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   1782篇
  免费   139篇
  国内免费   16篇
耳鼻咽喉   13篇
儿科学   25篇
妇产科学   18篇
基础医学   281篇
口腔科学   13篇
临床医学   168篇
内科学   547篇
皮肤病学   35篇
神经病学   179篇
特种医学   50篇
外科学   266篇
综合类   15篇
预防医学   85篇
眼科学   5篇
药学   89篇
中国医学   3篇
肿瘤学   145篇
  2024年   2篇
  2023年   22篇
  2022年   35篇
  2021年   97篇
  2020年   39篇
  2019年   78篇
  2018年   75篇
  2017年   71篇
  2016年   50篇
  2015年   50篇
  2014年   81篇
  2013年   99篇
  2012年   158篇
  2011年   170篇
  2010年   82篇
  2009年   86篇
  2008年   120篇
  2007年   98篇
  2006年   101篇
  2005年   94篇
  2004年   72篇
  2003年   94篇
  2002年   66篇
  2001年   9篇
  2000年   9篇
  1999年   10篇
  1998年   9篇
  1997年   9篇
  1996年   11篇
  1995年   9篇
  1994年   3篇
  1993年   3篇
  1992年   3篇
  1991年   3篇
  1990年   5篇
  1989年   5篇
  1988年   2篇
  1987年   4篇
  1986年   1篇
  1982年   1篇
  1974年   1篇
排序方式: 共有1937条查询结果,搜索用时 15 毫秒
1.
J C Monier  C Auger  N Corvee  C Stahli  N Fabien 《Thymus》1988,11(3):173-183
Anti-thymosin alpha 1 monoclonal antibodies recognized, on immunoblots, 1 to 2 bands corresponding to molecules of 34 and 35 Kd when using aqueous extracts of thymus, spleen, kidney, liver, brain, pituitary and adrenal glands from rats or mice. Anti-bovine thymopoietin polyclonal antibodies, in the same conditions, labelled analogous 34, 35 and 35.5 Kd molecules in brain and thymus extracts but also a 40 Kd molecules in thymus and a 90 Kd in brain extracts. Anti-synthetic thymulin monoclonal antibodies recognized irregularly and poorly a 52 Kd molecule from thymus and brain extracts. These results suggest that thymopoietin, thymulin and specially Thymosin alpha 1 are first synthesized in large precursors. Finally, other organs seem capable of synthesizing thymosin alpha 1 and probably thymopoietin, but for thymulin, the results are too irregular to conclude.  相似文献   
2.
We investigated the effects of short duration running training on resting and exercise lung function in healthy prepubescent children. One trained group (TrG) (n = 9; three girls and six boys; age = 9.7 ± 0.9 year) participated in 8 weeks of high-intensity intermittent running training and was compared to a control group (ContG) (n = 9; four girls and five boys; age = 10.3 ± 0.7 year). Before and after the 8-week period, the children performed pulmonary function tests and an incremental exercise test on a cycle ergometer. After the 8-week period, no change was found in pulmonary function in ContG. Conversely, an increase in forced vital capacity (FVC) (+7 ± 4% ; P = 0.026), forced expiratory volume in one second (+11 ± 6% ; P = 0.025), peak expiratory flows (+17 ± 4% ; P = 0.005), maximal expiratory flows at 50% (+16 ± 10% ; P = 0.019) and 75% (+15 ± 8% ; P = 0.006) of FVC were reported in TrG. At peak exercise, TrG displayed higher values of peak oxygen consumption (+15 ± 4% ; P<0.001), minute ventilation (+16 ± 5% ; P = 0.033) and tidal volume (+15 ± 5% ; P = 0.019) after training. At sub-maximal exercise, ventilatory response to exercise was lower (P = 0.017) in TrG after training, associated with reduced end-tidal partial oxygen pressure (P<0.05) and higher end-tidal partial carbon dioxide pressure (P = 0.026). Lower deadspace volume relative to tidal volume was found at each stage of exercise in TrG after training (P<0.05). Eight weeks of high-intensity intermittent running training enhanced resting pulmonary function and led to deeper exercise ventilation reflecting a better effectiveness in prepubescent children.  相似文献   
3.
The RET proto-oncogene has been demonstrated to be expressed in medullary thyroid carcinomas and pheochromocytomas, and was mutated in patients with the multiple endocrine neoplasia type 2A (MEN 2A). The results presented herein show its expression in normal human thyroid parafollicular C cells. Since RET is predicted to encode a receptor for a still unknown ligand, these data confirm its involvement in the regulation and growth of these cells.  相似文献   
4.
5.
