全文获取类型
收费全文 | 775篇 |
免费 | 65篇 |
国内免费 | 110篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 146篇 |
妇产科学 | 8篇 |
基础医学 | 95篇 |
口腔科学 | 32篇 |
临床医学 | 119篇 |
内科学 | 152篇 |
皮肤病学 | 18篇 |
神经病学 | 20篇 |
特种医学 | 73篇 |
外科学 | 60篇 |
综合类 | 43篇 |
预防医学 | 42篇 |
眼科学 | 28篇 |
药学 | 62篇 |
中国医学 | 1篇 |
肿瘤学 | 47篇 |
出版年
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 13篇 |
2016年 | 11篇 |
2015年 | 15篇 |
2014年 | 12篇 |
2013年 | 27篇 |
2012年 | 19篇 |
2011年 | 23篇 |
2010年 | 21篇 |
2009年 | 22篇 |
2008年 | 19篇 |
2007年 | 86篇 |
2006年 | 46篇 |
2005年 | 45篇 |
2004年 | 35篇 |
2003年 | 25篇 |
2002年 | 33篇 |
2001年 | 18篇 |
2000年 | 19篇 |
1999年 | 18篇 |
1998年 | 50篇 |
1997年 | 40篇 |
1996年 | 42篇 |
1995年 | 21篇 |
1994年 | 26篇 |
1993年 | 15篇 |
1992年 | 15篇 |
1991年 | 12篇 |
1990年 | 14篇 |
1989年 | 16篇 |
1988年 | 18篇 |
1987年 | 16篇 |
1986年 | 15篇 |
1985年 | 13篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1972年 | 3篇 |
1897年 | 3篇 |
排序方式: 共有950条查询结果,搜索用时 0 毫秒
101.
Pramana IA Latzin P Schlapbach LJ Hafen G Kuehni CE Nelle M Riedel T Frey U 《European journal of medical research》2011,16(5):223-230
Objective
While respiratory symptoms in the first year of life are relatively well described for term infants, data for preterm infants are scarce. We aimed to describe the burden of respiratory disease in a group of preterm infants with and without bronchopulmonary dysplasia (BPD) and to assess the association of respiratory symptoms with perinatal, genetic and environmental risk factors.Methods
Single centre birth cohort study: prospective recording of perinatal risk factors and retrospective assessment of respiratory symptoms during the first year of life by standardised questionnaires. Main outcome measures: Cough and wheeze (common symptoms), re-hospitalisation and need for inhalation therapy (severe outcomes). Patients: 126 preterms (median gestational age 28.7 weeks; 78 with, 48 without BPD) hospitalised at the University Children''s Hospital of Bern, Switzerland 1999-2006.Results
Cough occurred in 80%, wheeze in 44%, rehospitalisation in 25% and long term inhalation therapy in wheezers in 13% of the preterm infants. Using logistic regression, the main risk factor for common symptoms was frequent contact with other children. Severe outcomes were associated with maximal peak inspiratory pressure, arterial cord blood pH, APGAR and CRIB-Score.Conclusions
Cough in preterm infants is as common as in term infants, whereas wheeze, inhalation therapy and re-hospitalisations occur more often. Severe outcomes are associated with perinatal risk factors. Preterm infants who did not qualify for BPD according to latest guidelines also showed a significant burden of respiratory disease in the first year of life. 相似文献102.
Frederick H Koh Jason MW Chua Joselyn LJ Tan Fung-Joon Foo Winson J Tan Sharmini S Sivarajah Leonard Ming Li Ho Bin-Tean Teh Min-Hoe Chew 《World journal of gastrointestinal surgery》2021,13(8):734-755
A growing body of evidence has demonstrated the prognostic significance of sarcopenia in surgical patients as an independent predictor of postoperative complications and outcomes. These included an increased risk of total complications, major complications, re-admissions, infections, severe infections, 30 d mortality, longer hospital stay and increased hospitalization expenditures. A program to enhance recovery after surgery was meant to address these complications; however, compliance to the program since its introduction has been less than ideal. Over the last decade, the concept of prehabilitation, or “pre-surgery rehabilitation”, has been discussed. The presurgical period represents a window of opportunity to boost and optimize the health of an individual, providing a compensatory “buffer” for the imminent reduction in physiological reserve post-surgery. Initial results have been promising. We review the literature to critically review the utility of prehabilitation, not just in the clinical realm, but also in the scientific realm, with a resource management point-of-view. 相似文献
103.
