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   474篇
  免费   28篇
  国内免费   8篇
耳鼻咽喉   6篇
儿科学   7篇
妇产科学   4篇
基础医学   59篇
口腔科学   22篇
临床医学   46篇
内科学   96篇
皮肤病学   4篇
神经病学   3篇
特种医学   53篇
外科学   49篇
综合类   71篇
预防医学   33篇
眼科学   5篇
药学   10篇
中国医学   3篇
肿瘤学   39篇
  2022年   2篇
  2021年   5篇
  2020年   2篇
  2019年   9篇
  2018年   14篇
  2017年   8篇
  2016年   9篇
  2015年   13篇
  2014年   12篇
  2013年   16篇
  2012年   23篇
  2011年   15篇
  2010年   24篇
  2009年   20篇
  2008年   23篇
  2007年   32篇
  2006年   26篇
  2005年   16篇
  2004年   13篇
  2003年   13篇
  2002年   18篇
  2001年   16篇
  2000年   4篇
  1999年   15篇
  1998年   24篇
  1997年   16篇
  1996年   18篇
  1995年   6篇
  1994年   15篇
  1993年   13篇
  1992年   4篇
  1991年   5篇
  1990年   5篇
  1989年   13篇
  1988年   5篇
  1987年   5篇
  1986年   3篇
  1985年   3篇
  1983年   3篇
  1982年   3篇
  1981年   1篇
  1980年   3篇
  1978年   5篇
  1977年   2篇
  1976年   1篇
  1975年   1篇
  1973年   1篇
  1972年   2篇
  1971年   2篇
  1968年   1篇
排序方式: 共有510条查询结果,搜索用时 546 毫秒
1.
Medicine, Health Care and Philosophy - It is often claimed in parts of the psychiatric literature that neuroscientific research into the biological basis of mental disorder undermines dualism in...  相似文献   
2.
3.
4.
Needle core biopsy guided with mammography: a study of cost- effectiveness   总被引:2,自引:0,他引:2  
Lindfors  KK; Rosenquist  CJ 《Radiology》1994,190(1):217
  相似文献   
5.
6.
It has been reported that hepatitis B virus (HBV) mutants carrying mutations in the pre-S region can be found in infected patients. In this study, we investigated the prevalence of the HBV variant with the pre-S mutant in different geographic regions, including countries with low and high levels of endemic HBV infection, and analyzed the correlation with clinical findings. We examined 387 HBV DNA-positive serum samples from individuals among 12 countries, consisting of Vietnam, Myanmar, Thailand, China, Korea, Nepal, Japan, Russia, Spain, United States, Bolivia, and Ghana. HBV pre-S mutants were detected in 71 (18.3%) of 387 serum samples tested. This mutant was the most prevalent in Vietnam (36%), followed by Nepal (27.3%), Myanmar (23.3%), China (22.4%), Korea (14.3%), Thailand (10.5%), Japan (7.7%), and Ghana (4.3%). In contrast, no case with this mutation was found in Russia, Spain, United States, and Bolivia. Among the HBV deletion mutations, 15.5% (11 of 71) occurred in the pre-S1 and 46.5% (33 of 71) in the pre-S2 regions. Eight (11.3%) cases had a mutation in both the pre-S1 and pre-S2 regions. In addition, a point mutation at the pre-S2 starting codon was observed in 19 (26.7%) cases. The detection rate of the HBV mutant in patients with hepatocellular carcinoma was significantly higher than in other patients (P < 0.05). Furthermore, these mutants were found more frequently in genotype B (25%) and genotype C (24.5%) than in the other genotypes (P < 0.05). Our results indicated that there was a high prevalence of HBV pre-S mutation in regions of endemic HBV infection in Asia. Furthermore, the pre-S mutation appeared to be correlated with hepatocellular carcinoma and HBV genotypes.  相似文献   
7.
