全文获取类型
收费全文 | 4994篇 |
免费 | 212篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 47篇 |
儿科学 | 138篇 |
妇产科学 | 247篇 |
基础医学 | 714篇 |
口腔科学 | 109篇 |
临床医学 | 360篇 |
内科学 | 990篇 |
皮肤病学 | 71篇 |
神经病学 | 429篇 |
特种医学 | 135篇 |
外科学 | 686篇 |
综合类 | 83篇 |
一般理论 | 4篇 |
预防医学 | 431篇 |
眼科学 | 123篇 |
药学 | 299篇 |
中国医学 | 16篇 |
肿瘤学 | 336篇 |
出版年
2024年 | 26篇 |
2023年 | 52篇 |
2022年 | 95篇 |
2021年 | 206篇 |
2020年 | 100篇 |
2019年 | 138篇 |
2018年 | 158篇 |
2017年 | 103篇 |
2016年 | 118篇 |
2015年 | 139篇 |
2014年 | 176篇 |
2013年 | 235篇 |
2012年 | 366篇 |
2011年 | 353篇 |
2010年 | 184篇 |
2009年 | 146篇 |
2008年 | 285篇 |
2007年 | 275篇 |
2006年 | 264篇 |
2005年 | 255篇 |
2004年 | 236篇 |
2003年 | 200篇 |
2002年 | 203篇 |
2001年 | 41篇 |
2000年 | 43篇 |
1999年 | 33篇 |
1998年 | 44篇 |
1997年 | 45篇 |
1996年 | 25篇 |
1995年 | 28篇 |
1994年 | 41篇 |
1993年 | 31篇 |
1992年 | 32篇 |
1991年 | 28篇 |
1990年 | 32篇 |
1989年 | 23篇 |
1988年 | 31篇 |
1987年 | 22篇 |
1986年 | 25篇 |
1985年 | 17篇 |
1984年 | 20篇 |
1983年 | 17篇 |
1982年 | 24篇 |
1981年 | 20篇 |
1980年 | 21篇 |
1979年 | 24篇 |
1978年 | 17篇 |
1976年 | 14篇 |
1975年 | 14篇 |
1969年 | 10篇 |
排序方式: 共有5218条查询结果,搜索用时 15 毫秒
61.
Exacerbation of acute pancreatitis by combined cholinergic stimulation and duct obstruction 总被引:1,自引:0,他引:1
BACKGROUND: The role of cholinergic pathways in the pathogenesis of bile-pancreatic duct ligation (BPDL)-induced acute pancreatitis in rats remains controversial. We hypothesized that cholinergic stimulation exacerbates acute pancreatic inflammation in the presence of duct obstruction. METHODS: We studied 34 rats divided into 5 groups as follows: (1) sham operation; (2) BPDL; (3) BPDL with duodenal bile-pancreatic juice (BPJ) replacement fresh from a donor rat; (4) BPDL with BPJ replacement as in 3 above, and carbachol (CCh) 5 ug/h subcutaneously; or (5) CCh 5 ug/h subcutaneously only. Rats were killed after 6 hours. RESULTS: The P value was less than .05 by analysis of variance. Pancreatic morphologic changes and zymogen fraction hyperamylasemia seen with duct ligation (2 vs. 1) were ameliorated significantly by duodenal BPJ replacement (3 vs. 2), but not when exogenous CCh was administered (4 vs. 3), whereas CCh alone showed no significant changes compared with sham (5 vs. 1). CONCLUSIONS: Cholinergic stimulation and duct obstruction synergistically amplify acinar hyperstimulation and exacerbate acute pancreatitis. 相似文献
62.
