全文获取类型
收费全文 | 5600篇 |
免费 | 326篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 153篇 |
妇产科学 | 217篇 |
基础医学 | 717篇 |
口腔科学 | 99篇 |
临床医学 | 589篇 |
内科学 | 1102篇 |
皮肤病学 | 95篇 |
神经病学 | 376篇 |
特种医学 | 294篇 |
外科学 | 891篇 |
综合类 | 87篇 |
一般理论 | 6篇 |
预防医学 | 427篇 |
眼科学 | 193篇 |
药学 | 361篇 |
中国医学 | 28篇 |
肿瘤学 | 256篇 |
出版年
2022年 | 36篇 |
2021年 | 92篇 |
2020年 | 60篇 |
2019年 | 77篇 |
2018年 | 106篇 |
2017年 | 73篇 |
2016年 | 66篇 |
2015年 | 72篇 |
2014年 | 116篇 |
2013年 | 187篇 |
2012年 | 255篇 |
2011年 | 323篇 |
2010年 | 151篇 |
2009年 | 191篇 |
2008年 | 295篇 |
2007年 | 314篇 |
2006年 | 350篇 |
2005年 | 303篇 |
2004年 | 321篇 |
2003年 | 241篇 |
2002年 | 294篇 |
2001年 | 58篇 |
2000年 | 55篇 |
1999年 | 69篇 |
1998年 | 83篇 |
1997年 | 61篇 |
1996年 | 65篇 |
1995年 | 40篇 |
1994年 | 38篇 |
1993年 | 52篇 |
1992年 | 40篇 |
1991年 | 44篇 |
1990年 | 35篇 |
1989年 | 36篇 |
1987年 | 40篇 |
1986年 | 39篇 |
1985年 | 40篇 |
1984年 | 42篇 |
1983年 | 63篇 |
1982年 | 56篇 |
1981年 | 54篇 |
1980年 | 49篇 |
1979年 | 33篇 |
1978年 | 51篇 |
1977年 | 49篇 |
1976年 | 46篇 |
1975年 | 36篇 |
1974年 | 33篇 |
1973年 | 38篇 |
1972年 | 34篇 |
排序方式: 共有5939条查询结果,搜索用时 15 毫秒
41.
The termwell-baby clinic (literally, a clinic that concerns itself with healthy infants) is probably better known in the United States, where such clinics exist, than in central Europe, where, on the whole, they do not. For the convenience of readers accustomed to it a formal definition is proffered: A well-baby clinic is a service center, with emphasis on physical and mental hygiene and prophylaxis, where mothers are seen with their young, healthy infants and helped to understand and manage the infant's unfolding maturation [1: p. 5] and development [1: p. 5]. This may serve to differentiate well-baby clinics, on the one hand, from clinics for sick children and child guidance clinics (usually resorted to after disturbances have emerged) and, on the other hand, from maternity and child welfare clinics, whose primary object is to safeguard physical health. (Maternity and child welfare clinics are also known as family health clinics, child health clinics, and infant welfare clinics. The extent to which they can cater to the psychological needs of mother and infant depends on their staff's training.)This paper forms part of a research project entitled Childhood Pathology: Impact on Later Mental Health, which is being conducted at the Hampstead Child-Therapy Course and Clinic, London. The project is financed by National Institute of Mental Health Grant MH-05683-11. Appreciation is expressed to Anna Freud, Elizabeth Model, Professor A. J. Solnit, and Dr. Josefine Stross for their valuable suggestions. The authors acknowledge with gratitude the freedom to quote from the Well-Baby Clinic's annual reports, compiled by the clinic's pediatrician, Dr. Josefine Stross, with the active help of her past assistants, Annemarie Curson, Manna Friedmann, and Joyce Robertson, and her present assistants, Irene Freud and E. Model.This paper was originally published in German, in volume 2 of theJahrbuch der Psychohygiene, Ed. Gerd Biermann, Ernst Reinhardt Verlag, München/Basel, 1974. 相似文献
42.
