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   10418篇
  免费   723篇
  国内免费   24篇
耳鼻咽喉   54篇
儿科学   512篇
妇产科学   271篇
基础医学   1118篇
口腔科学   669篇
临床医学   955篇
内科学   1840篇
皮肤病学   154篇
神经病学   849篇
特种医学   553篇
外国民族医学   2篇
外科学   1610篇
综合类   239篇
一般理论   6篇
预防医学   792篇
眼科学   242篇
药学   627篇
  1篇
中国医学   76篇
肿瘤学   595篇
  2021年   136篇
  2019年   109篇
  2018年   140篇
  2017年   120篇
  2016年   105篇
  2015年   127篇
  2014年   197篇
  2013年   283篇
  2012年   351篇
  2011年   418篇
  2010年   268篇
  2009年   253篇
  2008年   417篇
  2007年   402篇
  2006年   421篇
  2005年   386篇
  2004年   396篇
  2003年   313篇
  2002年   321篇
  2001年   290篇
  2000年   277篇
  1999年   243篇
  1998年   129篇
  1997年   136篇
  1996年   134篇
  1995年   124篇
  1994年   121篇
  1993年   94篇
  1992年   227篇
  1991年   221篇
  1990年   222篇
  1989年   256篇
  1988年   226篇
  1987年   246篇
  1986年   213篇
  1985年   189篇
  1984年   182篇
  1983年   122篇
  1981年   92篇
  1980年   89篇
  1979年   142篇
  1978年   116篇
  1977年   100篇
  1976年   115篇
  1975年   106篇
  1974年   112篇
  1973年   132篇
  1972年   103篇
  1971年   87篇
  1957年   88篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
31.
32.
The urinary bladder, as do all smooth muscle organs, depends on the delivery of oxygen and metabolic substrates for proper functioning. Although glucose metabolism has been studied and evaluated for a variety of smooth muscle systems, little is known about carbohydrate metabolism of the urinary bladder. In the present investigation glucose metabolism and glycogen formation of the urinary bladder of the rabbit was studied in vitro. Isolated urinary bladder strips were prepared from bladder base and body and the following metabolic determinations were made: glucose utilization, glycogen formation, CO2, and lactic acid formation. In addition, the effect of insulin on glucose metabolism was investigated. Glucose utilization was similar in bladder base and body (6.57 +/- 0.67 mumols/gm./2 hours in combined tissues). Eighty-one percent of the glucose utilized was metabolized to lactate whereas 11% was oxidized to CO2 and 4.7% was incorporated into glycogen. Insulin caused a small but significant increase in glucose utilization by bladder strips.  相似文献   
33.
To determine whether prenatal thiamine deficiency, a frequent concomitant of alcoholism, reduces the response to ethanol during adulthood in the rat as does ethanol exposure in utero (Abel et al. 1981), pregnant Sprague-Dawley rats received either control or thiamine deficient diets together with daily injections of the thiamine antagonist pyrithiamine. At 7 months of age, male offspring were exposed to precisely regulated ethanol vapor concentrations in an inhalation chamber for 24 h and blood ethanol concentrations (BECs) and ethanol-induced intoxication were determined. Prenatally thiamine deficient rats and controls were indistinguishable in terms of appearance, body and liver weights, and the ratios of liver to body weight and brain to liver weight. However, total body water was significantly greater, and BECs and behavioral impairment were decreased, in the experimental rats. These findings indicate that prenatal thiamine deprivation is associated with reduced pharmacologic effect of ethanol as a result of increases in its volume of distribution and rate of metabolism.  相似文献   
34.
24 cases of fulminant hepatitis (FH) hospitalized in the Clínica de Doen?as Infecciosas e Parasitárias do Hospital das Clínicas da Faculdade de Medicina da Universidade de S?o Paulo during the period from January 1976 to December 1986 were reviewed from their clinical, epidemiological and laboratorial aspects. 88% of the patients died; 20 patients (83%) presented hemorrhages and, of these, 19 died. Bacterial infections occurred in 14 patients (58%) all of whom died. Ascitis was noted in 3 cases; cerebral edema was present in 16 cases. Maximal ALT levels for each patient during hospitalization ranged widely from 81 to 4,460 UI/l. Thirteen patients presented high creatinine levels (54%). Prothrombin time activity ranged from 2.1% to 67%. Fever was present in 20 cases (83%). Encephalopathy occurred within the first 2 weeks of illness in 72% of the cases. In 7 cases other illnesses were present. The etiology could not be determined in 13 cases. In 3 cases it was due to yellow fever and 6 cases were caused by viruses other than yellow fever. In one case the cause was drug usage and in another case, possibly alcohol. The authors believe that the clinical definition of FH requires further discussion before it is established. In this study FH is a young person's disease. The mortality found was similar to that by other authors. Factors that contributed to death were: hemorrhages and bacterial infection. Factors that worsened the prognosis of hepatitis were: associated illnesses and surgical procedure. The levels of ALT during hospitalization did not correlate well with the severity of the hepatitis.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
35.