OBJECTIVES: To use 3-dimensional ultrasonography (3D-US) to determine the frequency of post-voiding residual volume (PVRV) > or =100 mL in primiparae 3 days after receiving epidural anesthesia for vaginal delivery. Potential relationships between day-3 PVRV > or =100 mL and obstetrical-pediatric parameters, especially those possibly implicated in post-obstetrical bladder dysfunction, were examined. STUDY DESIGN: We recruited 154 primiparae who vaginally delivered term singletons following uncomplicated pregnancies in the maternity unit of a French teaching hospital. All women had been systematically catheterized 2-h postpartum to measure precisely the volume of urine retained. On the morning of discharge (day 3), when the patient felt the urge to urinate, her 3D-US pre-voiding bladder volume was determined with BladderScan (BVI-3000), then her spontaneously voided urine was collected to accurately quantify its volume and 3D-US was repeated immediately to evaluate the PVRV. PVRV > or =100 mL on day 3 was considered pathological. RESULT: Among these 154 women, 88 (57%) felt the need to urinate and 97 (63%) had a retained volume > or =500 mL at 2-h postpartum. On day-3 postpartum, the median [range] volumes for the entire cohort were: 426.7 [158-999.7] mL 3D-US-measured pre-voiding, 350 [15-1000] mL collected by spontaneous urination, 82.2 [5.3-433.3] mL 3D-US-determined post-voiding; PVRV exceeded 100 mL for 55 (36%). According to our univariate analysis, no factor considered was able to predict PVRV > or =100 mL on day 3. CONCLUSION: Our observations confirmed the existence of PVRV > or =100 mL on day 3 in more than one-third of these primiparae who delivered vaginally under epidural anesthesia. No obstetrical-pediatric factor could be implicated in this bladder dysfunction. Therefore, we recommend frequent and systematic non-invasive 3D-US monitoring of all postpartum patients at least until day 3 to avoid excessive urine retention.  相似文献   
6.
Phyllodes tumors are a rare distinctive fibroepithelial tumors of the breast and their management continues to be questioned. The aim of our study was to examine the treatment and outcome of 165 patients with phyllodes tumors and to review the options for surgical management. This is a retrospective study of 165 patients who presented to the Institut Curie between January 1994 and November 2008 for benign, borderline or malignant phyllodes tumors. The median follow-up was 12.65 months [range 0-149.8]. The median age at diagnosis was 44 years [range 17-79]. One hundred and sixty patients (97%) had breast-conserving treatment, of whom 3 patients (1.8%) had oncoplastic breast surgery. Younger women had a significantly higher chance of having a benign phyllodes tumor (p = 0.0001) or a tumor of small size (p < 0.0001). Histologic examination showed 114 benign (69%), 37 borderline (22%) and 14 malignant tumors (9%). The median tumor size was 30 mm [range 5-150]. The tumor margins were considered incomplete (< 10 mm) in 46 out of 165 cases (28%) with 52% revision surgery. Only the tumor grade was a significant risk factor for incomplete tumor margins (p = 0.005). Fifteen patients developed local recurrence (10%) and two, metastases. In univariate analysis, the histologic grade (p = 0.008), and tumor size (p = 0.02) were significative risk factors for local recurrence with an accentuated risk for "borderline" tumors and tumors of large size.).Similar results were obtained using multivariate analysis (p = 0.07). The mainstay of treatment for phyllodes tumors remains excision with a safe surgical margin, taking advantage breast conserving surgery where amenable. For borderline or malignant phyllodes tumors or in cases of local tumor recurrence, mastectomy, and immediate breast reconstruction may become the preferred option. Genetic analysis will potentially supplement classical histologic examination in order to improve our management of these tumors. The role of adjuvant treatments is unproven and must be considered on a case-by-case basis.  相似文献   
7.
8.