Joseph G Rajendran David A Mankoff Finbarr O'Sullivan Lanell M Peterson David L Schwartz Ernest U Conrad Alexander M Spence Mark Muzi D Greg Farwell Kenneth A Krohn 《Clinical cancer research》2004,10(7):2245-2252
PURPOSE: The aim of this study is to compare glucose metabolism and hypoxia in four different tumor types using positron emission tomography (PET). (18)F-labeled fluorodeoxyglucose (FDG) evaluates energy metabolism, whereas the uptake of (18)F-labeled fluoromisonidazole (FMISO) is proportional to tissue hypoxia. Although acute hypoxia results in accelerated glycolysis, cellular metabolism is slowed in chronic hypoxia, prompting us to look for discordance between FMISO and FDG uptake. EXPERIMENTAL DESIGN: Forty-nine patients (26 with head and neck cancer, 11 with soft tissue sarcoma, 7 with breast cancer, and 5 with glioblastoma multiforme) who had both FMISO and FDG PET scans as part of research protocols through February 2003 were included in this study. The maximum standardized uptake value was used to depict FDG uptake, and hypoxic volume and maximum tissue:blood ratio were used to quantify hypoxia. Pixel-by-pixel correlation of radiotracer uptake was performed on coregistered images for each corresponding tumor plane. RESULTS: Hypoxia was detected in all four patient groups. The mean correlation coefficients between FMISO and FDG uptake were 0.62 for head and neck cancer, 0.47 for breast cancer, 0.38 for glioblastoma multiforme, and 0.32 for soft tissue sarcoma. The correlation between the overall tumor maximum standardized uptake value for FDG and hypoxic volume was small (Spearman r = 0.24), with highly significant differences among the different tumor types (P < 0.005). CONCLUSIONS: Hypoxia is a general factor affecting glucose metabolism; however, some hypoxic tumors can have modest glucose metabolism, whereas some highly metabolic tumors are not hypoxic, showing discordance in tracer uptake that can be tumor type specific. 相似文献
43.
Neil E Martin Thomas B Brunner Krystina D Kiel Thomas F DeLaney William F Regine Mohammed Mohiuddin Ernest F Rosato Daniel G Haller James P Stevenson Debbie Smith Barnali Pramanik Joel Tepper Wesley K Tanaka Briggs Morrison Paul Deutsch Anjali K Gupta Ruth J Muschel W Gillies McKenna Eric J Bernhard Stephen M Hahn 《Clinical cancer research》2004,10(16):5447-5454
PURPOSE: Preclinical and clinical studies have demonstrated that inhibition of prenylation can radiosensitize cell lines with activation of Ras and produce clinical response in patients with cancer. The aim of this study was to determine the maximally tolerated dose of the dual farnesyltransferase and geranylgeranyltransferase I inhibitor L-778,123 in combination with radiotherapy for patients with locally advanced pancreatic cancer. EXPERIMENTAL DESIGN: L-778,123 was given by continuous intravenous infusion with concomitant radiotherapy to 59.4 Gy in standard fractions. Two L-778,123 dose levels were tested: 280 mg/m2/day over weeks 1, 2, 4, and 5 for dose level 1; and 560 mg/m2/day over weeks 1, 2, 4, 5, and 7 for dose level 2. RESULTS: There were no dose-limiting toxicities observed in the eight patients treated on dose level 1. Two of the four patients on dose level 2 experienced dose-limiting toxicities consisting of grade 3 diarrhea in one case and grade 3 gastrointestinal hemorrhage associated with grade 3 thrombocytopenia and neutropenia in the other case. Other common toxicities were mild neutropenia, dehydration, hyperglycemia, and nausea/vomiting. One patient on dose level 1 showed a partial response of 6 months in duration. Both reversible inhibition of HDJ2 farnesylation and radiosensitization of a study patient-derived cell line were demonstrated in the presence of L-778,123. K-RAS mutations were found in three of the four patients evaluated. CONCLUSIONS: The combination of L-778,123 and radiotherapy at dose level 1 showed acceptable toxicity in patients with locally advanced pancreatic cancer. Radiosensitization of a patient-derived pancreatic cancer cell line was observed. 相似文献
44.
