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   9952篇
  免费   610篇
  国内免费   80篇
耳鼻咽喉   63篇
儿科学   257篇
妇产科学   307篇
基础医学   1536篇
口腔科学   242篇
临床医学   815篇
内科学   2244篇
皮肤病学   233篇
神经病学   1035篇
特种医学   343篇
外科学   1000篇
综合类   54篇
一般理论   5篇
预防医学   800篇
眼科学   194篇
药学   667篇
中国医学   55篇
肿瘤学   792篇
  2024年   11篇
  2023年   107篇
  2022年   242篇
  2021年   362篇
  2020年   234篇
  2019年   280篇
  2018年   321篇
  2017年   244篇
  2016年   291篇
  2015年   329篇
  2014年   412篇
  2013年   494篇
  2012年   801篇
  2011年   826篇
  2010年   418篇
  2009年   406篇
  2008年   590篇
  2007年   656篇
  2006年   588篇
  2005年   600篇
  2004年   518篇
  2003年   429篇
  2002年   379篇
  2001年   77篇
  2000年   69篇
  1999年   83篇
  1998年   85篇
  1997年   69篇
  1996年   57篇
  1995年   61篇
  1994年   40篇
  1993年   54篇
  1992年   34篇
  1991年   37篇
  1990年   44篇
  1989年   30篇
  1988年   33篇
  1987年   36篇
  1986年   30篇
  1985年   25篇
  1984年   20篇
  1983年   18篇
  1982年   16篇
  1981年   14篇
  1980年   15篇
  1979年   21篇
  1978年   13篇
  1971年   13篇
  1969年   11篇
  1966年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
The retinal ganglion cell (RGC)-like RGC-5 line can be differentiated with staurosporine to stop dividing, extend neurites, and increase levels of several ganglion cell markers. This allows study of regulation of neurite development on a single cell basis. However, it is unclear whether the neurites induced by differentiation have features characteristic of dendrites or axons. To address this question, RGC-5 cells were differentiated with staurosporine and then immunoblotted for microtubule-associated protein 2 (MAP2) and actin, or stained immunocytochemically for different MAP2 isoforms, tau, growth-associated protein 43 (GAP-43), or the neuronal marker beta-III-tubulin. We found that staurosporine-induced differentiation led to an upregulation of MAP2c, a MAP2 isoform expressed in developing neurons. Some neurites expressed MAP2c but not the dendritic markers MAP2a and MAP2b, consistent with an axonal phenotype. Some neurites expressed the axonal marker tau in a characteristic proximal-to-distal gradient, and had GAP-43 labeling characteristic of axonal growth cones. The presence of MAP2c in differentiated RGC-5 cells is indicative of RGC-like neurite development, and the pattern of staining for the different MAP2 isoforms, as well as positivity for tau and GAP-43, indicates that differentiation induces axon-like and dendrite-like neurites.  相似文献   
93.
94.

The Sexual Inhibition Scales and Sexual Excitation Scales (Janssen et al., 2002a), based on the dual control model by Bancroft and Janssen (2000), are part of a 45-item self-report questionnaire evaluating individual tendencies to sexual inhibition or excitation according to three factors: two inhibition factors, SIS1, threat of performance failure, and SIS2, threat of performance consequences, and one excitation factor, SES. In this paper, we aimed to validate and explore psychometric properties of the SIS/SES in a sample of 2260 Italian men and women aged 18 to 75 years. Confirmatory factor analyses showed that the three-factor structure proposed in the original version of the scales fit with our sample. Moreover, our data confirmed the results of the original validation sample: Women scored higher on the SIS and lower on the SES than men did, but no significant differences appeared in the factor scores by age group, except for a gender × age interaction, where younger women had higher SIS2 scores. The SIS/SES appeared to be an effective, appropriate cross-cultural measurement of human sexuality in Italian samples, also shedding light on sexual arousal differences in women and men in our country. We also discuss clinical and therapeutic aspects.

  相似文献   
95.
We studied X-chromosome inactivation patterns in blood cells from normal females in three age groups: neonates (umbilical cord blood), 25–32 years old (young women group) and >75 years old (elderly women). Using PCR, the differential allele methylation status was evaluated on active and inactive X chromosomes at the human androgen receptor (HUMARA) and phosphoglycerate kinase (PGK) loci. A cleavage ratio (CR)  3.0 was adopted as a cut-off to discriminate between balanced and unbalanced X-chromosome inactivation. In adult women this analysis was also performed on hair bulbs. The frequency of skewed X-inactivation in polymorphonuclear (PMN) cells increased with age: CR  3.0 was found in 3/36 cord blood samples, 5/30 young women and 14/31 elderly women. Mathematical analysis of patterns found in neonates indicated that X-chromosome inactivation probably occurs when the total number of haemopoietic stem cell precursors is 14–16. The inactivation patterns found in T lymphocytes were significantly related to those observed in PMNs in both young ( P  < 0.001) and elderly women ( P  < 0.01). However, the use of T lymphocytes as a control tissue for distinguishing between skewed inactivation and clonal proliferation proved to be reliable in young females, but not in elderly women, where overestimation of the frequency of clonal myelopoiesis may appear.  相似文献   
96.
97.
98.
Introduction:The relationship between chronic empyema and malignant tumors, most of which are lymphoma, has been recognized for many decades. Sarcomatoid carcinoma associated with chronic empyema is extremely rare, may metastasize to other organs in the early stage, and rapidly progresses to death. As far as we know, this was the first case report on sarcomatoid carcinoma associated chronic empyema.The patient''s main concerns and important clinical findings:A 59-year-old man presented to our hospital with a 9-year history of chronic empyema and a chief complaint of left chest wall pain for 5 months. The diagnostic contrast-enhanced computed tomography (CT) showed a large irregular soft tissue mass located on the left lower hemithorax at the margin of the empyema cavity extending to the adjacent chest wall and lung parenchyma. In addition, CT revealed pleural and pulmonary metastases surrounded by ground glass opacity.The main diagnosis, therapeutics interventions, and outcomes:The patient underwent CT guided percutaneous core needle biopsy (PCNB). The histopathological evaluation showed carcinomatous proliferation of pleomorphic spindle cells with extensive necrosis. Immunohistochemically, tumor cells were positive for cytokeratin and vimentin. The final histopathological diagnosis was sarcomatoid carcinoma underlying chronic empyema. The tumors showed rapid progression on serial simple radiography. Palliative treatments were performed, but the patient still developed severe dyspnea and died shortly after on day 16.Conclusion:Sarcomatoid carcinoma can occur very rarely as a complication of chronic empyema, and is more aggressive than usual. Early detection of developing malignancy during the follow-up of chronic empyema is an important factor for patient prognosis.  相似文献   
99.
100.
Inflammation Research - Allergic rhinitis (AR) is characterized by typical symptoms that are dependent on inflammation. Poly-allergy is a frequent phenomenon. Phenotyping AR represents an...  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