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   6124篇
  免费   451篇
  国内免费   93篇
耳鼻咽喉   10篇
儿科学   67篇
妇产科学   421篇
基础医学   893篇
口腔科学   19篇
临床医学   488篇
内科学   351篇
皮肤病学   123篇
神经病学   221篇
特种医学   61篇
外国民族医学   4篇
外科学   2082篇
综合类   601篇
一般理论   1篇
预防医学   642篇
眼科学   17篇
药学   305篇
中国医学   170篇
肿瘤学   192篇
  2023年   67篇
  2022年   58篇
  2021年   195篇
  2020年   198篇
  2019年   203篇
  2018年   173篇
  2017年   177篇
  2016年   184篇
  2015年   199篇
  2014年   323篇
  2013年   477篇
  2012年   316篇
  2011年   331篇
  2010年   288篇
  2009年   258篇
  2008年   346篇
  2007年   326篇
  2006年   306篇
  2005年   260篇
  2004年   265篇
  2003年   210篇
  2002年   180篇
  2001年   144篇
  2000年   137篇
  1999年   106篇
  1998年   63篇
  1997年   66篇
  1996年   73篇
  1995年   68篇
  1994年   58篇
  1993年   68篇
  1992年   50篇
  1991年   55篇
  1990年   37篇
  1989年   43篇
  1988年   27篇
  1987年   33篇
  1986年   25篇
  1985年   32篇
  1984年   37篇
  1983年   36篇
  1982年   28篇
  1981年   33篇
  1980年   31篇
  1979年   27篇
  1978年   20篇
  1977年   10篇
  1975年   4篇
  1974年   4篇
  1973年   4篇
排序方式: 共有6668条查询结果,搜索用时 31 毫秒
1.
2.
淫羊藿是一种常用的中药材,淫羊藿苷是从淫羊藿中提取的一种黄酮类化合物,也是淫羊藿中最主要的活性物质。研究发现,淫羊藿苷具有促进成骨细胞的生成和活化、调节免疫、抗衰老和抗炎等多种功能。临床上淫羊藿(苷)用于治疗生殖系统、骨关节系统、呼吸系统、神经系统、心血管系统和免疫系统等多种疾病。淫羊藿(苷)对男性生殖系统的作用及机制主要包括具有雄性激素样作用,促进睾内睾酮的合成和分泌。淫羊藿(苷)通过改善精子发生的微环境、增强睾丸抗氧化作用促进精子生成,增加精子密度,改善精子活力,减缓生殖衰退。此外,淫羊藿(苷)可促进阴茎勃起,治疗勃起功能障碍及早泄。  相似文献   
3.
4.
5.
目的 分析男性乳腺癌的临床病理及分子分型特点。方法 回顾分析宁波市临床病理诊断中心2013年1月至2019年3月38例男性乳腺癌病例的临床病理和分子分型资料。结果 38例男性乳腺癌病人,占同期乳腺癌病人0.83%,中位年龄68.5(24~88)岁,病灶位于左侧20例,位于右侧18例。其中29例为浸润性导管癌,2例为分泌性癌,1例为实性乳头状癌伴微浸润, 2例为导管内乳头状癌伴微浸润,4例为包裹性乳头状癌(其中2例伴微浸润)。浸润性导管癌组织学分级Ⅰ级2例,Ⅱ级20例,Ⅲ级7例。16例伴淋巴结转移。免疫组化染色:36例ER 阳性,35例PR阳性。分子分型Luminal A型18例,Luminal B型16例,基底细胞型2例。结论 男性乳腺癌少见,发病年龄较晚,临床分期较高,预后较差,且发生第2种原发性癌的可能性增加,加强对其认识,争取早期诊断、治疗及监测非常重要。男性乳腺癌仍须扩大样本量进一步研究。  相似文献   
6.
The accessory glands of male moths secrete several proteins, which are known to affect post-mating behaviour in females such as calling, reduction in receptivity, rate of egg maturation and laying, sperm maintenance and release and formation of mating plug. Helicoverpa armigera (Hübner) is a polyphagous pest of numerous crops and it is widely distributed on the Indian subcontinent where it causes severe economic losses. In the present study, receptivity- and calling-inhibiting substance (RCIS), a peptide secreted from the accessory glands of male H. armigera, was sequenced, cloned and expressed in a prokaryote, Escherichia coli. RCIS is a peptide comprising 58 amino acids and had a theoretical molecular weight of 6.03 kDa. It showed 64% similarity with pheromonostatic peptide 1, identified in Helicoverpa zea (Kingan et al., 1995) but differed regarding deletion of four and one amino acids at positions 14–17 and 44, respectively, and insertion of one and five amino acids at position 38 and the terminal position of RCIS, respectively. H. armigera females injected with recombinant RCIS showed reduced receptivity and calling behaviour (in 70–80% of the treated individuals), and mating frequencies decreased by 80%. Recombinant RCIS may be employed to artificially induce non-receptivity in virgin females in order to prevent reproduction.  相似文献   
7.
Most male breast diseases are benign, although malignancies can also occur. Gynecomastia, the most common abnormality in the male breast, has characteristic imaging findings differentiating it from cancer. Fewer than 1% of patients with breast cancer are men, but the incidence of male breast cancer is increasing worldwide. Additionally, breast cancer often presents at a more advanced stage in men than in women due to delayed diagnosis. Understanding imaging features of male breast disease is important for an accurate diagnosis and optimal care. This article reviews ultrasonography and mammography findings of benign and malignant diseases of the male breast.  相似文献   
8.
47,XYY syndrome is a sex chromosomal anomaly in men, which may be associated with infertility and has an incidence of 0.1% of male births. The clinical and paraclinical characteristics of men suffering from this anomaly have not been fully described. In this retrospective study, we present 37 cases of 47,XYY infertile men with sperm counts varying from normal to azoospermia, referred to the Genetics Laboratory at the Royan Institute, Iran. Thirteen individuals were mosaic and 24 non-mosaics. Non-mosaic patients were classified as azoospermic (nine cases) and normospermic/oligozoospermic men (15 cases). Two of the non-mosaic and three mosaic patients had secondary infertility. In addition, 13 of them underwent IUI, IVF or ICSI, and in seven cases, there was a biochemical pregnancy. The remaining 14 patients did not have ART. The 47,XYY syndrome is relatively unusual and can be missed clinically because of the lack of symptoms and of diverse phenotypes. Diagnosis of this aneuploidy can provide valuable data for counselling and early management of the patients who undergo fertility evaluation.  相似文献   
9.

