全文获取类型
收费全文 | 1251篇 |
免费 | 55篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 7篇 |
妇产科学 | 46篇 |
基础医学 | 123篇 |
口腔科学 | 5篇 |
临床医学 | 78篇 |
内科学 | 341篇 |
皮肤病学 | 2篇 |
神经病学 | 91篇 |
特种医学 | 37篇 |
外科学 | 345篇 |
综合类 | 10篇 |
一般理论 | 1篇 |
预防医学 | 55篇 |
眼科学 | 4篇 |
药学 | 72篇 |
肿瘤学 | 81篇 |
出版年
2022年 | 10篇 |
2021年 | 38篇 |
2020年 | 9篇 |
2019年 | 27篇 |
2018年 | 28篇 |
2017年 | 20篇 |
2016年 | 27篇 |
2015年 | 25篇 |
2014年 | 36篇 |
2013年 | 43篇 |
2012年 | 71篇 |
2011年 | 80篇 |
2010年 | 45篇 |
2009年 | 44篇 |
2008年 | 52篇 |
2007年 | 46篇 |
2006年 | 60篇 |
2005年 | 44篇 |
2004年 | 58篇 |
2003年 | 66篇 |
2002年 | 68篇 |
2001年 | 36篇 |
2000年 | 51篇 |
1999年 | 37篇 |
1997年 | 9篇 |
1995年 | 8篇 |
1992年 | 12篇 |
1991年 | 8篇 |
1990年 | 15篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 11篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1979年 | 13篇 |
1978年 | 6篇 |
1977年 | 11篇 |
1975年 | 11篇 |
1973年 | 7篇 |
1972年 | 6篇 |
1971年 | 8篇 |
1970年 | 7篇 |
1969年 | 6篇 |
1968年 | 6篇 |
1967年 | 10篇 |
1966年 | 6篇 |
1964年 | 6篇 |
1960年 | 6篇 |
排序方式: 共有1307条查询结果,搜索用时 15 毫秒
1.
2.
The sp act of galactose-1-phosphate uridyltransferase has been measured in individual regions of adult rat brain to see if site-specific differences in enzyme activity can aid in the understanding of brain abnormalities observed in well-treated galactosemic patients. The sp act in the cerebellum, brain stem, and midbrain were higher than in the cortex, hippocampus, and striatum. Activity in the cerebellum was 2-fold greater than that found in the cortex. Steady state levels of mRNA of the enzyme in the cerebellum were twice that of the cortex corresponding to the ratio of enzyme sp act in the two regions. Measurement of the kinetic parameters in tissue from the cerebellum and cortex revealed that the regional specificity in enzyme activity observed in the brain represents differences in the Vmax. Inhibition of the enzyme by uridine and uridine triphosphate was essentially the same for all regions and was not influenced by the 2-fold differences observed in the levels of enzyme. Inhibition by uridine was significantly greater than that for uridine triphosphate. 相似文献
3.
Patricia Lye Charlotte Heidenreich Rebekah Wang-Cheng Dawn Bragg Deborah Simpson 《Ambulatory Pediatrics》2003,3(2):93-97
OBJECTIVES: To determine if experienced clinical educators (CEs) can improve their teaching by incorporating 4 literature-based teaching methods into their instruction. METHODS: We trained 7 experienced CEs on the teaching methods during a monthly faculty development program. Each CE recorded use of these methods during 10 months on a personal digital assistant. We compared the CEs' teaching evaluations with those of nonparticipating faculty by analysis of variance at baseline, during the study period, and for 1 year after the study. RESULTS: Reported use of 2 teaching methods (priming and feedback) increased significantly over use at baseline; use of 2 other methods (teaching in the patient's presence and 1-2 focal teaching points) remained constant. Scores on the CEs' teaching evaluations were significantly higher during the study period on 1 item, whereas the comparison group showed no changes. The changes persisted during the follow-up period. CEs reported that the teaching methods focused the learner and teacher, making subsequent encounters more productive. They also found that the act of entering data daily prompted them to reflect on their teaching. CONCLUSIONS: Experienced teachers can be persuaded to incorporate new methods into their daily teaching. Reflection on teaching is enhanced with group support and daily reminders. With these interventions, teaching effectiveness of these experienced educators improved. 相似文献
4.
