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   1185篇
  免费   47篇
  国内免费   9篇
耳鼻咽喉   4篇
儿科学   67篇
妇产科学   19篇
基础医学   121篇
口腔科学   37篇
临床医学   101篇
内科学   230篇
皮肤病学   7篇
神经病学   70篇
特种医学   110篇
外科学   232篇
综合类   25篇
一般理论   1篇
预防医学   68篇
眼科学   10篇
药学   70篇
中国医学   1篇
肿瘤学   68篇
  2021年   17篇
  2020年   13篇
  2019年   20篇
  2018年   25篇
  2017年   16篇
  2016年   19篇
  2015年   24篇
  2014年   26篇
  2013年   44篇
  2012年   52篇
  2011年   39篇
  2010年   43篇
  2009年   38篇
  2008年   49篇
  2007年   52篇
  2006年   63篇
  2005年   51篇
  2004年   37篇
  2003年   26篇
  2002年   29篇
  2001年   24篇
  2000年   24篇
  1999年   18篇
  1998年   25篇
  1997年   25篇
  1996年   20篇
  1995年   18篇
  1994年   18篇
  1993年   15篇
  1992年   16篇
  1991年   20篇
  1990年   29篇
  1989年   27篇
  1988年   24篇
  1987年   21篇
  1986年   23篇
  1985年   24篇
  1984年   19篇
  1983年   9篇
  1982年   11篇
  1981年   8篇
  1980年   11篇
  1979年   14篇
  1978年   9篇
  1977年   10篇
  1975年   8篇
  1972年   11篇
  1970年   9篇
  1968年   6篇
  1967年   7篇
排序方式: 共有1241条查询结果,搜索用时 15 毫秒
71.
Despite the widespread use of liposome-mediated gene transfer in cancer therapy protocols, little is known about the tissue distribution of intralesionally administered DNA. We have previously shown that antisense gene therapy targeting the epidermal growth factor receptor (EGFR) inhibited tumor growth in a human head and neck squamous cell carcinoma (HNSCC) xenograft model. Further investigation demonstrated lack of systemic toxicity with intramuscular or intratumoral administration of this liposomal-DNA complex. In the present study, we compared two approaches to determine the presence of exogenous DNA in the plasma and tissues of mice treated with intramuscular injection of EGFR antisense gene therapy. PCR analysis using genomic DNA plus plasmid DNA as template was 83-fold more sensitive than PCR using a mixture of total RNA and plasmid DNA as template. With the more sensitive method (able to detect fewer than 500 molecules of EGFR antisense DNA in 1 microg of genomic DNA), foreign DNA was detected in all organs up to 1 month following a single injection. In contrast, using RNA plus plasmid DNA as template, exogenous DNA was only detected at the injection site at 1 week, and was undetectable at 1 month. Optical imaging studies demonstrated plasmid DNA only at the injection site. Although less sensitive than PCCR, Southern blot hybridization showed no evidence of integration of foreign DNA into the host genome in vitro or in vivo. These results emphasize the importance of defining the assays used to detect foreign DNA and suggest that the ability to detect intralesionally administered liposomal gene therapy, in organs distant from the injection site, is directly correlated with the sensitivity of the method employed.  相似文献   
72.
Currently, axillary lymph node dissection is increasingly being replaced by the sentinel node procedure. This method is time-consuming and the full immunohistochemical evaluation is usually only first known postoperatively. This study was designed to evaluate the accuracy of preoperative ultrasound-guided fine needle aspirations (FNAs) for the detection of non-palpable lymph node metastases in primary breast cancer patients. We evaluated the material of 183 ultrasound-guided FNAs of non-palpable axillary lymph nodes of primary breast cancer patients. The cytological results were compared with the final histological diagnosis. Ultrasound-guided FNA detected metastases in 44% (37/85) of histologically node-positive patients, in 20% of the total patient population studied. These pecentages are likely to be higher when women with palpable nodes are included. Cytologically false-negative and false-positive nodes were seen in 28 (15%) and three cases (1.6%), respectively. Interestingly 25% (n=7) of the false-negative nodes, revealed micrometastases on postoperative histology. The sensitivity was 57%, the specificity 96%. We conclude that ultrasound-guided FNA of the axillary lymph nodes is an effective procedure that should be included in the preoperative staging of all primary breast cancer patients. Whether lymph nodes are palpable or not, it will save considerable operating time by selecting those who need a complete axillary lymph node dissection at primary surgery and would save a significant number of sentinel lymph node dissections (SLNDs).  相似文献   
73.
74.
Visual loss after renal transplantation   总被引:2,自引:0,他引:2  
  相似文献   
75.
STUDY OBJECTIVE: To compare the ease of insertion of a warmed standard tracheal tube to that of a wire reinforced tracheal tube when placed over a flexible fiberoptic bronchoscope. DESIGN: Randomized controlled trial. SETTING: Tertiary care hospital. PATIENTS: 50 patients undergoing elective general anesthesia. INTERVENTIONS: Patients' tracheas were intubated with a flexible fiberoptic bronchoscope and had either a standard or wire-reinforced tracheal tube inserted. If resistance was met, the tube was withdrawn, rotated, and readvanced. This was repeated two times. If unsuccessful, the flexible fiberoptic bronchoscope was removed, and intubation was attempted with the other type of tracheal tube. MEASUREMENTS: The ability to advance the tracheal tube was determined. MAIN RESULTS: There were no demographic differences between the two groups. There was a similar ease of advancement of the two tracheal tubes. CONCLUSIONS: When performing elective flexible fiberoptic bronchoscopy for intubation, we recommend using the less expensive warmed standard tracheal tube.  相似文献   
76.