N-ras gene point mutations in childhood acute lymphocytic leukemia correlate with a poor prognosis 总被引:2,自引:2,他引:2
Lubbert M; Mirro J Jr; Miller CW; Kahan J; Isaac G; Kitchingman G; Mertelsmann R; Herrmann F; McCormick F; Koeffler HP 《Blood》1990,75(5):1163-1169
Ras genes can be altered by point mutations at critical portions of their coding regions to acquire transforming ability in vitro. These point mutations have been detected in a variety of human malignancies. However, their relevance for the clinical and biologic behavior of the subgroups of patients exhibiting these mutations in unclear. We analyzed 100 patients with childhood acute lymphocytic leukemias (ALLs) for point mutations of exons 1 and 2 of all three ras genes (H-ras, K- ras, and N-ras) by polymerase chain reaction and a combination of oligonucleotide hybridization and direct DNA sequencing. A 6% incidence of N-ras gene mutations was detected, all of which occurred at different nucleotides of codons 12 or 13 of N-ras. When correlating presence of ras mutations with the clinical and biologic features and the clinical outcome of these cases, a significantly higher risk for hematologic relapse (P = .01) and a trend toward a lower rate of complete remission (P = .07) was noted. The two groups did not differ in any of the known high-risk factors of ALL. These results suggest that presence of an N-ras mutation in children with ALL may be an independent predictor for worse clinical outcome and therefore may have therapeutic implications; further studies to confirm these findings are required because of the small number of patients with N-ras mutations. 相似文献
63.
Ethnopharmacological relevance
Gouania longipetala leaves are commonly used in folkloric medicine in Africa and other parts of the world for treatment of edema, febrifuges, veneral diseases, lumbago, heart diseases, diabetes mellitus malaria, etc. This study therefore evaluated safety profile of the methanol leaf extract of the plant using acute and sub-chronic studies in rat model.Materials and methods
Acute toxicity test of the plant lasted for 48 h with oral administration of graded doses (100–4000 mg/kg) of Gouania longipetala extract (GLE) in rats. The rats were observed for signs of toxicity and death. The sub-chronic toxicity was evaluated by administration of different doses (2.5, 5 and 10 mg/kg) of GLE daily in feed for 90 days. On days, 30, 60 and 90, blood samples collected from the retro-orbital plexus of the eye of the rats were used for evaluation of serum biochemistry, hematology, lipid peroxidation and in vivo antioxidant activities. Histopathological evaluations of the kidney, liver, lungs and heart were also done.Results
The acute toxicity test revealed no observable signs of toxicity or morbidity. Sub-chronic study showed that GLE significantly (p<0.05) increased relative liver weight on day 90 at 10 mg/kg. There were no significant variations in the hematological parameters of both GLE treated and untreated rats. The extract significantly (p<0.05) reduced total cholesterol, triglycerides, very low density lipoproteins and increased high density lipoproteins which was more prominent on day 90 at the dose of 10 mg/kg. The extract significantly (p<0.05) increased liver enzyme markers at the doses used. GLE also significantly (p<0.05) increased serum urea at the dose of 10 mg/kg on day 90. The extract caused dose-dependent and significant (p<0.05) increase in superoxide dismutase and decrease in malondiadehyde. Histopathological studies revealed degenerative changes in the kidney and liver.Conclusion
The results of the study suggest that Gouania longipetala is well tolerated in short term therapies, but may have long term toxic effects on the kidney and liver. 相似文献64.
María Isabel Barrionuevo-Sánchez Albert Ariza-Solé Daniel Ortiz-Berbel José González-Costello Joan Antoni Gómez-Hospital Victòria Lorente Oriol Alegre Isaac Llaó José Carlos Sánchez-Salado Josep Gómez-Lara Arnau Blasco-Lucas Josep Comin-Colet 《老年心脏病学杂志》2022,15(2):115-124
65.
66.