LJ Gould J Mushkudiani H Hou OY Grinberg S Grinberg HM Swartz 《Wound repair and regeneration》2004,12(2):A29-A29
Methods to reliably measure tissue oxygenation in situ are currently lacking. We have developed a vertically oriented, dorsal, bipedicle flap model that is easy to perform, reliably reproduces tissue ischemia, eliminates craniocaudal variation, and is amenable to studying therapeutic modalities. The effect of narrowing this flap on tissue oxygenation measured with Licox electrodes has previously been presented. In this study we utilize in situ EPR spectroscopy to demonstrate the oxygen gradient in the flap as a function of flap width and placement of a silicone sheet directly under the flap. The effect of wound healing over a 2 week period is demonstrated. Twenty four, 300 gm male Sprague‐Dawley rats underwent creation of the bipedicle flap according to the following groups: 2.5 cm flap with silicone, 2.0 cm flap without silicone, 2.0 cm flap with silicone. Each group of 6 animals was injected with EMS char at 2 cm intervals along the flap and one injection in the control, non‐ischemic tissue. A 4th group underwent 2.0 cm flaps with silicone and use of lithium phthalocyanin as the paramagnetic material. Wound measurements and EPR spectroscopy were performed on days 3, 7, 10 and 14. On day 14, after EPR measurements, the animals were sacrificed and their wounds excised. One flap and one control wound were preserved for histologic analysis, the other flap and control wounds were prepared for lactate measurements. EPR spectroscopy demonstrated a gradient of oxygen that was lowest in the center of the flap and greatest at either end. Changes in the oxygen gradient correlated with narrowing and placement of the intervening silicone sheet. This new technology has never been utilized in an animal model of impaired wound healing. Comparison of recently developed paramagnetic materials for optimal tissue oxygen and free radical measurements will be presented. 相似文献
104.
Karen Broekhuizen Mireille NM van Poppel Lando LJ Koppes Johannes Brug Willem van Mechelen 《BMC public health》2010,10(1):69
Background
Because of a high cardiovascular disease (CVD) risk in people with Familial Hypercholesterolemia (FH), early prevention of cardiovascular disease is important for health gain and cost reduction. This project focuses on the development and evaluation of an innovative intervention aiming to reduce CVD risk by promoting a healthy lifestyle among people with FH. 相似文献105.
Effects of neonatal castration and testosterone treatment on sexual partner preference in the ferret
Groups of male and female ferrets were tested in a T maze to determine whether they preferred to approach and interact with a sexually active male or an estrous female. Control male and female ferrets gonadectomized (GX) on postnatal Day 35 and tested in adulthood while receiving no hormone or testosterone (T) displayed no significant preference. When given estradiol benzoate (EB), however, control males preferred stimulus females whereas control females preferred stimulus males. When tested in adulthood with EB treatment, males GX on postnatal Day 5 showed a significant reduction in their approach to stimulus females, although they did not switch their preference to stimulus males and thereby resemble control females. Female ferrets GX on postnatal Day 5 and given a high dosage of T over postnatal Days 5–20 showed a significant reduction in their approach to stimulus males, although they did not switch their preference to stimulus females, and thereby resemble control males. The results suggest that extended perinatal exposure of male ferrets to T is required for the development of a sociosexual preference for females. 相似文献
106.
