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   2136篇
  免费   202篇
  国内免费   33篇
耳鼻咽喉   9篇
儿科学   71篇
妇产科学   112篇
基础医学   375篇
口腔科学   106篇
临床医学   221篇
内科学   376篇
皮肤病学   29篇
神经病学   125篇
特种医学   219篇
外科学   214篇
综合类   43篇
一般理论   1篇
预防医学   170篇
眼科学   77篇
药学   148篇
肿瘤学   75篇
  2023年   15篇
  2021年   43篇
  2020年   18篇
  2019年   25篇
  2018年   32篇
  2017年   20篇
  2016年   19篇
  2015年   26篇
  2014年   34篇
  2013年   74篇
  2012年   72篇
  2011年   78篇
  2010年   56篇
  2009年   40篇
  2008年   71篇
  2007年   101篇
  2006年   98篇
  2005年   106篇
  2004年   103篇
  2003年   61篇
  2002年   75篇
  2001年   76篇
  2000年   78篇
  1999年   68篇
  1998年   32篇
  1997年   26篇
  1996年   28篇
  1995年   25篇
  1994年   26篇
  1993年   30篇
  1992年   45篇
  1991年   66篇
  1990年   57篇
  1989年   70篇
  1988年   59篇
  1987年   48篇
  1986年   48篇
  1985年   42篇
  1984年   31篇
  1983年   25篇
  1982年   21篇
  1981年   16篇
  1979年   18篇
  1978年   27篇
  1977年   22篇
  1976年   23篇
  1975年   16篇
  1971年   21篇
  1970年   16篇
  1969年   17篇
排序方式: 共有2371条查询结果,搜索用时 15 毫秒
1.
This pilot study examined a behavioral treatment to increase calorie intake in toddlers with cystic fibrosis. Eight toddlers were randomly assigned to behavioral plus nutrition (BEH) or nutrition intervention (NTR) conditions. Calorie intake and weight were measured at pre- and posttreatment. The BEH group showed a trend for changes in calorie intake pre- to posttreatment (p = .07; 40% increase). Results for the BEH and NTR groups did not differ significantly. Most participants achieved weight gains consistent with normal growth. Seventy-five percent had not shown this pattern during the year prior to intervention. These results support the feasibility and potential for behavioral interventions in this age group.  相似文献   
2.
BK virus nephropathy (BKVN) is now recognized as a major cause of renal allograft loss. Recent reports suggest that retransplantation in patients with graft loss due to BKVN is safe after return to dialysis. Since early transplantation is associated with improved outcomes, it would be advantageous if this procedure could be performed prior to ultimate graft loss. However, little data are available regarding the safety of this approach during active viremia. In this report, we describe successful preemptive retransplantation with simultaneous allograft nephrectomy in two patients with active BKVN and viremia at the time of surgery. With 21- and 12-month follow-up, respectively, both patients have stable allograft function and no evidence for active viral replication. We conclude that preemptive retransplantation can be considered in patients with failing allografts due to BKVN.  相似文献   
3.
The authors describe their experience with methyl tertiary butyl ether (MTBE) in a larger series of patients than previously reported in order to acquaint physicians with both its effectiveness for dissolution of common bile duct calculi and the limitations of its use. Ten patients with 13 biliary calculi underwent percutaneous stone dissolution treatment with the experimental cholesterol solvent, MTBE. Three stones completely dissolved within 30 minutes, seven were reduced in size, and three were visibly unaffected. All stones not completely dissolved were easily extracted by means of a stone basket except for one in a patient taken to surgery. Although MTBE perfusion is an effective technique for management of biliary calculi, practitioners should be aware that its use is quite time consuming and its odor difficult to control.  相似文献   
4.
Sequential salivary gland scintigraphy with 99mTc-technetium pertechnetate (Tc-99) is a safe, minimally invasive test for study of major salivary glands. However, its relationship to salivary function has not been investigated in detail. We have investigated the relationship between major salivary gland flow rates and Tc-99 scans and developed a new rating scale using scans of a control group with normal salivary function. Salivary flow rates and Tc-99 scans were obtained from healthy, non-medicated subjects (n = 33) and from xerostomic patients (n = 22). There were significant differences between the groups for salivary flow rates and Tc-99 ratings. Significant correlations were found between salivary flow rates and Tc-99 ratings in the control and xerostomic groups. The Tc-99 rating scale proved reliable in assessing salivary dysfunction, and showed a high inter-examiner correlation. These results demonstrate the usefulness of salivary gland scintigraphy in assessing major salivary gland flow rates and the utility of a new rating scale.  相似文献   
5.
The recently introduced Technicon H1 analyser uses an improved optical principle to measure the size and haemoglobin concentration of erythrocytes. We have made a serial study of ten patients undergoing phlebotomy to induce mild iron deficiency. The instrument showed the early development of anisohypochromia with subsequent fall in the mean cell haemoglobin concentration (MCHC). Cell volume was preserved until relatively late and during early iron deficient erythropoiesis cell volume would appear to be maintained at the expense of haemoglobin concentration. The Technicon H6000 (conventional technology) used in parallel produced contrasting results indicating anisomicrocytosis with preservation of cell haemoglobin concentration until relatively late. Five cases of severe iron deficiency treated with iron were similarly studied and showed comparable changes on both instruments, with characteristically bimodal cell volume histograms and large increases in red cell distribution width. Our results indicate that the new generation of instruments will generate red cell data of additional clinical value.  相似文献   
6.
Intestinal obstruction proximal to a transition zone without an interposed physical barrier usually indicates Hirschsprung disease. The authors report one case of focal small bowel muscular thinning just distal to a transition zone that produced clinical and radiographic findings that simulated long-segment Hirschsprung disease in a 2-day-old infant.  相似文献   
7.
Image-directed percutaneous biopsies with a biopsy gun   总被引:3,自引:0,他引:3  
Core tissue for histologic study is believed by many pathologists to be more diagnostic than material from needle aspiration. Recently, a biopsy "gun" has been introduced, which simplifies core biopsies. With this device, 182 biopsies of multiple anatomic sites were performed with ultrasonic, computed tomographic, and fluoroscopic guidance and 18-gauge needles. High-quality histopathologic specimens were obtained in 177 of the biopsies, and diagnostic target tissue was obtained in 167. Only three significant complications occurred: one bleeding complication that required transfusion and two cases of pneumothorax that necessitated placement of chest tubes. The biopsy gun eliminated the disjointed movements of conventional "skinny" needle biopsies, and none of the samples demonstrated significant "crush" artifact or obscuring blood, problems that are commonly associated with manual biopsy techniques. Patient discomfort was decreased with this system compared with that of manual biopsies, and the total procedure time was reduced. Because of these distinct advantages, the authors now use the biopsy gun exclusively for all percutaneous biopsies and recommend that other institutions consider the use of this biopsy method.  相似文献   
8.
Legionella gormanii sp. nov   总被引:15,自引:18,他引:15       下载免费PDF全文
A new species of Legionella was isolated from soil collected from a creek bank. The name Legionella gormanii sp. nov. is proposed.  相似文献   
9.
The nucleotide sequences of variable segments (VS) 1, 2, and 4 for the major outer membrane protein gene (omp1) of Chlamydia trachomatis were determined for serologically defined subtypes D', I', and L2'. Asymmetric DNA amplification was used to produce single-stranded DNA for direct sequencing. Amino acid substitutions were detected in VS1, VS2, and VS4 for I', in VS2 for L2', and in VS4 for D'. DNA sequencing of omp1 variant regions may be an important method for evaluating the molecular epidemiology of Chlamydia spp.  相似文献   
10.
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