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   1029篇
  免费   46篇
  国内免费   1篇
耳鼻咽喉   23篇
儿科学   25篇
妇产科学   24篇
基础医学   164篇
口腔科学   17篇
临床医学   50篇
内科学   135篇
皮肤病学   11篇
神经病学   148篇
特种医学   125篇
外科学   218篇
综合类   12篇
预防医学   41篇
眼科学   2篇
药学   40篇
中国医学   2篇
肿瘤学   39篇
  2021年   7篇
  2019年   7篇
  2018年   10篇
  2017年   6篇
  2016年   12篇
  2015年   16篇
  2014年   15篇
  2013年   22篇
  2012年   39篇
  2011年   33篇
  2010年   36篇
  2009年   35篇
  2008年   41篇
  2007年   52篇
  2006年   53篇
  2005年   35篇
  2004年   27篇
  2003年   34篇
  2002年   46篇
  2001年   32篇
  2000年   39篇
  1999年   39篇
  1998年   25篇
  1997年   21篇
  1996年   22篇
  1995年   13篇
  1994年   13篇
  1993年   14篇
  1992年   28篇
  1991年   16篇
  1990年   19篇
  1989年   11篇
  1988年   16篇
  1987年   20篇
  1986年   24篇
  1985年   19篇
  1984年   7篇
  1983年   14篇
  1982年   9篇
  1981年   8篇
  1980年   14篇
  1979年   11篇
  1978年   8篇
  1977年   15篇
  1976年   10篇
  1975年   11篇
  1971年   6篇
  1970年   6篇
  1969年   6篇
  1968年   7篇
排序方式: 共有1076条查询结果,搜索用时 15 毫秒
61.
BACKGROUND: In patients with head and neck squamous cell carcinoma (HNSCC), the presence of lymph node metastases is the most important prognosticator. Sentinel node (SN) biopsy has been shown to be an accurate staging technique for patients with breast cancer and melanoma and might also be suited for patients with HNSCC. This study was undertaken to determine whether the SN concept holds true for HNSCC and could be exploited for SN biopsy. METHODS: In 22 patients with T2 to T4 N0 oral or oropharyngeal squamous cell carcinoma (SCC) who were scheduled to undergo combined primary tumor excision and elective unilateral (n = 17) or bilateral (n = 5) neck dissection, SN identification was performed the day before surgery by use of lymphoscintigraphy after peritumoral injections of 99mTc-labeled colloidal albumin. After the neck dissection specimens were removed, all SNs, all other radioactive lymph nodes, and all nonradioactive lymph nodes were retrieved for histopathologic analysis, including serial sectioning at 250-microm intervals and immunohistochemical analysis (IHC). RESULTS: Overall, in 21 (78%) of 27 neck sides, an SN was identified by scintigraphy. Of the six neck sides in which SNs were not identified by scintigraphy, four were from three patients who underwent bilateral neck dissection. In another patient treated by bilateral neck dissection, the SN identified by scintigraphy could not be found in the specimen. In the remaining 20 neck dissection specimens, 23 SNs and 30 additional radioactive lymph nodes could be found. At histologic examination of the 20 neck specimens in which the SN was found, at least one SN was tumor positive in eight cases. In one neck specimen, a metastasis was detected in a nonradioactive lymph node, whereas the SN was tumor free, also at serial sectioning and IHC. In the remaining 11 neck sides in which the SN was tumor negative, none of the other radioactive (n = 13) and none of the nonradioactive (n = 279) lymph nodes contained tumor at histopathologic analysis, including serial sectioning and IHC. The sensitivity of the SN procedure for predicting lymph node metastases, therefore, was 89% (eight of nine neck specimens) when an SN was identified by scintigraphy and found in the specimen. The overall accuracy of the SN procedure for predicting the presence or absence of lymph node metastases in the neck was 95% (19 of 20 neck specimens). CONCLUSIONS: Our study seems to validate the SN hypothesis for oral and oropharyngeal cancer. The role of SN biopsy in the management of the N0 neck in such patients has yet to be established through prospective trials. SN identification (and thus biopsy) does not seem to be reliable in patients with tumors located in or close to the midline.  相似文献   
62.
Cardiopulmonary function is a determinant of the utmost importance in thoracic surgery. A large battery of tests is available, however, only a relatively limited part of it is obligatory. The essential procedures include testing of global ventilation (inspiratory vital capacity, FEV1), relation of lung volumes (residual volume) and regional quantitation of perfusion (scan). Other costly and invasive tests can be regarded as complementary. This is true in planned lung resection for cancer, where the indication for surgery is of vital importance. Other types of thoracic surgery need a more precise evaluation of risk factors balanced against the expected general improvement of cardiopulmonary function, as in cardiac surgery, decortication, and resection of bullae. But since thoracic surgery is practised mainly for the purpose of lung resection with ensuing loss of function, major attention is paid to this field in order to avoid inconclusive but costly testing, and to discuss indication and use of involved technique in high-risk patients.  相似文献   
63.