目的分析2005年1月~2011年12月在北京医院维持性血液透析死亡患者的病例特点和死亡原因。方法回顾性的检出维持血液透析大于3个月的死亡患者共83例,计算本中心从2005年起每年维持透析患者的死亡人数和死亡率;将死亡患者根据年龄分为3组,60岁以下中年组,60~79岁老年组和80岁以上高龄组,分析3组的人口学资料、有无糖尿病、透析龄和死亡原因等。结果从2005年起,北京医院每年维持透析患者的死亡率依次为11.00%,10.90%,8.30%。8.10%,10.10%,8.70%和6.34%;83例死亡患者中,男性49例,女性34例,平均年龄71.812.0岁(42岁~94)岁,中年组(小于60岁)14例,老年组(60~79)岁46例,高龄组(大于80)岁23例;3组患者在性别上无统计学差异。透析龄在中年组最长,平均77.2±73.0月,高龄组为44.0±35.5月,老年组透析龄最短,平均为33.2±28.1月;3组之间的差异有统计学意义。老年组患者糖尿病肾病居多;死亡原因在各组有明显的差别,中年组50%死于脑血管疾病,脑出血居多;高龄组56.50%死于感染中毒性休克。老年组死亡原因较复杂,死亡率超过10%的依次为感染中毒性休克、心肌梗死或心力衰竭、肿瘤、营养不良-炎症-动脉粥样硬化综合征(Malnutrition-inflammation-atherosclerosissyndrome,MIAsyndrome)和猝死。结论北京医院单中心血液透析死亡患者绝大多数为老年患者。年龄不是决定透析预后不良的主要危险因素,糖尿病是影响预后的重要因素,不同年龄组患者死亡原因不同,中年患者脑血管疾病多见,高龄患者感染中毒性休克常见,老年患者的死亡原因多样化,包括心脑血管疾病、感染、肿瘤和MIA综合征。± 相似文献
107.
Stockman A Tait BD Wolfe R Brand CA Rowley MJ Varney MD Buchbinder R Muirden KD 《Rheumatology international》2006,26(6):500-509
We investigated the relationship between clinical, laboratory and genetic markers and outcome measures in 159 patients with
recent onset of inflammatory arthritis (IA). The majority of patients were managed in community-based rheumatology practice.
Median duration of arthritis at baseline was 3 months with median follow-up of 4.0 years (range 0–10). Markers of disease
activity and 1987 ACR criteria for rheumatoid arthritis (RA) were estimated every 6 months for the first 2 years and annually
thereafter. Presence of shared epitopes (SE) was established by PCR-based method. Main outcome variables were attainment of
remission and presence of erosions on X-rays of hands and feet at 3 years. Remission was seen in 34.3% of patients and was
independently related to age 60 and older (odds ratio (OR) 3.2; 95% confidence interval (CI), 1.2–8.7) and inversely to the
presence of rheumatoid factor (RF) (OR 8.3; 95% CI, 3.2–21.3 for persistent arthritis). Patients with two SE were likely to
have persistent arthritis (P=0.006), but this was not significant when corrected for RF. Independent predictors for erosions at 3 years were RF (OR 7.5;
95% CI, 1.9–29.5) and area under the curve for number of swollen joints (OR 1.08; 95% CI, 1.02–1.16). SE status was not predictive
of erosions at 3 years (OR 1.6; 95% CI, 0.7–3.7). In univariate analysis, patients possessing DERAA motif on DRB1 were less
likely to have erosive disease than without this motif at 4 years (OR 0.21; 95% CI, 0.0–0.9, P=0.037) but this finding was partly explained by adjusting for RF (adjusted OR 0.24; 95% CI 0.04–1.37). In this study of recent
onset IA, active disease and RF were associated with poor outcome. Whilst SE did not predict erosive disease, patients with
DERAA motif may be protected against erosions whilst the presence of two SE alleles suggests persistence of arthritis. 相似文献
108.
Jochim S Terhaar sive Droste Mike E Craanen Rene WM van der Hulst Joep F Bartelsman Dick P Bezemer Kim R Cappendijk Gerrit A Meijer Linde M Morsink Pleun Snel Hans ARE Tuynman Roy LJ van Wanrooy Eric IC Wesdorp Chris JJ Mulder 《World journal of gastroenterology : WJG》2009,15(9):1085-1092
AIM: To assess the prevalence and location of advanced neoplasia in patients undergoing colonoscopy, and to compare the yield per indication. METHODS: In a multicenter colonoscopy survey (n = 18 hospitals) in the Amsterdam area (Northern Holland), data of all colonoscopies performed during a three month period in 2005 were analyzed. The location and the histological features of all colonic neoplasia were recorded. The prevalence and the distribution of advanced colorectal neoplasia and differences in yield between indication clusters were evaluated. Advanced neoplasm was defined as adenoma 〉 10 mm in size, with 〉 25% villous features or with high-grade dysplasia or cancer. RESULTS: A total of 4623 eligible patients underwent a total colonoscopy. The prevalence of advanced neoplasia was 13%, with 281 (6%) adenocarcinomas and 342 (7%) advanced adenomas. Sixty-seven percent and 33% of advanced neoplasia were located in the distal and proximal colon, respectively. Of all patients with right-sided advanced neoplasia (n = 228), 51% had a normal distal colon, whereas 27% had a synchronous distal adenoma. Ten percent of all colonoscopies were performed in asymptomatic patients, 7% of whom had advanced neoplasia. In the respective procedure indication clusters, the prevalence of rightsided advanced neoplasia ranged from 11%-57%. CONCLUSION: One out of every 7-8 colonoscopies yielded an advanced colorectal neoplasm. Colonoscopy is warranted for the evaluation of both symptomatic and asymptomatic patients. 相似文献
109.
