全文获取类型
收费全文 | 5714篇 |
免费 | 422篇 |
国内免费 | 108篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 139篇 |
妇产科学 | 199篇 |
基础医学 | 717篇 |
口腔科学 | 163篇 |
临床医学 | 647篇 |
内科学 | 1365篇 |
皮肤病学 | 92篇 |
神经病学 | 337篇 |
特种医学 | 428篇 |
外科学 | 718篇 |
综合类 | 152篇 |
预防医学 | 202篇 |
眼科学 | 161篇 |
药学 | 410篇 |
中国医学 | 38篇 |
肿瘤学 | 418篇 |
出版年
2023年 | 21篇 |
2022年 | 65篇 |
2021年 | 118篇 |
2020年 | 73篇 |
2019年 | 92篇 |
2018年 | 146篇 |
2017年 | 107篇 |
2016年 | 127篇 |
2015年 | 246篇 |
2014年 | 212篇 |
2013年 | 240篇 |
2012年 | 387篇 |
2011年 | 371篇 |
2010年 | 241篇 |
2009年 | 179篇 |
2008年 | 282篇 |
2007年 | 326篇 |
2006年 | 279篇 |
2005年 | 259篇 |
2004年 | 238篇 |
2003年 | 294篇 |
2002年 | 261篇 |
2001年 | 197篇 |
2000年 | 174篇 |
1999年 | 139篇 |
1998年 | 84篇 |
1997年 | 75篇 |
1996年 | 65篇 |
1995年 | 51篇 |
1994年 | 38篇 |
1993年 | 58篇 |
1992年 | 93篇 |
1991年 | 76篇 |
1990年 | 70篇 |
1989年 | 76篇 |
1988年 | 62篇 |
1987年 | 68篇 |
1986年 | 55篇 |
1985年 | 32篇 |
1984年 | 27篇 |
1983年 | 23篇 |
1982年 | 19篇 |
1981年 | 18篇 |
1980年 | 21篇 |
1979年 | 27篇 |
1978年 | 16篇 |
1977年 | 16篇 |
1975年 | 10篇 |
1974年 | 10篇 |
1972年 | 11篇 |
排序方式: 共有6244条查询结果,搜索用时 15 毫秒
101.
OBJECTIVE: Because survival from admission to discharge does not provide parents and physicians information about future life expectancy in the premature neonate, we characterized the actuarial survival, defined as the future life expectancy from a given postnatal age, in a large inborn population of premature infants < 30 weeks' gestation. STUDY DESIGN: We determined daily actuarial survival of 1925 inborn infants (23 to 29 weeks' gestation) admitted to the Baylor Affiliated Nurseries from July 1986 through December 1994, stratified by 100-g birth weight and by 1-week gestational-age intervals. RESULTS: In the 501- to 600-g birth weight stratum, actuarial survival improved from 31% at birth, to 61% on day of life 7, and then to 75% on day of life 28; in the 901- to 1000-g birth weight stratum, actuarial survival improved from 88%, to 94%, and then to 98% throughout the same times, respectively. Similar trends were obtained when data were stratified by gestational age. CONCLUSIONS: Survival in the smallest infants improves dramatically during the first few days of life, but there is a significant risk for late death in the smallest of these infants. 相似文献
102.
