positive cultures for yeasts. The results indicate that birds of prey and in particular, F. tinnunculus and B. buteo, may act as carriers and spreaders of C. neoformans and other zoonotic yeasts. 相似文献
140.