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:      
  示例: 沙坡头地区,人工植被区,变化  检索词用空格隔开表示必须包含全部检索词,用“,”隔开表示只需满足任一检索词即可!
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   18738篇
  免费   429篇
  国内免费   78篇
耳鼻咽喉   112篇
儿科学   494篇
妇产科学   370篇
基础医学   2895篇
口腔科学   350篇
临床医学   1496篇
内科学   4552篇
皮肤病学   310篇
神经病学   1856篇
特种医学   451篇
外科学   1338篇
综合类   48篇
一般理论   5篇
预防医学   1400篇
眼科学   212篇
药学   1331篇
  2篇
中国医学   62篇
肿瘤学   1961篇
  2024年   163篇
  2023年   208篇
  2022年   392篇
  2021年   679篇
  2020年   416篇
  2019年   574篇
  2018年   586篇
  2017年   484篇
  2016年   553篇
  2015年   600篇
  2014年   757篇
  2013年   1000篇
  2012年   1623篇
  2011年   1619篇
  2010年   891篇
  2009年   800篇
  2008年   1307篇
  2007年   1205篇
  2006年   1154篇
  2005年   996篇
  2004年   907篇
  2003年   758篇
  2002年   652篇
  2001年   84篇
  2000年   47篇
  1999年   94篇
  1998年   122篇
  1997年   99篇
  1996年   93篇
  1995年   50篇
  1994年   44篇
  1993年   49篇
  1992年   28篇
  1991年   25篇
  1990年   23篇
  1989年   9篇
  1988年   12篇
  1987年   17篇
  1986年   10篇
  1985年   7篇
  1984年   17篇
  1983年   11篇
  1982年   12篇
  1981年   10篇
  1980年   9篇
  1979年   6篇
  1978年   5篇
  1975年   5篇
  1973年   10篇
  1971年   4篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The study discusses the construct of spontaneity and its causal relationship with psychological well-being. It develops a preview phase of validation of the SAI-R and its correlation with the Clinical Outcomes for Routine Evaluation-Outcome Measure (CORE-OM) and the Beck Depression Inventory (BDI-II) and assumes the hypothesis that a high level of spontaneity is correlated negatively with low level of well-being and positively with depression. The research involved Italian and Austrian participants, consisting of 166 Italian and 146 Austrian university students. The findings suggested a causal relationship between low spontaneity and psychological suffering. The results obtained confirm the hypothesized model, showing significant negative causal relationship. The verification of this theoretical model on non-clinical samples allows us to set the ground for future use in clinical samples. Furthermore, this result encourages the development of further research into the use of SAI-R.  相似文献   
42.
The aim of this study was to identify at species level and to investigate the antibiotic susceptibility of oral streptococcal strains isolated from 100 pus samples collected from Romanian patients with different odontogenic infections. The isolates were identified at species level using the Rapid ID 32 STREP system and their susceptibility was testing by the Etest, against: penicillin G, ampicillin, erythromycin, clindamycin and tetracycline. For the investigation of erythromycin resistance phenotype the disk diffusion test was used. The isolates belonged to several species, with Streptococcus anginosus and Streptococcus oralis predominating. Reduced susceptibility to beta-lactam antibiotics was found only among the isolates belonging to S. mitis and S. sanguinis groups. Resistance to erythromycin was detected among all species, except for: S. constellatus, S. intermedius and S. gordonii, and the M phenotype was established, while resistance to tetracycline was detected within all species but S. gordonii. In contrast, clindamycin was fully active. As most odontogenic infections are mixed infections, often involving strictly anaerobic bacteria, which are frequently beta-lactamase producers, the association of a penicillin and a beta-lactamase inhibitor, like Amoxiclav, is recommended when the antimicrobial treatment is necessary.  相似文献   
43.
Even though very precise at describing pelvic organ position, our criticism to the Pelvic Organ Prolapse Quantification (POP-Q) system is its limited ability to quantify the prolapse itself, since it still classifies prolapse into four stages, almost the same way as Baden and Walker (Clin Obstet Gynecol 15(4):1070-1072, 1972) did in 1972. As a result, the same grade can include a wide prolapse intensity range. The objective of this study was to assess inter-observer reliability in the Pelvic Organ Prolapse Quantification Index (POP-Q-I; Lemos et al., Int Urogynecol J 18(6):609-611, 2007) on a prospective randomized trial. Fifty consecutive women were prospectively examined by two members of the urogynecology staff, blinded to each other's results. Spearman's rank correlation was used to assess inter-observer reliability. Excellent correlation coefficients were observed, with an overall coefficient of 96.5% (CI: 0.889-1.042; p < 0.0001). The POP-Q-I is a method that makes POP research more efficient by directly measuring prolapse as a continuous variable, which is statistically more powerful than the categorical variables proposed by the POP-Q system. This study suggests that the POP-Q-I is applicable to clinical POP research.  相似文献   
44.

