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   174689篇
  免费   884篇
耳鼻咽喉   1121篇
儿科学   6606篇
妇产科学   2988篇
基础医学   16440篇
口腔科学   1537篇
临床医学   12286篇
内科学   30670篇
皮肤病学   677篇
神经病学   16338篇
特种医学   8899篇
外科学   28671篇
综合类   2305篇
预防医学   18027篇
眼科学   2719篇
药学   9382篇
中国医学   623篇
肿瘤学   16284篇
  2019年   18篇
  2018年   21921篇
  2017年   17364篇
  2016年   19509篇
  2015年   879篇
  2014年   774篇
  2013年   734篇
  2012年   6884篇
  2011年   20933篇
  2010年   18775篇
  2009年   11483篇
  2008年   19429篇
  2007年   21626篇
  2006年   481篇
  2005年   2090篇
  2004年   3302篇
  2003年   4279篇
  2002年   2422篇
  2001年   274篇
  2000年   407篇
  1999年   163篇
  1998年   197篇
  1997年   198篇
  1996年   88篇
  1995年   97篇
  1994年   96篇
  1993年   62篇
  1992年   45篇
  1991年   95篇
  1990年   130篇
  1989年   79篇
  1988年   66篇
  1987年   43篇
  1986年   27篇
  1985年   29篇
  1984年   20篇
  1983年   20篇
  1982年   26篇
  1980年   40篇
  1974年   20篇
  1970年   19篇
  1969年   20篇
  1968年   17篇
  1939年   20篇
  1938年   61篇
  1937年   25篇
  1935年   23篇
  1934年   30篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
991.
Metastatic prostate cancer (PC) is incurable by androgen deprivation therapy alone, due to the presence of androgen-independent/supersensitive cells in hormone-naive PC. A 67-year-old man was diagnosed with PC (Gleason score, 5 + 4) with multiple bone metastases. He was treated by chemohormonal therapy with cisplatin and estramustine phosphate (EMP) followed by maximal androgen blockade, and showed a complete response. As of the time of writing, no clinical or prostate-specific antigen recurrence has been observed for over 15 years, despite cessation of the treatment. This is the first report to indicate a possible cure of metastatic PC by chemohormonal therapy combined with appropriate anti-tumor drugs targeted to both androgen-independent and -dependent clones before the hormone-refractory state.  相似文献   
992.
High hepatic duct resection sometimes is unavoidable in achieving curative resection of hilar cholangiocarcinoma, as tumor cells can extend further than expected along the bile ducts from the macroscopically evident cancer. In patients undergoing left hemihepatectomy with caudate lobectomy whose bile duct must be severed at the subsegmental bile duct levels, the orifices of the posterior bile ducts would lie behind the right portal vein. Conventional hepaticojejunostomy would be risky in such cases because an anastomosis performed in the usual manner would be subjected to strain. Instead, between 2002 and 2004, three patients underwent retroportal hepaticojejunostomy using a jejunal limb mobilized and positioned behind the hepatoduodenal ligament. Primary tumors were classified as type IV in the Bismuth–Corlette classification. Tension-free hepaticojejunal anastomosis was performed successfully in all three patients; insufficiency of the hepaticojejunostomy did not develop. Neither early nor late complications directly related to this method occurred. Retroportal hepaticojejunostomy, thus, permits more peripheral resection of the hepatic duct while providing a sufficient operative field for safe, tension-free anastomosis. This technique is very useful for patients undergoing left hemihepatectomy requiring high hilar resection of the bile duct.  相似文献   
993.
The objective of the present study was to develop a short prediction questionnaire for estimating the risk of no return to work (RTW) within 3 months of sick leave to facilitate triage and management of a patient population of subacute low-back pain (LBP) sufferers. We conducted a prospective study with a 3-month follow-up on 186 patients with LBP introducing a claim for sickness benefits to the largest sickness fund in Belgium. Patients completed a screening questionnaire within 2 weeks after claim submission. All patients were invited for clinical assessment, at 6–8 weeks of sick leave, by the medical adviser. Patients’ work status was recorded by the sickness fund. About 20% of the patients did not resume work at 3 months’ sick leave. They were more likely to experience pain below the knee, to have an own previous prediction of a 100% no RTW and to have a severe interference of pain on daily activities. The screening tool based on these three items correctly classified 73.7% of the non-resumers and 78.4% of the resumers at a cut-off score of 0.22. The findings of this study provide evidence of the utility of a short screening questionnaire for future use in intervention studies in a social security setting.  相似文献   
994.
