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   3106篇
  免费   204篇
  国内免费   6篇
耳鼻咽喉   12篇
儿科学   91篇
妇产科学   80篇
基础医学   379篇
口腔科学   42篇
临床医学   337篇
内科学   710篇
皮肤病学   96篇
神经病学   427篇
特种医学   90篇
外科学   210篇
综合类   31篇
预防医学   129篇
眼科学   404篇
药学   140篇
肿瘤学   138篇
  2021年   33篇
  2020年   31篇
  2019年   31篇
  2018年   32篇
  2017年   27篇
  2016年   46篇
  2015年   60篇
  2014年   53篇
  2013年   117篇
  2012年   149篇
  2011年   136篇
  2010年   75篇
  2009年   75篇
  2008年   134篇
  2007年   152篇
  2006年   136篇
  2005年   122篇
  2004年   132篇
  2003年   127篇
  2002年   89篇
  2001年   89篇
  2000年   99篇
  1999年   93篇
  1998年   51篇
  1997年   34篇
  1996年   33篇
  1995年   42篇
  1994年   35篇
  1993年   36篇
  1992年   56篇
  1991年   66篇
  1990年   64篇
  1989年   68篇
  1988年   69篇
  1987年   63篇
  1986年   56篇
  1985年   63篇
  1984年   48篇
  1983年   28篇
  1982年   34篇
  1981年   28篇
  1980年   26篇
  1979年   58篇
  1978年   35篇
  1977年   22篇
  1975年   34篇
  1974年   26篇
  1973年   28篇
  1970年   20篇
  1966年   19篇
排序方式: 共有3316条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
Steady flattening of the tumor, increasing reflectivity and decreasing vascularity are echographic signs of successful irradiation treatment. The specific example of an irradiated choroidal melanoma shows that the absence of echographic changes by no means excludes tumor destruction. Because of a dense vitreous body hemorrhage, the melanoma could only be evaluated echographically. Since the echogram lacked evidence of regression, the tumor was locally resected 5 months later. Histology, however, revealed an amorphous mass of dead tissue pervaded by intact vessels. Apparently a successfully irradiated melanoma may generate an echo typical of vital melanoma tissue. The authors therefore draw the conclusion that only a steady tumor growth, as substantiated by an echogram, may be considered an unambiguous sign of tumor vitality.  相似文献   
5.
There is growing evidence that obesity in women lead to a more severe form of hyperandrogenism and other endocrine abnormalities which may have some health implications later in life. Obese females are at higher risk for metabolic syndrome due to severe hyperandrogenemia. Calculated values for free testosterone are equivalent to those obtained by equilibrium dialysis, which is one of the reference measurement procedures (RMP) for estimation of free testosterone and may be capable of replacing values estimated using RMP's. For adult women correlations of body mass index (BMI) with calculated free (cFT) and bioavailable testosterone (cBT) are still rare, while these data are reported for peripubertal and adolescent girls. In this study we aimed to investigate the association between BMI and different androgen parameters (including calculated free and bioavailable testosterone, free androgen index, and sex hormone-binding globulin [SHBG]) in adult women with Hirsutism and with PCOS. In hirsute women with BMI > or = 25 kg/m2 measured total testosterone (TT) was significantly higher, SHBG was significantly lower and the calculated androgen parameter (FAI, cFT and cBT) were significantly higher compared to women with BMI < 25 kg/m2. In PCOS women with BMI > or = 25 kg/m2 TT was significantly higher, SHBG was significantly lower and the calculated androgen parameter (FAI, cFT and cBT) were also significantly higher compared to women with BMI < 25 kg/m2. In both the Hirsutism and PCOS-group there was a positive correlation between BMI and TT, cFT, and cBT, while BMI was negatively correlated with SHBG. In summary, in adult women with Hirsutism and PCOS obesity is associated with increased levels of TT and decreased levels of SHBG resulting in significant elevated calculated free and bioavailable testosterone levels. Obesity might lead to a more severe form of hyperandrogenism with elevated calculated free and bioavailable testosterone in the study population.  相似文献   
6.
7.
8.
Background and objectives: The aim of this study was to evaluate the practical value of the dermatoscopic classification of Clark nevi Patients and methods: Dermatoscopic images of 268 lesions clinically and dermatoscopically diagnosed as Clark nevi were presented to 2 dermatologists without knowledge of the histological diagnosis. The dermatologists evaluated the lesions according to a simplified version of the classification scheme for Clark nevi proposed by Hofmann‐Wellenhof and differentiated between 12 different types of Clark nevi. Results: The most common type of Clark nevus was the reticular‐homogenous type (n = 64, 23,9 %), followed by the globular‐homogeneous type (n = 32, 12 %) and by the homogenous type (n = 30, 11,2 %). The overall inter‐rater agreement between the examiners was moderate to good (kappa = 0,58). The highest level of agreement was found for the peripheral hyperpigmented type (kappa = 0,83). Histologically, 17 lesions (6,3 %) were diagnosed as melanomas. The frequency of melanoma was highest among the peripheral‐hyperpigmented type for one observer and among the homogenous type for the other observer. No melanoma was found among the globular, reticular‐globular, and the central‐hyperpigmented types. Conclusions: A dermatoscopic classification of Clark nevi is practically feasible and allows – to some extent – a risk stratification of Clark nevi, which could be useful for clinical management.  相似文献   
9.
Psychological and neuropsychological assessments of psychiatric patients are usually designed to contribute to or document psychiatric diagnoses. The present article suggests that reframing the task to focus on cognitive rehabilitation issues can contribute significantly to the treatment of the chronic patient. A test protocol is proposed and exemplary tests suggested.  相似文献   
10.
In a prospective study of the effect of postoperative radiation therapy for the prevention of reproliferation of membranes and recurrent proliferative vitreoretinopathy (PVR) two similar groups of patients with retinal detachment and PVR grade D1 to D3 in one eye were compared. Half the eyes (30) received a total dose of 3000 cGy after surgery; the other half remained untreated. After a followup of 6 months and 14 months or more (maximum 36 months) the anatomical and functional results of each group were compared. After 6 months in the unirradiated group 57% (17/30) remained attached and 43% (13/30) had detached again. In the irradiated group 63% (19/30) were attached and 37% (11/30) had detached. However, there was no statistically significant difference between the two groups (P=0.479, Fisher's Exact Test). After 14 months the number of cured and uncured eyes remained the same in the unirradiated group, while in four of the eyes in the irradiated group a later onset of reproliferation and detachment occurred (after 7, 8, 12 and 14 months, respectively). A final cure rate of 57% (17/30) was achieved in the unirradiated group and a 50% (15/30) cure rate in the irradiated group. Thus the failure rate was 43% (13/30) in the unirradiated group and 50% (15/30) in the irradiated group (P=0.473, Fisher's Exact Test). No side effects from the radiation were observed in any case and no radiation retinopathy occurred during an observation period of up to 3 years. The visual acuity of the cured treated and cured untreated eyes was similar in the two groups. From these results we conclude that immediate radiation treatment does not improve the long-term results and does not reduce the number of reoperations. In a considerable number of treated eyes the onset of reproliferation was delayed from 7 to 14 months, whereas in the untreated group reproliferation was always observed during the first 6 months. A combination of various antiproliferative and antiinflammatory therapies are needed to suppress recurrent PVR after succesful vitreoretinal surgery and to minimize the side effects of these treatments.Presented in part at the XVIIth Meeting of the Club Jules Gonin, 1–6 September 1990, Lausanne  相似文献   
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