This paper describes the tragic case of a young woman who died of cancer of the colon after successfully donating eggs to her younger sister. Although there is no direct link between her operation and the subsequent development of bowel carcinoma, this case imparts a feeling of unease when seen in conjunction with other cases reported during the last few years. It is a reminder that little is known of the long-term consequences of some aspects of assisted conception. Women undergoing ovarian stimulation for themselves or a matched recipient have the right to be advised, in an agreed format, that there is some concern about unproven potential risks from the stimulatory drugs. The safety of egg donors must assume priority over all other considerations, including lack of donors or any moral position. The recent decision by the Human Fertilisation and Embryology Authority (HFEA) to withdraw any form of payment or recompense to egg donors does not seem to us to be based on a balance of scientific advances, patient needs and the ethics of gamete supply. They state that the intention to withdraw payments was implicit in the 1990 Human Fertilisation and Embryology (HFE) Act. However the Act was based on the Warnock report made 6 years earlier. Even in 1990 ovum donation was uncommon and fertility drugs had not yet caused any unease. The Act provided the HFEA with discretionary powers to issue directions so that the future policies would be consistent with any emerging new medical evidence. It is imperative that the HFEA provide convincing evidence on how the current policy of payment to donors harms society, donors or recipients, and how in the UK the new policy will improve medical practice in assisted conception. Successful pilot studies must precede the implementation of any new policy. Failure to do this could cause irreversible harm to the practice of assisted conception using donor gametes, which will ultimately be against the basic aims of the 1990 HFE Act.   相似文献   
8.
Parathyroid hormone secretion is negatively regulated by a 7- transmembrane domain, G-protein coupled Ca(2+)-sensing receptor. We hypothesized that activating mutations in this receptor might cause autosomal dominant hypoparathyroidism (ADHP). Consistent with this hypothesis, we identified, in two families with ADHP, heterozygous missense mutations in the Ca(2+)-sensing receptor gene that cosegregated with the disorder. None of 50 normal controls had either mutation. We also identified a de novo, missense Ca(2+)-sensing receptor mutation in a child with severe sporadic hypoparathyroidism. The amino acid substitution in one ADHP family affected the N-terminal, extracellular domain of the receptor. The other mutations involved the transmembrane region. Unlike patients with acquired hypoparathyroidism, patients with these mutations had hypercalciuria even at low serum calcium concentrations. Their greater hypercalciuria presumably reflected activation of Ca(2+)-sensing receptors in kidney cells, where the receptor negatively regulates calcium reabsorption. This augmented hypercalciuria increases the risk of renal complications and thus has implications for the choice of therapy.   相似文献   
9.
Fibrous hamartoma of infancy   总被引:1,自引:0,他引:1  
Fibrous hamartoma of infancy is an uncommon fibroproliferative lesion that occurs only in infancy and childhood. The present case is unusual for the presence of two separate lesions, infiltration into the superficial muscle, infiltration and entrapment of nerves, and rapid recurrence after initial surgery. Despite these unusual and suspicious features, follow-up evaluations over the 15 months subsequent to the last resection showed no evidence of recurrence.  相似文献   
10.
Neuron-specific enolase, S-100 protein, and Leu 7 are present in cells showing neuroendocrine differentiation. Leu 7 recognizes myelin-associated glycoprotein, and recent evidence suggests that it further recognizes a subset of neurosecretory granules. Forty-six primary and metastatic carcinoid tumors from various sites were evaluated immunohistochemically with antisera to neuron-specific enolase, S-100, and Leu 7. Only one tumor, a rectal carcinoid, failed to stain with neuron-specific enolase. The remaining cases showed four patterns of staining: nuclear, diffuse cytoplasmic, globular cytoplasmic, or mixed. The pattern of reaction did not correlate with either the embryonic origin or histologic pattern of the tumor. Two patterns of staining were obtained with anti-Leu 7: diffuse cytoplasmic, or dot or ring-like deposition of reaction product. The latter pattern was entirely confined to appendiceal carcinoids. Reactivity with S-100 was in the form of dense positivity in individual cells having a stellate outline. Less intense cytoplasmic positivity and, uncommonly, a mixture of both types of staining were also seen. These histochemical results may lend support to recent evidence suggesting the existence of identifiable subsets of neurosecretory granules in neuroendocrine tumors, including carcinoids.  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