Alfred E Buxton Hugh Calkins David J Callans John P DiMarco John D Fisher H Leon Greene David E Haines David L Hayes Paul A Heidenreich John M Miller Athena Poppas Eric N Prystowsky Mark H Schoenfeld Peter J Zimetbaum Paul A Heidenreich David C Goff Frederick L Grover David J Malenka Eric D Peterson Martha J Radford Rita F Redberg 《Journal of the American College of Cardiology》2006,48(11):2360-2396
5.
Results of intersphincteric resection of the rectum with direct coloanal anastomosis for rectal carcinoma. 总被引:13,自引:0,他引:13
J Braun K H Treutner G Winkeltau U Heidenreich M M Lerch V Schumpelick 《American journal of surgery》1992,163(4):407-412
Between 1977 and 1987, 519 patients underwent operation for rectal carcinoma. Sixty-three patients underwent intersphincteric resection with direct coloanal anastomosis (CAA), and 77 had an abdominoperineal resection (APR). Curative surgery was achieved in 57 and 65 patients, respectively. Both groups were comparable regarding age, stage of tumors, and localization of tumors. During the mean period of 6.7 years (range: 3 to 13.6 years), all patients were examined according to a predefined follow-up plan. From those patients with curative surgery, 11% presented with pelvic recurrence and 33% with distant metastases after coloanal anastomosis; the rates of recurrence and distant metastases after APR were 17% and 35%, respectively. The corrected 5-year survival rates were 62% following CAA and 53% following APR. Eighty-five percent of the patients with CAA reported good functional results regarding anal continence. Our study demonstrates that the intersphincteric resection with CAA is a valuable surgical technique for rectal carcinoma with the benefit of preservation of continence. It is suitable for neoplasms with high- and medium-grade differentiation (G1 to G2) and a localization that allows a minimum distal clearence of 3 cm. 相似文献
6.
Jonathan S. Jahr Fedor Lurie Bernd Driessen Jessica A. Davis Robert Gosselin Robert A. Gunther 《Journal canadien d'anesthésie》2002,49(3):243-248
PURPOSE: Accuracy of measurement of low hemoglobin concentrations using the HemoCue, a B-hemoglobin photometer (HemoCue AB, Angelholm, Sweden) may exhibit significant variability. Infusion of hemoglobin-based oxygen carriers (HBOC) results in low concentrations of plasma hemoglobin. Our study assessed B-hemoglobin photometer measurement accuracy of three HBOC: (hemoglobin glutamer-200 (bovine; Oxyglobin, Biopure Corp., Cambridge, MA, USA); hemoglobin glutamer-250 (bovine; Hemopure, Biopure Corp, Cambridge, MA, USA), and hemoglobin-raffimer, (human; Hemolink, Hemosol, Inc., Toronto, Ontario, Canada). METHODS: In the laboratory, 45 split canine plasma samples were mixed with hemoglobin glutamer-200 (8.13, 16.25, 32.5 g x L(-1) concentrations), 45 samples were mixed with hemoglobin glutamer-250 (8.13, 16.25, 32.5 g x L(-1) concentrations), 45 with hemoglobin-raffimer (12.5, 25.0, 50.0 g x L(-1) concentrations), and measured. Plasma samples without HBOC served as control. Hemoglobin concentration was determined by a laboratory analyzer (Coulter Corporation, Hiafeah, FL, USA) and B-hemoglobin photometer (HemoCue, Angelholm, Sweden). Two independent technicians performed blinded sample measurements and randomly tested each sample five times. Results were analyzed according to Bland and Altman analysis. RESULTS: B-hemoglobin photometer demonstrated high repeatability for all three HBOCs. Repeatability coefficients were 0.37 g x L(-1) and 0.48 g x L(-1) for hemoglobin glutamer-200, 0.39 g x L(-1) and 0.4 g x L(-1) for hemoglobin glutamer-250 and 1.07 g x L(-1) and 0.85 g x L(-1) for hemoglobin-raffimer. An acceptable agreement was found between the B-hemoglobin photometer and the laboratory analyzer for all three HBOCs tested. CONCLUSION: The B-hemoglobin photometer accurately determined the concentration of three HBOC solutions dissolved in canine plasma. 相似文献
7.
