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   1875篇
  免费   84篇
  国内免费   17篇
耳鼻咽喉   7篇
儿科学   37篇
妇产科学   43篇
基础医学   277篇
口腔科学   96篇
临床医学   102篇
内科学   529篇
皮肤病学   6篇
神经病学   107篇
特种医学   65篇
外科学   344篇
综合类   2篇
预防医学   34篇
眼科学   20篇
药学   71篇
肿瘤学   236篇
  2023年   13篇
  2022年   21篇
  2021年   43篇
  2020年   29篇
  2019年   48篇
  2018年   44篇
  2017年   30篇
  2016年   55篇
  2015年   61篇
  2014年   70篇
  2013年   71篇
  2012年   140篇
  2011年   139篇
  2010年   84篇
  2009年   62篇
  2008年   119篇
  2007年   113篇
  2006年   101篇
  2005年   122篇
  2004年   120篇
  2003年   110篇
  2002年   107篇
  2001年   21篇
  2000年   16篇
  1999年   21篇
  1998年   21篇
  1997年   13篇
  1996年   18篇
  1995年   17篇
  1994年   14篇
  1993年   18篇
  1992年   23篇
  1991年   10篇
  1990年   15篇
  1989年   9篇
  1988年   10篇
  1987年   7篇
  1986年   7篇
  1985年   2篇
  1984年   2篇
  1983年   4篇
  1982年   6篇
  1981年   2篇
  1979年   3篇
  1977年   2篇
  1976年   2篇
  1972年   2篇
  1968年   1篇
  1938年   2篇
  1937年   1篇
排序方式: 共有1976条查询结果,搜索用时 15 毫秒
21.
The periodic structure of 24-hour blood pressure variation(circadian rhythm of blood pressure by ambulatory blood pressure monitoring(ABPM) in hypertensive CAPD patients was investigated by a new method of analysis based upon the maximum entropy method(MEM). In addition, this method allows the adequacy of antihypertensive therapies to be evaluated in such patients. The results were as follows; 1) The frequency of non-dipper type hypertension was 88%(36/41 cases), and the remaining 12% (5/41) were dipper type hypertension patients. The rise in morning blood pressure(morning surge: MS) was noted in 64% of the former. 2) Night time systolic blood pressure(182 +/- 22 mmHg, n = 36) was higher in patients with non-dipper type hypertension than in those with the dipper type(151 +/- 17 mmHg, n = 5, p < 0.01). 3) The standardized level of systolic blood pressure(SLSBP) calculated by MEM analysis in patients with non-dipper type hypertension(177 +/- 7 mmHg) was comparable with that in those with dipper type hypertension(168 +/- 13 mmHg, ns). 4) Treatment with long-acting Ca antagonist alone significantly reduced both SLSBP and the area over the SLSBP from 188 +/- 18 mmHg to 160 +/- 7 mmHg(p < 0.01, n = 8), and area over the SLSBP from 2,735 +/- 340 mmHg.hr to 1,945 +/- 298 mmHg.hr(p < 0.01, n = 8). 5) In addition to long-acting Ca antagonist, administration of alpha 1-blocker given at bed time was significantly efficacious in reducing the rise in morning blood pressure, MS. The present study using MEM analysis of ABPM suggests that the blood pressure profile of hypertensive CAPD patients is characterized by a non-dipper type dominance and a frequent morning surge. Furthermore, the combined therapy with long-acting Ca antagonist and alpha 1-blocker was substantially effective both in reducing the overall blood pressure level, and in inhibiting the MS. This combined antihypertensive therapy may be potentially useful to prevent CAPD patients from the future development of cardiovascular complications.  相似文献   
22.
23.
We report a case of pineal parenchymal tumor (PPT) in an 11-year-old girl. Brain magnetic resonance imaging (MRI) revealed a large tumor (48?mm) located in the pineal region with heterogeneous enhancement after gadolinium administration. The patient underwent tumor removal with craniotomy; only partial tumor resection could be performed because of massive intratumoral bleeding. Histopathological examination of the tumor showed lobular proliferation of round cells with moderate atypia. Cellularity varied by area, and focal Homer Wright rosettes were identified. Examination of tumor cells revealed a few mitoses (two mitotic figures per 10 high-powered fields), and immunohistochemical staining revealed positivity for synaptophysin, slight positivity for neurofilament protein (NFP) with antibody clone 2F11, and strong positivity for NFP with clone NF-M+H. The pathological diagnosis was pineal parenchymal tumor of intermediate differentiation grade II according to World Health Organization criteria despite a high (22%) MIB-1 labeling index (LI). The patient had a favorable clinical course after an intensified chemotherapy regimen designed for pineoblastoma and radiotherapy administered to the entire neuraxis, followed by stereotactic radiotherapy. In conclusion, MIB-1 LI could be a useful tool for deciding therapeutic strategies for PPT treatment when there is a discrepancy between clinical findings and pathological grading.  相似文献   
24.
25.
26.
Higuchi  Tadashi  Ozawa  Soji  Koyanagi  Kazuo  Ninomiya  Yamato  Yatabe  Kentaro  Yamamoto  Miho  Tajima  Kohei  Nomura  Takakiyo  Niwa  Tetsu 《Esophagus》2021,18(4):764-772
Purpose