Background/purpose

No studies have investigated the cosmetic outcome of current approaches to pyloromyotomy in infants with hypertrophic pyloric stenosis. The purpose of this study was to evaluate the final appearance of the scar in patients undergoing circumumbilical pyloromyotomy.

Methods

During a 16-year period, 86 infants underwent circumumbilical pyloromyotomy at our institution. A detailed questionnaire was created to document the family members' perceptions of the esthetic appearance of the scar. Data were collected by telephone interview and at clinic visit. In addition, cosmesis was assessed by 5 staff members who scored blindly the esthetic outcome of the scars with comparative photographs, using a categorical scale.

Results

Fifty-seven families were tracked by telephone contact. In the family questionnaire, 100% of families reported an excellent or good scar. Of these, forty-one (72%) were available for cosmetic assessment. Follow-up ranged between 5 months and 15 years (mean, 6 years). The panel members ranked the scar, on average, as excellent or good for 90% of the patients. No assessor stated that a scar was unacceptable. Intra- and interobserver agreement was 0.72 and 0.78, respectively.

Conclusions

Overall satisfaction with the cosmetic outcome of circumumbilical pyloromyotomy is very high.  相似文献   
45.

Background

Surgical resection is the only possibility of long term survival in patients with Klatskin tumours. However, surgical resection is a challenging problem and hepatic resection is often necessary.

Objective

The aim of our study was to assess the need for biliary drainage, resection rate and outcome of hilar cholangiocarcinoma in a single tertiary referral centre.

Patients and methods

From 2005 to 2008, 26 patients with Klatskin tumours were identified and assessed prospectively with multidetector CT and MR cholangiography in special cases. Seven patients (27%) were deemed to be unresectable in pre-operative staging. A total of 19 surgical procedures were performed, 8 left hepatectomies, 5 right hepatectomies and 6 resections exclusively of the biliary tree.

Results

Resection rate was 73%, transfusion rate 53% and preoperative biliary drainage was performed only in 7 cases (37%). Major complications occurred in 11 (58%), including two post-operative deaths (10%).There were no differences in the epidemiological data, when we separately analysed the outcomes of the 9 patients with bilirubin <15 mg/dL and the 10 patients with bilirubin >15 mg/dL. Biliary drainage was required in 6 (67%) patients in the group with low bilirubin levels vs. 1(10%) in the other group (P=0.02). The mean bilirubin level in the jaundiced group was 22.1±3.9 vs. 4.7±4.3 (P<0.001) in the other group. There were no differences in the postoperative outcome between both groups.

