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   441篇
  免费   20篇
  国内免费   6篇
耳鼻咽喉   6篇
儿科学   11篇
妇产科学   18篇
基础医学   66篇
口腔科学   7篇
临床医学   12篇
内科学   114篇
皮肤病学   2篇
神经病学   12篇
特种医学   8篇
外科学   97篇
预防医学   6篇
眼科学   35篇
药学   28篇
中国医学   1篇
肿瘤学   44篇
  2023年   2篇
  2022年   9篇
  2021年   2篇
  2020年   4篇
  2019年   8篇
  2018年   11篇
  2017年   3篇
  2016年   15篇
  2015年   5篇
  2014年   8篇
  2013年   13篇
  2012年   16篇
  2011年   34篇
  2010年   17篇
  2009年   16篇
  2008年   33篇
  2007年   40篇
  2006年   37篇
  2005年   22篇
  2004年   19篇
  2003年   22篇
  2002年   13篇
  2001年   9篇
  2000年   8篇
  1999年   3篇
  1998年   8篇
  1996年   2篇
  1995年   4篇
  1994年   4篇
  1993年   7篇
  1992年   2篇
  1991年   6篇
  1990年   5篇
  1989年   5篇
  1988年   2篇
  1987年   3篇
  1986年   4篇
  1984年   2篇
  1983年   2篇
  1980年   2篇
  1979年   5篇
  1978年   4篇
  1977年   3篇
  1974年   7篇
  1973年   5篇
  1972年   3篇
  1968年   2篇
  1967年   2篇
  1959年   1篇
  1958年   1篇
排序方式: 共有467条查询结果,搜索用时 265 毫秒
1.
OBJECTIVE: To clarify the position of on-pump beating coronary artery bypass (CAB) and to define preoperative indicators of intentional conversion to the procedure in the era of advancement of off-pump CAB (OPCAB), we assessed on-pump beating CAB performed after the introduction of OPCAB. SUBJECTS AND METHODS: We assessed 130 patients who underwent single CAB [117 (90%) with OPCAB and 13 (10%) with on-pump beating CAB] between August 1999 (when OPCAB was selected as the first-line surgical procedure) and December 2004. RESULTS: No significant differences were seen between the groups in the number of coronary lesions or the prevalence of left main trunk (LMT) lesion. Reduced left cardiac function, cardiac dilatation, and mitral regurgitation (MR) were more remarkable in the on-pump beating CAB group. Preoperative ischemic condition was generally unstable in the both groups. A conversion to on-pump beating CAB occurred at anastomosis for the left anterior descending (LAD) branch in 61% and for the left circumflex (LCX) branch in 15%. LAD patients had more severe left cardiac dysfunction and cardiac dilatation than LCX patients. CONCLUSION: To perform safe and reliable CAB surgery, cardiovascular surgeons should define preoperative indicators of difficult OPCAB and convert OPCAB to on-pump beating CAB intentionally without hesitation when unstable hemodynamics is detected.  相似文献   
2.
Lupus nephritis in a sister and brother pair was histologically analyzed. The 12-year-old sister showed clinically progressive renal failure and her renal pathology disclosed segmental necrotizing and disorganizing glomeru-lonephritis. On the contrary, the 14-year-old brother exhibited nephrotic syndrome and his renal biopsy showed diffuse exudative and proliferative glomerulonephritis with segmental membraneous changes. Although the familial incidence of SLE suggests both genetic and environmental factors existing in the background of SLE of identical twins and siblings, the differences of clinical manifestation and histopathological findings imply that there might be little direct genetic and environmental control on determining the expression of the disease. ACTA PATH. JAP. 29: 607–613, 1979.  相似文献   
3.
CD56 is an important marker for prospecting clinicopathologic features of cytotoxic T-cell and natural killer (NK)/T-cell lymphomas. We examined 22 cases of subcutaneous panniculitis-like lymphoma and classified these into CD56-positive and CD56-negative groups. The 11 CD56-negative cases were mainly in the younger age group and had systemic subcutaneous nodules without ulceration. They exhibited subcutaneous invasion by medium-sized lymphoma cells, scattered erythrophagocytosis, patchy necrosis, and little tumor invasion in the superficial dermis. Their lymphoma cells had characteristics of CD3 epsilon-, CD8-, TcR beta F1-, T-cell intracellular antigen (TIA)1-, and granenzyme B-positive cytotoxic T cells and were negative for apoptosis-promoting proteins CD95 (Fas), Bax, CPP32 (caspase 3), and p53 (DO7). Ten patients were alive despite clinical signs of hemophagocytic syndrome and relapses in 7 cases. The 11 CD56-positive cases had systemic ulcerative skin tumors composed of pleomorphic lymphoma cells with massive necrosis and little erythrophagocytosis involving the subcutis and also often the whole dermis. Their tumor cells were positive for CD3 epsilon, TIA1, granenzyme B, CD95, CD95L (Fas ligand), Bax, and CPP32. Three cases were of the TcR beta F1-positive phenotype, 1 was of the TcR gamma/delta-positive T-cell phenotype, and 6 were of the TcR beta F1- and TcR gamma/delta-negative NK/T-cell phenotype. Six cases were p53 (DO7) positive. Seven cases had complications of liver dysfunction and cytopenia, and 8 died of disease. One CD56-negative case and 3 CD56-positive cases had nuclear signals of Epstein-Barr virus-encoded RNA in their lymphoma cells. The 2 groups had significantly (P <0.01) different prognoses by Kaplan-Meier and log-rank methods. Patients with CD56-negative and CD56-positive groups had statistically different clinicopathologic, immunohistologic, and functional findings and prognoses.  相似文献   
4.
PurposeThe purpose of this study was to determine the computed tomography (CT) and magnetic resonance imaging (MRI) characteristics of ovarian mature teratoma in patients with anti-N-methyl-d-aspartate receptor encephalitis (NMDAR-E).Materials and MethodsA total of 125 women (mean age, 40.9 ± 17.8 [SD] years; age range: 12–85 years) with 146 histopathologically or radiologically proven ovarian mature teratomas who underwent preoperative CT and MRI examinations were retrospectively included. Eight patients with 11 teratomas had NMDAR-E, whereas 117 patients with 135 teratomas did not have NMDAR-E. CT and MRI examinations were retrospectively reviewed and teratomas in patients with NMDAR-E were compared to those in patients without NMDAR-E. Comparisons were performed using Mann-Whitney U test or Fisher exact test.ResultsIn patients with NMDAR-E, maximum diameter of teratomas (26.1 ± 9.3 [SD] mm), prevalence of teeth/calcification (36%) and rate of occupation by fat components (26%) were lower than those in patients without NMDAR-E (67.0 ± 37.6 [SD] mm [P < 0.01]; 75% [P < 0.05]; and 65%[P < 0.01], respectively). More than 75% of space was occupied by fat components in 76/135 teratomas (56%) in patients without NMDAR-E, whereas this was not observed in any teratoma in patients without NMDAR-E.ConclusionBy comparison with teratomas in patients without NMDAR-E, teratomas in patients with NMDAR-E are smaller, have few teeth/calcification, and the amount of space occupied by fat components is smaller.  相似文献   
5.

