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   980篇
  免费   27篇
  国内免费   6篇
耳鼻咽喉   9篇
儿科学   24篇
妇产科学   30篇
基础医学   87篇
口腔科学   9篇
临床医学   60篇
内科学   205篇
皮肤病学   62篇
神经病学   86篇
特种医学   29篇
外科学   220篇
综合类   2篇
预防医学   24篇
眼科学   8篇
药学   94篇
肿瘤学   64篇
  2022年   8篇
  2021年   11篇
  2020年   5篇
  2019年   15篇
  2018年   5篇
  2016年   7篇
  2015年   15篇
  2014年   21篇
  2013年   17篇
  2012年   40篇
  2011年   34篇
  2010年   5篇
  2009年   15篇
  2008年   27篇
  2007年   33篇
  2006年   43篇
  2005年   26篇
  2004年   36篇
  2003年   27篇
  2002年   25篇
  2001年   30篇
  2000年   31篇
  1999年   28篇
  1998年   15篇
  1997年   10篇
  1996年   15篇
  1995年   8篇
  1994年   9篇
  1993年   16篇
  1992年   48篇
  1991年   38篇
  1990年   47篇
  1989年   31篇
  1988年   47篇
  1987年   30篇
  1986年   24篇
  1985年   19篇
  1984年   21篇
  1983年   20篇
  1982年   8篇
  1980年   8篇
  1979年   12篇
  1977年   9篇
  1976年   8篇
  1974年   7篇
  1972年   7篇
  1971年   7篇
  1970年   5篇
  1969年   7篇
  1968年   8篇
排序方式: 共有1013条查询结果,搜索用时 31 毫秒
61.
As a three-dimensional carrier for cell culture, a honeycomb structure cell scaffold was created from atelopeptide collagen Types I, II, and III. The diameter of the honeycomb pores ranged from 100 to 1,000 microm. The depth of the pores was from 10 to 3,000 mm. The scaffold was elastic and hard. Creation of various shapes was easy, and these shapes were easily maintained. Human fibroblasts, CHO-K1, BHK-21, and bovine endothelial cells were cultured with the scaffold. The growth curves of these cells were satisfactory. These results suggest that this carrier is a suitable scaffold for cell culture and will be useful as a three-dimensional tissue engineering scaffold.  相似文献   
62.
Primary pulmonary hypertension is a progressive disease. Most affected patients are young and middle-aged women. Etiology is unknown, although a familial and genetic factor is present in up to 6% of cases. Endothelial dysfunction and abnormalities in calcium channels of smooth muscle fibers are the present pathogenetics theories. Diagnostic tests try to exclude secondary causes of pulmonary hypertension and to evaluate its severity. Acute vasodilatory test is vital in the selection of treatment. Oral anticoagulation is indicated in all patients. Lung transplant is performed when medical treatment is unsuccessful. Atrial septostomy is an alternative and palliative treatment for selected cases. Chronic thromboembolic pulmonary hypertension is a special form of secondary pulmonary hypertension, clinically undistinguishable from primary primary hypertension, is of mandatory diagnosis because it can be cured with thromboembolectomy.Pulmonary embolism is common in hospitalised patients. The mortality rate for pulmonary embolism continues to be high: up to 30% in untreated patients. The accurate detection of pulmonary embolism remains difficult, as pulmonary embolism can accompany as well as mimic other cardiopulmonary illnesses. Non-invasive diagnostic tests have poor specificity and sensitivity. The D-dimer level and the spiral CT angiography have also been employed as new alternatives and important tools for precise diagnosis of suspected pulmonary embolism. The standard therapy of pulmonary embolism is intravenous heparin for 5 to 10 days in conjunction with oral anticoagulants posteriorly for 3 to 6 months. The incidence of deep venous thrombosis, pulmonary embolism and death due to pulmonary embolism, can be reduced significantly and shown clear benefits only by adoption of a prophylactic strategy with low-molecular-weight-heparins or dextrans in patients at risk.  相似文献   
63.
