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   28127篇
  免费   1885篇
  国内免费   258篇
耳鼻咽喉   511篇
儿科学   482篇
妇产科学   452篇
基础医学   3924篇
口腔科学   602篇
临床医学   2566篇
内科学   5711篇
皮肤病学   865篇
神经病学   1945篇
特种医学   1823篇
外科学   3788篇
综合类   809篇
现状与发展   1篇
一般理论   18篇
预防医学   1278篇
眼科学   1013篇
药学   2114篇
中国医学   214篇
肿瘤学   2154篇
  2023年   263篇
  2022年   576篇
  2021年   1021篇
  2020年   594篇
  2019年   762篇
  2018年   926篇
  2017年   698篇
  2016年   929篇
  2015年   1203篇
  2014年   1417篇
  2013年   1555篇
  2012年   2408篇
  2011年   2348篇
  2010年   1333篇
  2009年   1164篇
  2008年   1594篇
  2007年   1598篇
  2006年   1529篇
  2005年   1421篇
  2004年   1130篇
  2003年   940篇
  2002年   775篇
  2001年   554篇
  2000年   536篇
  1999年   436篇
  1998年   170篇
  1997年   141篇
  1996年   101篇
  1995年   97篇
  1994年   97篇
  1993年   74篇
  1992年   165篇
  1991年   176篇
  1990年   145篇
  1989年   135篇
  1988年   123篇
  1987年   138篇
  1986年   110篇
  1985年   103篇
  1984年   82篇
  1983年   75篇
  1982年   42篇
  1979年   63篇
  1977年   40篇
  1975年   38篇
  1974年   40篇
  1973年   37篇
  1972年   37篇
  1970年   36篇
  1969年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
PURPOSE: The epothilones are a novel class of nontaxane microtubule-stabilizing agents. BMS-247550 is a semisynthetic analog of the natural product epothilone B. We conducted a phase I study administering BMS-247550 as a 1-hour intravenous infusion daily for 5 consecutive days every 21 days. PATIENTS AND METHODS: Twenty-one patients received BMS-247550 without filgrastim in the first cycle. An additional six patients were enrolled at a starting dose of 8 mg/m2/d with filgrastim support. Twenty-one of the 27 patients had received prior paclitaxel, docetaxel, or both. RESULTS: One hundred seven cycles were administered to 27 patients. The maximum-tolerated dose was 6 mg/m2 of BMS-247550 administered as a 1-hour intravenous infusion daily for 5 consecutive days every 21 days. Dose-limiting toxicity at a dose of 8 mg/m2/d was neutropenia with or without filgrastim support. Nonhematologic grade 3 toxicities included fatigue (seven cycles), stomatitis (two cycles), and anorexia (one cycle). The mean terminal half-life of BMS-247550 was 16.8 +/- 6.0 hours, the volume of distribution at steady-state was 798 +/- 375 L, and the clearance was 712 +/- 247 mL/min. Objective responses were observed in patients with breast, cervical, and basal cell cancer. Reductions in CA-125 levels were noted in patients with ovarian cancer. CONCLUSION: The recommended phase II dose of BMS-247550 on the daily schedule for 5 days is 6 mg/m2/d. Neutropenia was dose limiting, but higher doses were tolerated by a large fraction of patients with filgrastim support. Peripheral neuropathy was mild, even after multiple cycles of therapy, and was not dose limiting.  相似文献   
93.
PURPOSE: To determine the efficacy and toxicity of a combined-modality regimen of irradiation with platinum-based combination chemotherapy in small-cell carcinoma of the cervix (SCCC). PATIENTS AND METHODS: Thirty-four patients with SCCC were seen and treated at the British Columbia Cancer Agency between May 1988 and November 2002. Two protocols were used, SMCC (May 1988 to December 1995) and SMCC2 (January 1996 to November 2002). Both protocols used cisplatin, etoposide, and involved-field irradiation (essentially pelvis plus or minus para-aortics) with concurrent chemotherapy. In addition, SMCC2 included carboplatin and paclitaxel, and the para-aortics were irradiated routinely. RESULTS: Thirty-one patients received either SMCC (n = 17) or SMCC2 (n = 14), and three patients did not (disease too extensive, n = 1; patient refusal, n = 1; and alternative regimen, n = 1). For the 31 patients treated on one of the protocols, the 3-year overall and failure-free survival (FFS) rates were 60% and 57%, respectively. The results were equivalent for SMCC and SMCC2. Radiologic stage was the only independent predictor for FFS (80% at 3 years for stage I and II patients v 38% at 3 years for stage III and IV patients). Distant failure (28%) was the most common cause of failure, with local failure occurring in 13% of patients. The switch to SMCC2 did not improve efficacy but did lessen the toxicity. CONCLUSION: SCCC can be successfully treated in approximately 55% of patients with a combination of irradiation and platinum-based chemotherapy. Disease extent predicts for chance of curability.  相似文献   
94.
95.
96.