Chlorpropamide-induced pure white cell aplasia 总被引:2,自引:0,他引:2
We investigated the mechanism for isolated agranulocytosis and marrow pure white cell aplasia in an elderly man receiving 0.5 to 1.0 g per day of chlorpropamide (Chl) without other toxic drug exposure or overt systemic illness. Patient marrow revealed an absence of recognizable granulocytic precursors; megakaryocytes and erythroid precursors were normal. The WBC count was 1800/mm3 on admission with only 2% neutrophils; the absolute neutrophil count first exceeded 500/mm3 on the 17th day following cessation of Chl. A serum Chl level on admission was 100 micrograms/mL (acute phase, AP); no Chl was detected in serum (convalescent phase, CP) assessed on the 22nd hospital day. Antineutrophil antibodies were not detected, and T cell depletion failed to augment patient in vitro granulopoiesis. Patient AP serum produced potent complement-mediated inhibition (87% +/- 7%) of autologous granulocyte progenitors (CFU-GM) with minimal inhibition of erythroid (11% +/- 5%) or multipotent (5% +/- 4%) progenitor cells. Selective inhibition by patient AP serum of CFU-GM (74% +/- 11%) was also seen against two allogeneic marrows. Patient CP serum no longer inhibited (6% +/- 4%) autologous CFU-GM. Addition of Chl (5 to 120 micrograms/mL) to CP serum but not to control serum resulted in potent drug concentration-dependent complement-mediated inhibition of autologous and allogeneic CFU-GM. Inhibition of CFU-GM in the presence of Chl was no longer demonstrable following immunoabsorbent removal of IgG from patient serum. Patient serum in the presence of Chl had limited activity against morphologically recognizable marrow granulocytic precursors in a microimmunofluorescence assay. These results are most consistent with the development of Chl-dependent, selective antibody-mediated immune inhibition of granulopoiesis. 相似文献
110.
Monoclonal antibody to the gastrin receptor on parietal cells recognizes a 78-kDa protein. 总被引:1,自引:0,他引:1 下载免费PDF全文
F T Mu G Baldwin J Weinstock D Stockman B H Toh 《Proceedings of the National Academy of Sciences of the United States of America》1987,84(9):2698-2702
Four monoclonal antibodies reactive by immunofluorescence and by flow microfluorimetry with canine and porcine gastric parietal cell membranes were produced by fusion of mouse NS-1 myeloma cells with splenocytes from mice immunized with a population of canine gastric mucosal cells containing 60-70% parietal cells. One of these, an IgM antibody designated 2C1, reacted with the surface membranes of parietal cells by immunofluorescence, flow microfluorimetry, and immunogold electron microscopy; competed with 125I-labeled gastrin for binding to gastric cells; and inhibited by 56% maximal gastrin stimulation of [14C]aminopyrine uptake in parietal cells. The antibody immunoprecipitated 125I-labeled samples of a 78-kDa gastrin-binding protein purified from membrane extracts of porcine gastrin mucosa but did not recognize the same protein labeled covalently with 125I-labeled gastrin-(2-17)-hexadecapeptide. These observations suggest that the previously identified 78-kDa gastrin-binding protein is the gastrin receptor and that the antibody 2C1 is directed against the gastrin binding site of the gastrin receptor. 相似文献