首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   13939篇
  免费   637篇
  国内免费   86篇
耳鼻咽喉   124篇
儿科学   249篇
妇产科学   113篇
基础医学   1737篇
口腔科学   309篇
临床医学   885篇
内科学   3795篇
皮肤病学   357篇
神经病学   852篇
特种医学   544篇
外科学   2540篇
综合类   69篇
预防医学   385篇
眼科学   211篇
药学   836篇
中国医学   59篇
肿瘤学   1597篇
  2023年   106篇
  2022年   222篇
  2021年   354篇
  2020年   190篇
  2019年   235篇
  2018年   331篇
  2017年   253篇
  2016年   337篇
  2015年   286篇
  2014年   421篇
  2013年   477篇
  2012年   859篇
  2011年   861篇
  2010年   534篇
  2009年   432篇
  2008年   840篇
  2007年   884篇
  2006年   836篇
  2005年   854篇
  2004年   807篇
  2003年   738篇
  2002年   777篇
  2001年   228篇
  2000年   219篇
  1999年   213篇
  1998年   199篇
  1997年   169篇
  1996年   132篇
  1995年   125篇
  1994年   109篇
  1993年   108篇
  1992年   154篇
  1991年   140篇
  1990年   105篇
  1989年   125篇
  1988年   127篇
  1987年   97篇
  1986年   86篇
  1985年   82篇
  1984年   71篇
  1983年   57篇
  1982年   36篇
  1981年   35篇
  1980年   36篇
  1979年   41篇
  1975年   28篇
  1974年   27篇
  1973年   29篇
  1970年   28篇
  1969年   25篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.

Background

Controversy continues as to whether single-incision laparoscopic cholecystectomy, with the somewhat larger incision at the umbilicus, may lead to a worse postoperative quality of life and more pain compared with the more classic 4-port laparoscopic cholecystectomy. The aim of this study was to compare single-incision and 4-port laparoscopic cholecystectomy from the perspective of quality of life.

Methods

This study was a multicenter, parallel-group, open-label, randomized clinical trial. A total of 120 patients who were scheduled to undergo elective cholecystectomy were randomly assigned 1:1 into the single-incision laparoscopic cholecystectomy or the 4-port laparoscopic cholecystectomy group and then assessed continuously for 2 weeks during the postoperative period. The primary outcome was quality of life, defined as the time to resume normal daily activities. Postoperative pain was also assessed. To explore the heterogeneity of treatment effects, we assessed the interactions of sex, age, and working status on recovery time.

Results

A total of 58 patients in the single-incision group and 53 in the 4-port group (n?=?111, 47 male, mean age 57 years) were analyzed. The mean time to resume daily activities was 10.2 days and 8.8 days, respectively, for single-incision and 4-port laparoscopic cholecystectomy (95% confidence interval –0.4 to 3.2, P?=?.12). Similarly, the time to relief from postoperative pain did not differ significantly between the groups. Statistically insignificant but qualitative interactions were noted; in the subgroups of women, full-time workers, and patients younger than 60 years, recovery tended to be slower after single-incision laparoscopic cholecystectomy.

