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   475篇
  免费   19篇
  国内免费   37篇
耳鼻咽喉   1篇
儿科学   17篇
妇产科学   9篇
基础医学   25篇
口腔科学   7篇
临床医学   49篇
内科学   94篇
皮肤病学   10篇
神经病学   21篇
特种医学   144篇
外科学   52篇
综合类   16篇
预防医学   23篇
眼科学   5篇
药学   23篇
肿瘤学   35篇
  2023年   1篇
  2022年   3篇
  2021年   3篇
  2020年   4篇
  2019年   7篇
  2018年   2篇
  2017年   11篇
  2016年   11篇
  2015年   6篇
  2014年   8篇
  2013年   13篇
  2012年   15篇
  2011年   14篇
  2010年   23篇
  2009年   18篇
  2008年   12篇
  2007年   40篇
  2006年   10篇
  2005年   17篇
  2004年   18篇
  2003年   10篇
  2002年   20篇
  2001年   18篇
  2000年   12篇
  1999年   12篇
  1998年   26篇
  1997年   16篇
  1996年   19篇
  1995年   8篇
  1994年   16篇
  1993年   19篇
  1992年   5篇
  1991年   8篇
  1990年   14篇
  1989年   13篇
  1988年   10篇
  1987年   6篇
  1986年   14篇
  1985年   14篇
  1984年   6篇
  1983年   2篇
  1982年   1篇
  1981年   7篇
  1980年   12篇
  1979年   1篇
  1976年   2篇
  1975年   1篇
  1972年   1篇
  1968年   1篇
  1966年   1篇
排序方式: 共有531条查询结果,搜索用时 0 毫秒
81.
PURPOSE: To evaluate local control and patterns of failure in patients treated with intraoperative electron beam radiotherapy (IOERT) after total mesorectal excision (TME), to appraise the effectiveness of intraoperative target definition. METHODS AND MATERIALS: We analyzed the outcome of 243 patients with rectal cancer treated with IOERT (median dose, 10 Gy) after TME. Eighty-eight patients received neoadjuvant and 122 patients adjuvant external beam radiotherapy (EBRT) (median dose, 41.4 Gy), and in 88% simultaneous chemotherapy was applied. Median follow-up was 59 months. Results: Local failure was observed in 17 patients (7%), resulting in a 5-year local control rate of 92%. Only complete resection and absence of nodal involvement correlated positively with local control. Considering IOERT fields, seven infield recurrences were seen in the presacral space, resulting in a 5-year local control rate of 97%. The remaining local relapses were located as follows: retrovesical/retroprostatic (5), anastomotic site (2), promontorium (1), ileocecal (1), and perineal (1). CONCLUSION: Intraoperative electron beam radiotherapy as part of a multimodal treatment approach including TME is a highly effective regimen to prevent local failure. The presacral space remains the site of highest risk for local failure, but IOERT can decrease the percentage of relapses in this area.  相似文献   
82.

Aim  

To study the effects of infusion of atrial natriuretic peptide (ANP) versus the inhalation of nitric oxide (NO) in patients with an early acute respiratory distress syndrome (ARDS).  相似文献   
83.
84.
PURPOSE: To evaluate an indwelling retrobulbar catheter for repeatable postoperative retrobulbar injections of local anesthetics for titratable analgesia after intraocular surgery. METHODS: The prospective study included all 124 patients (124 eyes) who consecutively underwent retinal or cyclocryocoagulation (n = 22), pars plana vitrectomy, or retinal detachment surgery (n = 102), and who were operated on by the same surgeon with local anesthesia within a period of 12 months. Using commercially available retrobulbar needles with a diameter of 0.60 mm or 0.80 mm and a length of 38 mm, 5 ml of mepivacaine 2% with hyaluronidase were injected. Through the same needle, a 28-gauge commercially available flexible catheter was introduced into the retrobulbar space, the needle was withdrawn, and the catheter was fixed in place. When the patients started to feel pain after surgery, 2 ml of mepivacaine 2% or 2 ml of bupivacaine 0.75% were reinjected through the catheter. The catheter was removed 24 to 72 hours after surgery. RESULTS: Because of increasing pain in the postoperative period, 93 patients (93 of 124, or 75%) received a reinjection 4.2+/-2.0 hours after the preoperative injection. Seventy patients received a second reinjection after an additional 2.7+/-1.9 hours, and 42 patients received a third reinjection 3.1+/-2.0 hours later. After each reinjection, the patients became pain free. Removal of the catheter after surgery was unremarkable. CONCLUSIONS: An indwelling retrobulbar catheter for repeatable postoperative injection of short-acting local anesthetics is useful and effective for titratable postoperative analgesia after intraocular surgery, and it allows patients to avoid the side effects of systemic analgesics and sedatives.  相似文献   
85.

