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   2354篇
  免费   125篇
  国内免费   10篇
耳鼻咽喉   70篇
儿科学   50篇
妇产科学   90篇
基础医学   421篇
口腔科学   44篇
临床医学   190篇
内科学   640篇
皮肤病学   59篇
神经病学   165篇
特种医学   31篇
外科学   269篇
综合类   10篇
预防医学   111篇
眼科学   67篇
药学   183篇
中国医学   7篇
肿瘤学   82篇
  2023年   19篇
  2022年   66篇
  2021年   151篇
  2020年   50篇
  2019年   55篇
  2018年   71篇
  2017年   61篇
  2016年   59篇
  2015年   58篇
  2014年   90篇
  2013年   104篇
  2012年   186篇
  2011年   185篇
  2010年   102篇
  2009年   66篇
  2008年   152篇
  2007年   174篇
  2006年   142篇
  2005年   133篇
  2004年   116篇
  2003年   136篇
  2002年   106篇
  2001年   13篇
  1999年   7篇
  1998年   9篇
  1997年   7篇
  1996年   6篇
  1995年   6篇
  1994年   5篇
  1993年   5篇
  1990年   5篇
  1989年   6篇
  1988年   5篇
  1987年   4篇
  1985年   4篇
  1984年   4篇
  1982年   4篇
  1981年   5篇
  1938年   3篇
  1933年   5篇
  1932年   5篇
  1929年   4篇
  1928年   4篇
  1926年   7篇
  1922年   3篇
  1914年   3篇
  1913年   7篇
  1912年   6篇
  1910年   3篇
  1908年   4篇
排序方式: 共有2489条查询结果,搜索用时 15 毫秒
21.
Risk stratification of patients with early stage breast cancer may support adjuvant chemotherapy decision‐making. This review details the development and validation of six multi‐gene classifiers, each of which claims to provide useful prognostic and possibly predictive information for early stage breast cancer patients. A careful assessment is presented of each test's analytical validity, clinical validity, and clinical utility, as well as the quality of evidence supporting its use.  相似文献   
22.
Epigenetics is a series of alterations regulating gene expression without disrupting the DNA sequence of bases. These regulatory mechanisms can result in embryogenesis, cellular differentiation, X-chromosome inactivation, and DNA-protein interactions. The main epigenetic mechanisms considered to play a major role in both health and disease are DNA methylation, histone modifications, and profiling of non-coding RNA. When the fragile balance between these simultaneously occurring phenomena is disrupted, the risk of pathology increases. Thus, the factors that determine proper epigenetic modeling are defined and those with disruptive influence are sought. Several such factors with proven negative effects have already been described. Diet and nutritional substances have recently been one of the most interesting targets of exploration for epigenetic modeling in disease states, including autoimmunity. The preventive role of proper nutrition and maintaining sufficient vitamin D concentration in maternal blood during pregnancy, as well as in the early years of life, is emphasized. Opportunities are also being investigated for affecting the course of the disease by exploring nutriepigenetics. The authors aim to review the literature presenting vitamin D as one of the important nutrients potentially modeling the course of disease in selected autoimmune disorders.  相似文献   
23.
IntroductionA potential way to explain the relationships between sleep disorders and cognitive disorders during menopausal transition is the identification of genetic markers related to changes in cognitive functions, as well as changes in quality of sleep during menopause. The objective was an analysis of the relationship between sleep disorders and cognitive disorders, according to the possessed oestrogen receptor α gene polymorphism (ESR1) in perimenopausal and postmenopausal women.Material and methodsThe study included 300 women aged 44–66 years, employed as non-manual workers. A computerised battery of the Central Nervous System Vital Signs (CNS VS) test was used to diagnose cognitive functions. ESR1 polymorphisms were genotyped using PCR-RFLP methods. The Athens Insomnia Scale was used to diagnose sleep disorders.ResultsMore severe insomnia was related to worse complex memory, visual memory, and simple attention in the total group of examined women. More severe insomnia was related to worse simple attention in women with genotypes AG Xba I or TC Pvu II ESR1, in perimenopausal women with genotypes AG Xba I or TC Pvu II ESR1. During the postmenopausal period, the severity of insomnia negatively correlated with visual memory in carriers of Pvu II TT, and with reaction time in carriers of Xba I AA.ConclusionsThe results indicate an important role of oestrogen receptor α gene polymorphism in the modulation of the effect of insomnia on cognitive functions in peri- and postmenopausal women.  相似文献   
24.