Incident type 2 diabetes mellitus in African American and white adults: the Atherosclerosis Risk in Communities Study 总被引:11,自引:0,他引:11
Context Although the excess prevalence of type 2 diabetes mellitus in African Americans is well established, few studies have compared incident diabetes in African American and white persons. Objectives To compare risk of incident diabetes in African American vs white adults and to identify explanatory factors for racial disparities. Design Prospective cohort study using baseline data collected from 1986 to 1989 from the ongoing Atherosclerosis Risk in Communities (ARIC) Study, with 9 years of follow-up. Setting and Participants A total of 2646 African American and 9461 white adults aged 45 to 64 years without diabetes at baseline, sampled from 4 US communities. Main Outcome Measures Incident type 2 diabetes, ascertained by self-report of physician diagnosis, use of diabetes medications, or fasting glucose level of at least 7.0 mmol/L (126 mg/dL), compared among white and African American subjects and by presence of potentially modifiable risk factors. Results Diabetes incidence per 1000 person-years was about 2.4-fold greater in African American women (25.1 [95% confidence interval {CI}, 22.4-28.1] vs 10.4 [95% CI, 9.4-11.4]) and about 1.5-fold greater in men (23.4 [95% CI, 19.9-27.2] vs 15.9 [95% CI, 14.6-17.2]) than in their white counterparts (P<.001). Results from proportional hazards regression models indicated that racial differences in potentially modifiable risk factors, particularly adiposity, accounted for 47.8% of the excess risk in African American women but accounted for little excess risk in African American men. Compared with their white counterparts, African American men and women had higher blood pressures before diabetes onset (diastolic blood pressure difference=5.6 mm Hg in women and 8.4 mm Hg in men; P=.005). Conclusions Our data indicate that compared with their white counterparts, middle-aged African Americans are at greater risk of developing type 2 diabetes and have higher blood pressure prior to development of diabetes. In women, almost 50% of this excess risk might be related to potentially modifiable factors. 相似文献
103.
Antisense RNA-mediated reduction of p53 induces malignant phenotype in nontumorigenic rat urothelial cells 总被引:2,自引:1,他引:2
p53 mutation is commonly associated with high-grade, high-stage human
urothelial carcinomas. Recent studies suggest that p53 mutation in low-
grade, low-stage bladder carcinomas may be correlated with the progression
of the disease. In the present study, we used antisense RNA methodology in
vitro to evaluate the significance of the loss of p53 function at an early
stage of urinary bladder carcinogenesis. An immortalized nontumorigenic rat
urothelial cell line (MYP3) that strongly expresses wild-type (WT) p53 was
transfected with a plasmid (pcDL-SR alpha-296) containing a rat WT p53 cDNA
in antisense orientation. The transfection resulted in a significant
reduction in p53 mRNA expression and protein synthesis, in stimulation of
anchorage- dependent growth, and in acquisition of anchorage-independent
growth potential. Three such clones, when tested in athymic nude mice, all
formed muscle-invasive, high-grade transitional cell carcinomas at s.c.
injection sites. When cells were inoculated into an orthotopic site
(urinary bladder), one of two antisense transfectants tested formed bulky
tumors in the bladder in all seven nude mice and metastases to lungs in
three of the seven mice. Analysis of these cells revealed a decrease in the
expression of p21 (WAF1, sdi1, or CIP1) and retinoblastoma (Rb) gene
product. Phosphorylation of Rb protein was not inhibited when the cells
were starved. No significant difference was observed in the expression of
p16 protein. In cell cycle analysis, all antisense transfectants tested
escaped from G1 arrest by starvation. Furthermore, secretion of interleukin
(IL)-6 into culture medium was increased significantly. Treatment with
anti-IL-6 antibody suppressed anchorage-dependent growth. This study
directly demonstrates that the loss of p53 function at an early stage of
urothelial carcinogenesis may result in acquisition of a malignant
phenotype by regulating IL-6 production as well as cell cycle related
genes.
相似文献
104.
105.
艾灸足三里治疗顺铂所致迟发性呕吐的临床观察 总被引:9,自引:0,他引:9
目的:观察艾灸足三里治疗顺铂所致迟发性呕吐的临床效果.方法:100例患者随机分A、B两组各50例,A组(治疗组):枢星3mg 0.9%NS20ml化疗前30min iv d1-3 艾灸足三里d1-7;B组(对照组):枢星3mg 0.9%NS20ml化疗前30min iv d1~3,观察化疗后7d内呕吐情况.结果:A组控制迟发性呕吐的有效率明显高于B组(P<0.05).结论:艾灸足三里治疗顺铂所致迟发性呕吐疗效好、经济、方便、安全. 相似文献
106.