Ernest C Borden Laurence H Baker Robert S Bell Vivien Bramwell George D Demetri Burton L Eisenberg Christopher D M Fletcher Jonathan A Fletcher Marc Ladanyi Paul Meltzer Brian O'Sullivan David R Parkinson Peter W T Pisters Scott Saxman Samuel Singer Murali Sundaram Allan T van Oosterom Jaap Verweij Jill Waalen Sharon W Weiss Murray F Brennan 《Clinical cancer research》2003,9(6):1941-1956
Sarcomas--like leukemias, which are also mesodermal malignancies--carry biological significance disproportionate to their clinical frequency. Identification of mutations and translocations associated with these tumors has illuminated aberrant signaling pathways that cause these diseases, determine their behavior, and are therapeutic targets. Activated receptor-associated tyrosine kinase c-kit, mutated in most gastrointestinal stromal tumors, has proven a clinically effective target for enzyme inhibition. A translocation involving a single gene family, consisting of EWS and related genes, has been identified in five different sarcomas, and its chimeric protein products could prove similarly amenable to inhibitors. Resolution of the histopathological complexity is being aided by data from molecular and chromosomal characterization. Improvements in imaging, definition of prognostic factors, and surgical and radiotherapeutic treatment have resulted in improved local control. Continued progress will depend on further adapting the rapidly evolving technologies of genomics and proteomics. It will also depend upon accurate histopathological diagnosis based on validated reagents and consistent methodologies applied to adequate tissue samples derived from patients with complete clinical data. Finally, multicenter, coordinated trials, such as those that occurred with assessment of imatinib mesylate in metastatic gastrointestinal stromal tumors, will assure the most rapid reductions in morbidity and mortality. 相似文献
45.
Background: Clearance of large molecules from the interstitialspace is an important function of lymphatics andis affected by local pathologic changes.Objective: To determine if the clearance rate ofinterstitially injected albumin is correlated to tumour characteristicsand outcome in women with invasive breast cancer.Method: In a consecutive series of women comingto biopsy for suspected breast cancer, technetium-tagged albuminwas injected into the tissue adjacent to thepalpable mass. The isotope disappearance rate was measuredover two hours. Also assessed were the maximumvessel density (MVD – using Factor VIII polyclonalantisera), the proliferation rate (using Ki-67 antisera), nodestatus, tumour size, histologic and nuclear grade, mitoticrate, and p53 and c-erbB-2 oncoproteins. All patientswere followed until relapse and for a minimumof 10 years.Results: In multivariate analysis, an association between relapse-freesurvival and isotope clearance rate was suggested (p= 0.024). The best outcome was seen inpatients with the least isotope clearance. Node status,size, histologic and nuclear grade, and mitotic ratecorrelated with survival. MVD did not correlate withsurvival and was inversely related to the isotopeclearance rate. Tumour proliferation rate, and the c-erbB-2and p53 oncoproteins did not relate to outcome.Conclusion: The role of lymphatics in breast canceris difficult to study. Measurement of interstitial clearancemay be a useful technique and could bea prognostic factor. 相似文献
46.
Benjamin Z. Koplewitz A. Daneman Ernest Cutz Jonathan Hellmann 《Pediatric radiology》1998,28(12):958-962
We reviewed the clinical, sonographic and pathologic findings in eight neonates in whom diffuse enlargement and abnormal
echogenicity of the adrenal glands was documented sonographically. Four of the patients suffered from perinatal asphyxia and
two others required mechanical ventilation for other reasons. Six patients died and one suffers from severe development delay,
cerebral palsy and failure to thrive. Sonographically, the glands were enlarged, their surface was smooth and there was loss
of the central echogenic stripe. Diffuse sinusoidal congestion was found histologically in all five in whom autopsies were
performed. These sonographic findings represent part of the spectrum of adrenal changes in neonatal asphyxia and other causes
of perinatal stress, and may be associated with poor outcome because of other sequelae of asphyxia.
Received: 12 March 1998 Accepted: 8 June 1998 相似文献
47.
