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   8176篇
  免费   579篇
  国内免费   32篇
耳鼻咽喉   136篇
儿科学   316篇
妇产科学   191篇
基础医学   1151篇
口腔科学   132篇
临床医学   732篇
内科学   1503篇
皮肤病学   101篇
神经病学   914篇
特种医学   222篇
外科学   1155篇
综合类   108篇
一般理论   15篇
预防医学   577篇
眼科学   210篇
药学   571篇
中国医学   10篇
肿瘤学   743篇
  2023年   88篇
  2022年   181篇
  2021年   264篇
  2020年   189篇
  2019年   212篇
  2018年   263篇
  2017年   222篇
  2016年   243篇
  2015年   255篇
  2014年   327篇
  2013年   421篇
  2012年   626篇
  2011年   537篇
  2010年   353篇
  2009年   263篇
  2008年   401篇
  2007年   443篇
  2006年   385篇
  2005年   354篇
  2004年   341篇
  2003年   323篇
  2002年   328篇
  2001年   133篇
  2000年   113篇
  1999年   138篇
  1998年   67篇
  1997年   61篇
  1996年   45篇
  1995年   44篇
  1994年   30篇
  1993年   32篇
  1992年   74篇
  1991年   65篇
  1990年   62篇
  1989年   71篇
  1988年   59篇
  1987年   55篇
  1986年   58篇
  1985年   64篇
  1984年   43篇
  1983年   44篇
  1982年   39篇
  1981年   29篇
  1979年   52篇
  1977年   31篇
  1976年   35篇
  1975年   31篇
  1974年   27篇
  1973年   34篇
  1972年   31篇
排序方式: 共有8787条查询结果,搜索用时 15 毫秒
61.
We present a rare case of fistulation of a dermoid cyst with the transverse colon. We illustrate how an infected dermoid cyst can be diagnosed as an appendix abscess although the management of these is quite different. The general surgeon should be aware of this as a differential diagnosis for an appendix abscess.  相似文献   
62.
63.
64.
65.
Immunohistochemical stains are routinely used to detect abnormal DNA mismatch repair (MMR) protein expression in colorectal carcinomas, particularly when Lynch syndrome is suspected. Complete loss of MMR protein expression is often associated with underlying microsatellite instability (MSI), and the combined results of mutL homolog 1 (MLH1), postmeiotic segregation increased 2 (PMS2), mutS homolog 2 (MSH2), or mutS homolog 6 (MSH6) immunostains may point to the defective MMR protein in tumors with MSI. We have noted that some neoadjuvantly treated colorectal carcinomas display loss of MMR protein immunoexpression, despite a lack of underlying MSI and preserved staining in pretreatment tumor samples. The purpose of this study was to determine the frequency of this finding. We identified 51 neoadjuvantly treated resected colorectal cancers. Posttreatment tumor samples were immunohistochemically stained with MLH1, PMS2, MSH2, and MSH6 antibodies. Loss of staining for any marker was followed by analysis for MSI and assessment of MMR protein expression in pretreatment tumor samples. All of the 51 posttreatment tumor samples showed preserved MLH1, PMS2, and MSH2, but 10 posttreatment tumor samples (20%) showed decreased MSH6 staining. Of these, 9 posttreatment tumor samples displayed loss of staining in less than 100% of tumor cells, but preserved MSH6 expression in pretreatment tumor samples. One case showed a complete absence of MSH6 staining in both pretreatment and posttreatment tumor samples. All 10 cases were microsatellite stable. We conclude that extensive loss of MSH6 immunoexpression is common among neoadjuvantly treated colorectal carcinomas, but generally does not reflect underlying MSI. Therefore, diminished MSH6 staining in treated tumors should prompt immunohistochemical evaluation of pretreatment biopsy samples before genetic testing for Lynch syndrome.  相似文献   
66.
Sir, Neutrophil gelatinase-associated lipocalin (NGAL), a memberof the lipocalin family, is readily excreted and detected inurine, due to its small molecular size (25 kDa) and resistanceto degradation. NGAL is highly accumulated in the human kidneycortical tubules, blood and urine, after nephrotoxic and ischaemicinjuries [1]. Thus, NGAL might represent an early, sensitive,non-invasive biomarker for acute renal injury [2], and urinaryNGAL might serve as an early marker for ischaemic renal injuryin children after cardiopulmonary bypass [3]. On the other hand,serum cystatin C was proposed as a new marker of glomerularfiltration rate (GFR), even in chronic kidney disease [4]. CystatinC has a low molecular weight (13 kDa) and is freely filtered  相似文献   
67.
Purpose  Congenital clasped thumb is a deformity that is associated with heterogeneous congenital anomalies and it has been addressed in many congenital syndromes. The aim of this study was to diagnose and evaluate cases of clasped thumb as regards the associated congenital anomalies and syndromes, and evaluation of the results of treatment of such cases. Methods  A prospective study on 40 patients with 73 clasped thumbs was done. All the patients’ data regarding their personal, family, pregnancy and developmental histories were recorded. All the patients were exposed to thorough clinical and radiological examination and genetic assessment. The cases were classified using the Tsuyuguchi et al. (J Hand Surg [Am] 10:613–618, 1985) classification into three types. Conservative treatment was adopted in ten hands, and surgical treatment was performed for 28 hands in 17 patients, with an average follow-up of 26 months. Results  Positive consanguinity was recorded in 57.5% of cases. Associated anomalies were recorded in 77.5% of cases. Type I was the most common one, followed by type III and then type II. Conservative treatment is effective in type I cases when presented early, and all patients were satisfied with the results of surgical treatment. Conclusions  We reported associated anomalies which are to our knowledge have not mentioned before in the literature which include; congenital blindness, radial deviation of the index finger and ventricular septal defect. We found that 68% of the patients had associated syndromes, and this has not been mentioned before. In this study, we found that there were no difference between type II and type III clasped thumb as regards the pathological findings, severity, the operative procedures, the treatment protocol and the operative results. Properly planned treatment gives satisfactory results.  相似文献   
68.
Background: Blockade of parietal nociceptive afferents by the use of continuous wound infiltration with local anesthetics may be beneficial in a multimodal approach to postoperative pain management after major surgery. The role of continuous preperitoneal infusion of ropivacaine for pain relief and postoperative recovery after open colorectal resections was evaluated in a randomized, double-blinded, placebo-controlled trial.