Purpose

To evaluate the efficacy and safety of intense pulsed light (IPL) combined with meibomian gland expression (MGX) for treatment of refractory meibomian gland dysfunction (MGD).

Methods

Ninety eyes of 45 patients were randomly assigned to receive either the combination of IPL and MGX or MGX alone (control). Each eye underwent eight treatment sessions at 3-week intervals. Parameters were evaluated before and during treatment as well as at 3–11 weeks after the last treatment session. Measured parameters included the Standard Patient Evaluation of Eye Dryness (SPEED) questionnaire score, noninvasive breakup time (NIBUT), fluorescein breakup time (BUT), lipid layer grade, lipid layer thickness (LLT), lid margin abnormalities, corneal and conjunctival fluorescein staining (CFS) score, meibum grade, and meiboscore.

Results

A significant improvement in lipid layer grade was apparent in the IPL-MGX group from 6 to 32 weeks after treatment onset (adjusted P?<?0.001) but was not observed in the control group. The IPL-MGX group also showed significant improvements in LLT, NIBUT, BUT, lid margin abnormalities, and meibum grade compared with the control group at 24 and 32 weeks (adjusted P?<?0.001) as well as significant improvements in the SPEED score at 32 weeks (adjusted P?=?0.044) and in CFS score at 24 (adjusted P?=?0.015) and 32 (adjusted P?=?0.006) weeks.

