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   27141篇
  免费   1365篇
  国内免费   150篇
耳鼻咽喉   278篇
儿科学   559篇
妇产科学   635篇
基础医学   3461篇
口腔科学   1044篇
临床医学   1949篇
内科学   7214篇
皮肤病学   916篇
神经病学   2030篇
特种医学   503篇
外科学   4385篇
综合类   174篇
一般理论   3篇
预防医学   1950篇
眼科学   442篇
药学   1479篇
中国医学   122篇
肿瘤学   1512篇
  2023年   208篇
  2022年   436篇
  2021年   962篇
  2020年   446篇
  2019年   902篇
  2018年   1046篇
  2017年   583篇
  2016年   597篇
  2015年   765篇
  2014年   1121篇
  2013年   1400篇
  2012年   2204篇
  2011年   2253篇
  2010年   1332篇
  2009年   1164篇
  2008年   1828篇
  2007年   1879篇
  2006年   1728篇
  2005年   1537篇
  2004年   1430篇
  2003年   1365篇
  2002年   1254篇
  2001年   179篇
  2000年   157篇
  1999年   188篇
  1998年   197篇
  1997年   150篇
  1996年   148篇
  1995年   126篇
  1994年   100篇
  1993年   84篇
  1992年   83篇
  1991年   69篇
  1990年   64篇
  1989年   45篇
  1988年   46篇
  1987年   38篇
  1986年   25篇
  1985年   40篇
  1984年   38篇
  1983年   40篇
  1982年   47篇
  1981年   45篇
  1980年   45篇
  1979年   18篇
  1978年   24篇
  1977年   26篇
  1975年   24篇
  1974年   23篇
  1973年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
921.
922.
923.
924.
925.
926.
The aim of this study was to assess morphometrically and histologically, the effects of light-emitting diode (LED) (λ630?±?20 nm) phototherapy on reepithelialization and wound contraction during tissue repair in hypothyroid rats. Thyroid hormone deficiency has been associated with disorders of tissue repair. LED phototherapy has been studied using several healing models, but their usefulness in the improvement of hypothyroidism wound healing remains unknown. Under general anesthesia, a standard surgical wound (1 cm2) was produced on the dorsum of 48 male Wistar rats divided into four groups of 12 animals each: EC—control euthyroid, ED—euthyroid + LED, HC—control hypothyroid, and HD—Hypothyroid + LED. The irradiation started immediately after surgery and was repeated every other day for 7 and 14 days. Photographs of the wound were taken at the day of the surgical procedure and on days 8 and 15 after surgery, when animals’ deaths occurred. The specimens were removed, routinely processed, and stained with hematoxylin/eosin. Seven days after the surgery, it was possible to observe statistically significant reductions in the wound area of the irradiated euthyroid group, in comparison to hypothyroid group, irradiated and non-irradiated (ANOVA, p?<?0.05). The reepithelialization was significantly higher in the euthyroid and hypothyroid groups irradiated with LED than in the non-irradiated groups (Fisher’s test, p?<?0.05). No significant difference was found in the experimental period of 14 days among the groups. The hypothyroidism delayed wound healing and the LED phototherapy, at these specific parameters, improved the process of reepithelialization in the presence of hypothyroidism.  相似文献   
927.
928.

Background

Recent evidence supports the use of robotic surgery for the minimally invasive surgical management of adrenal masses.

Objective

To describe a contemporary step-by-step technique of robotic adrenalectomy (RA), to provide tips and tricks to help ensure a safe and effective implementation of the procedure, and to compare its outcomes with those of laparoscopic adrenalectomy (LA).

Design, setting, and participants

We retrospectively reviewed the medical charts of consecutive patients who underwent RA performed by a single surgeon between April 2010 and October 2013. LA cases performed by the same surgeon between January 2004 and May 2010 were considered the control group.

Surgical procedure

The main steps of our current surgical technique for RA are described in this video tutorial: patient positioning, port placement, and robot docking; exposure of the adrenal gland; identification and control of the adrenal vein; circumferential dissection of the adrenal gland; and specimen retrieval and closure.

Outcome measurements and statistical analysis

Demographic parameters and main surgical outcomes were assessed.