Initial multicenter experience with double nucleoside therapy for human immunodeficiency virus infection during pregnancy. 总被引:3,自引:0,他引:3 下载免费PDF全文
N S Silverman D H Watts J Hitti D M Money E Livingston J Axelrod J M Ernest D Robbins M M DiVito 《Infectious diseases in obstetrics and gynecology》1998,6(6):237-243
OBJECTIVE: To study maternal and neonatal effects of combination nucleoside analog therapy administered to human immunodeficiency virus (HIV)-infected pregnant women for maternal indications. METHODS: A multicenter, prospective observational study was undertaken at six perinatal centers in the United States and Canada that supported regional referral programs for the treatment of HIV-infected pregnant women. Demographic, laboratory, and pregnancy outcome data were collected for 39 women whose antiretroviral treatment regimens were expanded to include more than one nucleoside analog for maternal indications. The 40 newborns were monitored at pediatric referral centers through at least three months of age to ascertain their HIV infection status. RESULTS: For all 39 women, zidovudine (ZDV) therapy was instituted at 13.4 +/- 8.2 weeks, with a second agent (lamivudine [3TC] in 85% of cases) being added at a mean gestational age of 17.6 weeks. Duration of therapy with two agents was 20.6 +/- 10.4 weeks overall, with no women stopping medications because of side effects or toxicity. No significant changes in maternal laboratory values were seen, except for an increase in mean corpuscular volume, over the course of pregnancy. No clinically significant adverse neonatal outcomes were noted, with all but the three preterm newborns leaving hospital with their mothers. Neonatal anemia (hematocrit < 50%) was seen in 62% of newborns, with no children needing transfusion; mild elevations of liver function tests, primarily aspartate aminotransferase, were noted in 58% of newborns tested, though none were clinically jaundiced. Overall rate of neonatal HIV infection was 2.5% (95% confidence interval: 0.1-13.2%). CONCLUSION: Combination antiretroviral therapy during pregnancy with two nucleoside analogs was well-tolerated by mothers and newborns, with no significant short-term toxicities or side effects noted. Surveillance of exposed newborns' hematologic and liver function appears warranted. 相似文献
48.
Colorectal cancer prevention. 总被引:10,自引:0,他引:10
Colorectal cancer is the second leading cause of mortality in the United States. In the United States, the cumulative lifetime risk of developing colorectal cancer for both men and women is 6%. Despite advances in the management of this disease, the 5-year survival rate in the United States in only 62%. Because only 38% of patients are diagnosed when the cancers are localized to the bowel wall, it is likely that widespread implementation of screening could significantly improve the outcome. Colorectal cancer screening is cost effective, irrespective of the methods used. In addition to currently available methods (fecal occult blood, flexible sigmoidoscopy, colonoscopy, and double contrast barium enema), computed tomographic colonography (virtual colonoscopy) and stool-based molecular screening are under development. Four classes of chemopreventive compounds have demonstrated efficacy in reducing recurrent colorectal adenomas and/or cancer in randomized, controlled trials. They are selenium, calcium carbonate, hormone replacement therapy, and nonsteroidal anti-inflammatory drugs. The mechanisms of action of nonsteroidal anti-inflammatory drugs include inhibition of the cyclooxygenase system as well as cyclooxygenase-independent effects. Considerable effort is being expended to define chemopreventive activity, optimal dose, administration schedule, and toxicity for the coxibs in adenoma recurrence prevention trials. The threshold for tolerating toxicities is very low in asymptomatic individuals at minimally increased risk for colorectal neoplasia. 相似文献
49.
50.
Hyperglycosylated chorionic gonadotropin (CG-H) signals placental cytotrophoblast cell growth and invasion, and chorionic gonadotropin (CG) promotes uterine vascularization. A hypothesis is presented relating the evolution of these molecules to the evolution of human hemochorial implantation and that of the human brain. Deep placental invasion, vascularization and hemochorial placentation, under the influence of CG and CG-H, are a critical part of the nutrition and energy-generating mechanisms needed for human brain development and thus for the evolution of humans. Insufficient CG-H production and the resulting inappropriate implantation is associated with an unduly high incidence of pregnancy failures in humans. Low levels of CG-H and inappropriate hemochorial placentation also appear to be associated with subsequent preeclampsia. It is also of note that human CG-H drives invasion by gestational trophoblastic neoplasms that have been described only in humans. 相似文献