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   6577篇
  免费   490篇
  国内免费   24篇
耳鼻咽喉   82篇
儿科学   149篇
妇产科学   100篇
基础医学   943篇
口腔科学   164篇
临床医学   638篇
内科学   1551篇
皮肤病学   85篇
神经病学   657篇
特种医学   261篇
外科学   1023篇
综合类   59篇
一般理论   5篇
预防医学   366篇
眼科学   131篇
药学   334篇
中国医学   8篇
肿瘤学   535篇
  2023年   60篇
  2022年   101篇
  2021年   187篇
  2020年   134篇
  2019年   167篇
  2018年   199篇
  2017年   148篇
  2016年   163篇
  2015年   197篇
  2014年   264篇
  2013年   330篇
  2012年   524篇
  2011年   503篇
  2010年   325篇
  2009年   259篇
  2008年   467篇
  2007年   445篇
  2006年   391篇
  2005年   384篇
  2004年   314篇
  2003年   308篇
  2002年   268篇
  2001年   56篇
  2000年   40篇
  1999年   55篇
  1998年   49篇
  1997年   37篇
  1996年   40篇
  1995年   45篇
  1994年   30篇
  1993年   41篇
  1992年   32篇
  1991年   32篇
  1990年   29篇
  1989年   32篇
  1988年   39篇
  1987年   34篇
  1986年   25篇
  1985年   22篇
  1984年   28篇
  1983年   27篇
  1982年   28篇
  1981年   26篇
  1980年   13篇
  1979年   21篇
  1978年   16篇
  1975年   12篇
  1974年   17篇
  1973年   13篇
  1972年   13篇
排序方式: 共有7091条查询结果,搜索用时 15 毫秒
941.
INTRODUCTION: Controversy continues about the mere existence of the celiac artery compression syndrome. Earlier results of treatment of unselected patients groups showed varying, mostly disappointing, results. The recently introduced gastric exercise tonometry test is able to identify patients with actual gastrointestinal ischemia. We prospectively studied the use of gastric exercise tonometry as a key criterion for revascularization treatment in patients with otherwise unexplained abdominal complaints and significant stenosis of the celiac artery by compression of the arcuate ligament. METHODS: Patients were prospectively selected using abdominal artery angiography and gastric exercise tonometry. Patients with a significant compression of the celiac artery, typical abdominal complaints, and abnormal tonometry were considered for revascularization. RESULTS: Over a 7-year period, 43 patients with significant celiac artery compression were included in this study, and 30 patients were diagnosed as ischemic. Twenty-nine patients had revascularization, 22 (76 %) had a trunk release only. After a median follow-up of 39 months, 83% of patients were free of symptoms. The repeated tonometry after treatment improved in 100% of patients free of symptoms, compared with 25% in patients with persistent complaints after revascularization. CONCLUSIONS: The results of this study suggest that the celiac axis compression syndrome exists and that the actual ischemia can be detected by gastric exercise tonometry and treated safely, with success.  相似文献   
942.
Purpose This study was designed to evaluate the diagnostic accuracy of serum procalcitonin (PCT) for the diagnosis of severity in acute pancreatitis (AP), compared with routine clinical, biochemical, radiological, and combination severity scoring systems. Methods Quantitative meta-analysis was performed on prospective studies, comparing serum PCT, against validated scoring systems for diagnosing severe AP. The sensitivity, specificity, and diagnostic odds ratio were calculated for each study. Summary receiver operating characteristic (SROC) curves and subgroup analysis were undertaken. Study quality and heterogeneity were evaluated. Meta-regression meta-analysis was used to evaluate the effect of using serum PCT in the diagnostic accuracy severity scoring in AP. Results Summary receiver operating characteristic analysis of nine studies showed an overall sensitivity and specificity of 74% (range: 66%–81%) and 83% (range: 79%–87%), respectively. Overall unweighted area under the curve (AUC) was 0.91 (DOR = 16.26 95% CI: 5.68–46.60), demonstrating significant heterogeneity (Q-value = 25.32; P = 0.001). When high-quality studies alone were evaluated, there was an increase in the overall sensitivity (89%); however, specificity was similar (82%), with an overall unweighted AUC of 0.94 (DOR 41.46, 95% CI: 17.95–95.80), with no significant heterogeneity. Meta-regression analysis confirmed the significant effect of study quality on the diagnostic accuracy of severity scoring using serum PCT (P = 0.025). Conclusions The use of PCT for severity scoring in AP has a moderate sensitivity but higher specificity. However, the overall accuracy for predicting severity in AP is high. The prognosis of severity, especially early on (<48 hours from onset of symptoms), and the evaluation of potential infectious complications of AP may be the most useful factors to assess in subsequent clinical trials to identify its exact application in clinical practice in the management of AP.  相似文献   
943.
OBJECTIVE: To investigate and compare patterns of practice in prostate cancer management in Australia and New Zealand from 1995 to 2000, as there are insufficient randomized trials to guide clinicians in the management of prostate cancer. SUBJECTS AND METHODS: This study represents the two largest published surveys of Australian and New Zealand clinicians dealing with prostate cancer. We sent structured questionnaires on the management of prostate cancer patients to 804 urologists, radiation oncologists and medical oncologists in Australia and New Zealand in December 2000. We compared responses to a similar survey of 579 specialist clinicians in 1995. RESULTS: The response rates were 56% in 1995 and 62% in 2000. In the management of clinically localized disease, the proportion recommending surgery or radiotherapy remained relatively constant between 1995 and 2000, although there was an increase in the use of brachytherapy and adjuvant hormonal therapy, and a reduced tendency to treat pelvic nodes. In the treatment of locally advanced disease, there was an increased use of hormonal treatment and local radiotherapy, with a reduction in the use of total androgen blockade and orchidectomy. In managing positive margins after prostatectomy, there was a clear lack of consensus, with a wide variety of treatment options proposed. CONCLUSIONS: Practice has changed in several areas in 2000 compared to 1995, but not all changes were influenced by the publication of randomized trials or evidence-based guidelines.  相似文献   
944.