The value of parental report for diagnosis and management of dehydration in the emergency department
STUDY OBJECTIVES: We define the predictive value of parents' computer-based report for history and physical signs of dehydration for a primary outcome of percentage of dehydration (fluid deficit) and 2 secondary outcomes: clinically important acidosis and hospital admission. We also sought to compare the reports of physical signs related to dehydration made by parents and nurses. METHODS: We performed a prospective observational trial in an urban pediatric emergency department. A convenience sample of parents completed a computer-based interview covering historical details and physical signs (ill appearance, sunken fontanelle, sunken eyes, decreased tears, dry mouth, cool extremities, and weak cry) related to dehydration. Nurses independently completed an assessment of physical signs for enrolled children. The primary outcome was the degree of dehydration (fluid deficit), which was defined as the percentage difference between initial ED weight and stable final weight after the illness. Secondary outcomes included clinically important acidosis (defined as a serum CO(2) value of =15 mEq/L) and hospital admission. RESULTS: One hundred thirty-two parent-child dyads comprised the final sample. Parent-reported data manifested higher sensitivity (range 73% to 100%) than specificity (range 0% to 49%) for the prediction of dehydration of 5% or greater. Likelihood ratios (LRs) near zero (<0.1) suggest that a normal history of fluid intake and urine output reduced the likelihood of significant dehydration. Parental report of a normal tearing state reduced the likelihood of significant dehydration and clinically important acidosis (negative LRs of 0.4 and 0.1, respectively). Two physical signs reported by parents, sunken fontanelle and decreased tears, were associated with hospital admission (positive LR of 3.4 and 4.0, respectively). CONCLUSION: Parents' report of history and observations for children captured through computer-based interview demonstrates predictive value for relevant outcomes in dehydration. 相似文献
67.
Farías Llamas OA López Ramírez MK Morales Amezcua JM Medina Quintana M Buonocunto Vázquez G Ruiz Chávez IE González Ojeda A 《Revista de gastroenterologia de Mexico》2005,70(2):169-179
Tuberculosis is a public health problem. The most common presentation is pulmonary disease. The diagnosis of any extrapulmonary forms are quite difficult. Clinical manifestations of gastrointestinal tuberculosis are non-specific and compatible with pathologies such as inflammatory bowel disease, advanced ovarian cancer, deep mycosis, yersinia infection and amebomas. Abdominal form is located at 6th place of the extrapulmonary forms, after lymphatic, genitourinary, osteoarticular, miliary and meningeal infections. Eventually, 25 to 75% of patients with abdominal tuberculosis will require surgery. These procedures should be limitated with the purpose to preserve small bowel. Resection should be limitated for complicated cases. The surgical indications include: Intestinal occlusion (15-60%), perforation (1-15%), abscesses and fistulas (2-30%) and hemorrhage (2%). CONCLUSIONS: In most of the cases, the diagnosis of peritoneal or intestinal tuberculosis is made during a laparoscopy or laparotomy even during surgery performed by different purposes. Excessive manipulation of the intraabdominal organs may produced unexpected bowel lesions, increasing morbidity and mortality. Medical treatment is highly effective in the resolution of moderate complications such as bowel obstruction. Resectional procedures should be reserved for complications like perforation, bleeding or stenosis non-suitable for stricturoplasty. 相似文献
68.
Yoseph Shalev Menashe Epstein Oded Ayzenberg Abraham Caspi Herzl Ben-Hur Zion Hagay Isaac Blickstein Alan Gelven 《Clinical cardiology》1993,16(10):754-756
Acute myocardial infarction during pregnancy is considered to be associated with approximately 50% mortality of both mother and fetus. However, there are not enough data regarding the role of acute myocardial ischemia. We present a 36-year-old, pregnant, white female who was admitted twice at 18 and 20 weeks of gestation with acute myocardial ischemia. Cardiac catheterization revealed 70–80% stenosis of the mid left anterior descending artery (LAD) with normal antegrade flow and very good retrograde filling of the LAD from distal collaterals of the right coronary artery. Therefore, due to angiographic suggestion of protected LAD territory, we recommended medical therapy and scheduled a vaginal delivery that was successfully completed without cardiovascular complications. A stress thallium test performed 6 months later was normal, supporting our clinical judgment. In conclusion, every case of a pregnant woman with coronary insufficiency should be treated according to individual coronary anatomy and blood supply to the territory of the diseased artery, and should not be based on the old data in the literature. The decision for revascularization prior to delivery versus medical therapy, or Caesarean section versus natural delivery, should be made by a team of a cardiologist and an obstetrician. 相似文献
69.
70.