Purpose. The mobility of protein molecules in lyophilized protein formulations was compared with that of excipient molecules based on the spin-lattice relaxation time (T1) of each molecule determined by high resolution 13C solid-state NMR. The relationship between molecular mobility and protein stability is discussed. Methods. Protein aggregation of lyophilized bovine serum --globulin (BGG) formulation containing dextran was measured by size exclusion chromatography. The T1 of the BGG carbonyl carbon and dextran methin carbon in the formulation was determined by high resolution 13C NMR, and subsequently used to calculate the correlation time (C) of each carbon. The spin-spin relaxation time (T2) of BGG and dextran protons was measured by pulsed NMR spectrometry, and the critical temperature of appearance of Lorentzian relaxation due to liquid BGG and dextran protons (Tmc) was determined. Results. The C of dextran methin carbon in BGG-dextran formulations exhibited a linear temperature dependence according to the Adam-Gibbs-Vogel equation at lower temperatures, and a nonlinear temperature dependence described by the Vogel-Tamman-Fulcher equation at higher temperatures. The temperature at which molecular motion of dextran changed was consistent with the Tmc. The C of BGG carbonyl carbon exhibited a similar temperature dependence to the C of the dextran methin carbon and substantially decreased at temperatures above Tmc in the presence of dextran. The temperature dependence of BGG aggregation could be described by the Williams-Landel-Ferry equation even at temperatures 20°C lower than Tmc. Conclusions. High resolution 13C solid-state NMR indicated that the molecular motion of BGG was enhanced above Tmc in association with the increased global segmental motion of dextran molecules.  相似文献   
64.
From November 1985 through September 1986, 20 cases of upper urinary tract calculi (14 kidney, 7 ureter) were treated by the one-stage procedure percutaneous nephrolithotripsy. Renal and ureteral calculi were successfully removed in all 20 cases (100%). After the procedure, a few small stone fragments remained in 3 cases (the rate of remnant stone : 14%). High fever was noted in 7 patients but did not last longer than 3 days. No patients required blood transfusion. The one-stage percutaneous procedure was considered a more efficient procedure to remove the upper urinary tract calculi, than open surgery or two stage percutaneous nephrolithotripsy. In one-stage percutaneous nephrolithotripsy, however, serum sodium concentration was lowered significantly after the procedure, although the hematocrit remained unchanged throughout. This should be carefully corrected by the supplement of irrigation fluid and intravenous infusion during the procedure.  相似文献   
65.
To investigate the efficacy and the safety of RU23908 for the treatment of prostatic cancer, an early phase 2 study with the oral administration of 150 or 300 mg daily was performed in 47 patients with stage C or D prostatic cancer at 15 institutions from April 1987 to June 1988. Forty patients were evaluable for efficacy. Concerning the effect on the object lesion, the results of the overall evaluation revealed that complete or partial response (CR + PR) was obtained in 34 of the 40 cases (85.0%). As to the effect classified by site, CR + PR were observed in 35 out of the 40 cases with primary lesion (87.5%), in 10 of the 22 cases with bone metastasis (45.5%), in 5 of the 6 cases with lymph node metastasis (83.3%) and CR was observed in one case with lung metastasis. In the PAP evaluation, 33 out of the 34 cases were judged to be CR + PR (97.1%). The improvement rate of clinical symptoms was 88.9% for bone pain, 83.3% for dysuria and 45.5% for performance status. Adverse reactions were observed in 29 of the 47 cases (61.7%) investigated and 7 cases (14.9%) were withdrawn. During the study period of 12 weeks and the subsequent period of continued administration, 6 cases (12.8%) and 2 possible cases of interstitial pneumonia were diagnosed. From the above results, the treatment of prostatic cancer with RU23908 150 mg/day or 300 mg/day in combination with surgical castration showed an excellent clinical effect compared to conventional endocrine therapy, but has a problem of safety. Therefore, this drug may be expected to be a highly useful therapeutic drug, if safely is improved in the future by reviewing the dose.  相似文献   
66.
