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   1597篇
  免费   172篇
  国内免费   22篇
耳鼻咽喉   4篇
儿科学   41篇
妇产科学   25篇
基础医学   248篇
口腔科学   51篇
临床医学   160篇
内科学   256篇
皮肤病学   26篇
神经病学   145篇
特种医学   146篇
外科学   200篇
综合类   37篇
一般理论   1篇
预防医学   239篇
眼科学   14篇
药学   142篇
中国医学   1篇
肿瘤学   55篇
  2021年   26篇
  2020年   18篇
  2019年   30篇
  2018年   40篇
  2017年   25篇
  2016年   28篇
  2015年   33篇
  2014年   53篇
  2013年   46篇
  2012年   58篇
  2011年   62篇
  2010年   53篇
  2009年   46篇
  2008年   70篇
  2007年   67篇
  2006年   62篇
  2005年   57篇
  2004年   52篇
  2003年   43篇
  2002年   46篇
  2001年   39篇
  2000年   54篇
  1999年   46篇
  1998年   30篇
  1997年   42篇
  1996年   28篇
  1995年   31篇
  1994年   24篇
  1993年   26篇
  1992年   40篇
  1991年   38篇
  1990年   26篇
  1989年   53篇
  1988年   34篇
  1987年   36篇
  1986年   34篇
  1985年   34篇
  1984年   24篇
  1983年   22篇
  1982年   14篇
  1981年   17篇
  1980年   14篇
  1979年   18篇
  1978年   19篇
  1977年   11篇
  1975年   14篇
  1971年   12篇
  1970年   9篇
  1968年   9篇
  1967年   9篇
排序方式: 共有1791条查询结果,搜索用时 15 毫秒
31.

Objectives

To evaluate the efficacy of combined finasteride and flutamide therapy in men with advanced prostate cancer by determining (1 ) the short-term tolerability of finasteride monotherapy and its effect on serum prostate-specific antigen (PSA) and hormone (testosterone, dihydrotestosterone) levels, and (2) the effects of the addition of flutamide on tolerability and on serum PSA and hormone levels.

Methods

Thirteen hormone-naive men with advanced prostate cancer (4 with Stage D2, 1 with Stage D1, 1 with Stage DO, 7 with rising PSA levels after radical prostatectomy [n = 2]or definitive radiation therapy [n = 5]) were initially treated with 5 mg finasteride daily. Flutamide (250 mg three times a day) was added after serum PSA levels stabilized.

Results

Finasteride alone (median 5 weeks) had no significant effect on serum PSA levels (P>0.05). Combined finasteride and flutamide resulted in a mean 91% reduction in serum PSA levels, with 85% of men achieving a nadir serum PSA level of less than 4.0 ng/mL and 46% achieving undetectable levels (0.2 ng/mL or less). Finasteride alone had no significant effect on serum testosterone levels (P>0.05) but did result in a mean 74% reduction in serum dihydrotestosterone levels. Combined finasteride and flutamide resulted in a mean 56% increase in serum testosterone levels but had no additional effect on serum dihydrotestosterone levels (P>0.05). Side effects occurred in 85% (gynecomastia or breast tenderness in 62% [8 of 13]and diarrhea in 23% [3 of 13]) of men on combined therapy. Potency was preserved in 66%. Combined finasteride and flutamide therapy was withdrawn from 15% (2 of 13) because of flutamide-induced diarrhea and from 23% (3 of 13) because of disease progression. All remaining patients (8 of 13) have serum PSA levels below 4.0 ng/mL and 4 of these 8 have undetectable levels. These men have received combined finasteride and flutamide for a median 11 months (range 6 to 19).

Conclusions

Finasteride monotherapy is inadequate therapy for advanced prostate cancer, but combined finasteride and flutamide may be a reasonable alternative for men with advanced prostate cancer who refuse conventional hormone therapy.  相似文献   
32.
33.
34.
35.
Although there is wide variation, humans possess on average 900,000 nephrons per kidney. So far as is known, nephrons cannot regenerate; therefore, an individual’s nephron endowment has profound implications in determining his or her long-term risk of developing chronic kidney disease. Most of the variability in human nephron number is determined early in life. Nephrogenesis is a complex and carefully orchestrated process that occurs during a narrow time window until 36 weeks gestation in humans, and disruption of any part of this sequence may lead to reduced nephron number. In utero, genetic abnormalities, toxic insults, and nutritional deficiencies can each alter final nephron number. Infants born prematurely must continue nephrogenesis in an ex utero environment where there may be multiple threats to successful nephrogenesis. Once the nephron endowment is determined, postnatal factors (such as acute kidney injury or chronic illnesses) can only decrease nephron number. Current techniques for estimating nephron number require an invasive procedure or complete destruction of the tissue, making noninvasive means for counting nephron surgently needed. A better understanding of nephron number and its determinants, particularly during growth and maturation, could allow the development of therapies to support, prolong, or resume nephrogenesis.  相似文献   
36.
37.
38.
39.
40.
ObjectiveUniversal salt iodization is an effective strategy to optimize population-level iodine. At the same time as salt-lowering initiatives are encouraged globally, there is concern about compromised iodine intakes. This study investigated whether salt intakes at recommended levels resulted in a suboptimal iodine status in a country where salt is the vehicle for iodine fortification.MethodsThree 24-h urine samples were collected for the assessment of urinary sodium and one sample was taken for urinary iodine concentrations (UICs) in a convenience sample of 262 adult men and women in Cape Town, South Africa. Median UIC was compared across categories of sodium excretion equivalent to salt intakes lower than 5, 5 to 9, and greater than or equal to 9 g/d.ResultsThe median UIC was 120 μg/L (interquartile range 75.3–196.3), indicating iodine sufficiency. Less one-fourth (23.2%) of subjects had urinary sodium excretion values within the desirable range (salt <5 g/d), 50.7% had high values (5–9 g/d), and 22.8% had very high values (≥9 g/d). No association between urinary iodine and mean 3 × 24-h urinary sodium concentration was found (r = 0.087, P = 0.198) and UIC status did not differ according to urinary sodium categories (P = 0.804).ConclusionIn a country with mandatory universal salt iodization, consumers with salt intakes within the recommended range (<5 g/d) are iodine replete, and median UIC does not differ across categories of salt intake. This indicates that much of the dietary salt is provided from non-iodinated sources, presumably added to processed foods.  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