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   1203篇
  免费   84篇
  国内免费   4篇
耳鼻咽喉   19篇
儿科学   27篇
妇产科学   38篇
基础医学   161篇
口腔科学   14篇
临床医学   108篇
内科学   210篇
皮肤病学   8篇
神经病学   98篇
特种医学   86篇
外科学   146篇
综合类   23篇
一般理论   1篇
预防医学   120篇
眼科学   10篇
药学   75篇
中国医学   4篇
肿瘤学   143篇
  2021年   17篇
  2020年   11篇
  2019年   15篇
  2018年   13篇
  2017年   16篇
  2016年   15篇
  2015年   17篇
  2014年   24篇
  2013年   42篇
  2012年   64篇
  2011年   51篇
  2010年   37篇
  2009年   37篇
  2008年   54篇
  2007年   61篇
  2006年   58篇
  2005年   45篇
  2004年   43篇
  2003年   46篇
  2002年   30篇
  2001年   35篇
  2000年   37篇
  1999年   34篇
  1998年   29篇
  1997年   18篇
  1996年   20篇
  1995年   19篇
  1994年   13篇
  1993年   22篇
  1992年   28篇
  1991年   31篇
  1990年   32篇
  1989年   35篇
  1988年   25篇
  1987年   27篇
  1986年   19篇
  1985年   14篇
  1984年   13篇
  1983年   11篇
  1980年   9篇
  1978年   9篇
  1977年   7篇
  1976年   11篇
  1974年   6篇
  1972年   7篇
  1967年   5篇
  1965年   5篇
  1957年   6篇
  1956年   5篇
  1954年   5篇
排序方式: 共有1291条查询结果,搜索用时 15 毫秒
1.
In 17 cases the author has removed intraglandular submandibular calculi by an oral route utilizing blunt soft tissue dissection after an incision of the mucosa only. General anesthesia is used and the patient discharged after an overnight stay. No complications were encountered. All patients were back on full diet in 48 hours.  相似文献   
2.
PURPOSE: Bevacizumab, a monoclonal antibody against vascular endothelial growth factor, increases survival when combined with irinotecan-based chemotherapy in first-line treatment of metastatic colorectal cancer (CRC). This randomized, phase II trial compared bevacizumab plus fluorouracil and leucovorin (FU/LV) versus placebo plus FU/LV as first-line therapy in patients considered nonoptimal candidates for first-line irinotecan. PATIENTS AND METHODS: Patients had metastatic CRC and one of the following characteristics: age > or = 65 years, Eastern Cooperative Oncology Group performance status 1 or 2, serum albumin < or = 3.5 g/dL, or prior abdominal/pelvic radiotherapy. Patients were randomly assigned to FU/LV/placebo (n = 105) or FU/LV/bevacizumab (n = 104). The primary end point was overall survival. Secondary end points were progression-free survival, response rate, response duration, and quality of life. Safety was also assessed. RESULTS: Median survival was 16.6 months for the FU/LV/bevacizumab group and 12.9 months for the FU/LV/placebo group (hazard ratio, 0.79; P = .16). Median progression-free survival was 9.2 months (FU/LV/bevacizumab) and 5.5 months (FU/LV/placebo); hazard ratio was 0.50; P = .0002. Response rates were 26.0% (FU/LV/bevacizumab) and 15.2% (FU/LV/placebo) (P = .055); duration of response was 9.2 months (FU/LV/bevacizumab) and 6.8 months (FU/LV/placebo); hazard ratio was 0.42; P = .088. Grade 3 hypertension was more common with bevacizumab treatment (16% v 3%) but was controlled with oral medication and did not cause study drug discontinuation. CONCLUSION: Addition of bevacizumab to FU/LV as first-line therapy in CRC patients who were not considered optimal candidates for first-line irinotecan treatment provided clinically significant patient benefit, including statistically significant improvement in progression-free survival.  相似文献   
3.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.  相似文献   
4.
5.
6.
Isolated sperm from normo-, oligo- and astheno-spermic men were incubated for 20 h in medium supplemented with 8% heat-inactivated or untreated human serum, and in medium with heated or untreated serum deficient in complement factor C3. Before and after incubation, sperm motility was assessed by means of a computer-assisted semen analyser. The results did not show significant differences between the motility of sperm incubated in heated or untreated serum. It is concluded that heating of homologous serum is not necessary for preserving sperm motility and in some cases may even be disadvantageous.  相似文献   
7.