Thaveau F  Zoll J  Rouyer O  Chafke N  Kretz JG  Piquard F  Geny B 《Journal of vascular surgery》2007,46(3):541-7; discussion 547
OBJECTIVE: Defective mitochondrial function has been reported in patients presenting with peripheral arterial disease, suggesting it might be an important underlying mechanism responsible for increased morbidity and mortality. We therefore determined the effects of prolonged ischemia on energetic skeletal muscle and investigated whether ischemic preconditioning might improve impaired electron transport chain and oxidative phosphorylation in ischemic skeletal muscle. METHODS: Thirty rats were divided in three groups: the control group (sham, n = 9) underwent 5 hours of general anesthesia without any ischemia, the ischemia-reperfusion (IR) group (n = 11) underwent 5 hours ischemia induced by a rubber band tourniquet applied on the left root of the hind limb, and in the third group, preconditioning (PC group, n = 10) was performed just before IR and consisted of three cycles of 10 minutes of ischemia, followed by 10 minutes reperfusion. Maximal oxidative capacities (V(max)) of the gastrocnemius muscle and complexes I, II, and IV of the mitochondrial respiratory chain were determined using glutamate-malate (V(max)), succinate (V(s)), and N, N, N,'N'-tetramethyl-p-phenylenediamine dihydrochloride ascorbate as substrates. RESULTS: Physiologic characteristics were similar in the three groups. Ischemia reduced V(max) by 43% (4.5 +/- 0.4 vs 7.9 +/- 0.5 micromol O(2)/(min x g dry weight), P < .01) and V(s) by 55% (2.9 +/- 0.3 vs 6.3 +/- 0.4 micromol O(2)/min/g dry weight; P < .01) in the IR and sham groups, respectively, and impairments of mitochondrial complexes I and II activities were evident. Of interest was that preconditioning prevented ischemia-induced mitochondrial dysfunction. Both V(max) and V(s) were significantly higher in the PC rats than in IR rats (+32% and +41%, respectively; P < .05), and were not different from sham values. CONCLUSIONS: Ischemic preconditioning counteracted ischemia-induced impairments of mitochondrial complexes I and II. These data support that ischemic preconditioning might be an interesting approach to reduce muscular injuries in the setting of ischemic vascular diseases.  相似文献   
9.
ObjectivesTo analyze to what extent partial nephrectomy (PN) is superior to radical nephrectomy (RN) in preserving renal function outcome in relation to tumor size indication.Methods and materialsClinical data from 973 patients operated at 9 academic institutions were retrospectively analyzed. Glomerular filtration rate (GFR) before and after surgery was calculated with the abbreviated Modification of the Diet in Renal Disease equation. For a fair comparison between the 2 techniques, all imperative indications for PN were excluded. A shift to a less favorable GFR group following surgery was considered clinically significant.ResultsMedian age at diagnosis was 60 years (19–91). Tumor size was smaller than 4 cm in 665 (68.3%) cases and larger than 4 cm in 308 (31.7%) cases. PN and RN were performed in 663 (68.1%) and 310 (31.9%) patients, respectively. In univariate analysis, patients undergoing PN had a smaller risk for developing significant GFR change following surgery than those undergoing RN did. This was true for tumors≤4 cm (P = 0.0001) and for tumors>4 cm (P = 0.0001). In multivariate analysis, the following criteria were independent predictive factors for developing significant postoperative GFR loss: the use of RN (P = 0.0001), preoperative GFR<60 ml/min (P = 0.0001), tumor size≥4 cm (P = 0.0001), and older age at diagnosis (P = 0.0001).ConclusionsThe renal function benefit carried out by elective PN over RN persists even when expanding nephron-sparing surgery indications beyond the traditional 4-cm cutoff.  相似文献   
10.
The 2007 World Health Organization histologic grading of meningiomas is associated with recurrence and clinical outcome. However, distinction of grade I from grade II (atypical) meningiomas can be challenging. In the World Health Organization classification, there are 4 parameters on the basis of which grade II status can be determined: mitotic rate, cytoarchitectural features, brain invasion, and/or histologic subtype. Furthermore, this classification fails to detect grade I recurrent meningiomas, for which other prognostic criteria would be needed. The aim of this study was to evaluate the respective value of several markers involved in cell cycle as effective tools to predict recurrence. This retrospective study was based on a series of 59 meningiomas (grade I: 32 of 59, grade II: 27 of 59, all harboring ≥4 mitoses/1.6 mm), analyzed with the following immunohistochemical markers: MCM6, Ki-67, PHH3, cyclin D1, and p53. We found a significant correlation between histologic grade and mean labeling index for MCM6 (grade I: 21.8% vs. grade II: 65.8%; P<0.001), Ki-67 (3.2% vs. 16.9%; P<0.001), PHH3 (0.7‰ vs. 2.8‰; P<0.001), cyclin D1 (50.4% vs. 70.0%; P=0.005), and p53 (17.3% vs. 32.4%; P=0.017). Histologic grading and mitotic index were correlated with progression-free survival (P=0.010 and P=0.020, respectively). A nearly linear correlation was found between progression-free survival and staining for MCM6 (P<0.001), Ki-67 (P=0.003), and PHH3 (P=0.037) but not for cyclin D1 (P=0.400) and p53 (P=0.758). The interobserver agreement coefficients for MCM6, Ki-67, PHH3, cyclin D1, and p53 were, respectively, 0.97 (95% confidence interval, 0.95-0.98), 0.93 (0.89-0.96), 0.81 (0.70-0.88), 0.90 (0.83-0.94), and 0.84 (0.73-0.90). In conclusion, because of its strong level of expression and sharp difference in labeling index between indolent and recurrent tumors, MCM6 is the most efficient marker to identify tumors with a high risk of recurrence.  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