Background and purpose:

Chemokines orchestrate neutrophil recruitment to inflammatory foci. In the present study, we evaluated the participation of three chemokines, KC/CXCL1, MIP-2/CXCL2 and LIX/CXCL5, which are ligands for chemokine receptor 2 (CXCR2), in mediating neutrophil recruitment in immune inflammation induced by antigen in immunized mice.

Experimental approach:

Neutrophil recruitment was assessed in immunized mice challenged with methylated bovine serum albumin, KC/CXCL1, LIX/CXCL5 or tumour necrosis factor (TNF)-α. Cytokine and chemokine levels were determined in peritoneal exudates and in supernatants of macrophages and mast cells by elisa. CXCR2 and intercellular adhesion molecule 1 (ICAM-1) expression was determined using immunohistochemistry and confocal microscopy.

Key results:

Antigen challenge induced dose- and time-dependent neutrophil recruitment and production of KC/CXCL1, LIX/CXCL5 and TNF-α, but not MIP-2/CXCL2, in peritoneal exudates. Neutrophil recruitment was inhibited by treatment with reparixin (CXCR1/2 antagonist), anti-KC/CXCL1, anti-LIX/CXCL5 or anti-TNF-α antibodies and in tumour necrosis factor receptor 1-deficient mice. Intraperitoneal injection of KC/CXCL1 and LIX/CXCL5 induced dose- and time-dependent neutrophil recruitment and TNF-α production, which were inhibited by reparixin or anti-TNF-α treatment. Macrophages and mast cells expressed CXCR2 receptors. Increased macrophage numbers enhanced, while cromolyn sodium (mast cell stabilizer) diminished, LIX/CXCL5-induced neutrophil recruitment. Macrophages and mast cells from immunized mice produced TNF-α upon LIX/CXCL5 stimulation. Methylated bovine serum albumin induced expression of ICAM-1 on mesenteric vascular endothelium, which was inhibited by anti-TNF-α or anti-LIX/CXCL5.

Conclusion and implications:

Following antigen challenge, CXCR2 ligands are produced and act on macrophages and mast cells triggering the production of TNF-α, which synergistically contribute to neutrophil recruitment through induction of the expression of ICAM-1.  相似文献   
86.
The present study investigated the effects of dietary oltipraz on cigarette smoke-related lipophilic DNA adduct formation. Female Sprague- Dawley rats were exposed daily to sidestream cigarette smoke in a whole- body exposure chamber 6 h/day for 4 consecutive weeks. One group of rats was maintained on control diet while another group received the same diet supplemented with either a low (167 p.p.m.) or high (500 p.p.m.) dose of oltipraz, starting 1 week prior to initiation of smoke exposure until the end of the experiment. Analysis of lipophilic DNA adducts by the nuclease P1-mediated 32P-post-labeling showed up to five smoke-related adducts. Adduct no. 5 predominated in both the lung and the heart while adduct nos 3 and 2 predominated in the trachea and bladder, respectively. Quantitative analysis revealed that the total adduct level was the highest in lungs (270+/-68 adducts/10(10) nucleotides), followed by trachea (196+/-48 adducts/10(10) nucleotides), heart (141+/-22 adducts/10(10) nucleotides) and bladder (85+/-16 adducts/10(10) nucleotides). High dose oltipraz treatment reduced the adduct levels in lungs and bladder by >60%, while the reduction in lungs in the low-dose group was approximately 35%. In trachea, the effect of low and high dietary oltipraz on smoke DNA adduction was equivocal, while smoke-related DNA adducts in the heart were minimally inhibited by high-dose oltipraz. In a repeat experiment that employed a 3-fold lower dose of cigarette smoke, oltipraz (500 p.p.m.) was found to inhibit the formation of DNA adducts in rat lungs and trachea by 80 and 65%, respectively. These data clearly demonstrate a high efficacy of oltipraz in inhibiting the formation of cigarette smoke-induced DNA adducts in the target tissues.   相似文献   
87.