The study aimed to evaluate the usefulness of prone-position computed tomography (CT) for predicting relevant thoracic procedure outcomes in minimally invasive esophagectomy (MIE) for thoracic esophageal cancer.

Materials and methods

A total of 59 patients underwent esophagectomy between May 2019 and December 2020 in Tokai University Hospital. Preoperative CT imaging was conducted with the patient in both the supine and prone positions, and the magnitude of change in the intramediastinal space was calculated. In the 56 patients (94.9%) who had undergone MIE, the effects of such a difference on the surgical outcomes were analyzed.

Results

A significant correlation of the magnitude of change in VE (distance between ventral aspect of the vertebral body and the midpoint of the esophagus) with the surgical outcome was revealed in the 17 patients (30.4%) in whom the magnitude of change in VE was over the 75th percentile. That is, in this subgroup, the magnitude of change in VE showed a negative correlation with the thoracic operation time (rs?=???0.57, p?=?0.01) and blood loss during the thoracic procedure (rs?=???0.46, p?=?0.01). Multivariate analysis identified a magnitude of change in VE?≥?9 mm (OR?=?0.14, p?=?0.03) as an independent risk factor for postoperative pneumonia.

Conclusions

This study indicates that preoperative prone-position CT imaging is useful for predicting the level of ease or difficulty of securing an adequate operative field, surgical outcomes, and the risk of postoperative pneumonia in MIE.

  相似文献   
27.
28.
29.
A significant increase in the CD38(+) population among T lymphocytes has been observed in human immunodeficiency virus type 1 (HIV-1)-infected carriers. We previously reported a higher replication rate of T-tropic HIV-1 in the CD4(+)CD38(+)CD62L(+) than CD38(-) subset under conditions of mitogen stimulation after infection. Here, we revealed a similarly high susceptibility in the CD38(+) subset on culture with conditioned medium containing Th2 cytokine, interleukin (IL)-4 that was produced endogenously from this subset on stimulation with mitogen or anti-CD3 antibody for 3 days. The contribution of IL-4 to the upregulated production of virus in the CD38(+) subset was confirmed by culture of this subset with recombinant human IL-4. In contrast, the rate of replication in the CD38(-) subset was not augmented in the conditioned medium from either subset or with IL-4. However, there were no differences in the surface expression of IL-4 receptor or HIV-1 receptors CD4 and CXCR4 between the two subsets. Thus, the CD4(+)CD38(+)CD62L(+) subset comprises a specific cell population secreting endogenous Th2 cytokine that contributes to the efficient production of T-tropic HIV-1 through upregulation at a certain stage of the viral life cycle, probably after the adsorption step.  相似文献   
30.
The cornea is sensitive to nociceptive stimuli and receives dense sensory innervations from the trigeminal ganglion, which also innervates the upper eyelid. We investigated the morphological and immunohistochemical characterization of the trigeminal ganglion neurons innervating the cornea and upper eyelid. We injected the retrograde tracer Fluoro-Gold (FG) into the cornea and the retrograde tracer cholera toxin subunit b (CTb) into the upper eyelid of the same animal. Less than 10% of the FG-labeled neurons were also labeled with CTb. The FG-labeled neurons were small (29.6 ± 0.6 μm), while the CTb-labeled neurons were large (36.1 ± 0.5 μm). We also characterized the neurons in the trigeminal ganglion with the retrograde tracer FG following its injection into the cornea or the upper eyelid, and immunohistochemical double-labeling with nociception-related neuronal markers, such as calcitonin gene-related peptides (CGRP), transient receptor potentiated vanilloid 1 (TRPV1), and substance P (SP). About 27% of the neurons innervating the cornea were double-labeled with CGRP, about 23% with TRPV1, and about 8% with SP. About 4% of the neurons innervating the upper eyelid were double-labeled for CGRP, about 11% for TRPV1, and 3% for SP. Thus, the percentages of double-labeled neurons for the neurons innervating the cornea were higher than those for the neurons innervating the upper eyelid. These results indicate that the cornea and the upper eyelid receive innervations mainly from different neurons of the trigeminal ganglia. The cornea is innervated by many characteristic sensory neurons containing nociception-related neuronal markers.  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