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   7050篇
  免费   472篇
  国内免费   53篇
耳鼻咽喉   78篇
儿科学   242篇
妇产科学   185篇
基础医学   873篇
口腔科学   466篇
临床医学   546篇
内科学   1473篇
皮肤病学   187篇
神经病学   674篇
特种医学   335篇
外科学   811篇
综合类   68篇
一般理论   2篇
预防医学   709篇
眼科学   70篇
药学   486篇
中国医学   19篇
肿瘤学   351篇
  2023年   61篇
  2022年   136篇
  2021年   237篇
  2020年   138篇
  2019年   218篇
  2018年   253篇
  2017年   161篇
  2016年   184篇
  2015年   194篇
  2014年   264篇
  2013年   350篇
  2012年   502篇
  2011年   489篇
  2010年   271篇
  2009年   217篇
  2008年   364篇
  2007年   375篇
  2006年   331篇
  2005年   337篇
  2004年   251篇
  2003年   234篇
  2002年   240篇
  2001年   153篇
  2000年   134篇
  1999年   106篇
  1998年   73篇
  1997年   81篇
  1996年   74篇
  1995年   64篇
  1994年   44篇
  1993年   44篇
  1992年   83篇
  1991年   87篇
  1990年   74篇
  1989年   62篇
  1988年   65篇
  1987年   82篇
  1986年   56篇
  1985年   51篇
  1984年   34篇
  1983年   50篇
  1982年   34篇
  1981年   34篇
  1980年   28篇
  1979年   22篇
  1978年   19篇
  1977年   20篇
  1976年   32篇
  1975年   16篇
  1970年   14篇
排序方式: 共有7575条查询结果,搜索用时 15 毫秒
71.
Complications of operative gynecological laparoscopy.   总被引:2,自引:0,他引:2  
OBJECTIVE: To assess the incidence and type of laparoscopic complications. METHODS: A series of 2140 operative laparoscopies were reviewed in a retrospective study of patient records. The setting was a tertiary-care university hospital. Operative laparoscopy included minor procedures (minimal adhesiolysis, destruction of minimal endometriosis foci, ovarian biopsy, ovarian puncture, tubal sterilization), major laparoscopic surgery (extended adhesiolysis, tuboplasties, uterine suspension, treatment for ectopic pregnancy, salpingitis, ovarian cyst, moderate and severe endometriosis), and advanced laparoscopic surgery (hysterectomy, myomectomy, bladder neck suspension). RESULTS: Two major vascular complications, 3 intestinal injuries, 1 anesthesiological complication, and 4 urinary tract injuries occurred. Two minor and 5 postoperative complications were noted. The overall complication rate was 17/2140 (0.79%). The major complication rate was 10/2140 (0.46%). CONCLUSIONS: This review is useful for helping surgeons reduce the risk of injuries and to inform patients about potential complications. These rates are similar to those that have been previously reported.  相似文献   
72.
PURPOSE: Primary neuroendocrine tumors of the bladder are rare and they include small and large cell variants. We reviewed our experience with treating these tumors with radical cystectomy to evaluate their histopathological characteristics and clinical outcomes. MATERIALS AND METHODS: From August 1971 to June 2004, 2,005 patients underwent radical cystectomy for primary bladder cancer at our institution, of whom 25 (1.2%) had neuroendocrine tumors of the bladder, including small cell carcinoma in 20 and large cell carcinoma in 5. Pure neuroendocrine-type histology was identified in 16 cases, including 1 with small and large cell features, while the remaining 9 had mixed histology, that is transitional cell carcinoma in 8 and adenocarcinoma in 1. Multi-agent chemotherapy was administered to 14 patients. RESULTS: Median patient age was 68 years (range 40 to 82) and 19 patients were male (76%). A total of 19 patients (76%) had lymph node involvement, of whom 2 had small liver metastases found intraoperatively, while only 4 (16%) had organ confined tumors and 2 (8%) had extravesical, node negative disease. These tumors tended to have a flat, ulcerative gross appearance with lymphovascular invasion, carcinoma in situ and necrosis present microscopically. Median followup was 11.8 years (range 18 days to 15.1 years). Five-year overall and recurrence-free survival was 10% and 13%, respectively. There was no significant survival difference between small and large cell carcinoma. Mixed histologies tended to do better than pure neuroendocrine tumors, although this did not attain statistical significance (p = 0.064). Patients receiving multimodality therapy had significantly better overall (p = 0.051) and recurrence-free (p = 0.003) survival than those treated with cystectomy alone. CONCLUSIONS: Neuroendocrine tumors of the bladder usually present with advanced pathological stage and portend a poor prognosis. Adjuvant chemotherapy protocols may provide improved survival compared with cystectomy alone.  相似文献   
73.
The purpose of the current study was to compare the workout volume (sets x resistance x repetitions per set) completed during two upper body resistance exercise sessions that incorporated 1 minute versus 3 minute rest intervals between sets and exercises. Twelve trained men completed two experimental sessions that consisted of 5 upper body exercises (i.e. barbell bench press, incline barbell bench press, pec deck flye, barbell lying triceps extension, triceps pushdown) performed for three sets with an 8-RM load. The two experimental sessions differed only in the length of the rest interval between sets and exercises; one session with a 1-minute and the other session with a 3-minute rest interval. The results demonstrated that for each exercise, significantly greater workout volume was completed when resting 3 minutes between sets and exercises (p < 0.05). These results indicate that during a resistance exercise session, if sufficient time is available, resting 3 minutes between sets and exercises allows greater workout volume for the upper body exercises examined.