Methods: After obtaining written informed consents, a multiholed wound catheter was placed by the surgeon in the preperitoneal space at the end of surgery in patients scheduled to undergo elective open colorectal resection by midline incision. They were thereafter randomly assigned to receive through the catheter either 0.2% ropivacaine (10-ml bolus followed by an infusion of 10 ml/h during 48 h) or the same protocol with 0.9% NaCl. In addition, all patients received patient-controlled intravenous morphine analgesia.

Results: Twenty-one patients were evaluated in each group. Compared with preperitoneal saline, ropivacaine infusion reduced morphine consumption during the first 72 h and improved pain relief at rest during 12 h and while coughing during 48 h. Sleep quality was also better during the first two postoperative nights. Time to recovery of bowel function (74 +/- 19 vs. 105 +/- 54 h; P = 0.02) and duration of hospital stay (115 +/- 25 vs. 147 +/- 53 h; P = 0.02) were significantly reduced in the ropivacaine group. Ropivacaine plasma concentrations remained below the level of toxicity. No side effects were observed.  相似文献   

69.
Reports on genetically informative steroid-responsive (sensitive) idiopathic nephrotic syndrome (SSNS) families are lacking. We studied an extended SSNS Bedouin (B) family with a high rate of consanguinity. The clinical presentation and steroid response of its 11 affected individuals were similar to those of sporadic SSNS (spontaneous remission towards puberty and minimal change disease by kidney biopsy). Genome-wide linkage analysis, using a 382 microsatellite-markers mapping set and additional markers adjacent to 80 candidate genes of the index family, did not support linkage to any chromosomal locus. Retrospective analysis of all additional children with SSNS treated by our institution in the past 20 years (n = 96, 50% of them of Jewish origin) revealed another five non-related B families with 2–3 first-degree cousins affected with SSNS in each. The overall familial SSNS rate among the B population (excluding the index family) was 28%, compared with 4% among Jews (Js) (OR 1.8–64, P < 0.005). There were more Bs with simple SSNS than there were Js (71% and 40%, respectively; OR 3.58, 95% CI 1.41–9.23, P < 0.01). In summary, SSNS in this index family was not linked to any of the presently known chromosomal loci nor predicted to be caused by mutation in any one of a list of genes associated with nephrotic syndrome (NS). The presence of other B families affected by SSNS supports the role for susceptibility genes enrichment, exposing highly consanguineous populations to an increased incidence of SSNS. An erratum to this article can be found at  相似文献   
70.
OBJECTIVE: To obtain a comprehensive view of differences in current comorbidity between bipolar I and II disorders (BD) and (unipolar) major depressive disorder (MDD), and Axis I and II comorbidity in BD in secondary-care psychiatric settings. METHOD: The psychiatric comorbidity of 90 bipolar I and 101 bipolar II patients from the Jorvi Bipolar Study and 269 MDD patients from the Vantaa Depression Study were compared. We used DSM-IV criteria assessed by semistructured interviews. Patients were inpatients and outpatients from secondary-care psychiatric units. Comparable information was collected on clinical history, index episode, symptom status, and patient characteristics. RESULTS: Bipolar disorder and MDD differed in prevalences of current comorbid disorders, MDD patients having significantly more Axis I comorbidity (69.1% vs. 57.1%), specifically anxiety disorders (56.5% vs. 44.5%) and cluster A (19.0% vs. 9.9%) and C (31.6% vs. 23.0%) personality disorders. In contrast, BD had more single cluster B personality disorders (30.9% vs. 24.6%). Bipolar I and bipolar II were similar in current overall comorbidity, but the prevalence of comorbidity was strongly associated with the current illness phase. CONCLUSIONS: Major depressive disorder and BD have somewhat different patterns in the prevalences of comorbid disorders at the time of an illness episode, with differences particularly in the prevalences of anxiety and personality disorders. Current illness phase explains differences in psychiatric comorbidity of BD patients better than type of disorder.  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