Conclusion

Postoperative quality of life did not differ substantially between single-incision laparoscopic cholecystectomy and 4-port laparoscopic cholecystectomy. Patients younger than 60 years, women, and full-time workers tended to have a somewhat slower recovery after single-incision laparoscopic cholecystectomy.  相似文献   
2.
Mutations in the gene encoding 11beta-hydroxysteroid dehydrogenase type 2, HSD11B2, cause a rare monogenic juvenile hypertensive syndrome called apparent mineralocorticoid excess (AME). In AME, defective HSD11B2 enzyme activity results in overstimulation of the mineralocorticoid receptor (MR) by cortisol, causing sodium retention, hypokalemia, and salt-dependent hypertension. Here, we have studied whether genetic variations in HDS11B2 are implicated in essential hypertension in Japanese hypertensives and the general population. By sequencing the entire coding region and the promoter region of HDS11B2 in 953 Japanese hypertensives, we identified five missense mutations in 11 patients (L14F, n = 5; R74H, n = 1; R147H, n = 3; T156I, n = 1; R335H, n = 1) and one novel frameshift mutation (4884Gdel, n = 1) in a heterozygous state, in addition to 19 genetic variations. All genetic variations identified were rare, with minor allele frequencies less than 0.005. Four of 12 patients with the missense/frameshift mutations showed renal failure. Four missense mutations, L14F, R74H, R147H, and R335H, were successfully genotyped in the general population, with a sample size of 3,655 individuals (2,175 normotensives and 1,480 hypertensives). Mutations L14F, R74H, R147H, and R335H were identified in hypertensives (n = 6, 8, 3, and 0, respectively) and normotensives (n = 8, 12, 5, and 0, respectively) with a similar frequency, suggesting that these missense mutations may not strongly affect the etiology of essential hypertension. Since the allele frequency of all of the genetic variations identified in this study was rare, an association study was not conducted. Taken together, our results indicate that missense mutations in HSD11B2 do not substantially contribute to essential hypertension in Japanese.  相似文献   
3.
4.
5.
6.
7.
The second derivative of the finger photoplethysmogram (SDPTG) has been used as a non-invasive examination for arterial stiffness. The present study sought to elucidate independent determinants of the SDPTG among various cardiovascular risk factors in middle-aged Japanese men. The SDPTG was obtained from the cuticle of the left-hand forefinger in 973 male workers (mean age: 44+/-6 years) during a medical checkup at a company. The SDPTG indices (b/a and d/a) were calculated from the height of the wave components. Multiple logistic regression analyses revealed that the independent determinants of an increased b/a (highest quartile of the b/a) were age (odds ratio [OR]: 1.12 per 1-year increase, 95% confidence interval [CI]: 1.09-1.15), hypertension (OR: 1.65, 95% CI: 1.03-2.65), dyslipidemia (OR: 1.51, 95% CI: 1.09-2.09), impaired fasting glucose/diabetes mellitus (OR: 2.43, 95% CI: 1.16-5.07), and a lack of regular exercise (OR: 2.00, 95% CI: 1.29-3.08). Similarly, independent determinants of a decreased d/a (lowest quartile of the d/a) were age (OR: 1.11 per 1-year increase, 95% CI: 1.08-1.14), hypertension (OR: 3.44, 95% CI: 2.20-5.38), and alcohol intake 6 or 7 days per week (OR: 2.70, 95% CI: 1.80-4.06). No independent association was observed between the SDPTG indices and blood leukocyte count or serum C-reactive protein levels. In conclusion, the SDPTG indices reflect arterial properties affected by several cardiovascular risk factors in middle-aged Japanese men. The association between inflammation and the SDPTG should be evaluated in further studies.  相似文献   
8.
9.
The ultrastructural localization of adhalin and its relations to dystrophin, β-dystroglycan, and β-spectrin were studied in normal murine skeletal myofibers. The C-terminal peptides of adhalin and β-dystroglycan were synthesized based on their cDNAs, and the affinity-purified antibodies against these peptides were produced. Single-immunolabeling electron microscopy showed that the adhalin was located just inside the muscle plasma membrane or inside the myofiber a short distance from the plasma membrane. The adhalin signal was also noted at the sarcoplasmic side of plasmalemmd invaginations or at vesicular structures in subsarcolemmal areas. Double-immunogold-labeling electron microscopy disclosed a similar localization of dystrophin, β-dystroglycan, and β-spectrin. The close association of adhalin with dystrophin or β-dystroglycan was demonstrated by formation of doublets by signals of antibodies of adhalin with those of dystrophin or β-dystroglycan and was confirmed by statistical analyses. This study demonstrated that the location of adhalin is close to that of dystrophin and β-dystroglycan at the muscle plasma membrane.  相似文献   
10.
M Yano  T Otsuka 《Brain and nerve》1988,40(10):925-928
In 9 severe head injuries whose respiration was controlled by a ventilator, continuous measurements of energy expenditure (MEE) were carried out by the ERICA Metabolic Computer. Age was ranged 19 to 69 years old (Mean 48.3 years). Glasgow Coma Scale score was 3 to 11 which were assessed the best score during 6 hours of admission. The MEE was carried out within 7 days of admission and was continued to measure more than 3 days. It measured O2 consumption and CO2 output, and calculated the indirect energy expenditure. The data were displayed and recorded every 1, 15, 60 min. The value of MEE was compared with predicted energy expenditure (PEE) which was calculated by the Harris-Benedict formula. Out of 9 patients, 6 patients were survived. High dose barbiturate therapy was performed in 7 patients to control and decrease the intracranial hypertension. Of them 3 patients died. The value of MEE in all 9 patients was variable from 77% to 212% of PEE. The value of MEE in 6 survived patients was 98.0 to 212.0% of PEE. Out of 6 patients, 4 patients who were administered high dose barbiturate showed variable data of MEE. Two patients showed about 100% of the PEE, one showed about 150%, and another one about 200%. Remaining 2 survivors who were not administered barbiturate showed about 125% of PEE, which was low value. These results were divided into two groups. In 2 patients, the value of MEE was 150% or more in spite of barbiturate therapy. In remaining 7 patients, the value of MEE was 125% or less of PEE.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号