Key points

  • The length of the rest interval between sets is an important variable when designing a resistance exercise program and may vary depending on the characteristic being emphasized (i.e. maximal strength, hypertrophy, localized muscular endurance, power).
  • Although acknowledged, this variable is rarely monitored precisely in field settings.
  • Previous studies that examined rest interval lengths from 1 to 5 minutes between sets for single exercises demonstrated significant differences in repetition performance and the exercise volume completed.
  • There is a need for further research to compare the workout volume (sets x resistance x repetitions per set) completed over an entire resistance exercise session with different rest intervals between sets.
  • The results of the current study indicate that during a resistance exercise session, if sufficient time is available, resting 3 minutes between sets and exercises allows greater workout volume for the upper body exercises examined.
Key words: Recovery, fatigue, strength, muscle endurance, weight training, strength training  相似文献   
74.

Background

In bariatric surgery, there are no guidelines available for intraoperative fluid administration. Goal-directed fluid therapy (GDFT) is a new concept of perioperative fluid management that has been shown to improve the prognosis of patients undergoing abdominal surgery. The aim of our study is to assess the impact of the implementation of a GDFT protocol in morbidly obese patients who underwent laparoscopic sleeve gastrectomy (LSG).

Methods

A before-after intervention study, in morbidly obese patients who underwent LSG, was conducted at the Obesity Unit of the General University Hospital Elche. Data from the GDFT implementation group (January 2014 to December 2015) were prospectively collected and compared with a preimplementation group (January 2012 to December 2013).

Results

Baseline demographic and comorbidity data between the two groups of patients were similar. The length of stay in the hospital was significantly shortened in GDFT group from 4.5 to 3.44 days (p?<?0.001). Intraoperative fluid administration was significantly lower in the GDFT group (1002.4 vs 1687.2 ml in preimplementation group, p?<?0.001). In the postoperative period, there was a statistically significant reduction in postoperative nausea and vomiting (PONV) after GDFT implementation (48 to 14.3 %, p?<?0.001).