In 16 patients with severe chest injuries the pulmonary function was evaluated as early as possible. Special emphasis was laid upon the basic criteria for the indication of an early decortication in cases of organized hematothorax. A follow-up study of ten patients, who were treated conservatively and of six patients, who underwent decortication, showed that the inspiratory and exspiratory reserve volume and the compliance of the lung were the most reliable criteria. They showed, if a traumatic disturbance of the lung function was reversible or irreversible. It seems that patients improve faster after decortication. If, however, signs of a quick spontaneous recovery of the lung function is seen, there is no indication for surgery.  相似文献   
64.
Severe hypoxaemia was present in four patients with instability of the traumatised chest. After operative correction of the instability there was a spontaneous normalization of pO2 in 3 patients without the need of artificial ventilation. In one patient with preexisting broncho-pulmonary disease, a brief period of controlled ventilation resulted in an even more rapid normalization of blood-gas values. Due to operative correction of chest instability after severe trauma, the need for artificial ventilation seems to be greatly diminished.  相似文献   
65.
OBJECTIVE: The purpose of this study was to compare anticipatory and postprocedure pain perception in female patients who undergo multichannel urodynamic evaluation in an office setting. STUDY DESIGN: One hundred consecutive patients completed a visual analogue pain scale before and after urodynamic testing. RESULTS: The mean postprocedure pain score of 2.32 cm was significantly lower than the anticipatory pain rating of 4.35 cm (P<.05). The lower postprocedure pain score was not influenced by previous hysterectomy, body mass index, menopausal status, estrogen replacement therapy, or analgesic or psychiatric medication usage. Patients who had undergone previous anti-incontinence surgery reported significantly higher levels of pain during the procedure (mean visual analogue pain scale score, 3.10 cm vs 2.06 cm; P=.027). CONCLUSION: Patients who undergo urodynamic testing anticipate higher degrees of discomfort than they perceive during the procedure. Previous anti-incontinence surgery appears to lower the pain threshold.  相似文献   
66.
In order to measure errors in pin positions, a tibia with referenced pin insertions was radiographed in various locations using a mini C-arm. Changes in pin position locations up to seven millimeters and twelve degrees were found. To minimize these errors, limbs should be centered and parallel to the plane of the imaging screen of the C-arm. If possible, pin insertions should be made in this plane. Magnification due to the distance from the screen should be determined for precise pin positioning.  相似文献   
67.
OBJECTIVES: The anterior curvature of the femur affects intramedullary nail insertion, revision prosthesis design, and the biomechanics of the proximal femur. Two previous studies, using small numbers of femurs, determined femoral curvature and showed that it was significantly greater than that of the several intramedullary nails they evaluated. In this study, the curvature of 948 femurs (474 matched pairs) was determined and compared with current intramedullary nails. The correlation of femoral curvature to age, gender, femoral size, and race was also evaluated. SETTING: Museum skeletal collections and a hospital biomechanics laboratory. METHODS: The curvature of 892 femurs (446) from the skeletal collections of 2 museums was measured by processing the digital images of the femurs with a computer curve-fitting program. Fifty-six additional, embalmed femurs (28 pairs) from our collection were also digitally imaged and then radiographed and their medullary curvatures similarly determined for comparison. Curvatures of 8 current antegrade intramedullary nails and 3 long-stemmed femoral hip prostheses were obtained from manufacturers and confirmed by measurements from their templates after digitization. RESULTS: We found the average femoral anterior radius of curvature was 120 cm (+/- 36 cm). There was no effect of age on femoral curvature nor was there a correlation between femoral width or femoral length to curvature. Black donor femurs had less curvature than white donor femurs (P < 0.001). There was close correlation (r = 0.967) between the femoral curvatures determined from the digital images and the radiographs. Radii of curvature of the intramedullary nails ranged from 186 to 300 cm (eg, straighter than the femurs). CONCLUSIONS: There was a large mismatch between the curvature of some current antegrade intramedullary nails and the average femur. Although this is only 1 factor affecting nail insertion, the mismatch warrants a reappraisal of these intramedullary nail designs. CLINICAL RELEVANCE: Because ease of intramedullary nail insertion and possibility of cortical comminution are determined by a number of factors including insertion point and fracture location, it appears that a decrease in radii of curvature (less straight) of current nail designs is warranted, particularly for those larger diameter nails designed for hip fracture stabilization that have greater rigidity due to design or material.  相似文献   
68.
69.
70.
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