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   3367532篇
  免费   272803篇
  国内免费   6032篇
耳鼻咽喉   48520篇
儿科学   107541篇
妇产科学   93033篇
基础医学   475001篇
口腔科学   99424篇
临床医学   306561篇
内科学   652551篇
皮肤病学   70358篇
神经病学   280694篇
特种医学   134320篇
外国民族医学   1248篇
外科学   507049篇
综合类   82922篇
现状与发展   4篇
一般理论   1426篇
预防医学   271970篇
眼科学   79743篇
药学   252288篇
  6篇
中国医学   6248篇
肿瘤学   175460篇
  2018年   33629篇
  2016年   28902篇
  2015年   33050篇
  2014年   46939篇
  2013年   71798篇
  2012年   96480篇
  2011年   102044篇
  2010年   60289篇
  2009年   57557篇
  2008年   97163篇
  2007年   102922篇
  2006年   104089篇
  2005年   101208篇
  2004年   98237篇
  2003年   94578篇
  2002年   93349篇
  2001年   153539篇
  2000年   159005篇
  1999年   134999篇
  1998年   39152篇
  1997年   35500篇
  1996年   34997篇
  1995年   33941篇
  1994年   31928篇
  1993年   29866篇
  1992年   109697篇
  1991年   106068篇
  1990年   102961篇
  1989年   99470篇
  1988年   92457篇
  1987年   91222篇
  1986年   86625篇
  1985年   83060篇
  1984年   63003篇
  1983年   54078篇
  1982年   32665篇
  1981年   29179篇
  1980年   27490篇
  1979年   59843篇
  1978年   42094篇
  1977年   35523篇
  1976年   33318篇
  1975年   35271篇
  1974年   43493篇
  1973年   41546篇
  1972年   38704篇
  1971年   36032篇
  1970年   33647篇
  1969年   31421篇
  1968年   28663篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
991.
Cidofovir is an acyclic nucleoside phosphonate with broad-spectrum activity against DNA viruses, including human papilloma virus (HPV). However, data on the efficacy of cidofovir in an immunosuppressive setting remain contradictory. We report for the first time on the promotion of the healing of recalcitrant warts in a patient with myelodysplastic syndrome with intravenous cidofovir treatment.  相似文献   
992.
OBJECTIVES: To evaluate changes in the mobility of the whole urethra, in the proximal urethra (funneling) and in the thickness of the urinary bladder wall, after a successful tension-free vaginal tape (TVT) procedure. METHODS: This prospective longitudinal study included 52 women with urodynamically confirmed stress urinary incontinence who had undergone a successful TVT procedure. Ultrasound examination was performed before the TVT procedure and at a median of 3 (range, 3-6) months after surgery. For all women, the changes to the urethra and urinary bladder induced by surgery were examined. For three mobility groups (low, intermediate and high urethral mobility before surgery) we compared the changes induced by the operation and the typical position and mobility of the tape. RESULTS: The position of the urethra at rest was not influenced by surgery. The operation significantly decreased the mobility of all parts of the urethra during Valsalva. The absolute changes of the vector of the urethral movement differed according to the mobility group (average decrease, 6 mm; decrease for women with low, intermediate and high mobility, respectively, 2-3 mm, 4-6 mm and 9 mm). The change in relative mobility was the same in all groups. The operation decreased funneling (width and depth) during maximal Valsalva. After surgery there was an increase in the thickness of the bladder wall (by 0.64 and 0.73 mm, respectively, at the anterior part and trigone). CONCLUSIONS: A successful TVT procedure did not influence the position of the urethra at rest but significantly decreased the mobility of the urethra during Valsalva and also decreased funneling at maximal Valsalva.  相似文献   
993.
994.