Results and limitations

A total of 76 cases (RA: 30; LA: 46) were included in the analysis. Median tumor size on computed tomography (CT) was significantly larger in the LA group (3 cm [interquartile range (IQR): 3] vs 4 cm [IQR: 3]; p = 0.002). A significantly lower median estimated blood loss was recorded for the robotic group (50 ml [IQR: 50] vs 100 ml [IQR: 288]; p = 0.02). The RA group presented five minor complications (16.7%) and one major (Clavien 3b) complication (3.3%), whereas four minor complications (8.7%) and one major (Clavien 3b) complication (2.3%) were observed in the LA group. No significant difference was noted between groups in terms of malignant histology (p = 0.66) and positive margin rate (p = 0.60). Distribution of pheochromocytomas in the LA group was significantly higher than in the RA group (43.5% vs 16.7%; p = 0.02).

Conclusions

The standardization of each surgical step optimizes the RA procedure. The robotic approach can be applied for a wide range of adrenal indications, recapitulating the safety and effectiveness of open surgery and potentially improving the outcomes of standard laparoscopy.

Patient summary

In this report we detail our surgical technique for robotic removal of adrenal masses. This procedure has been standardized and can be offered to patients, with excellent outcomes.  相似文献   
929.
Disease recurrence occurs frequently after surgical treatment for squamous cell carcinoma of the penis (SCCp). We sought to determine prognostic factors that influence cancer-specific mortality (CSM) after disease recurrence in patients with SCCp. We performed a retrospective analysis of 314 patients who experienced disease recurrence after surgical treatment for SCCp between 1949 and 2012. Competing risk regression analysis addressed factors associated with CSM after SCCp recurrence. Median time from surgery to disease recurrence was 10.5 mo (interquartile range [IQR]: 5.9–21.3). Of the recurrences, 165 (53%), 118 (38%), and 31 (9.9%) were local, regional, or distant, respectively. Within a median follow-up of 4.5 yr (IQR: 2.0–6.5), 108 patients died of SCCp and 41 patients died of causes other than SCCp. Shorter time to disease recurrence was found to be significantly associated with a higher risk of CSM (p = 0.0006). Lymph node metastasis at the time of initial treatment (subdistribution hazard ratio [SHR]: 1.96; 95% confidence interval [CI] 1.23– 3.11; p = 0.005) and regional recurrence (SHR: 4.14; 95% CI, 2.16–7.93; p < 0.0001) or distant recurrence (SHR: 5.75; 95% CI, 2.59–12.73; p < 0.0001) were associated with increased risk of CSM after disease recurrence. Inclusion of time to recurrence into risk stratification may help patient counseling and treatment planning.  相似文献   
930.
Current micro–computed tomography (µCT) systems allow scanning bone at resolutions capable of three‐dimensional (3D) characterization of intracortical vascular porosity and osteocyte lacunae. However, the scanning and reconstruction parameters along with the image segmentation method affect the accuracy of the measurements. In this study, the effects of scanning resolution and image threshold method in quantifying small features of cortical bone (vascular porosity, vascular canal diameter and separation, lacunar porosity and density, and tissue mineral density) were analyzed. Cortical bone from the tibia of Sprague‐Dawley rats was scanned at 1‐µm and 4‐µm resolution, reconstructions were density‐calibrated, and volumes of interest were segmented using approaches based on edge‐detection or histogram analysis. In 1‐µm resolution scans, the osteocyte lacunar spaces could be visualized, and it was possible to separate the lacunar porosity from the vascular porosity. At 4‐µm resolution, the vascular porosity and vascular canal diameter were underestimated, and osteocyte lacunae were not effectively detected, whereas the vascular canal separation and tissue mineral density were overestimated compared to 1‐µm resolution. Resolution had a much greater effect on the measurements than did threshold method, showing partial volume effects at resolutions coarser than 2 µm in two separate analyses, one of which assessed the effect of resolution on an object of known size with similar architecture to a vascular pore. Although there was little difference when using the edge‐detection versus histogram‐based threshold approaches, edge‐detection was somewhat more effective in delineating canal architecture at finer resolutions (1–2 µm). In addition, use of a high‐resolution (1 µm) density‐based threshold on lower resolution (4 µm) density‐calibrated images was not effective in improving the lower‐resolution measurements. In conclusion, if measuring cortical vascular microarchitecture, especially in small animals, a µCT resolution of 1 to 2 µm is appropriate, whereas a resolution of at least 1 µm is necessary when assessing osteocyte lacunar porosity. © 2014 American Society for Bone and Mineral Research.  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