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   16011篇
  免费   1301篇
  国内免费   389篇
耳鼻咽喉   155篇
儿科学   362篇
妇产科学   320篇
基础医学   1606篇
口腔科学   208篇
临床医学   1468篇
内科学   2431篇
皮肤病学   327篇
神经病学   802篇
特种医学   878篇
外国民族医学   8篇
外科学   3675篇
综合类   2001篇
现状与发展   1篇
一般理论   1篇
预防医学   390篇
眼科学   131篇
药学   621篇
  13篇
中国医学   151篇
肿瘤学   2152篇
  2024年   28篇
  2023年   287篇
  2022年   549篇
  2021年   741篇
  2020年   745篇
  2019年   615篇
  2018年   674篇
  2017年   576篇
  2016年   659篇
  2015年   583篇
  2014年   1020篇
  2013年   1042篇
  2012年   784篇
  2011年   849篇
  2010年   720篇
  2009年   759篇
  2008年   764篇
  2007年   770篇
  2006年   668篇
  2005年   603篇
  2004年   542篇
  2003年   440篇
  2002年   393篇
  2001年   316篇
  2000年   236篇
  1999年   208篇
  1998年   213篇
  1997年   208篇
  1996年   210篇
  1995年   168篇
  1994年   146篇
  1993年   122篇
  1992年   119篇
  1991年   118篇
  1990年   102篇
  1989年   88篇
  1988年   75篇
  1987年   61篇
  1986年   55篇
  1985年   82篇
  1984年   55篇
  1983年   38篇
  1982年   46篇
  1981年   43篇
  1980年   41篇
  1979年   34篇
  1978年   29篇
  1977年   29篇
  1976年   15篇
  1973年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
目的 探讨深插胃镜对十二指肠乳头以下病变的诊断价值。方法 回顾性分析行胃镜检查[深插至十二指肠空肠曲(屈氏韧带附近)]的320例患者的临床资料、操作方法及检查结果。结果 320例患者中,深插至十二指肠升部成功率为93.12%,其中最多可以观察到十二指肠空肠以下8~10cm,所用时间约3~15min,发现十二指肠降部及以下病变85例。结论 深插胃镜对十二指肠乳头以下部位病变具有较好的诊断及治疗价值。  相似文献   
32.
本文介绍了44例经皮肺活检的经验,40例诊断正确,占90.9%;气胸发生率6.8%,作者认为 Menghini 针具有操作简单,无气栓发生,更换注射器方便等优点。同时对导向的选用及穿剌方法的改进也做了介绍。  相似文献   
33.
超声引导下VacoraTM旋切系统的实验研究   总被引:1,自引:0,他引:1  
目的探讨VacoraTM真空辅助活检系统的准确性和安全性,为临床应用奠定基础。方法选用里脊肉和鱼丸作为实验材料,根据鱼丸大小将实验分为5组:0.5、0.8、1.0、1.5及2.0cm组,每组鱼丸3~5个。采用VacoraTM活检系统,先行灰阶超声扫查肌肉后将鱼丸置入肌肉中,超声扫查置入的鱼丸,同轴套管针在超声引导下插入鱼丸底部,在套管针引导和超声监视下行旋切真空抽吸术;旋切后取出采样腔内的组织标本,用超声检查肌肉内的残腔,确定无鱼丸残留声像图。结果每次旋切组织条比较完整,其大小为20.0mm×0.6mm,旋切次数随鱼丸大小的增加而增加;0.5、0.8、1.0、1.5及2.0cm组里脊肉内鱼丸全部切除的平均旋切次数分别为12、15、19、26和31。所用的平均时间分别为15、18、23、27和34min。结论VacoraTM真空辅助活检系统定位准确、取样完整、操作简便。可为良恶性病变的诊断提供足够量的病理检查标本,为良性病变的完全切除提供具有潜在价值的手段。  相似文献   
34.
Tacrolimus has a narrow therapeutic window and is characterized by a large inter-individual variability in bioavailability. The impact of tacrolimus exposure on subclinical evolution of graft histology has not been studied in renal recipients. This analysis included 239 protocol biopsies (obtained at implantation, 3 and 12 months) of 120 consecutive kidney recipients treated with tacrolimus, mycophenolate mofetil (MMF) and corticosteroids. Biopsies were scored according to the Banff 2001 criteria and a chronicity score was calculated. Prospective pharmacokinetic data were included in the analysis (5544 tacrolimus predose blood concentrations and tacrolimus AUC(0-12) at 3 and 12 months). Higher donor age and higher number of human leukocyte antigen-DR (HLA-DR) mismatches were independent predictors of subclinical acute rejection at 3 months, present in 8.7% of patients. The number of HLA-DR mismatches was independently associated with biopsy-proven clinical acute rejection. Biopsy-proven acute rejection episodes and low mean tacrolimus exposure were independently associated with higher increase in chronicity scores between 3 and 12 months after transplantation. This observational study suggests that rejection phenomena and immune-mediated mechanisms remain important in the early progression of chronic allograft pathology. Tacrolimus doses or systemic exposure were not associated with lesions of calcineurin inhibitor nephrotoxicity, suggesting that other factors determine susceptibility to tacrolimus nephrotoxicity.  相似文献   
35.
