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   1853篇
  免费   77篇
  国内免费   29篇
耳鼻咽喉   2篇
儿科学   49篇
妇产科学   9篇
基础医学   199篇
口腔科学   62篇
临床医学   133篇
内科学   771篇
皮肤病学   9篇
神经病学   95篇
特种医学   27篇
外科学   278篇
综合类   7篇
一般理论   1篇
预防医学   36篇
眼科学   5篇
药学   142篇
中国医学   2篇
肿瘤学   132篇
  2023年   7篇
  2022年   9篇
  2021年   22篇
  2020年   13篇
  2019年   23篇
  2018年   19篇
  2017年   22篇
  2016年   33篇
  2015年   25篇
  2014年   37篇
  2013年   54篇
  2012年   91篇
  2011年   120篇
  2010年   55篇
  2009年   45篇
  2008年   94篇
  2007年   112篇
  2006年   129篇
  2005年   131篇
  2004年   120篇
  2003年   125篇
  2002年   118篇
  2001年   60篇
  2000年   62篇
  1999年   55篇
  1998年   36篇
  1997年   30篇
  1996年   24篇
  1995年   21篇
  1994年   20篇
  1993年   17篇
  1992年   34篇
  1991年   21篇
  1990年   20篇
  1989年   14篇
  1988年   13篇
  1987年   16篇
  1986年   13篇
  1985年   11篇
  1984年   9篇
  1983年   12篇
  1982年   6篇
  1981年   8篇
  1980年   5篇
  1979年   8篇
  1978年   4篇
  1974年   5篇
  1972年   3篇
  1969年   4篇
  1966年   4篇
排序方式: 共有1959条查询结果,搜索用时 15 毫秒
101.
E-selectin is an adhesion molecule developed as an important material for hematogenous metastasis of cancer cells on vascular endothelial cells. It is expected that if we can restrain a manifestation of E-selectin then hematogenous metastasis can be restrained. We divided gastric cancer and the colorectal cancer patients, who performed chemotherapy, into two groups of cimetidine administrated group and a non-administration group, and reviewed whether cimetidine inhibited an expression of E-selectin on vascular endothelial cells by measuring E-selectin in plasma. We experienced one example that showed an interesting change of E-selectin and the quantity of E-selectin in plasma fell during the cimetidine dosage. However, we report that E-selectin has risen after the cimetidine dosage was cancelled in the cimetidine administrated group.  相似文献   
102.
In order to confirm the efficacy of dexamethasone (DXM) incorporated into liposomes (DXM-liposomes) on atherosclerosis, drug delivery to atherosclerotic lesions and the antiatherosclerotic effect by DXM-liposomes were investigated in atherogenic mice. DXM-liposomes were prepared with egg yolk phosphatidylcholine, cholesterol and dicetylphosphate in a lipid molar ratio of 7/2/1 by the hydration method and then adjusted to three different particle sizes to clarify the influence of particle size on the drug delivery to atherosclerotic lesions and the effect on atherosclerosis. The particle sizes of DXM-liposomes were 519 nm (L500), 202 nm (L200) and 68.6 nm (L70), respectively. In both size, DXM concentration and DXM/lipid molar ratio in DXM-liposomes suspension were 1 mg DXM/ml and 0.134 mol DXM/mol total lipids, respectively. Atherogenic mice used as an experimental model develop an atherosclerotic lesion in the aorta and they were prepared by feeding an atherogenic diet for 14 weeks. The aortic pharmacokinetics of DXM-liposomes was examined by intravenous administration to atherogenic mice. The aortic uptake clearance of DXM in atherogenic mice treated with L200 was 2.6--3.2 fold greater than that in animals treated with L500, L70 or free DXM (f-DXM). Furthermore, the effects of DXM-liposomes on atherosclerosis were examined by intravenous administration to atherogenic mice once a week from 8 to 14 weeks. The antiatherosclerotic effects of DXM-liposomes were evaluated by determination of the aortic cholesterol ester (CE) level. The aortic CE level in atherogenic mice treated with L200 (55 microg DXM/kg) was significantly lower than that in animals treated with PBS. The antiatherosclerotic effect of L200 (55 microg DXM/kg) was significantly more potent than that of f-DXM (550 microg DXM/kg). These findings suggest that efficient delivery of DXM to the atherosclerotic lesions by L200 induces an excellent antiatherosclerotic effect at a lower dose. Therefore, L200 may be useful in the development of drug delivery systems for atherosclerotic therapy.  相似文献   
103.