Conclusions

The combination of IPL and MGX improved homeostasis of the tear film and ameliorated ocular symptoms in patients with refractory MGD and is thus a promising modality for treatment of this condition.  相似文献   
6.
PURPOSE: The aims of this study were to evaluate potential predictors of exfoliated free cancer cells in the peritoneal cavity and to assess intraoperative peritoneal lavage cytology as a prognostic indicator in patients with colorectal cancer. METHODS: From 1985 to 1987, intraoperative peritoneal lavage cytology was performed in 140 patients with colorectal cancer. Among them, 88 patients underwent curative resection and 52 patients had noncurative surgery. Cytology was examined twice,i.e., immediately after opening the peritoneal cavity (precytology) and just before closing the abdomen (postcytology). One hundred milliliters of saline was poured into the peritoneal cavity and it was retrieved by suction after irrigation. Cytologic examination was performed after staining with Papanicolaou, Giemsa, periodic acid-Schiff, and Alcian blue stains. RESULTS: Among the 140 patients examined, the incidence of positive cytology in the prelavage was 15 percent, and that in the postlavage was 9 percent, although it was 16 percent in either lavage. Among patients with curative resection, 10 percent had positive cytology. Seven characteristics were identified as features of tumors which are prone to exfoliate cells into the peritoneal cavity: 1) macroscopic peritoneal dissemination, 2) liver metastasis, 3) more than 20 ml of ascites, 4) ulcerated tumors without definite borders, 5) invasion of the serosal surface or beyond, 6) semiannular or annular shape, and 7) moderate or marked lymphatic invasion. In patients undergoing curative surgery, among these features, circumferential involvement was the only one correlated closely with positive cytology (P<0.02). Positive cytology was associated with a worse outcome. In patients who were resected curatively, the postcytology had a stronger influence on local recurrence than the precytology; the local recurrence rate in patients with positive postcytology was higher than in those with negative postcytology, regardless of the precytology. All patients with cancer cells in the peritoneal cavity at the end of surgery had recurrence. CONCLUSIONS: Seven characteristics were identified as risk factors for exfoliation of cancer cells into the peritoneal cavity in patients with colorectal cancer. These findings may be helpful for the choice of laparoscopic surgery in this era of increasing port-site metastases after laparoscopic procedure. The results of peritoneal lavage cytology at the end of surgery were correlated with the long-term postoperative outcome of colorectal cancer. Thus, meticulous follow-up and possibly adjuvant chemotherapy may be beneficial for patients with free cancer cells in lavage fluid, even after curative surgery.  相似文献   
7.
The cardioprotective effects of R56865 were studied in isolated rabbit hearts, blood-perfused with a support rabbit system. The effect on ischemic injury was evaluated by comparing myocardial contracture and contents of ATP catabolites and of lactate during 60 min of normothermic ischemia in untreated hearts (group I) and in hearts treated with 0.63 mg/kg of R56865 starting 20 min before ischemia (group II; n = 5 in each group). R56865 delayed the onset, and decreased the extent of ischemic contracture, but had no effect on the myocardial content of ATP, of its catabolites or of lactate. The effect on reperfusion injury was studied by monitoring left ventricular function during 80-min reperfusion after the 60-min ischemia in three groups (n = 6 in each): an untreated group (group I) and two groups treated with R56865 given either before (group II) or after ischemia (group III). Ultrastructural changes and cellular calcium distribution after reperfusion were also studied. R56865 improved the recovery of function and prevented contracture during reperfusion. Left ventricular end-diastolic pressure was 13.2 ± 2.8 mmHg in group II and 31.3 ± 8.1 mmHg in group III vs 45.0 ± 2.6 mmHg in group I (P < 0.0001 for II vs I; P > 0.05 for III vs I). Left ventricular developed pressure, maximum dP/dt and minimum dP/dt recovered to 71.0 ± 5.4%, 98.9 ± 6.1%, 85.3 ± 4.8% of baseline values, respectively, in group II, to 64.5 ± 3.0% (P > 0.05), 76.8 ± 3.0%, 70.2 ± 4.0% in group III, vs 52.0 ± 6.5%, 58.9 ± 6.9% and 53.6 ± 5.8% in untreated hearts (P < 0.05 for II or III vs I). Coronary flow was 24.5 ± 2.2 ml/min and 19.8 ± 1.8 ml/min in groups II and III vs 14.8 ± 0.7 ml/min (P < 0.05) in the untreated group. On histology the myocardium in hearts treated either before after ischemia was well protected and calcium distribution was almost normal after reperfusion, while in untreated hearts, most of the myocardium displayed irreversible damage accompanied by massive intracellular calcium accumulation. We conclude that R56865 could attenuate Ca2+-overload, thereby reducing myocardial ischemia-reperfusion injury after an extended period of ischemia.  相似文献   
8.
Receptors for androgen and estrogen in the rat lung   总被引:2,自引:0,他引:2  
W K Morishige  C A Uetake 《Endocrinology》1978,102(6):1827-1837
By the use of sucrose density gradient and protamine sulfate analyses, the cytosol fraction of rat lung has been found to contain binding activities for both androgenic and estrogenic steroids. These activities are present in lungs of rats of both sexes and at all ages examined. Both activities interacted stereospecifically with, and possessed high affinity for, the respective ligand, and sedimented in the 8-9S region of low salt sucrose density gradients. The androgen-binding activity appeared to bind 5alpha-dihydrotestosterone (DHT) and testosterone with similar affinities, but in vitro, whole lung incubation studies demonstrated that DHT is the perdominant androgen found in lung nuclei. In the immature male rat, removal of endogenous androgen by castration-adrenalectomy had no effect on DHT-binding activity in lung cytosol. In the adult, however, this procedure led to a marked cycloheximide-sensitive increase in binding activity. During postnatal development in male rats, relatively constant levels of both androgen- and estrogen-binding activities were found in the lung until the peripubertal period, from which time a striking increase in DHT binding and a decline in that of estradiol were observed. In female rats, cyclic changes in the level of both binding activities were evident during the estrous cycle. When considered in the light of evidence that sex steroids influence certain aspects of lung biochemistry, these data suggest that the demonstrated binding activities represent hormone receptor activities which may mediate a variety of biological events in the lung.  相似文献   
9.
10.
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