Postero-medio-anterior approach of the ankle for the pilon fracture 总被引:17,自引:0,他引:17
A good view of the operative field is important for better reduction and fixation in surgical treatment of fractures. The exposure of the ankle joint for the pilon fracture is commonly through the anterior approach, or combined with the medical approach. But sometimes it is still difficult to have complete viewing of the articular surface and to apply internal fixation by that approach. In recent years, we developed a "postero-medio-anterior" approach of the ankle joint by one incision. This approach provides an excellent exposure of the anterior, medial and posterior aspects of the ankle joint with a clear view of the articular surface. In our 45 cases of pilon fracture during 1991 to 1995, there was no incisional injury to the neurovascular bundle. Superficial wound edge necrosis was noted in two cases which healed later without further procedure. Therefore, we recommend this approach as a simple and reliable incision for open reduction of pilon fractures. 相似文献
107.
108.
BACKGROUND: Many publications recommend nonoperative treatment for stable blunt hepatic injury patients. Unstable hemodynamic status is the only indication for surgery. When operation is indicated, controversies exist regarding which operative procedure will be more beneficial to the patients. The purposes of this study are to compare the results of operative and nonoperative management of patients with blunt hepatic injuries and to identify the optimal surgical approach when surgery is indicated. METHODS: Different prospective protocols of treating adult blunt hepatic injuries were conducted. From 1992 to 1993 (group I), urgent surgery would be performed in the presence of hemoperitoneum. The policy shifted to aggressive nonoperative approach between 1996 and 1997 (group II). The patients from each period were divided into three subgroups. Group A included the patients who received nonoperative treatment in either period. Group B consisted of the patients who received surgery in the first period and nonoperative management in the second period. Group C included the patients who were operated on in either group. Comparisons were made between matched groups. RESULTS: Groups IA and IIA patients had minor injuries and could be successfully treated nonoperatively. The results of groups IB and IIB were similar concerning hospital stay, morbidity, and mortality. Transfusion requirements of group IIB patients were significantly higher (2.2 vs. 1.1 units,p = 0.01) than those of group IB. However, 25 (58%) celiotomies of group IB patients were nontherapeutic. When surgery was indicated, group IC patients had significantly higher liver-related mortality (14 of 49 vs. 3 of 55, p = 0.002). Anatomic resection was performed more frequently in that period. CONCLUSION: Nonoperative treatment significantly decreased the rate of nontherapeutic laparotomy but carried the risks of higher transfusion requirements and delaying operation. When surgery was indicated, the policy of minimal intervention positively affected the patients' outcomes. The goal of surgery should be hemorrhage control rather than resection of the injured liver tissues. 相似文献
109.
110.
Gwinn DE Wilckens JH McDevitt ER Ross G Kao TC 《The American journal of sports medicine》2000,28(1):98-102
The purpose of this study was to evaluate the relative risk of anterior cruciate ligament injury in female versus male midshipmen at the United States Naval Academy. From 1991 to 1997, we recorded the incidence of anterior cruciate ligament injury during intercollegiate athletics, intramural athletics, and military training. The subjects were male and female varsity athletes, coed intramural athletes, and participants in military training consisting of the obstacle course and instructional wrestling. All patient data were collected at the time of injury. Records filed at the intramural sports office, along with a questionnaire completed by coaches and trainers, were used to estimate midshipmen exposures. Results showed that in intercollegiate soccer, basketball, and rugby, women had a relative injury risk of 3.96 compared with men. In coed soccer, basketball, softball, and volleyball, the women's relative injury risk was 1.40 compared with men. In military training, women had a relative injury risk of 9.74 compared with men. In comparing overall annual anterior cruciate ligament injury rates among midshipmen, we found that women had a relative injury risk of 2.44 compared with men. We concluded that female midshipmen have an increased relative risk of anterior cruciate ligament injury as compared with men in intercollegiate athletics, basic military training, and throughout their service academy career. This increase was not statistically significant at the intramural level of athletics. 相似文献