Diabetic foot ulceration and gangrene are preventable long-term complications of diabetes mellitus. This cross-sectional study was conducted to evaluate the impact of secondary foot complications on hospital admission and activities of the diabetes service of Yaoundé Central Hospital (YCH). A total of 207 patient files were included in this study, the period of which was from November 1999 to October 2000, 1 year of activity of the inpatient department of the Diabetes and Endocrine Unit of YCH. General characteristics of the patients were considered, the reason for their admission, the duration of their hospitalization in the service, and the outcome. The diabetic foot problem was the second most common cause of hospital admission in 27 (13%) patients. Secondary foot complication was the associated cause of mortality in 19.3% of cases of death (6 out of 31) in this study. The highest duration of hospitalization was recorded in patients with foot problems (29.4+/-5.4 days), the finding being statistically significant. Foot problems accounted for 0.25% of bed occupancy for the selected period. Five patients underwent amputation because of foot problems. A high rate of hospital discharge upon request was recorded among patients with foot problems (25% of the cases). This study suggests that diabetic foot is the second biggest cause of hospital admission in this setting; however, it is the main cause of prolonged hospital stay and bed occupancy.  相似文献   
945.
946.
Pulmonary hamartoma is a benign neoplasm that rarely recurs or undergoes malignant transformation. Herein, we report a 48-year-old woman with a history of an incomplete excised nonchondroid pulmonary hamartoma presenting as an indolent tumor recurrence. Excision of the tumor revealed a well-differentiated liposarcoma arising from the hamartomatous component. Fluorescence in situ hybridation analysis for HMGA2 and MDM2 was performed on both hamartomatous and liposarcomatous component. MDM2 and HMGA2 amplification were found in a subset of stromal cells in the hamartomatous component and in most cells of the well-differentiated liposarcoma. No rearrangement HMGA2 was found in the pulmonary hamartoma component. These findings suggest that the formation of the 12q14-q15 chromosome amplicon, the characteristic cytogenetic finding of well-differentiated liposarcomas and the structural genomic component of the supernumerary ring and giant rod chromosomes, occurred before the morphologic changes characteristic of these malignant adipose tissue tumors and likely represents a very early molecular event in their development.  相似文献   
947.
Objective: This study aims at combined surgical therapy options concerning patients with a clinically relevant and long-established capsular contracture following subglandular breast augmentation in a glandular ptotic breast. Methods: This is a review of 23 patients with capsular contracture. Three patients had a revision surgery for capsular contracture and implant dislocation before. The mean implant duration in the case of the twenty patients without any previous revision was 96 months. A revision implant has been re-located in a dual-plane position and further corrective surgery was carried out to adapt the glandular ptotic breast. Between 2001 and 2003, a chart review was performed on all patients for capsular contracture and ptotic breast by using the technique presented in this study. Results: In each case, the operation was performed as a one-stage procedure. The procedure included the following steps: Removal of the implant and total capsulectomy, preparation of an inferior de-epithelialised skin pedicle above the inframammary crease, release of the inferior origins of the pectoralis major muscle, creation of a new implant pocket by continuous connection of the inferior muscle border with the cranial edge of the inferior skin pedicle (dual-plane), adaptation of the soft-tissue/skin envelope by closing the cranial V over the implant coverage, preservation of the areola by creating a cranial or cranial medial pedicle. There was a follow-up for a period of up to 48 months, and any complication that occurred was documented. At follow-up period, all patients who had been implanted with a new implant pocket were free of a clinically relevant capsular contracture. Conclusions: In the cases of a severe capsular contracture and glandular-ptotic breasts, we presented the surgical corrections of the parenchyma/skin envelop as a one-stage procedure following the establishment of a new implant pocket.  相似文献   
948.
Oxidized regenerated cellulose (ORC) is widely used to cover the denuded mesothelium and to promote hemostasis. We evaluated ORG in a rabbit model to assess the potential for adhesion reduction after uterine trauma and intestinal anastomosis. After surgery, a second laparotomy was done on postoperative day 7 for macroscopic evaluation of adhesion formation. The traumatized uterine horns wrapped in ORC had more numerous and higher grade adhesions compared with the non-surgical left, intact horns. However, when compared to the contralateral uterine horn which underwent trauma without ORG, a significant decrease in the grade of adhesion formation was noted. Rabbits undergoing intestinal anastomosis had the most pronounced degree of adhesion formation. Typically, the area of healing was encapsulated in a fibrin clot with adhesions attached to adjacent viscera. When ORC remained between the lesion and adjacent organs during mesothelial regeneration, adhesion formation decreased. However, the soft, gelatinous mass of ORC was also an effective nidus for clot formation. Where post-and intra-operative ooze produced a fibrin clot in the ORC, dense adhesions formed.  相似文献   
949.
950.
Two messenger specific factors, phosphocellulose fractions 3 and 4, have been isolated from the initiation factor 3 fraction of red muscle initiation factors by chromatography on phosphocellulose. When added to a reticulocyte cell-free system containing both myoglobin and myosin mRNAs, phosphocellulose fraction 3 is found to specifically stimulate the synthesis of myoglobin while phosphocellulose fraction 4 is found to specifically stimulate the synthesis of myosin. In addition, a new RNA, isolated from the initiation factor 3 fraction, is shown to specifically inhibit the translation of heterologous mRNAs.  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