M R Ruggieri  P M Hanno  R M Levin 《Urology》1987,29(5):534-537
It has been recently suggested that nitrofurantoin may induce symptoms of interstitial cystitis by acting as a surface active agent that destroys glycosaminoglycan (GAG) on the bladder surface. Evidence accumulated over the past decade has demonstrated that the bladder surface GAG prevents bacterial adherence. In this experiment, exposure of the bladder lumen to nitrofurantoin at more than twice the therapeutic concentration did not destroy the bladder GAG layer (as evidenced by periodic acid-Schiff histochemistry) nor increase bacterial adherence as did a true surface active agent (Triton X-100). Acid treatment as well as all tested organic solvents except 50% dimethyl sulfoxide (DMSO) also removed the bladder GAG layer and increased bacterial adherence. These results indicate that neither nitrofurantoin nor 50% DMSO has adverse effects on the bladder surface and thus is unlikely to initiate the interstitial cystitis symptom complex by means of surfactant activity.  相似文献   
36.
J M Boone  D C Levin 《Radiology》1991,180(3):861-865
Radiation levels near an imaging chain commonly used in angiography were measured with both a 100- and a 200-mm-thick scatter phantom. The scatter was measured in lines parallel in space to the central ray of the x-ray beam, at lateral distances of 300, 500, and 800 mm. The effects of fluoroscopic kilovoltage and image intensifier magnification mode were also measured. The results indicate that the highest scattered radiation levels occur near the surface of the patient where the x-ray beam enters. Exposure rates were measured in both anteroposterior (AP) and posteroanterior (PA) geometries on a U-arm system. In PA geometry, the highest radiation levels occur below the angiographer's waist, an area well protected by the lead apron. The AP geometry increases the exposure rate to the neck, head, and upper extremities, areas where apron shielding is less effective.  相似文献   
37.
38.
Ureterocele containing calcified stone   总被引:1,自引:0,他引:1  
We describe here an uncommon case of simple ureterocele containing calcified stone, that was successfully treated.  相似文献   
39.
Changes in bladder function in the one year spontaneously diabetic BB rat.   总被引:2,自引:0,他引:2  
Micturition characteristics and in vitro urinary bladder function were investigated in insulin-treated spontaneously diabetic BB rats and age-matched non-diabetic controls one year after the onset of diabetes. BB rats weighed less than controls and were hyperglycemic. Diabetic rats consumed larger volumes of water and excreted larger volumes of urine than controls. The frequency of micturitions and the mean volumes of urine excreted per micturition were significantly increased in BB rats compared to age-matched controls. Associated with the micturition changes in the BB rats were significant increases in bladder body mass. Contractile responses of strips from bladder bodies and bases were measured in response to nerve stimulation, carbachol, phenylephrine, ATP, and KCl. No significant differences between controls and diabetics were found in the absolute contractile responses of bladder body strips to nerve stimulation, carbachol, ATP, or KCl. However, if the data were transformed to correct for the increases in tissue mass in the diabetics, there were significant decreases in the responses of bladder body strips from BB rats to carbachol, ATP, and KCl, but not to nerve stimulation. Even after transformation, there were no differences in the responses of bladder base strips to carbachol, phenylephrine, or KCl. The data indicate that significant changes in micturition characteristics are evident one year after the onset of diabetes in the spontaneously diabetic BB rat. These changes are slow in development, since they are absent six months after the onset of diabetes. The changes in micturition and bladder strip contractility are qualitatively similar to, but quantitatively modest in comparison with those caused by streptozotocin-induced diabetes mellitus. The quantitative differences are probably attributable to an ameliorative effect of the insulin received by the BB rat.  相似文献   
40.
Controlled studies of treatments effective with victims of natural disasters are almost nonexistent. This is a small study conducted under difficult conditions to test the effectiveness of Eye Movement Desensitization and Reprocessing (EMDR) in treating trauma related reactions following Hurricane Andrew. The results were positive in that EMDR produced significant improvement over wail list controls in perceived posttraumatic avoidance behaviors and thoughts as measured by changes in the Impact of Event Scale and significant improvement in subjective aversive reactions to representative experiences of the hurricane. These results suggest and support other studies that EMDR can be an effective therapeutic intervention for trauma reactions.  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