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   3606篇
  免费   154篇
  国内免费   8篇
耳鼻咽喉   27篇
儿科学   234篇
妇产科学   49篇
基础医学   302篇
口腔科学   66篇
临床医学   260篇
内科学   886篇
皮肤病学   47篇
神经病学   179篇
特种医学   77篇
外国民族医学   1篇
外科学   744篇
综合类   105篇
预防医学   145篇
眼科学   158篇
药学   280篇
中国医学   22篇
肿瘤学   186篇
  2024年   2篇
  2023年   29篇
  2022年   47篇
  2021年   159篇
  2020年   86篇
  2019年   102篇
  2018年   103篇
  2017年   75篇
  2016年   105篇
  2015年   117篇
  2014年   146篇
  2013年   193篇
  2012年   284篇
  2011年   293篇
  2010年   190篇
  2009年   140篇
  2008年   247篇
  2007年   251篇
  2006年   212篇
  2005年   191篇
  2004年   183篇
  2003年   165篇
  2002年   150篇
  2001年   37篇
  2000年   33篇
  1999年   26篇
  1998年   29篇
  1997年   17篇
  1996年   10篇
  1995年   15篇
  1994年   11篇
  1993年   12篇
  1992年   8篇
  1991年   10篇
  1990年   12篇
  1989年   14篇
  1988年   8篇
  1987年   4篇
  1986年   5篇
  1985年   5篇
  1984年   7篇
  1983年   8篇
  1982年   5篇
  1981年   5篇
  1980年   3篇
  1974年   2篇
  1973年   2篇
  1972年   2篇
  1971年   3篇
  1944年   1篇
排序方式: 共有3768条查询结果,搜索用时 15 毫秒
101.
102.
Estrogens and androgens are instrumental in the maturation of many hormone-dependent cancers. Consequently, the enzymes involved in their synthesis are cancer therapy targets. One such enzyme, steroid sulfatase (STS), hydrolyses estrone sulfate, and dehydroepiandrosterone sulfate to estrone and dehydroepiandrosterone respectively. These are the precursors to the formation of biologically active estradiol and androstenediol. This review focuses on three aspects of STS inhibitors: 1) chemical development, 2) biological activity, and 3) clinical trials. The aim is to discuss the importance of estrogens and androgens in many cancers, the developmental history of STS inhibitor synthesis, the potency of these compounds in vitro and in vivo and where we currently stand in regards to clinical trials for these drugs. STS inhibitors are likely to play an important future role in the treatment of hormone-dependent cancers. Novel in vivo models have been developed that allow pre-clinical testing of inhibitors and the identification of lead clinical candidates. Phase I/II clinical trials in postmenopausal women with breast cancer have been completed and other trials in patients with hormone-dependent prostate and endometrial cancer are currently active. Potent STS inhibitors should become therapeutically valuable in hormone-dependent cancers and other non-oncological conditions.  相似文献   
103.
Testicular vasculitis (TV) may be part of systemic (testicular) vasculitis (STV) or may exist as single-organ/isolated (testicular) vasculitis (ITV). In the current study we sought to identify clinical and histologic features that distinguish STV from ITV. The distinction was deemed important because it is already well established that in other forms of single organ vasculitis, surgical therapy alone may be curative. We identified patients with biopsy-proven TV from pathology databases from our institution and from an English-language PubMed search. Patients were included if data were available to determine TV extent confidently. Data recorded included clinical, laboratory, and histologic features; treatment; and clinical follow-up. The study included 72 patients with TV (mean age, 42 yr; range, 4-78 yr) (7 from our institution). About 74% of patients presented with painful testicular swelling/mass, 10% with a painless testicular swelling/mass, and 4% with epididymal swelling/mass. Eleven percent had no testicular complaints and vasculitis was discovered at autopsy or in other surgical interventions. Vasculitis involved the testicle in 80.3% of cases, the epididymis in 44.6%, and the spermatic cord in 30.6%. Thirty-seven (51%) patients had ITV and 35 (49%) had STV. No differences between ITV and STV patients were found in regards to age, presenting testicular features, duration of testicular symptoms, and time of follow-up. Compared to ITV patients, STV patients presented more often with constitutional/musculoskeletal symptoms (74.3% vs. 8.3%, respectively; p = 0.0001), elevated erythrocyte sedimentation rate (94.7% vs. 16%; p = 0.0001), and anemia (50% vs. 0%; p = 0.0001). Neoplasm was more frequently suspected in ITV than in STV (74.2% vs. 31.6%; p = 0.001), but only occurred in 2 ITV patients. Long-term glucocorticoid therapy was given only to STV patients, and 59.1% of them also received cytotoxic agents. ITV was diagnosed more often by orchiectomy (81.1% vs. 42.9%; p = 0.001) and less frequently by testicular biopsy (2.7% vs. 28.6%; p = 0.003) than STV. Nongranulomatous inflammation affecting medium-sized vessels occurred in most patients with both ITV and STV. Among STV, polyarteritis nodosa was the most frequently diagnosed (63%), followed by Wegener granulomatosis (17%).In summary, TV occurs as ITV in men usually presenting with a testicular mass in the absence of systemic symptoms and normal laboratory results. In most ITV patients, a testicular neoplasm is initially suspected, and TV is an unexpected finding. After surgical removal, ITV does not require systemic therapy. Polyarteritis nodosa is the systemic vasculitis most frequently associated with testicular involvement.  相似文献   
104.
105.
106.
107.
108.
109.
To present three rare mimics of primary angiitis of the central nervous system (PACNS). We describe 3 patients with rare diseases that can mimic PACNS at clinical presentation and neuroimaging. We describe the clinical course of these patients and also present a review of the literature regarding these three diagnoses. All 3 patients presented with neurological symptoms and had abnormal findings on neuroimaging suggestive of PACNS. After detailed history, careful review of systems, thorough laboratory workup and consideration of lack of a response to immunosuppressive therapy, PACNS was ruled out with identification of an alternative diagnosis. PACNS is a rare disease and a diagnostic challenge with many differentials. A thorough investigation and awareness of unusual disorders is critical in avoiding misdiagnosis.  相似文献   
110.
Aging and disease are accompanied with a reduction of complex variability in the temporal patterns of heart rate. This reduction has been attributed to a break down of the underlying regulatory feedback mechanisms that maintain a homeodynamic state. Previous work has established the utility of entropy as an index of disorder, for quantification of changes in heart rate complexity. However, questions remain regarding the origin of heart rate complexity and the mechanisms involved in its reduction with aging and disease. In this work we use a newly developed technique based on the concept of band-limited transfer entropy to assess the aging-related changes in contribution of respiration and blood pressure to entropy of heart rate at different frequency bands. Noninvasive measurements of heart beat interval, respiration, and systolic blood pressure were recorded from 20 young (21–34 years) and 20 older (68–85 years) healthy adults. Band-limited transfer entropy analysis revealed a reduction in high-frequency contribution of respiration to heart rate complexity (p < 0.001) with normal aging, particularly in men. These results have the potential for dissecting the relative contributions of respiration and blood pressure-related reflexes to heart rate complexity and their degeneration with normal aging.  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