The present study was undertaken to determine the effects of etidronate (ED) on calcitriol-induced aortic calcification and bone metabolism in rats with renal failure. Severe aortic calcification was induced by treatment with calcitriol for 3 weeks in rats in which 5/6 of the kidneys were removed (SNx group). Treatment of ED (10 mg/kg) together with calcitriol after subtotal nephrectomy (SNx) significantly inhibited thoracic and abdominal aortic calcification 3 weeks after the operation; however, ED (2 mg/kg) was ineffective. The serum levels of osteocalcin and pyridinoline decreased in ED (10 mg/kg) treated-renal failure rats compared with SNx rats. Total bone mineral density (BMD) in the SNx group was lower than that in the sham group, in which animals were treated with calcitriol after a sham operation. The total BMD value in the ED (10 mg/kg)-treated group was similar to that in the SNx group, whereas the levels of cancellous BMD were low in the ED (10 mg/kg)-treated rats. Our data show that ED at a dosage that suppresses bone metabolism markedly inhibits vascular calcification in rats with renal failure.  相似文献   
104.
Intracranial subdural haematoma has been reported to be an exceptionally rare complication of accidental dural puncture. An accidental lumbar dural puncture occurred in a 36-yr-old male undergoing orthopedic knee surgery. On the morning after the operation, the patient complained of severe occipital headache, although this was relieved with loxoprofen and rest. This was assumed to be a postdural puncture headache (PDPH) because it had a postural component (it was worse on sitting up). On the third day after the operation, the patient developed a severe diffuse headache together with nausea, which did not subside with analgesia and bed rest. Magnetic resonance imaging of the head showed a small acute subdural hematoma in the bilateral temporooccipital region with no mass effect. The patient was conscious and oriented. There was no focal neurological deficit. The patient was managed conservatively with bed rest and intravenous fluids. His condition improved without surgical decompression and was discharged on the 40 th day after the operation. Severe and prolonged PDPH shoud be considered as a warning sign of an intracranial complication.  相似文献   
105.
106.
We recently found that dietary raffinose suppressed allergic airway eosinophilia in ovalbumin-sensitized Brown Norway rats. Using this model in the present study, we compared the efficacy of other oligosaccharides with that of raffinose. Brown Norway rats were immunized s.c. with ovalbumin on d 0 and exposed to aerosolized ovalbumin on d 20; broncho-alveolar lavage fluid was obtained on d 21. In Expt. 1, rats were fed a control diet or diets supplemented with different oligosaccharides (50 g/kg diet, raffinose, alpha-linked galactooligosaccharide, fructooligosaccharide, and xylooligosaccharide). The number of eosinophils in the fluid was significantly lower in rats fed raffinose and alpha-linked galactooligosaccharide diets than in those fed the control diet. Dietary fructooligosaccharide and xylooligosaccharide did not affect airway eosinophilia. In Expt. 2, i.p. administration of raffinose and alpha-linked galactooligosaccharide, but not fructooligosaccharide and xylooligosaccharide, suppressed airway eosinophilia in rats fed the control diet. In Expt. 3, suppression of airway eosinophilia by dietary alpha-linked galactooligosaccharide occurred in cecectomized rats administered neomycin. Reduced levels of interleukin (IL)-4 and IL-5 mRNA in lung tissue were associated with the suppression of airway eosinophilia. We propose that indigestible oligosaccharides differ in their suppressive effect on allergic airway eosinophilia in ovalbumin-sensitized Brown Norway rats and that the effect appears not to be mediated by intestinal microflora.  相似文献   
107.
