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   3357篇
  免费   205篇
  国内免费   43篇
耳鼻咽喉   58篇
儿科学   76篇
妇产科学   77篇
基础医学   347篇
口腔科学   70篇
临床医学   245篇
内科学   1079篇
皮肤病学   20篇
神经病学   312篇
特种医学   110篇
外科学   586篇
综合类   7篇
预防医学   68篇
眼科学   25篇
药学   170篇
中国医学   21篇
肿瘤学   334篇
  2023年   19篇
  2022年   17篇
  2021年   92篇
  2020年   40篇
  2019年   56篇
  2018年   95篇
  2017年   70篇
  2016年   81篇
  2015年   103篇
  2014年   114篇
  2013年   152篇
  2012年   248篇
  2011年   242篇
  2010年   140篇
  2009年   121篇
  2008年   196篇
  2007年   236篇
  2006年   228篇
  2005年   221篇
  2004年   217篇
  2003年   216篇
  2002年   236篇
  2001年   38篇
  2000年   38篇
  1999年   24篇
  1998年   50篇
  1997年   43篇
  1996年   36篇
  1995年   44篇
  1994年   20篇
  1993年   27篇
  1992年   19篇
  1991年   20篇
  1990年   9篇
  1989年   8篇
  1988年   8篇
  1987年   7篇
  1986年   7篇
  1985年   13篇
  1984年   10篇
  1983年   4篇
  1982年   4篇
  1981年   4篇
  1980年   7篇
  1979年   2篇
  1978年   5篇
  1977年   4篇
  1976年   3篇
  1975年   3篇
  1969年   2篇
排序方式: 共有3605条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
5.
Whether germline (g) breast cancer susceptibility gene (BRCA) mutations are located within or outside the ovarian cancer cluster region (OCCR) (1380‐4062 bp for gBRCA1, and between 3249‐5681 bp and 6645‐7471 bp for gBRCA2) may influence risk variations for ovarian cancers. This ad hoc analysis of the CHARLOTTE epidemiological study in Japan assessed the distribution of gBRCA1/2 mutations in patients with newly diagnosed ovarian cancer, and investigated an association between gBRCA1/2 mutation locations and ovarian cancer risk. Differences in patient background and clinical characteristics in subgroups stratified by gBRCA1/2 mutation locations were also evaluated. We analyzed the data of 93 patients (14.7%) from the CHARLOTTE study who were positive for gBRCA1/2 mutations. After excluding 16 cases with L63X founder mutation, 28 (65.1%) of gBRCA1 mutations were within the OCCR. Of 30 gBRCA2 mutations, 15 (50.0%) were within the OCCR. Of 27 patients (one patient excluded for unknown family history) with gBRCA1 mutations located in the OCCR, 11 (40.7%) had a family history of ovarian cancer; the proportion of patients with a family history of ovarian cancer and gBRCA1 mutations outside the OCCR was lower (13.3%). Sixty percent of patients with gBRCA1 mutations outside the OCCR had a family history of breast cancer; the proportion of patients with a family history of breast cancer and gBRCA1 mutations within the OCCR was relatively lower (33.3%). Understanding the mutation locations may contribute to more accurate risk assessments of susceptible individuals and early detection of ovarian cancer among gBRCA mutation carriers.  相似文献   
6.
7.
Diffuse midline glioma, H3 K27M mutant arises from midline structures of the central nervous system and predominately affects pediatric patients. However, this disease entity was only recently established, and the clinical phenotypic spectrum remains largely unclear. We herein report a rare case of diffuse midline glioma, H3 K27M mutant with an unusual distribution in an elderly woman who presented with a diffuse glioma that invaded both sides of the thalami, and left hippocampus and frontoparietal lobes, thus mimicking a hemispheric malignant glioma. A biopsy of the lobular lesion led to a molecular diagnostic confirmation of diffuse midline glioma, H3 K27M mutant. The patient received concurrent bevacizumab and temozolomide therapy with radiation therapy and survived for 30 months. This case highlights the possibility that a glioma with cerebral hemispheric spread in an elderly patient may harbor the H3 K27M mutation.  相似文献   
8.
Here, we report a juvenile (18-year-old male) case of epilepsy-associated, isocitrate dehydrogenase wild-type/histone 3 wild-type diffuse glioma with a rare BRAF mutation and a focal atypical feature resembling diffuse astrocytoma. The patient presented with refractory temporal lobe epilepsy. Subsequently, magnetic resonance imaging revealed a hyperintense lesion in the right temporal lobe on fluid attenuated inversion recovery images. The patient underwent right lateral temporal lobectomy and amygdalohippocampectomy. Histopathologically, the tumor showed isomorphic, diffuse, infiltrative proliferation of glial tumor cells and intense CD34 immunoreactivity. The tumor cells were immunonegative for isocitrate dehydrogenase 1 (IDH1) R132H and BRAF V600E. Notably, the tumor cells showed the lack of nuclear staining for α-thalassemia/mental retardation syndrome, X-linked (ATRX). In addition, the Ki-67 labeling index, using a monoclonal antibody MIB-1, was elevated focally at tumor cells with p53 immunoreactivity. Molecular analyses identified a BRAFA598T mutation, the first case reported in a glioma. BRAFA598T is predicted to result in loss of kinase action; however, inactive mutants can stimulate mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK) signaling through CRAF activation. Thus, according to the recent update of the consortium to inform molecular and practical approaches to central nervous system tumor taxonomy (cIMPACT-NOW update 4), our case is also compatible with diffuse glioma with the mitogen-activated protein kinase (MAPK) pathway alteration. Thorough immunohistochemical and molecular studies are necessary for diagnosis of epilepsy-associated, diffuse gliomas. Partial resemblance in histopathological and molecular genetic features to diffuse astrocytoma also calls for attention.  相似文献   
9.
Background