Due to their properties, porous sliding bearings are considered to be maintenance-free, which means that no lubrication is required during operation. Their design enables operation at low rotational speeds with high load. Another effect of this bearing design is the lubrication continuity in the tribological pair. In this study, the selected tribological properties (such as load capacity and permeability) of new-generation iron porous bearings with boron nitride powder were experimentally investigated. Tests were carried out under various conditions, using unique test apparatus. The addition of 3% (weight) of hexagonal boron nitride (hBN) significantly increased the load capacity of tested porous bearings in comparison to the same standard bearings containing 2.5% copper. The obtained pgr·v rating reached almost 7 MPa, which is a value almost three times higher than the requirements for this type of bearing. It is worth emphasizing that such a result was obtained despite a noticeable deterioration in the air and oil permeability of the bearing.  相似文献   
25.
Nanoindentations and the Raman spectroscopy measurements were carried out on the (001) surface of undoped and S-doped InP crystal. The samples were indented with the maximum load ranging from 15 mN to 100 mN. The phase transition B3→B1 was not confirmed by spectroscopic experiments, indicating a plastic deformation mechanism governed by dislocations activity. Increasing the maximum indentation load shifts and the longitudinal and transverse optical Raman bands to lower frequencies reveals a reduction in the elastic energy stored in the plastic zone right below the indentation imprint. Mechanical experiments have shown that a shift in Raman bands occurs alongside the indentation size effect. Indeed, the hardness of undoped and S-doped InP crystal decreases as a function of the maximum indentation load.  相似文献   
26.
Purpose: The aim of this study is an estimation of the visual evoked potentials (VEP) in patients with psoriasis vulgaris. The role of the nervous system was pointed out in the pathogenesis of psoriasis. Also epidemiologic research confirms that patients with psoriasis are at increased risk of MS development. Materials and methods: A group of 30 psoriatic males aged between 18 and 54 was examined. The results were compared with those obtained from a group of 30 healthy age-matched males and they were correlated with the psoriasis area and severity index (PASI), the skin surface area involved, duration of the disease and duration of the last relapse. In neurological and ophthalmological examinations no pathological symptoms were detected in either group. The VEP examination was executed using pattern reversal (pr) and pattern flash (pf) stimulation. Results: Using pf stimulation, in the group of patients with psoriasis vulgaris, a statistically significant elongation in the latency of P-100 and reduction of response amplitude, not related to the PASI, nor the skin surface area involved, nor duration of the last relapse, were observed. Conclusions: The results of the study indicate subclinical damage of the visual pathway in patients with psoriasis vulgaris.  相似文献   
27.
Every year, a large number of individuals become dependent on mechanical ventilation because of a loss of diaphragm function. The most common causes are cervical spinal trauma and neuromuscular diseases. We have developed an experimental model to evaluate the performance of electrical stimulation of the diaphragm in rabbits using single-channel electrodes implanted directly into the muscle. Various current intensities (10, 16, 20, and 26 mA) produced tidal volumes above the baseline value, showing that this model is effective for the study of diaphragm performance at different levels of electrical stimulation  相似文献   
28.
29.
Journal of Thrombosis and Thrombolysis - According to guidelines, it is recommended to give P2Y12 inhibitors (preferably ticagrelor or prasugrel) at the time of first medical contact in patients...  相似文献   
30.
Clinical Rheumatology - One of the author’s name on this article was incorrectly spelled as “Sylvia C. L. Fahrat” . The correct spelling is “Sylvia C. L. Farhat” and...  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