The Japanese medical care system, highly rated internationally, has recently experienced a crisis that has placed a burden on all of its citizens, providers, and payers, due to the expansion of medical expenditures in rapidly aging society with the stagnant economy. To address this, in April 2003, Japan implemented a case-mix payment system, instead of conventional fee-for-service payment, based on an original case classification with 2552 groups (Diagnosis Procedure Combination: DPC), with inpatients from 82 special functioning hospitals. This system contains two parts: per diem prospective payment for hospital's fee with a three-level step down according to average length of stay for each diagnosis group, which is adjusted to secure the previous year's remuneration in each hospital; fee-for-service payment for doctor's fee based on national fee schedule. The payment system reduced average length of stay, but did not change inpatient expenditures and increased outpatient expenditures. The in-hospital mortality rate, although un-adjusted, did not changed, but the readmission rate increased mainly through an increase in planned, not accidental, readmissions. For the expansion of this system, ongoing program refinement, reflecting the results of data analysis, is indispensable.  相似文献   
108.
We report 3 patients with pulmonary hamartoma, all of whom had undergone nephrectomy for renal cell carcinoma. A lung tumor was detected 2 to 9-months following nephrectomy. Preoperative diagnosis was pulmonary metastasis from renal cell carcinoma and pulmonary tumor resection was performed in each case. There was a 9- to 12-month interval between the detection and resection of the lung tumor. The histological diagnosis of the lung tumor in all three patient was pulmonary hamartoma. Following the resection of the lung tumor, recurrence was not noted in any of the patients.  相似文献   
109.
OBJECTIVES: To evaluate the incidence among 80-year-olds of periapical lesions as detected on panoramic radiographs and to determine the relationship between sclerotic bone around the periapical lesions to heel bone density, body height, and hand-grip strength. STUDY DESIGN: Six hundred fifty-nine panoramic radiographs (262 males, 397 females), obtained from 80-year-old residents of Fukuoka Prefecture, Japan, were used for evaluation of periapical lesions. These findings were correlated with physical examination results to determine the relationship to general health. RESULTS: Of 659 panoramic radiographs, 31 (5%) were noted to have periapical lesions. Average size of the 31 periapical lesions was 6.1 +/- 2.2 mm. Of the 31 periapical lesions, 21 (68%) were accompanied by linear or diffuse types of sclerotic bone. Of the 21 sclerotic bones, 10 (48%) were of a linear type of sclerotic bone and 11 (52%) of a diffuse type of sclerotic bone. Of the 11 diffuse types of sclerotic bone, 10 (91%) were in the mandible and 1 (9%) in the maxilla. Periapical lesions in the mandible were more frequently accompanied by a diffuse type of sclerotic bone than those in the maxilla (P < .01). The hand-grip strength of those having periapical lesions, accompanied by a diffuse type of sclerotic bone, was stronger than those having no periapical lesions (P < .01) and those accompanied by a linear type of sclerotic bone (P < .03). However, there was no relationship between presence of sclerotic bone and heel bone density or body height. CONCLUSIONS: Periapical lesions accompanied by a diffuse type of sclerotic bone were more frequently seen in the mandible of 80-year-olds. To evaluate the clinical significance of sclerotic bone around periapical lesions in 80-year-olds, further study to evaluate the significance of endodontic treatment needs to be done.  相似文献   
110.
Placental transfer and body distribution of NiCl2 were studied in pregnant mice (ICR strain, 12–14 weeks old). A single injection of NiCl2 (4.6 mg/kg as Ni ip) was administered on the 16th day of gestation. Animals were killed at intervals of 2, 4, 6, 8, 10, 24, 30, and 48 hr after the injection and tissues were obtained for measurement of nickel concentration. Concentration of nickel in blood and placentas were found to be at maximum level (19.8 and 3.9 μg/g) 2 hr after injection, and those in liver, spleens, and kidneys reached maximum levels of 4.9, 1.3, and 56.2 μg/g, respectively, 4 hr after injection. Maximum concentration in fetal tissues (1.1 μg/g) was reached 8 hr after injection, and a slight gradual decrease was observed during 24 hr. Thereafter, there was a rapid decrease. The relative concentrations of Ni in blood, organs, and tissues of pregnant mice at 24 hr after injection were found in order from highest to lowest concentration: Kidneys > blood > placentas > fetuses ? liver > spleen. It is estimated that the Ni will be excreted in about 42 to 84 hr after injection from the calculated biological half-times.  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