Research question

Previous studies of aromatase inhibitors on male infertility have focused on men with low testosterone–oestradiol ratio of less than 10. Can aromatase inhibitors improve spermatogenesis in men with idiopathic male infertility with normal testosterone–oestradiol ratio?

Design

Prospective study of men with idiopathic severe oligozoospermia (sperm concentration <5 million/ml) carried out between February 2015 and March 2017. The objective was to assess if semen-analysis parameters improved after treatment with letrozole. Secondary objectives were to monitor the safety of letrozole in men, and to measure the alterations in serum FSH, LH, oestradiol and testosterone levels.

Results

Fifteen men with normal testosterone–oestradiol ratio (>10) were treated with letrozole 2.5 mg daily for 4 months. This produced a 5.5-fold increase in sperm concentration (P?=?0.0068). All men had increased total serum testosterone and suppressed oestradiol levels after treatment, thus raising the overall testosterone–oestradiol ratio (P < 0.0001). Adverse effects from letrozole were relatively minor and included loss of libido (54%), headaches (25%), fatigue (21%), weakness (13%), loss of hair (8%) and dry mouth (8%).

Conclusions

Letrozole improves sperm concentration and increases testosterone–oestradiol ratio for men with oligozoospermia who have normal testosterone–oestradiol ratio; its role in the treatment of male infertility may be extended to this group of patients. In addition, it is a relatively well-tolerated drug with no serious adverse effects.  相似文献   
10.
Dolichandrone serrulata flower (DSF) has been believed to reduce blood glucose in hyperglycaemic persons with sub-fertility but its effect on improvement of male reproductive impairment has never been elucidated scientifically. This study attempted to investigate the hypoglycaemic effects of DSF on male reproductive damages in type 2 diabetes mellitus (T2DM) rats. Adult Sprague Dawley rats were divided into four groups (control, T2DM, DSF200 + T2DM and DSF600 + T2DM; n = 10/each). Control rats received low-fat diet for 14 days before saline injection while streptozocin (50 mg/kg BW) induced T2DM groups received high-fat diet and were orally administered with DSF (200 and 600 mg/kg BW) for 28 days. At the end, fasted blood glucose (FBG), malondialdehyde (MDA), testosterone, sperm quality, histology and protein expressions were examined. The result showed that DSF decreased high FBG and testicular MDA and increased testosterone levels of T2DM-treated rats. Low-sperm quality and histological malfunction were ameliorated in DSF-treated group. There was significant decrease in the expression of androgen receptor, heat-shock 70 and steroidogenic acute regulatory proteins of T2DM-treated rats. Our study demonstrated changes of six bands (116, 51, 45, 39, 35 and 29 kDas) of tyrosine-phosphorylated proteins. In conclusion, DSF could reduce the FBGand ameliorate the reproductive damages in male T2DM rats.  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