Individuals with chronic renal failure (CRF) have a high prevalence of protein-energy malnutrition. There are many causes for this condition, chief among which is probably reduced nutrient intake from anorexia. In nondialyzed patients with CRF, energy intake is often below the recommended amounts; in maintenance dialysis patients, both dietary protein and energy intake are often below their needs. Although a number of studies indicate that rats with CRF have increased protein catabolism in comparison to control animals, more recent evidence suggests that increased catabolism in CRF rats is largely if not entirely due to acidemia, particularly if these animals are compared to pair-fed control rats. Studies in humans with advanced CRF also indicate that acidemia can cause protein catabolism. Indeed, nitrogen balance studies and amino acid uptake and release and isotopic kinetic studies indicate that in nondialyzed individuals with CRF, who are not acidemic, both their ability to conserve body protein when they ingest low protein diets and their dietary protein requirements appear to be normal. For patients undergoing maintenance hemodialysis or chronic peritoneal dialysis, dietary protein requirements appear to be increased. The increased need for protein is due, in part, to the losses into dialysate of such biologically valuable nitrogenous compounds as amino acids, peptides, and proteins. However, the sum of the dietary protein needs for CRF patients (of about 0.60 g/kg/day) and the dialysis losses of amino acids, peptides and proteins do not equal the apparent dietary protein requirements for most maintenance dialysis patients. This discrepancy may be due to a chronic state of catabolism in the clinically stable maintenance dialysis patient that is not present in the clinically stable nondialyzed individual who has advanced CRF. Possible causes for such a low grade catabolic state include resistance to anabolic hormones (for example, insulin, IGF-1) and a chronic inflammatory state associated with increased levels of pro-inflammatory cytokines.  相似文献   
97.
We report a case of an 80-year-old man with osteoblastic metastases from advanced carcinoma of the prostate presenting with a grand mal seizure resulting from severe hypocalcaemia. He had low serum phosphate and ionised calcium levels, elevated serum skeletal alkaline phosphatase and intact parathormone levels. 99mTc radioisotope bone scan revealed a "super bone scan" suggestive of osteomalacia. The serum 1, 25-dihydroxycholecalciferol level was unexpectedly elevated. The biochemical abnormalities persisted despite high dose calcium replacement, but improved with supraphysiological doses of 1,25 (OH)2 vitamin D3 (Rocaltrol) therapy. We hypothesise that the hypocalcaemia in this patient was due to vitamin D resistance secondary to a humoral factor secreted by the tumour.  相似文献   
98.
To determine relatively useful diagnostic procedures of carbon disulfide (CS2) poisoning in terms of validity and cost-effectiveness, several diagnostic tests are evaluated on 1,552 people by prevalence ratio (exposed/nonexposed), dose-response relationship, sensitivity and specificity, and the cost of the tests. Several symptoms with high kappa indices are found to be useful in various combinations, showing a consistent dose-response relationship and high exposed-nonexposed ratio. In clinicopathologic tests on functions of the kidney, liver and hematopoietic systems, eight items out of 22 have been shown to have significant dose-response relationship, mostly in liver function tests. A thorough dental examination failed to identify any useful indicator peculiar to the CS2 poisoning. Unlike Western people, the prevalence of coronary heart disease among Koreans was too low to be useful in the diagnosis of CS2 poisoning. Among four elective tests, i.e., Minnesota Multiphasic Personality Inventory (MMPI), Brain magnetic resonance imaging (MRI), nerve conduction velocity (NCV), and fluorescent angiography (FAG), the NCV appeared to be a more sensitive and specific test than the others are. Combinations of the tests improved the probability of diagnosing CS2 poisoning cases when any one test out of four was positive. Addition of other valid tests increased the probability of excluding non-cases. It was concluded that diagnosis of CS2 poisoning could be made validly and inexpensively if the diagnostic tests were carefully chosen step by step.  相似文献   
99.
(-)-Hydroxycitrate (HCA) is an active ingredient that is extracted from the rind of the Indian fruit, Garcinia cambogia, which is available as an herbal supplement and is used to lose weight. In this study, the acute and chronic effects of HCA on energy metabolism were examined in male Std ddY mice. Mice were placed into metabolic chambers and administered 10 mg HCA or water (control) orally. Serum free fatty acid levels were significantly higher 100 min after administration in the HCA group, but the respiratory exchange ratio was not different from that in the control group. The concentration of glycogen in the gastrocnemius muscle was higher in the HCA group 16 h after administration, and in a separate study, the maximum swimming time until fatigue was slightly longer (P: = 0. 21) than that in the control group on d 1. The difference was significant on d 3 after 3 d of HCA or water administration. Other mice were administered 10 mg HCA or water orally twice a day for 25 d. On d 26, they were placed into metabolic chambers after administration and allowed to rest for 1 h, followed by 1 h of running at 15 m/min. Respiratory gas was monitored. The respiratory exchange ratio was significantly lower in the HCA group during both resting and exercising conditions. These results suggest that chronic administration of HCA promotes lipid oxidation and spares carbohydrate utilization in mice at rest and during running.  相似文献   
100.
Dual therapy has been reported to produce H.pylori eradication rate of 75-80%. This study is designed to determine the efficacy of omeprazole 20 mg bd in combination with amoxycillin 500 mg tid (Group A), amoxycillin 750 mg tds (Group B) and clarithromycin 500 mg tid (Group C) in Singapore. One hundred and forty-eight patients with H. pylori positive duodenal ulcers between ages of 22 and 69 were enrolled from two centres. There were 48 patients in Group A, 50 patients in Group B and 50 patients in Group C. The medication was given for 14 days. The patients were re-evaluated with an upper GI endoscope 4 weeks after cessation of treatment Successful eradication was defined as H.pylori negative on histology and culture. Based on intention to treat analysis, the eradication rate was 47.8% in Group A, 68% in Group B and 66% in Group C. The difference between GroupA and B were statistically significant (p = 0.04). Based on all patient treated analysis, the eradication rate was 57.5% in Group A, 70.7% in Group B and 75% in Group C. The difference in eradication rates was not statistically significant. Adverse events were reported in 21% of all patients with no difference in the adverse event rate between all groups. The eradication rate achieved with dual therapy in this study was similar to that attained in Western population. Higher dose amoxycillin regime gives a significantly higher eradication than a lower dose amoxycillin.  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