Localized 1H NMR spectra of glutamate in the human brain.   总被引:2,自引:0,他引:2  
Localized 1H NMR spectra at TE = 12 ms were obtained from cerebral cortex of human subjects using ISIS with surface suppression. The 2.29-ppm resonance was assigned to C4 glutamate with contributions from C4 glutamine and GABA using in vivo spectral editing and comparison of chemical shift with pure compounds. The measured intensity ratio between the 2.29 resonance and the creatine resonance at 3.03 ppm was in good agreement with the ratio predicted from previously reported measurements of glutamate, glutamine, and GABA concentrations in biopsied human brain tissue.  相似文献   
8.
The purposes of this study were to determine the effects of E. coli endotoxin shock on coronary blood flow (CBF) and myocardial adenine nucleotides and to determine if reactive oxygen species are major causal factors in these effects of endotoxin. Twenty-three pentobarbital-anesthetized Beagle dogs were instrumented for recording cardiorespiratory parameters, injected i.v. with saline (time-matched controls; n = 6) or endotoxin (1.5 mg/kg; n = 17), and studied for 4 h. Endotoxin dogs also received either i.v. saline (shock controls; n = 6) or i.v. treatment with either deferoxamine (30 mg/kg; n = 5) or triple therapy (n = 6) with a combination of allopurinol (150 mg/kg), superoxide dismutase (SOD) (5 mg/kg), and catalase (CAT) (5 mg/kg). Cardiorespiratory and tissue blood flow variables were constant in sham-shock controls during the study, whereas endotoxin dogs developed typical canine endotoxemia with decreased left ventricular (LV) function. CBF was decreased by approximately 40% (P less than or equal to 0.5) in all endotoxin groups throughout the 4 h study period. However, based on hemodynamic estimates of myocardial O2 demand and endocardial/epicardial blood flow ratios, it seemed that coronary flow was matched to metabolic rate in all endotoxin groups. Endotoxin significantly lowered LV myocardial concentrations of ADP, AMP, NADH, and NADPH (range = 37 to 54%, P less than or equal to 0.05), but ATP, NAD, and NADP concentrations were not changed. The adenylate charge of the myocardium was between 0.91 and 0.95 in all endotoxin groups, suggesting that adequate energy was available in the myocardium during endotoxin shock. The lack of influence of deferoxamine, allopurinol, SOD, and CAT is indirect evidence that oxygen radicals are not primary pathophysiologic mediators in the cardiac response to gram-negative endotoxemia in this endotoxin model.  相似文献   
9.
AIM: To verify an impact of a lymph node revealing solution (LRS) on the number of lymph nodes (LN) revealed in colorectal resection specimens. MATERIAL AND METHOD: Fifty-nine cases of rectosigmoid carcinomas divided into two subgroups-stage pT2&3 (20 cases) and ypT2&3 (with pre-operative radiotherapy-39 cases)-were formalin fixed for 42-72 h, serially sectioned and re-fixed in LRS containing ethanol, diethyl ether, glacial acetic acid, and formalin for 24 h. The number of LNs was matched to a control group consisting of 34 cases of colorectal carcinoma, 14 pT2&3 and 20 ypT2&3 rectosigmoid carcinomas examined routinely. Results were statistically tested by Student's t-test. RESULTS: In the study group the total number of revealed LNs was 869, range 1-48, average 14.7 per specimen, median 15. In the control group the number of LNs was 200, range 0-13, average 5.9 per specimen, median 6. The difference between the study and the control group was statistically significant (P = 0.05). CONCLUSION: Using LRS leads to a significant increase in the number of revealed LNs in colorectal resection specimens and makes it possible to find more than 12 LNs in a majority of stage pT2 and pT3 adenocarcinomas.  相似文献   
10.
Image-directed percutaneous biopsies with a biopsy gun   总被引:3,自引:0,他引:3  
Core tissue for histologic study is believed by many pathologists to be more diagnostic than material from needle aspiration. Recently, a biopsy "gun" has been introduced, which simplifies core biopsies. With this device, 182 biopsies of multiple anatomic sites were performed with ultrasonic, computed tomographic, and fluoroscopic guidance and 18-gauge needles. High-quality histopathologic specimens were obtained in 177 of the biopsies, and diagnostic target tissue was obtained in 167. Only three significant complications occurred: one bleeding complication that required transfusion and two cases of pneumothorax that necessitated placement of chest tubes. The biopsy gun eliminated the disjointed movements of conventional "skinny" needle biopsies, and none of the samples demonstrated significant "crush" artifact or obscuring blood, problems that are commonly associated with manual biopsy techniques. Patient discomfort was decreased with this system compared with that of manual biopsies, and the total procedure time was reduced. Because of these distinct advantages, the authors now use the biopsy gun exclusively for all percutaneous biopsies and recommend that other institutions consider the use of this biopsy method.  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