Backgrounds Pelvic autonomic nerve preservation (PANP) with lateral lymph node dissection (LLND) has been introduced in rectal cancer surgery in Japan; however, its indication has not been standardized yet. Materials and methods Forty-four patients with advanced lower rectal cancer were randomized to either the standard treatment group (control group) or the intraoperative radiotherapy (IORT) group. All patients underwent potentially curative resection of the rectum with total mesorectal excision. The control group underwent bilateral LLND and limited PANP. The IORT group underwent bilateral LLND, complete PANP, and IORT. Patients allocated to the IORT group received IORT to the bilateral preserved pelvic nerve plexuses. Patients’ clinicopathologic parameters, postoperative complications, voiding function, and prognosis were compared between the two groups. Results Among 44 patients enrolled, three patients were excluded from the analysis, resulting in 19 patients in the IORT group and 22 patients in the control group. Patients’ demographic and pathological parameters and postoperative complications were well balanced between the two groups. Oncological outcomes including overall and disease-free survival were also similar. Local recurrence was observed in one patient in each group. Among the 34 patients not complicated with intrapelvic abscess, the mean duration of urinary catheter indwelling was 8 days in the IORT group and 13 days in the control group (p = 0.055). In the long term, medication for urination was necessitated in four patients in the control group, whereas in none in the IORT group (p = 0.059). Discussions Oncological outcomes in the IORT group are equal to those in the control group, and voiding functions in the IORT group are superior to those in the control group. These results suggest that IORT may be useful to expand the indication of complete PANP with LLND for advanced lower rectal cancer.  相似文献   
995.
Background Massive bleeding remains one of main factors of morbidity and death in liver resections. For this reason, the Pringle maneuver or total vascular exclusion is commonly used during liver resection. However, ischemic damage is still a major problem. Some surgeons used the “glissonean” approach for bleeding control, but the technique is tedious and also time consuming, with high incidence of bile leaks in the postoperative period. The aim of this paper is to describe a new bleeding control technique, rapid ligation of the corresponding inflow and outflow vessels without hilus dissection before the parenchyma transection during anatomical left liver resection and to analyze the feasibility, blood loss, transfusion requirements, and postoperative complications. Materials and methods During the past 18 years, we used the new hemorrhage control technique in left liver resection in 630 patients with malignant or benign tumors. Results The median blood loss in all 630 patients was 110 ± 250 ml (range 50–750), and no patient required blood transfusion. The median total operative time was 77 ± 35 min (range 25–155). No bile leaks and liver failure of the patients occurred postoperatively. There was no death within 30 postoperative days. Conclusion The rapid ligation of the corresponding inflow and outflow vessels without hilus dissection before the parenchyma transection is a feasible, safe, and bloodless technique during the left liver resection. A commentary on this paper is available at  相似文献   
996.
Purpose Gradually progressing contraction of airway smooth muscle is suggested to be due to the Rho-kinase signaling pathway. In our preliminary study in rat tracheas, landiolol, a β1-adrenoceptor antagonist, at high doses caused gradually progressing contraction, and this contraction reached a plateau after 20 min. Therefore, this study was carried out to clarify whether landiolol could stimulate the Rho-kinase pathway or the phosphatidylinositol (PI) response in the rat trachea. Methods Seventy-eight male Wistar rats weighing 250–350 g were used for the experiments. Their tracheas were cut into 3-mm-wide ring segments or 1-mm-wide slices. Measurements of isometric tension and [3H] inositol monophosphate (IP1) production were conducted, using these tracheal rings or slices. Data values are expressed as means ± SD, and statistical significance (P < 0.05) was determined using analysis of variance (ANOVA). Results Landiolol (700 μM)-induced contraction was completely inhibited by fasudil at 30 μM, while the landiolol-induced contraction was not inhibited by 4-diphenylacetoxy-N-methyl-piperidine methobromide (4-DAMP), ketanserin, or nicardipine. Landiolol did not stimulate IP1 production. Conclusion These results suggest that high concentrations of landiolol could cause airway smooth muscle contraction through the Rho-kinase pathway, but not through the PI response coupled with muscarinic M3 receptors, 5-HT receptors or the activation of L-type Ca2+ channels.  相似文献   
997.
Based on a review of recently published articles, we evaluated the current status of high-intensity focused ultrasound (HIFU) as a primary treatment option for localized prostate cancer and as a salvage therapy when radiation has failed. With mid-and long-term progression-free survival rates around 70%, negative postoperative prostate biopsies almost 90%, and an excellent morbidity profile, primary HIFU appears to be a valid alternative to active surveillance protocols in low-risk patients and standard therapies in patients with life expectancies of 10 or fewer years. Moreover, HIFU has a considerable potential for local-only recurrence after radiation failure. HIFU is a recent technology, and many improvements will undoubtedly expand its future indications and use for the management of prostate cancer.  相似文献   
998.
