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   849篇
  免费   45篇
  国内免费   2篇
耳鼻咽喉   2篇
儿科学   26篇
妇产科学   20篇
基础医学   93篇
口腔科学   7篇
临床医学   79篇
内科学   206篇
皮肤病学   33篇
神经病学   67篇
特种医学   48篇
外科学   132篇
综合类   3篇
预防医学   32篇
眼科学   2篇
药学   61篇
中国医学   1篇
肿瘤学   84篇
  2024年   2篇
  2023年   6篇
  2022年   21篇
  2021年   20篇
  2020年   17篇
  2019年   21篇
  2018年   38篇
  2017年   22篇
  2016年   21篇
  2015年   24篇
  2014年   41篇
  2013年   33篇
  2012年   66篇
  2011年   55篇
  2010年   34篇
  2009年   33篇
  2008年   61篇
  2007年   49篇
  2006年   55篇
  2005年   40篇
  2004年   37篇
  2003年   32篇
  2002年   27篇
  2001年   8篇
  2000年   12篇
  1999年   10篇
  1998年   5篇
  1997年   10篇
  1996年   4篇
  1995年   2篇
  1994年   5篇
  1993年   3篇
  1992年   9篇
  1991年   10篇
  1990年   5篇
  1989年   2篇
  1988年   7篇
  1987年   8篇
  1986年   9篇
  1985年   9篇
  1984年   4篇
  1983年   6篇
  1982年   4篇
  1981年   1篇
  1980年   1篇
  1979年   3篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
排序方式: 共有896条查询结果,搜索用时 15 毫秒
1.
2.
BACKGROUND: In maintenance haemodialysis patients, daily food intake is changeable; however, its relationship with nutritional status is unexplored. This study aimed to evaluate the isolated, long-term effect of daily nutrient intake on nutritional status in haemodialysis patients. METHODS: We performed a prospective 1-year controlled study in 27 chronic haemodialysis patients, without recognized risk factors for malnutrition. Each day for 1 week, four times in the year, we measured protein nitrogen appearance, and assessed dietary protein (DPI) and energy (DEI) intake from dietary diaries. We compared the nutritional outcome of patients spontaneously reducing nutrient intake below the threshold of 0.8 g/kg body weight/day for DPI and 25 kcal/kg body weight/day for DEI during the week (LOW, n = 8), with controls at adequate nutrient intake (CON, n = 19). An interventional 6-month study was then carried out in LOW to verify the cause-effect relationship. RESULTS: All patients showed a day-by-day reduction of whole nutrient intake during interdialytic period, which was mostly relevant in the third interdialytic day (L3). During the 1-year study, even in the presence of adequate dialysis dose and normal inflammatory indexes, body weight (68.0 +/- 5.5 to 65.8 +/- 5.9 kg), serum albumin (3.96 +/- 0.07 to 3.66 +/- 0.06 g/dl) and creatinine (9.2 +/- 1.1 to 8.1 +/- 0.7 mg/dl) significantly decreased in LOW but not in CON. Diaries evidenced in LOW a reduced number of meals at L3 that was explained by the fear of excessive interdialytic weight gain. During the interventional study, daily DPI and DEI increased at L3; this was associated with a significant increment of body weight, and serum albumin and creatinine levels. CONCLUSIONS: In maintenance haemodialysis patients the persistent, marked reduction of daily nutrient intake, even if limited to a single day of the week, is an independent determinant of reversible impairment of nutritional status.  相似文献   
3.
We conducted a study of the basal levels of gonadotropins in 38 patients with Turner's syndrome, 14 of whom were using hormone replacement therapy (HRT). The gonadotropin levels were compared with pubertal development and HRT. Seven patients had presented spontaneous menarche; five patients maintained their periods and normal gonadotropin levels, and two developed secondary amenorrhea and high gonadotropin levels. The majority of patients on HRT had high gonadotropin levels. Follicle stimulating hormone (FSH) levels were significantly lower (p = 0.001) in patients with breast development at stage 5, regardless of whether the patient had undergone a spontaneous or a hormonally induced puberty. We concluded that gonadotropin levels are normal in those patients with spontaneous periods, and are high in most patients on HRT; and that FSH levels are significantly lower in those patients with breasts at stage 5.  相似文献   
4.
The evolution of the progressive loss of semantic knowledge of a patient, VZ, with lesions mainly affecting the infero-medial temporal lobes, was followed for two years. At the beginning of the study VZ's performance was mainly characterized by a category-specific deficit for living things and a modality-specific deficit for perceptual attribute knowledge. As time went on, VZ's disorder affected all categories by changing the relationship between category and attribute knowledge. Data show that dissociations may change in the course of progressive cognitive breakdown, depending on both degeneration stage and task demands. VZ's performance is discussed in the light of the most influential theoretical accounts. Methodological suggestions regarding longitudinal studies of degenerative patients are also put forward.  相似文献   
5.
6.
Acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin's lymphomas (AIDS-NHLs) consistently derive from B cells, are histologically heterogeneous, and are associated with distinct molecular pathways depending upon histology. Recently, it has been proposed that inactivating mutations of the bax death agonist may contribute to the pathogenesis of human tumors. In particular, among B-cell malignancies, BAX mutations have been detected at a certain frequency in Burkitt lymphomas. This study is aimed at defining the status of the BAX gene throughout the clinicopathologic spectrum of AIDS-NHL (n = 54), including AIDS-related Burkitt lymphoma (n = 14), AIDS-related Burkitt-like lymphoma (n = 8), AIDS-related diffuse large cell lymphoma (n = 15), AIDS-related primary central nervous system lymphoma (n = 6), and AIDS-related primary effusion lymphoma (n = 11). All 6 BAX exons and flanking sequences were subjected to mutational analysis by polymerase chain reaction-single strand conformation polymorphism followed by DNA direct sequencing of positive cases. Mutations of BAX among AIDS-NHL were restricted to a cell line of AIDS-related primary effusion lymphoma, which harbored a frameshift mutation causing the introduction of a proximal stop codon. All other AIDS-NHL displayed wild-type BAX alleles. In order to investigate whether BAX inactivation in AIDS-NHL may occur through mechanisms other than gene mutation, bax protein expression was investigated by Western blot analysis or immunohistochemistry in selected cases. All AIDS-NHL analyzed expressed normal bax proteins. Overall, this study indicates that deregulation of apoptotic control in AIDS-NHL is not caused by BAX alterations. Genes Chromosomes Cancer 27:177-182, 2000.  相似文献   
7.
8.
We report a clinical update of the hemoglobin (Hb) variant [β27(B9)Ala→Gly; HBB: c.83C>G], named Hb Siirt, that was previously described as a silent variant in a 23-year-old Kurdish female. The patient was also a carrier of the codon 5 (–CT) (HBB: c.17_18delCT) frameshift mutation and of the ααα anti 3.7 triplication. Her initial moderate β-thalassemia intermedia (β-TI) phenotype worsened with time, causing the patient to become a transfusion-dependent subject at the age of ~40 years. Subsequent molecular characterization of both parents revealed that the Hb Siirt variant was inherited by the mother, while the other two globin alterations (HBB: c.17_18delCT and αααanti 3.7 triplication) were genetically transmitted by the father. The latter remained a carrier of a mild β-TI phenotype throughout his life, at least until the age of 65 years. We hypothesize that the worsened clinical conditions in the daughter were due to the additional, maternally inherited Hb Siirt variant. However, protein 3D conformational analysis did not seem to reveal substantial overall structural changes. Among the other three described variants [Hb Volga (HBB: c.83C>A), Hb Knossos (HBB: c.82?G>T), Hb Grange-Blanche (HBB: c.83C>T] that are due to nucleotide substitutions at codon 27 of the β-globin gene; only Hb Knossos causes a β+-thalassemia (β+-thal) phenotype.  相似文献   
9.
Introduction: Central nervous system (CNS) metastases represent an important cause of morbidity and mortality in non-small cell lung cancer (NSCLC) patients. Local approaches of neurosurgery (usually for single brain lesions), whole brain radiotherapy, and stereotactic radiosurgery are often withheld for the treatment of NSCLC-derived brain metastases (BMs). However, systemic treatment is consistently emerging as an option for patients with asymptomatic BMs, which could allow for delaying cranial radiotherapy at symptomatic/radiological progression.

Areas covered: Chemotherapy, monoclonal antibodies, tyrosine-kinase inhibitors (TKIs) for molecularly selected NSCLCs, such as epidermal growth factor receptor (EGFR)-mutant and anaplastic lymphoma kinase (ALK)-rearranged diseases, and immune checkpoint inhibitors are all systemic treatments that have shown activity against NSCLC-derived CNS metastases. Among these, EGFR- and ALK-TKIs will be discussed more in detail owing to their superior efficacy in this context.

Expert opinion: Up-front systemic treatment should be considered for patients with asymptomatic, multiple BMs, as recently acknowledged by the European Society of Medical Oncology guidelines. Nevertheless, it must be emphasized that the best treatment strategy for NSCLC-derived BMs has to be defined within a multidisciplinary team.  相似文献   

10.
Topiramate (TPM) is an antiepileptic drug able to play a role in both neurological and psychiatric disorders. TPM facilitates gamma-aminobutyric acid (GABA) transmission and inhibits glutamatergic transmission (i.e. AMPA/kainate receptors).Several studies reported that the modulation of GABAergic and glutamatergic synaptic transmission may reduce cocaine reinforcement. Therefore, TPM could be used in the management of cocaine dependence.  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