Purpose

Knowledge of the psychological distress of long- and very long-term (>10 years) prostate cancer (PC) survivors is limited. This study intended to examine the parameters influencing anxiety related to prostate-specific antigen (PSA) and PC in long-term survivors after radical prostatectomy.

Methods

We surveyed 4719 PC survivors from the German multicenter prospective database “Familial Prostate Cancer.” We evaluated the association of PC-related anxiety (MAX-PC) with sociodemographic characteristics, family history of PC, global health status/quality of life (EORTC QLQ-C30), depression and anxiety (PHQ-2; GAD-2), latest PSA level, time since radical prostatectomy, and current therapy.

Results

The survey participants’ mean age was 75.2 years (SD = 6.5). Median follow-up was 11.5 years, and 19.5% of participants had survived more than 15 years since the initial treatment. The final regression analysis found that younger age, lower global health status/quality of life, higher depression and anxiety scores, higher latest PSA level, and shorter time since radical prostatectomy predicted increased PSA-related anxiety and PC anxiety. Familial PC was predictive only of PSA anxiety (all p < 0.05). The final model explained 12% of the variance for PSA anxiety and 24% for PC anxiety.

Conclusions

PC-related anxiety remained relevant many years after prostatectomy and was influenced by younger age, psychological status, rising PSA level, and shorter time since initial treatment.

Implications for Cancer Survivors

Survivors with these characteristics are at increased risk of PC-related anxieties, which should be considered by the treating physician during follow-up.
  相似文献   
88.

Purpose

To investigate the complex breathing patterns in patients with hemidiaphragmatic paralysis due to malignant infiltration using four-dimensional magnetic resonance imaging (4D-MRI).

Patients and methods

Seven patients with bronchial carcinoma infiltrating the phrenic nerve were examined using 1.5 T MRI. The motion of the tumor and of both hemi-diaphragms were measured on dynamic 2D TrueFISP and 4D FLASH MRI sequences.

Results

For each patient, 3-6 breathing cycles were recorded. The respiratory-induced mean cranio-caudal displacement of the tumor was 6.6 mm (±2.8 SD). The mean displacement anterior-posterior was 7.4 mm (±2.6), while right-left movement was about 7.4 mm (±4.5). The mediastinum moved sidewards during inspiration, realizing a “mediastinal shift”. The paralyzed hemidiaphragm and the tumor showed a paradox motion during respiration in five patients. In two patients, the affected hemidiaphragm had a regular, however minimal and asynchronous motion during respiration. Respiratory variability of both tumor and diaphragm motions was about 20% although patients were instructed to breath normally. The findings showed significant differences compared to breathing patterns of patients without diaphragm dysfunction.

Conclusion

4D-MRI is a promising tool to analyze complex breathing patterns in patients with lung tumors. It should be considered for use in planning of radiotherapy to account for individual tumor motion.  相似文献   
89.
90.
Neue Verfahren     
Lung cancer staging according to the TNM system is based on morphological assessment of the primary cancer, lymph nodes and metastases. All aspects of this important oncological classification are measurable with MRI. Pulmonary nodules can be detected at the clinically relevant size of 4–5 mm in diameter. The extent of mediastinal, hilar and supraclavicular lymph node affection can be assessed at the same time. The predominant metastatic spread to the adrenal glands and spine can be detected in coronal orientation during dedicated MRI of the lungs. Search focused whole body MRI completes the staging. Various additional MR imaging techniques provide further functional and clinically relevant information during a single examination. In the oncological context the most important techniques are imaging of perfusion and tumor motion. Functional MRI of the lungs complements the pure staging and improves surgical approaches and radiotherapy planning.  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