Core decompression procedures have been used in osteonecrosis of the femoral head to attempt to delay the joint destruction that may necessitate hip arthroplasty. The efficacy of core decompressions has been variable with many variations of technique described. To determine whether the efficacy of this procedure has improved during the last 15 years using modern techniques, we compared recently reported radiographic and clinical success rates to results of surgeries performed before 1992. Additionally, we evaluated the outcomes of our cohort of 52 patients (79 hips) who were treated with multiple small-diameter drillings. There was a decrease in the proportion of patients undergoing additional surgeries and an increase in radiographic success when comparing pre-1992 results to patients treated in the last 15 years. However, there were fewer Stage III hips in the more recent reports, suggesting that patient selection was an important reason for this improvement. The results of the small-diameter drilling cohort were similar to other recent reports. Patients who had small lesions and were Ficat Stage I had the best results with 79% showing no radiographic progression. Our study confirms core decompression is a safe and effective procedure for treating early stage femoral head osteonecrosis.  相似文献   
999.
Background Although the feasibility of laparoscopic resection of gastric gastrointestinal stromal tumors (GISTs) has been established, various aspects are debated. This paper describes the problems of minimally invasive resection of gastric GISTs and compares this experience with an extensive literature review. Study Design Between August 2001 and December 2006, 21 consecutive patients undergoing laparoscopic resection of gastric GISTs were enrolled in a prospective study. A literature review of laparoscopic treatment was performed on Pubmed using keywords GIST and surgery. A comparison with authors’ experience with open wedge-segmental resection of GISTs (25 cases from November 1995 to December 2000) was also carried out. Statistical analysis was based on chi-squared test and t Student evaluation. Results Twenty-one patients, mean age 50.1 years (range, 34–68 years), were submitted to laparoscopic wedge- segmental gastric resections. Mean tumor size was 4.5 cm (range, 2.0–8.5 cm). Mean operative time was 151 min (range, 52–310 min), the mean blood loss was 101 mL (range, 10–250 mL), and the mean hospital stay was 4.8 days (range 3–7 days). There were no major operative complications or mortalities. All lesions had negative resection margins. At a mean follow-up of 35 months, all patients were disease-free. Morbidity, mortality, length of stay, and oncologic outcomes were comparable to the open surgery retrospective evaluation (p = not significant). Conclusions As found also in the literature review, the laparoscopic resection is safe and effective in treating gastric GISTs. Given these findings as well as the advantages afforded by laparoscopic surgery, a minimally invasive approach should be the preferred surgical treatment in patients with small- and medium-sized gastric GISTs.  相似文献   
1000.
Gut motility is modulated by adrenergic mechanisms. The aim of our study was to examine mechanisms of selective adrenergic receptors in rat jejunum. Spontaneous contractile activity of longitudinal muscle strips from rat jejunum was measured in 5-ml tissue chambers. Dose–responses (six doses, 10−7–3 × 10−5M) to norepinephrine (NE, nonspecific), phenylephrine (PH, α1), clonidine (C, α2), prenalterol (PR, β1), ritodrine (RI, β2), and ZD7714 (ZD, β3) were evaluated with and without tetrodotoxin (TTX, nerve blocker). NE(3 × 10−5M) inhibited 74 ± 5% (mean ± SEM) of spontaneous activity. This was the maximum effect. The same dose of RI(β2), PH(α1), or ZD(β3) resulted in an inhibition of only 56 ± 5, 43 ± 4, 33 ± 6, respectively. The calculated concentration to induce 50% inhibition (EC50) of ZD(β3) was similar to NE, whereas higher concentrations of PH(α1) or RI(β2) were required. C(α2) and PR(β1) had no effect. TTX changed exclusively the EC50 of RI from 4.4 ± 0.2 to 2.7 ± 0.8% (p < 0.04). Contractility was inhibited by NE (nonspecific). PH(α1), RI(β2), and ZD(β3) mimic the effect of NE. TTX reduced the inhibition by RI. Our results suggest that muscular α1, β2, and β3 receptor mechanisms mediate adrenergic inhibition of contractility in rat jejunum. β2 mechanisms seem to involve also neural pathways. Part of this work was presented as a poster at the annual meeting of the Society for Surgery of the Alimentary Tract, Orlando, FL, May 17–22, 2003, and published as an abstract in Gastroenterology 2003, 124(4):M1342.  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