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   19372篇
  免费   1552篇
  国内免费   61篇
耳鼻咽喉   258篇
儿科学   619篇
妇产科学   443篇
基础医学   2796篇
口腔科学   285篇
临床医学   1883篇
内科学   3646篇
皮肤病学   311篇
神经病学   1971篇
特种医学   719篇
外科学   2614篇
综合类   607篇
现状与发展   2篇
一般理论   27篇
预防医学   1532篇
眼科学   545篇
药学   1313篇
中国医学   40篇
肿瘤学   1374篇
  2023年   123篇
  2022年   241篇
  2021年   392篇
  2020年   243篇
  2019年   361篇
  2018年   443篇
  2017年   288篇
  2016年   380篇
  2015年   417篇
  2014年   530篇
  2013年   833篇
  2012年   1154篇
  2011年   1078篇
  2010年   675篇
  2009年   640篇
  2008年   1026篇
  2007年   1040篇
  2006年   929篇
  2005年   1018篇
  2004年   1030篇
  2003年   953篇
  2002年   866篇
  2001年   344篇
  2000年   351篇
  1999年   332篇
  1998年   232篇
  1997年   167篇
  1996年   170篇
  1995年   174篇
  1994年   139篇
  1993年   160篇
  1992年   247篇
  1991年   220篇
  1990年   234篇
  1989年   241篇
  1988年   220篇
  1987年   198篇
  1986年   202篇
  1985年   224篇
  1984年   183篇
  1983年   141篇
  1982年   153篇
  1981年   156篇
  1980年   135篇
  1979年   115篇
  1977年   99篇
  1976年   119篇
  1975年   105篇
  1974年   130篇
  1973年   95篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Konan AV  Roy D  Raymond J 《Neurosurgery》1999,44(3):663-666
OBJECTIVE AND IMPORTANCE: To illustrate that decompression of the facial nerve by transvenous endovascular treatment may relieve hemifacial spasm (HFS) caused by dilated veins. CLINICAL PRESENTATION: A 35-year-old man suffered severe chronic right HFS associated with a dilated right lateral mesencephalic vein lying in the vicinity of the facial nerve. This nonessential vein was recruited as a secondary collateral drainage from an inoperable left temporo-occipital arteriovenous malformation. INTERVENTION: The lateral mesencephalic vein was reached through the superior petrosal sinus using a transfemoral venous approach and was occluded with interlocking detachable coils (Target Therapeutics, Freemont, CA). There was complete remission of HFS without recurrence after 2.5 years of follow-up. CONCLUSION: This case report supports vascular compression in the pathogenesis of HFS and suggests that facial nerve injury is not essential for the therapeutic effect of surgical decompression.  相似文献   
102.
Nausea and vomiting are common side effects of opioids administered for pain control. This double-blind, randomized, parallel-group study evaluated the anti-emetic efficacy and tolerability of single intravenous (i.v.) doses of ondansetron 8 mg, ondansetron 16 mg and metoclopramide 10 mg in the treatment of opioid-induced emesis. Adult patients undergoing low emetogenic surgical procedures, using a standardized anaesthesia regimen were assessed for 24 h following administration of study anti-emetic to treat established post-surgical opioid-induced emesis. A total of 4511 patients were enrolled of whom 1366 experienced opioid-induced emesis and received randomized study medication. Ondansetron 8 mg and 16 mg were significantly better than metoclopramide 10 mg (P < 0.05) for both complete control of emesis, complete control of nausea and other efficacy measures. There were no significant differences between the two ondansetron groups. All three treatments were well tolerated. In conclusion, this large, multicentre study demonstrates that ondansetron is more effective than metoclopramide in the treatment of opioid-induced emesis following administration of post-surgical opioids to control pain.  相似文献   
103.
We believed that subtyping alcoholism might be an efficient strategy for mapping susceptibility genes. Cluster analysis is one of the possible statistical techniques for such a purpose. We required that, ideally, the variables to be used in cluster analysis should be: 1) related to alcoholism, 2) related to the severity of alcoholism, and 3) familial, i.e., correlated within families. Only three variables met all three conditions. Those included age of onset of ALDX1, smoking, and TPQ-HA. A global score of symptoms of alcoholism was systematically introduced as one of the variables composing a subset for cluster analysis, although this score did not show any familial aggregation. Our strategy led to a strong evidence of linkage at D15S230 in only 20 families whose members are mainly characterized by heavy smoking.  相似文献   
104.