Conclusions

Implementation of GDFT protocols can prevent intraoperative fluid overload in patients undergoing bariatric surgery. It could improve outcomes, for example decreasing PONV or even hospital stay.
  相似文献   
75.
Diabetic patients with end-stage renal disease have a high mortality rate. A combined kidney-pancreas transplant is associated with greater life expectancy. Pancreas islet transplantation is an alternative involving a lower degree of morbidity. We present two patients, of 41 and 37 years of age, with a long history of diabetes mellitus (C-peptide negative), both with a previous kidney transplant, who had been treated with 22 and 28 U of insulin/d, respectively. Both patients had frequent episodes of unawareness hypoglycemia. Pancreatic islets were infused to a total of 7809 and 19,180 IE/kg, respectively. Basal posttransplant C peptide levels were 2.9 and 1.3 ng/mL. After the implant, one patient required occasional doses of insulin, and the other patient more than 50% reduced dose. After the first implant neither patient had any episodes of unawareness hypoglycemia. HbA1c at 4 months were 6.2% and 6.9%. There were no transplant-related complications.  相似文献   
76.
BACKGROUND: In vitro, cold-induced injury is an important contributor to renal tubular cell damage. It is mediated by iron-dependent formation of reactive oxygen species and can be prevented by iron chelation. We studied whether iron chelators can prevent cold-induced damage in the isolated perfused rat kidney (IPK) model both after cold perfusion (CP) and after cold storage (CS). We hypothesized that in the CP model iron-dependent cold-induced injury is more pronounced, since oxygen is constantly provided. METHODS: The IPK was either flushed with University of Wisconsin (UW) solution and stored for 4, 18 or 24 h at 4 degrees C or perfused during 4 h at 4 degrees C with UW for machine perfusion. The iron chelators 2,2'-dipyridyl or desferal, or the negative control 4,4'-dipyridyl were added during the cold perfusion. Kidney function was measured during 2 h reperfusion at 37.5 degrees C and compared to a control group (without cold preservation). RESULTS: Compared to control perfusion, kidney function was decreased in all experimental protocols. glomerular filtration rate and FR(H2O) were significantly decreased, while FE(gluc) and FE(Na) were higher after 4 h CS and CP. After 4 h CP, also renal vascular resistance was increased. Addition of 2,2'-dipyridyl did not improve kidney function after either CS or CP. Prolonged periods of CS worsened kidney function. The addition of 2,2'-dipyridyl or desferal did not improve kidney function after longer periods of CS. CONCLUSIONS: Addition of an iron chelator to the preservation solution UW did not improve kidney function after both CS and CP. Iron chelation is not able to prevent cold-induced damage in the isolated perfused rat kidney.  相似文献   
77.
The chondroid syringoma is a rare benign tumor, also called mixed cutaneous tumor by the presence of epithelial and mesenchymal components, consisting of sweat elements in cartilaginous, collagenous, myxoid or osseous stroma, among others. It mainly affects middle-aged men and is characterized by asymptomatic and slowgrowing, dermal or subcutaneous nodules. The most common locations are the head and neck. It is rare on the extremities. There are reports of malignant variants predominantly in women, located on the extremities. We report a case of a female patient with a lesion on the toe, with excellent outcome after surgical treatment.  相似文献   
78.
After blunt chest trauma, early diagnosis of associated bronchial, vascular, and esophageal injuries must be attempted, as those lesions may be produced by the same mechanism. We report a case of successful management of associated bronchial transection and injury of the ascending aorta. Aortic repair required cardiopulmonary bypass and the use of prosthetic materials, although gross contamination of the mediastinum from the bronchial disruption is a theoretical contraindication to such a procedure. A separate approach to the vascular and airway injuries allowed successful management of both lesions.  相似文献   
79.
The purpose of this article is to report the use of the subepithelial connective tissue graft technique combined with the coronally positioned flap on a composite resin-restored root surface to treat Miller Class I gingival recessions associated with deep cervical abrasions in maxillary central incisors. Clinical measurements, including gingival recession height, probing depth, and bleeding on probing (BoP), were recorded during the preoperative clinical examination and at 2, 6, 12, and 24 months postoperatively. During the follow-up periods, no periodontal pockets or BoP were observed. The periodontal tissue of the teeth presented normal color, texture, and contouring. In addition, it was observed that creeping attachment had occurred on the restoration. This case report shows that this form of treatment can be highly effective and predictable in resolving gingival recession associated with a deep cervical abrasion.  相似文献   
80.
This paper describes and discusses the multidisciplinary treatment involving a permanent maxillary lateral incisor fused to a supernumerary tooth, both presenting pulp necrosis and periapical lesion. A 15-year-old male patient sought treatment complaining of pain, swelling and mobility on the maxillary right lateral incisor. After clinical and radiographic examination, root canal preparation was performed according to the crown-down technique and a calcium hydroxide dressing was placed for 15 days. The patient returned and the definitive endodontic filling was done with thermomechanical compaction of gutta-percha and sealer. After 18 months, clinical and radiographic examinations were carried out and no pain or swelling was reported. Two years after endodontic treatment, the patient returned for periodontal and cosmetic treatments. Nine months later, a cone-beam computed tomography (CBCT) revealed that the previously detected periodontal defect and periapical lesion were persistent. Apical endodontic surgery was indicated. The supernumerary tooth was removed, the communicating distal surface was filled and the surgical site received bioactive glass and demineralized bovine organic bone. The pathological tissue was submitted to histopathological examination and the diagnosis was periapical cyst. One year after the apical endodontic surgery, CBCT showed bone formation at maxillary lateral incisor apical area. Two years after the surgery, the restoration was replaced due to aesthetic reasons and periapical radiograph showed success after 5 years of treatment. A correct diagnosis and establishment of an adequate treatment plan resulted in a successful management of the case.  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