Osimertinib is effective in patients with T790M mutation-positive advanced non-small-cell lung cancer (NSCLC) resistant to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). However, its effectiveness and safety in patients with poor performance status (PS) are unknown.

Methods

Enrolled patients showed disease progression after treatment with gefitinib, erlotinib, or afatinib; T790M mutation; stage IIIB, IV, or recurrent disease; and PS of 2–4. Osimertinib was orally administered at a dose of 80 mg/day. The primary endpoint of this phase II study (registration, jRCTs061180018) was response rate and the secondary endpoints were progression-free survival (PFS), overall survival (OS), disease control rate, and safety.

Results

Thirty-three patients were enrolled, of which 69.7% and 24.2% had PS of 2 and 3, respectively. One patient was excluded due to protocol violation; in the remaining 32 patients, the response rate was 53.1%; disease control rate was 75.0%; PFS was 5.1 months; and OS was 10.0 months. The most frequent adverse event of grade 3 or higher severity was lymphopenia (12.1%). Interstitial lung disease (ILD) was observed at all grades and at grades 3–5 in 15.2% (5/33) and 6.1% (2/33) of patients, respectively. Treatment-related death due to ILD occurred in one patient. Patients negative for activating EGFR mutations after osimertinib administration had longer median PFS than those positive for these mutations.

Conclusion

Osimertinib was sufficiently effective in EGFR-TKI-resistant, poor PS patients with T790M mutation-positive advanced NSCLC. Plasma EGFR mutation clearance after TKI treatment could predict the response to EGFR-TKIs.

  相似文献   
10.
Objective: To evaluate the frequencies of fetal facial expressions among appropriate-for-gestational-age (AGA), small-for-gestational-age (SGA), and growth-restricted (FGR) fetuses.

Methods: Four-dimensional (4D) ultrasound was used to examine the facial expressions of 50 AGA, 25 SGA, and six FGR fetuses between 28 and 35 weeks of gestation. The frequencies of seven facial expressions during 15-minute recordings were assessed. Comparison of facial expressions among the three groups was performed.

Results: Mouthing was the commonest facial expression at 28–35 weeks, and the frequency of mouthing was significantly higher than those of the other six facial expressions in AGA fetuses. Mouthing was the most frequent facial expression, but there was no significant difference in the frequency among mouthing, smiling and blinking in SGA fetuses. Moreover, mouthing displayed a significantly higher frequency than the other facial expressions, except for yawning, smiling, and blinking in FGR fetuses. However, there was no significant difference in the frequency of each facial expression among the three groups.

Conclusions: Our results suggest that the frequencies of fetal facial expressions are not decreased in either SGA or FGR pregnancies. The absence of a decrease in the frequency of each fetal expression in FGR fetuses may be due to increased brain blood flow because of the brain-sparing effect. Moreover, accelerated maturation and development of the brain function, especially the central dopamine system, might be suspected in SGA and FGR fetuses.  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