Recombinant human erythropoietin (rHuEpo) has been used successfully in the treatment of cancer-related anemia. Clinical observations with several patients with multiple-myeloma treated with rHuEpo has shown, in addition to the improved quality of life, a longer survival than expected, considering the poor prognostic features of these patients. Based on these observations, we evaluated the potential biological effects of rHuEpo on the course of tumor progression by using murine myeloma models (MOPC-315-IgAlambda(2) and 5T33 MM-IgG(2b)). Here we report that daily treatment of MOPC-315 tumor-bearing mice with rHuEpo for several weeks induced complete tumor regression in 30-60% of mice. All regressors that were rechallenged with tumor cells rejected tumor growth, and this resistance was tumor specific. The Epo-triggered therapeutic effect was shown to be attributed to a T cell-mediated mechanism. Serum Ig analysis indicated a reduction in MOPC-315 lambda light chain in regressor mice. Intradermal inoculation of 5T33 MM tumor cells followed by Epo treatment induced tumor regression in 60% of mice. The common clinical manifestation of myeloma bone disease in patients with multiple-myeloma was established in these myeloma models. Epo administration to these tumor-bearing mice markedly prolonged their survival and reduced mortality. Therefore, erythropoietin seems to act as an antitumor therapeutic agent in addition to its red blood cell-stimulating activity.  相似文献   
77.
Thallium-201/technetium-99m pertechnetate subtraction scintigraphy of the parathyroid glands was performed in a prospective study of 33 patients who had undergone bilateral neck exploration for elevated serum calcium and serum parathyroid hormone levels. In 31 cases, the Tl-201/Tc-99m subtraction technique yielded an overall sensitivity of 81%, specificity of 99%, and accuracy of 94% for identifying solitary parathyroid adenomas. Tl-201/Tc-99m subtraction scintigraphy correctly identified 73% of parathyroid adenomas weighing less than 499 mg, 79% of those weighing 500-1,499 mg, and 100% of adenomas weighing more than 1,500 mg. In a subgroup of 24 patients with solitary parathyroid adenomas who underwent both scintigraphy and high-resolution sonography, the sensitivity, specificity, and accuracy of both procedures were similar.  相似文献   
78.
Evaluation of an on-line patient exposure meter in neuroradiology   总被引:1,自引:0,他引:1  
  相似文献   
79.
Haptoglobin phenotype and diabetic nephropathy   总被引:3,自引:0,他引:3  
Abstract Aims/hypothesis. To determine if the haptoglobin 2 allele is associated with an increased risk for the development of diabetic nephropathy. Methods. This study included 110 consecutive normotensive subjects with Type I (insulin-dependent) diabetes mellitus and Type II (non-insulin-dependent) diabetes mellitus seen in two outpatient clinics in Israel. Diabetes duration was greater than 10 years for Type I diabetes and more than 5 years for Type II diabetic subjects. Microalbuminuria was defined as urinary protein excretion of 30 to 300 mg/24 h, and macroalbuminuria was defined as urinary protein excretion of greater than 300 mg/24 h. Serum was taken from subjects for haptoglobin typing by gel electrophoresis. Results. Of the participating subjects 54 had Type I and 56 had Type II diabetes. None (0/18) of the subjects homozygous for the haptoglobin 1 allele (1–1) showed any sign of diabetic nephropathy, as compared with 34 % (19/55) of subjects homozygous for the haptoglobin 2 allele (2–2) and 27 % (10/37) of heterozygous subjects (2–1) (p < 0.04). Of the subjects 29 showed macroalbuminuria. The risk of developing macroalbuminuria was found to be greater in subjects with two haptoglobin 2 alleles (22 %) (12/55) as compared with one haptoglobin 2 allele (8 %) (3/37) or no haptoglobin 2 alleles (0 %) (0/18) (p < 0.03). Conclusion/interpretation. By showing a graded risk relation to the number of haptoglobin 2 alleles in Type I and Type II diabetic subjects, these studies further support our hypothesis that the haptoglobin phenotype is a major susceptibility gene for the development of diabetic nephropathy. [Diabetologia (2001) 44: 602–604] Received in revised from: 5 January 2001  相似文献   
80.
OBJECTIVE: To assess the levels of and the independent contributors to depressive affect and anxiety among partners of patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: The partners of 75 Latino and 113 European-American patients with type 2 diabetes were assessed for level of depressive affect and anxiety and for three groups of potential stressors: demographics (age, gender, and education), patient disease status (time since diagnosis, HbA(1c), comorbidities, and BMI), and family stress (disease impact, spouse conflict, and family closeness). Dependent variables were partner depressive affect (Center for Epidemiological Studies-Depression scale) and anxiety (Symptom Checklist [SCL-90] anxiety). Predictors of partner depressive affect and anxiety and partner-patient concordance rates were computed. RESULTS: Levels of depressive affect and anxiety and rates of likely depression (21.4%) were as high for partners as they were for patients. No differences were found on depressive affect or anxiety by ethnicity, but female partners scored higher than male partners on both measures. Partner-patient concordance rates were low. The family level variables accounted for the most variance in both depressive affect and anxiety, with demographics and disease status variables contributing modest or nonsignificant independent variance. CONCLUSIONS: Partners of patients with type 2 diabetes experience levels of psychological distress as high or even higher than patients, especially if the partner is female. Low levels of concordance suggest that partners can be distressed even if patients are not. Many life stresses contribute to psychological distress among partners, not just disease-related indicators. The findings suggest the utility of evaluating both partners and patients using a life-centered rather than a disease-focused perspective.  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