Eberhard Henze Gerhard Graf Malte Clausen Bertram Rail Rolf Weller Dieter Derichs Joachim Kreidler Peter Heidenreich F. Sitzmann Willi Ernst Adam 《European journal of nuclear medicine and molecular imaging》1990,16(2):97-101
The exact regional correlation of findings of facial bone scans, planar or SPECT, to dental orthopan X-ray films (OPT) is difficult because of the very different projection techniques. To improve correlative imaging in this regard a projection algorithm was developed that uses SPECT data of the skull for reconstructing an orthopan tomoscintigraphic projection. Fourteen conventional SPECT slices of the upper and lower jaws were obtained during bone scanning. All mandibular slices were superimposed resulting in a horseshoe shaped structure, which was marked by an ROI which was divided into segments. All 14 SPECT slices were then masked by this segmental ROI, thereby marking the teeth-carrying bone in all slices. The information from this horseshoe like ROI is then transformed into lines. Line by line arrangement results in an orthopan projection, the orthopan tomoscintigram. This new display allows 1:1 true scale superimposition with the X-ray OPT and markedly facilitates correlative imaging. 相似文献
8.
9.
Zusammenfassung Für die Therapie bei infizierten Thrombosen der großen Halsvenen und zentralen Venen gibt es kein standardisiertes therapeutisches Vorgehen. Sowohl konservative als auch aggressive, invasive Therapiestrategien werden beschrieben. Wir präsentieren den Fall einer septischen Thrombose der rechten V. jugularis interna nach einliegendem zentralem Venenkatheter bei einem immunsupprimierten Patienten nach Polychemotherapie wegen eines metastasierten Seminoms des rechten Hodens. Nach konservativem Therapieversuch mit intravenöser antibiotischer Therapie und therapeutischer Heparinisierung wurde wegen des sich verschlechternden septischen Zustandsbildes des Patienten die Indikation zur chirurgischen Intervention gestellt. Intraoperativ war eine Thrombektomie unmöglich, sodass eine vollständige Resektion der rechten V. jugularis interna durchgeführt wurde. Der postoperative Verlauf war komplikationslos. Der histopathologische Befund zeigte eine putride Thrombophlebitis mit ausgeprägter Periphlebitis; die kulturellen Untersuchungen aus dem Wundgebiet und Blutkulturen wiesen übereinstimmend Staphylococcus aureus nach. Vor allem der immunsupprimierte Patient mit Neutropenie und Thrombopenie erfordert ein aggressives chirurgisches Vorgehen zur sicheren und schnellen Befundsanierung. Abstract There is no therapeutic standard for the treatment of septic thrombosis of the central veins. We present a case of septic thrombosis of the right internal jugular vein. The immunocompromised patient had a central venous line for polychemotherapy of metastasized seminoma of the right testis. After conservative therapy with antibiotics and therapeutic heparinization the septic status of the patient worsened rapidly and surgical intervention was planned. Intraoperatively, thrombectomy was not feasible and complete resection of the right internal jugular vein became necessary. Postoperative reconvalescence was uneventful. Histopathological findings showed purulent suppurative thrombophlebitis and marked periphlebitis, mirobiology revealed staph. aureus both in the catheter insertion site and in blood cultures. Especially in immunocompromised patients with severe granulo- and thrombocytopenia, surgery may be attributed with less danger for the patient than prolongued septicemia. 相似文献
10.
Technical considerations in the surgical approach to multiple accessory pathways in the Wolff-Parkinson-White syndrome 总被引:1,自引:0,他引:1
J G Selle W C Sealy J J Gallagher J M Fedor R H Svenson S H Zimmern 《The Annals of thoracic surgery》1987,43(6):579-584
Surgical techniques for the approach to and division of atrioventricular accessory pathways have been designed and perfected during the past 18 years. The standard method of exposure of a single left free wall accessory pathway is by a left atriotomy. All other single accessory pathways are exposed through a right atriotomy. Up to twenty percent of patients with Wolff-Parkinson-White (WPW) syndrome harbor multiple atrioventricular accessory pathways. In this subgroup, classic operative techniques, especially the methods of approach, must be combined or modified depending on the specific locations of the accessory pathways encountered. Eighteen of 90 patients operated on for WPW syndrome at Charlotte Memorial Hospital from August, 1983, through September, 1986, had multiple accessory pathways. Thirty-eight of thirty-nine pathways were successfully divided. One posterior septal accessory pathway reappeared 2 months postoperatively and was catheter ablated. The most frequent combination of atrioventricular accessory pathways included a right free wall and a posterior septal accessory pathway (10 patients). This combination is approached by a right atriotomy. The posterior septal space dissection is extended onto the right free wall area. Technically the most difficult combination includes a left free wall and a posterior septal accessory pathway (3 patients in the present series). Our preferred approach is begun with a right atriotomy for the posterior septal space dissection, followed by an atrial septotomy to expose the left free wall area. There are other methods, however, that may be advantageous depending on the exact locations of the accessory pathways encountered. 相似文献