Objective. To evaluate the utility of the iSTAT blood analyzer, a bedside device for hematocrit, sodium, potassium, and glucose measurement during cardiopulmonary bypass (CPB).Methods. Forty patients scheduled for elective CPB were evaluated prospectively. In addition to using the iSTAT analyzer, blood samples were analyzed at four time points: following induction of anesthetic, 10 min. after initiation of CPB, 60 min. after initiation of CPB, and following heparin neutralization by protamine. Blood glucose concentration was measured by the hospital laboratory using a Kodak Analyzer and by a glucose meter, electrolytes were evaluated by the Kodak Analyzer and BGE (a device which is commonly used for satellite laboratory determinations of electrolyte and blood gas results), and hematocrit samples were measured by the hospital laboratory using an NE 8,000 and a centrifuge. The means and standard deviations of the differences between the methods were calculated.Results. The hematocrit values determined by the iSTAT machine, when adjusted for the level of total protein (according to manufacturer's directions), differed from the laboratory values by 0.53 = 1.46 percentage points. An alternative to measuring total protein and making the adjustment is simply adding 1 % to the hematocrit in the pre-CPB period and 3% on-CPB or post-CPB, which we found to yield values that differed from the laboratory by 0.52 ± 1.42 percentage points. For all four tests (hematocrit, sodium, potassium, and glucose) the iSTAT had a similar relationship to the laboratory values as did the other commonly used means (centrifuge, BGE, and glucose meter) of clinical evaluation.Conclusion. In summary, we found that in patients undergoing CPB, the iSTAT values agreed sufficiently well with standard laboratory values and that the iSTAT instrument can be relied upon for bedside measurements.Presented in part at the Annual Meeting of the Society of Cardiovascular Anesthesiologists, Philadelphia, PA, May 1995, and at the 70th meeting of the IARS, Washington DC, March 1996. Supported in part by a grant by iSTAT Corporation.  相似文献   
105.
A 16-year-old boy presented with a hyperpigmented, velvety, not compressible, plaque on the medial side of right leg just below the knee for the last 10 years. Biopsy report revealed the lesion was nothing but capillary haemangioma. The case is presented here due to unusual presentation with a tendency to persist.  相似文献   
106.
107.
108.
Summary Chondrocytes in epiphyseal cartilage were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) using freeze-fracture techniques. Freeze-fracture replicas showed large numbers of fingerlike, 0.11–0.15 m diameter, projections from the chondrocyte surface, with numerous 95–180 Å diameter intramembranous particles associated with both the cell membrane surface and these projections. With SEM, these cytoplasmic projections were also obvious, but appeared collapsed into clusters of globular-shaped projections on the surface of the chondrocytes. With freeze-fracture techniques, in which shrinkage artifacts were essentially eliminated, the cytoplasmic projections were often seen in intimate contact with the extracapsular matrix. However, with chondrocytes prepared by both SEM and conventional TEM, there was evidence of shrinkage, the cytoplasmic projections having little contact with the extracapsular matrix. These findings show that the cytoplasmic processes are not artifacts of tissue processing and provide morphological evidence in support of the hypothesis that matrix vesicles are of cellular origin.Correlation of Freeze-Fracture and Scanning Electron Microscopy of Epiphyseal Chondrocytes  相似文献   
109.
Spirochetes found in feces of normal and infected pigs during the eight days preceding the onset of the clinical signs of swine dysentery have been studied using electron and phase contrast microscopy. According to their dimensions, diameter, length and pitch, three morphological groups have been described: small, intermediate and large spirochetes. On the basis of their axial filaments arrangement, eight types have been observed. Compared to the control pigs, there was no increase in the total number of spirochetes in infected pigs, except at day 6 before the onset of clinical signs. However, infected pigs have shown a wide spectrum of different morphological types of spirochetes in comparison to control, uninfected pigs, which showed only the type "1-2-1" spirochete of axial filaments arrangement. This last type was predominant in infected swine during the entire incubation period as compared to other spirochete types described.  相似文献   
110.
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