The human beta(3)-adrenergic receptor (beta(3)AR) is expressed specifically in adipose tissues, and its activation is activated in brown adipose tissues during thermogenesis and in white adipose tissues during lipolysis. We investigated the relationship between a polymorphism of the beta(3)AR gene and the clinical features of type 2 diabetes mellitus. Studies were conducted in 30 type 2 diabetic patients (15 males and 15 females). Analysis of polymorphisms of the beta(3)AR gene was performed by a pin-point sequencing method using the hair of the subjects. Preperitoneal (P-fat) and subcutaneous fat (S-fat) levels were determined by ultrasonography. We found a Trp(64)Arg allele of the beta(3)AR gene in the hair of 27% of all patients. The patients with this mutation showed a significantly younger onset-age of diabetes than those of the wild type. The body mass index, serum GPT levels, fasting immunoreactive insulin (IRI) and daily urinary C-peptide reaction (CPR) in the mutation group were markedly higher than in the wild type group. The P-fat, serum cholesterol and leptin concentrations tended to be higher in the mutation group. Patients in the mutation group had a significantly higher prevalence of hypertension (80%) compared with those in the wild type group (20%). CONCLUSIONS: The present results suggest that the clinical features of diabetic patients with a missense mutation in the beta(3)AR gene are substantially distinct from those of the wild type patients. These specific features include obesity, hyperinsulinemia, hypertension, and an increase in preperitoneal fat.  相似文献   
67.
The relation between 14 urinary steroid excretions was investigated by intersteroidal regression analysis with urine from 59 follicular stage women, 135 luteal stage women and 5 female patients with adrenal disorders. The regularity of intersteroidal relation in urine, as detected for all steroid pairs of all groups studied, was explained in terms of the law of mass action, and a chemical equilibrium point was located with a high degree of reproducibility for each steroid and for each group. The theoretical and practical usefulness of urinary steroid regression analysis is emphasized in relation to the possible impact of multihormonal information on endocrinology.  相似文献   
68.
A sixty-year-old woman had a small papule within a plaque on the left arm. Histologically, the papule was similar to irritated seborrheic keratosis or inverted follicular keratosis and the plaque was intraepidermal epithelioma. However, both lesions included mature sebaceous cells showing sebaceous differentiation. This tumor may be closely related to the pilo-sebaceous unit or sebaceous gland. To our knowledge, no similar tumor has been reported in the literature.  相似文献   
69.
70.
It has been known that alpha 1-adrenoceptors play an important role in urethral contraction. The incompetence of the urethral contraction is a cause of stress incontinence. We studied the urodynamic effects of a selective alpha 1-adrenoceptor agonist (midodrine hydrochloride) on the bladder and urethra of female dogs. Under anesthesia with intravenous chloralose, four doses (0.03, 0.1, 0.3 and 1.0 mg/kg) of midodrine were administered intravenously and urodynamic studies including cystometry, urethral pressure profilometry and electromyography (EMG) of the external urethral sphincter were performed. The administration of midodrine induced a significant increase of the maximum closing pressure in the proximal portion of the urethra (p less than 0.05 at 0.03 mg/kg and p less than 0.01 at 0.1, 0.3, 1.0 mg/kg). There were no significant changes in the functional profile length, the closing pressure at the external sphincters, the maximum bladder pressure, bladder capacity and bladder compliance. The administration of 0.3 mg/kg or more of midodrine produced a significant increase in the mean arterial blood pressure. After midodrine administration, transient increases in the external sphincter EMG activities were recognized. The activities showed the synergistic pattern during the bladder contractions. In conclusion, lower dose administration of a selective alpha 1-adrenoceptor agonist (midodrine) specifically produced an increase of the closing pressure in the proximal portion of the urethra without affecting blood pressure. These results suggest that midodrine is useful for the treatment of stress incontinence in humans.  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