Conclusion

Resection and survival rates have increased recently but still carries the risk of significant morbidity and mortality. Major hepatectomies in selected patients without percutaneous biliary drainage are safe.  相似文献   
46.
Abstract:  This longitudinal study assessed the influence of post-transplant clinical and therapeutic variables in 50 kidney transplant recipients aged 2–19 yr receiving a triple immunosuppressive regimen consisting of cyclosporine microemulsion (CsA), steroids and MMF (300–400 mg/m2 body surface area twice daily), the full pharmacokinetic profile (10 points) of which was investigated on post-transplant days 6, 30, 180 and 360. Total plasma MPA was measured by Enzyme Multiplied Immunoassay Technique. CsA therapeutic drug monitoring (TDM) was performed via C2 blood monitoring, while MPA TDM via C0. MPA Cmax, tmax, AUC0-12 and AUC0-4 pharmacokinetic profile changed significantly during the first post-transplant year. C0 was a poor predictor of the total MPA exposure [as measured by the area under the concentration-time curve AUC)], while a truncated AUC was a good surrogate of the 12-h profile (r = 0.91; p < 0.001) Graft function and cyclosporine therapy influenced MPA pharmacokinetics, as shown by the univariate and multivariate analyses. We conclude that because after transplantation MPA exposure varied over time, a strict TDM is advisable in the pediatric population.  相似文献   
47.
Photobiomodulation is proposed as a non-linear process, and only low-level laser therapy (LLLT) is assumed to stimulate exposed cells, whereas high powered laser and fluences can cause negative effects, exhausting the cell’s energy reserve as a consequence of excessive photon-based stimulation. In our work, we investigated and compared the effects of 808-nm diode laser (CW) with a new flat-top handpiece. To this purpose, we tested the photobiomodulation effects of 1 and 3 J/cm2 fluence, both generated by 100 mW or 1 W of laser power and of 64 J/cm2 of fluence generated by 100 mW, 1 W, 1.5 W or 2 W, as expressed through oxygen consumption and ATP synthesis of Paramecium. Data collected indicates the incremental consumption of oxygen through irradiation with 3 J/cm2–100 mW or 64 J/cm2–1 W correlates with an increase in Paramecium ATP synthesis. The Paramecium respiration was inhibited by fluences 64 J/cm2–100 mW or 64 J/cm2–2 W and was followed by a decrease in the endogenous ATP concentration. The 1 J/cm2–100 mW or 1 W and 3 J/cm2–1 W did not affect mitochondrial activity. The results show that the fluence of 64 J/cm2–1 W more than the 3 J/cm2–100 mW causes greater efficiency in Paramecium mitochondria respiratory chain activity. Our results suggest that thanks to flat-top handpiece we used, high fluences by high-powered laser have to be reconsidered as an effective and non-invasive therapy. Possible associated benefits of deeper tissue penetration would increase treatment effectiveness and reduced irradiation time.  相似文献   
48.
Colitis cystica profunda is a rare intestinal lesion. Because of its clinical expression (rectorrhagia, mucorrhea and abdominal pain) and the way it appears to current imaging techniques this disease presents features which can be associated with colon neoplasm. Its diagnosis has to be confirmed histologically, and its etiology remains unclear. The following is a case report of colitis cystica profunda recurring 20 years after a first episode in a white woman, who had had an anterior resection of the sigmoid colon and upper rectum to deal with a colitis cystica profunda-induced stenosis of the sigmoid colon and at 41 underwent the transanal removal of a polypoid lesion. A review of 20 cases in the literature showed that colitis cystica profunda has a predilection for the male and generally affects the medial and lower rectum and the sigmoid colon. The literature also confirmed the association with ulcerative rectocolitis, Crohn's disease and rectal prolapse. The type of treatment varies from surgical, medical, and endoscopic to no treatment at all.  相似文献   
49.
Hepatitis B virus (HBV) recurrence after liver transplantation is significantly reduced by prophylaxis with hepatitis B immune globulins (HBIG) or antiviral drugs in nonreplicating patients and by the combination of both drugs in replicating patients. However, the load of HBV DNA, which defines replicating status in patients undergoing liver transplantation, remains unclear. This study analyzes the correlation between the viral load, tested with a single amplified assay, at the time of liver transplantation, and the risk of hepatitis B recurrence in 177 HBV carriers who underwent transplantation in a single center from 1990 to 2002. Overall, HBV relapsed after surgery in 15 patients (8.5%) with a 5- and 8-year actuarial rate of recurrence of 8% and 21%, respectively. After liver transplantation hepatitis B recurred in 9% of 98 selected subjects treated only with immune globulins and in 8% of 79 viremic patients who received immune globulins and lamivudine (P = NS). A linear correlation was observed between recurrence and viral load at the time of surgery. In transplant patients with HBV DNA higher than 100,000 copies/mL, 200-99,999 copies/mL, and DNA undetectable by amplified assay, hepatitis B recurred in 50%, 7.5%, and 0% of patients, respectively. Overall, a viral load higher than 100,000 copies/mL at the time of liver transplantation was significantly associated with hepatitis B recurrence (P = .0003). In conclusion, spontaneous or antiviral-induced HBV DNA viral load at the time of surgery classifies the risk of HBV recurrence after liver transplantation and indicates the best prophylaxis strategy.  相似文献   
50.
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