目的 总结和评价经直肠超声引导下前列腺穿刺活检术对前列腺癌诊断的准确率。方法 222 例直肠指检阳性或 PSA>4μg/L的患者应用经直肠超声引导下前列腺6点系统穿刺活检以明确诊断。结果 222 例受检者中病理证实前列腺结节性增生41例、前列腺炎24例、前列腺肉瘤3例、前列腺癌 154 例,其中低分化癌 74 例、中分化癌 58 例、高分化癌 22 例。术后血尿15例、发热6例,其中高热1例,经抗生素治疗后体温恢复正常、尿检阴性。结论 经直肠超声引导下前列腺穿刺活检无需麻醉,患者痛苦小、安全性高,是诊断前列腺癌的可靠方法。  相似文献   
36.
37.
OBJECTIVES: Lateral biopsies are thought to have a better cancer detection rate compared with standard sextant biopsies. This study aimed to determine whether lateral peripheral zone biopsies in Japanese men who underwent transrectal ultrasound-guided prostate biopsies provided a significantly higher cancer detection rate than sextant biopsies. METHODS: Between 1999 and 2004, data were collected from 461 men who underwent prostate biopsy and had enough data regarding the performance of lateral biopsies for statistical analysis. There were two categories in this study: (i) patients who underwent sextant prostate biopsies; and (ii) patients who underwent sextant biopsies plus lateral biopsies. RESULTS: Prostate cancer was detected in 141 (30.6%) of 461 patients. It was detected in 24 (22.2%) of 108 patients who underwent sextant biopsies and 117 (33.1%) of 353 patients who underwent sextant plus lateral biopsies. Lateral biopsies were not associated with a statistically higher rate of positive biopsy findings; however, we found a significantly higher ratio of patients with positive findings in those with prostate specific antigen (PSA) levels 10 ng/mL (one of 71, 1.4%) among those who had positive cores only in lateral biopsy samples (P < 0.0001). CONCLUSIONS: Lateral biopsies did not show a significantly higher detection ratio of prostate cancer compared to sextant biopsies. However, lateral biopsies were more effective than sextant biopsies in patients with lower PSA levels. Our findings might be useful for the establishment of biopsy strategies to detect prostate cancer, especially in patients with lower PSA levels.  相似文献   
38.
To examine the incidence of interstitial and vascular rejection in pancreas allografts and its impact on graft survival, we studied 36 percutaneous pancreas biopsies and 10 pancreas transplantectomy specimens from 32 patients who had undergone simultaneous pancreas-kidney transplantation. Interstitial rejection (IR) was predominantly found in the biopsies, while vascular rejection (VR) was most prominent in the transplantectomies. Pancreas graft survival was significantly decreased for pancreas grafts that had suffered from vascular rejection when compared to those with only interstitial rejection. Potential rejection markers, i. e., serum amylase, glucose, creatinine, and urinary amylase, did not correlate with histological signs of rejection, although increased levels of serum amylase were, in all but one case, associated with rejection.We conclude that a percutaneous pancreas biopsy remains the most reliable method to determine pancreas rejection, and that by distinguishing between IR andVR, a pancreas biopsy may provide important diagnostic as well as prognostic information. Received: 6 March 1997 Received after revision: 5 June 1997 Accepted: 30 June 1997  相似文献   
39.
Two patients with arteriovenous fistulas of the native kidney occurring after needle biopsy were evaluated using duplex and color Doppler ultrasonography. The first patient had a fistula with associated pseudoaneurysm: color Doppler showed the lesion as a small rounded area with whirling flow; spectral analysis allowed recognition of both the afferent artery with low impedance flow and the draining vein with pulsatile, arterialized flow. The second patient had a normal color Doppler study; however, spectral analysis demonstrated signals with low vascular impedance from an intra-parenchymal artery at the lower pole, and a jet of turbulent flow. Following disappearance of clinical findings, such Doppler abnormalities were no longer detectable. When a iatrogenic arteriovenous fistula is considered on clinical grounds, both color and Doppler spectral analysis of waveforms from intra-parenchymal vessels should be performed. Possibly, further advances in color Doppler technology will permit the use of this examination as the first imaging procedure in these clinical situations.Correspondence to: L. E. Derchi  相似文献   
40.
While systemic autoimmune diseases are the main possibilities in the differential diagnosis of scleritis, other less common etiologies such as infections must also be considered. The authors report four cases of infectious scleritis to review predisposing factors, clinical characteristics, methods of diagnostic approach, and response to therapy. Two patients had primary scleritis and two patients had secondary scleritis following extension of primary corneal infection (corneoscleritis). Diagnoses included three local infections (one each withStaphylococcus. Acanthamoeba, and herpes simplex) and one systemic infection (Lyme disease). Stains, cultures, or immunologic studies from scleral, conjunctival, and/or corneal tissues, and serologic tests were used to make the diagnosis. Medical therapy, including antimicrobial agents, was instituted in all patients, and surgical procedures were additionally required in two patients (scleral grafting in one and two penetrating keratoplasties in another); the patient who required two penetrating keratoplasties had corneoscleritis and underwent eventual enucleation. Infectious agents should be considered in the differential diagnosis of scleritis.  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