The lack of estrogen during menopause is associated with various symptoms including osteoporosis, cardiovascular diseases, and menopausal symptoms. For many years, conventional hormone replacement therapy has been successfully used to treat these conditions. However, in light of recent studies that draw attention to potential hazards of conventional HRT, various attempts were undertaken to search for alternatives of classical HRT. Phytoestrogens are supposed to ameliorate various discomforts associated with menopause. Resveratrol (RES) is present in red wine, grapes and peanuts and has been implicated in cardioprotection and prevention of adverse side effects observed after regular HRT. As the pituitary-thyroid axis is a target of estrogen action, we first assessed the effects of E2 administration on thyroid hormone stimulating hormone releasing hormone (TRH)-induced thyroid stimulating hormone (TSH) secretion from pituitary cell cultures in vitro. Our data reveal that E2 treatment augments the TRH-induced TSH secretion. We furthermore designed a long-term study of three months to assess the effects of subcutaneous and oral administration of 17beta-estradiol (E2), as well as the actions of RES on the pituitary-thyroid axis in ovariectomized (OVX) female rats. Our results demonstrate that serum levels of 1.0 and 8.1 microM RES lead to a significant increase in total serum triiodthyronine (T3) levels. OVX induces TSHbeta mRNA in the adenohypohysis and E2 treatment attenuates this effect. Treatment of rats with subcutaneous implants of E2 does not affect the pituitary-thyroid axis, whereas orally applied E2 benzoate (E2B) increases plasma TSH and total thyroxine (T4) in OVX rats. In all animals, we could not detect changes in thyroid morphology as assessed by hematoxylin-eosin (HE) and Perjod-Acid Schiff's (PAS) staining.  相似文献   
995.
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   
996.
997.
Esophageal foreign body causing direct aortic injury.   总被引:4,自引:0,他引:4  
Foreign bodies in the esophagus are uncommon causes of esophageal perforation. Many nonperforating cases are successfully managed by flexible gastroscopy. However, complicated foreign bodies such as those that result in esophageal perforation and vascular injury are best managed surgically. Gastroscopy remains the primary method of diagnosis. A case of a 59-year-old woman who developed retrosternal and intrascapular pain, odynophagia and hematemesis after eating fish is reported. Flexible gastroscopy showed arterial bleeding from the midthoracic esophagus. Computed tomography scan localized a 3 cm fish bone perforating the esophagus with surrounding hematoma. An aortogram did not reveal an actively bleeding aortoesophageal fistula. The fish bone was surgically removed and the patient recovered with no postoperative complications. This case illustrates the importance of early consideration for surgical intervention when confronted with a brisk arterial bleed from the esophagus with suggestive history of foreign body ingestion.  相似文献   
998.
This review discusses treatment options for men with premature ejaculation (PE), a common sexual dysfunction characterized by short ejaculatory latency, decreased sexual satisfaction, and distress. For a number of reasons, including embarrassment and the belief that PE is a normal part of aging, that it has no effective treatment, or that it will resolve itself, few men with PE seek treatment. Although several treatment options exist (eg, behavioral, cognitive, and sex therapy methods; desensitizing drugs; off-label use of antidepressants, phosphodiesterase type 5 inhibitors, or à-blockers), the majority of men with PE are not satisfied with their results. New pharmacologic drugs develped specifically for the treatment of PE are undergoing evaluation in clinical trials. For example, recent clinical research studies have revealed on-demand administration of one such drug, dapoxetine, which achieved significant improvements in ejaculatory latency, control over ejaculation, and satisfaction with sexual intercourse. In addition, partners of men who received dapoxetine likewise reported improved satisfaction with sexual intercourse. Future studies may reveal that integration of pharmacologic drugs with psychologic and/or behavioral therapy techniques may be the optimal approach to the management of PE. PE is a treatable condition, and new drugs in development may provide benefits over those available.  相似文献   
999.
1000.
Hepatitis C virus (HCV) infection is a major health care issue in liver and kidney transplantation. Besides negatively affecting both patient and graft survival, HCV is associated with a heightened risk for new onset diabetes mellitus (NODM). The mechanisms underlying the diabetogenicity of HCV are complex but are likely to involve insulin resistance caused by inhibitory actions of the virus on insulin regulatory pathways in the liver. The resultant glucose dysregulation is an important determinant of increased morbidity and mortality in liver and kidney recipients. This review highlights the concerns for outcomes in HCV-positive liver and kidney transplant patients with particular focus on the interrelationship between hepatitis C and diabetes. Data about the potential role of calcineurin inhibitors, corticosteroids and mycophenolate mofetil in HCV infection and HCV-associated NODM will also be discussed.  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