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   4616篇
  免费   288篇
  国内免费   29篇
耳鼻咽喉   28篇
儿科学   139篇
妇产科学   64篇
基础医学   679篇
口腔科学   71篇
临床医学   356篇
内科学   1181篇
皮肤病学   189篇
神经病学   387篇
特种医学   116篇
外科学   498篇
综合类   14篇
预防医学   211篇
眼科学   95篇
药学   412篇
中国医学   9篇
肿瘤学   484篇
  2024年   4篇
  2023年   36篇
  2022年   56篇
  2021年   118篇
  2020年   69篇
  2019年   100篇
  2018年   120篇
  2017年   103篇
  2016年   125篇
  2015年   128篇
  2014年   142篇
  2013年   191篇
  2012年   304篇
  2011年   337篇
  2010年   171篇
  2009年   173篇
  2008年   323篇
  2007年   309篇
  2006年   307篇
  2005年   309篇
  2004年   327篇
  2003年   318篇
  2002年   292篇
  2001年   54篇
  2000年   52篇
  1999年   55篇
  1998年   43篇
  1997年   39篇
  1996年   35篇
  1995年   31篇
  1994年   32篇
  1993年   30篇
  1992年   23篇
  1991年   30篇
  1990年   15篇
  1989年   13篇
  1988年   19篇
  1987年   13篇
  1986年   16篇
  1985年   9篇
  1984年   9篇
  1983年   8篇
  1982年   9篇
  1981年   5篇
  1980年   4篇
  1979年   4篇
  1977年   4篇
  1976年   3篇
  1968年   3篇
  1967年   2篇
排序方式: 共有4933条查询结果,搜索用时 15 毫秒
71.
Bilateral hydronephrosis identified by a local physician brought a 65-year-old man to our hospital. Emergency percutaneous nephrostomy was bilaterally established for obstructive renal failure. After recovering renal function, the patient underwent radical cystectomy under the diagnosis of invasive bladder cancer and the construction of an ileal conduit. The pathology reported well differentiated adenocarcinoma (pT2, pL1, pV1). Five years after the surgery, gross hematuria developed. A computed tomographic scan revealed right hydronephrosis with a solid mass in the upper calyx. The urinary cytology was negative. The patient underwent right nephrectomy in May, 1999. The pathology then revealed well differentiated adenocarcinoma in the renal pelvis and ureter (pT3, pL0, pV0 and pT1, pL0, pV0, respectively). He is alive with mild chronic renal insufficiency with evidence of tumor at ten months after surgery. To our knowledge, this is the first case of metachronous adenocarcinoma of the urinary bladder and the upper urinary tract reported in the Japanese literature.  相似文献   
72.
We studied the changes in the serum creatinine level and the volume of the remaining kidney following nephrectomy using contrast-enhanced compounded tomogram (CT) scans. Twenty-five patients undergoing nephrectomy for renal cell carcinoma without obvious disease in the remaining kidney were carefully followed for a period of at least two years at our hospital. Twelve patients received follow-up CT scans each year after nephrectomy. The ellipsoid volume of the kidney was calculated by measuring the 3-dimensional size on CT scans. The mean relative volume (%) of the remaining kidney increased up to year 3 postoperatively, and the final mean relative volume at varying periods from years 2 to 7 was 120%. Kidneys that were smaller prior to nephrectomy showed a tendency to have a larger final relative volume after nephrectomy, although there was no significant correlation between the kidney volume prior to nephrectomy and at final measurement. The mean serum creatinine level was significantly increased at one year after nephrectomy, but it decreased significantly over time. Therefore, both compensatory renal hypertrophy and improved renal function seemed to be established within several years after nephrectomy. However, the improvement of serum creatinine was delayed compared with the increase of kidney volume. That is, renal plasma flow might be increased early by compensatory renal hypertrophy, followed within a few years by an increase in glomerular filtration and a decrease of serum creatinine.  相似文献   
73.
The prevalence of abnormalities in androgen receptor gene (AR) among patients with ambiguous genitalia is unknown. Moreover, endocrinological data from prepubertal patients with AR mutation are very limited. Thus, the aim of this study was to examine the prevalence of abnormalities in AR among patients with both ambiguous genitalia, which was defined as a combination of two or more genital abnormalities (i.e. hypospadias, microphallus (penile length < 25 mm), hypoplastic scrotum, bifid scrotum, undescended testis) in this study, and normal to elevated T levels. We also compared the endocrinological data of prepubertal patients with AR mutation and ambiguous genitalia with that of those without the AR mutation. We screened 26 Japanese prepubertal 46,XY patients (five from three families were included) with both ambiguous genitalia and normal to elevated T levels. Mutations in AR were found in three (two of the three were related). Among the 23 patients without mutation in AR, the steroid 5-alpha-reductase 2 gene (SRD5A2) was also examined in eight patients with elevated T/dehydrotestosterone ratio after the hCG (>10) or with undervirilized family members. No mutation in SRD5A2 was found. Characteristics of the three patients with mutation in AR were compared with the 23 patients without mutation. In two patients, basal T levels (0.3, 0.2 ng/ml) and peak T levels after the hCG tests (8.3, 8.5 ng/ml) tended to be higher, and the peak LH/ peak FSH ratios after the GnRH tests (4.6, 4.0) were higher than in patients without mutation, at the ages of 1 yr and 9 mo and 3 yr and 8 mo, respectively. In conclusion, an abnormality in either AR or SRD5A2 was not common among patients with ambiguous genitalia and normal testosterone secretion. Elevated peak LH/peak FSH ratio (≥4) after the GnRH test in addition to detectable basal T levels and elevated peak T levels after the hCG test may infer AR abnormality in prepubertal patients with ambiguous genitalia at the age of one and over, although further study is needed, because our data were limited.  相似文献   
74.
75.
SHR/NDmcr-cp (SHR/NDcp) rats, which carry a nonsense mutation of the leptin receptor gene, are known to spontaneously develop hypertension, obesity and hyperlipidemia, and have therefore found use as an animal model of the metabolic syndrome and type 2 diabetes. However, some recent studies on SHR/NDcp rats revealed only mild elevation of blood glucose levels. To investigate whether metabolic factors including blood glucose and histopathological alterations of SHR/NDcp rats deteriorate with a diabetogenic diet, biochemical and histopathological examinations were conducted with animals fed normal or diabetogenic diets for 20 weeks. SHR/NDcp rats receiving the normal diet displayed obesity, hypertension, hyperlipidemia, and mild elevation of blood glucose and HbA1c levels. Urinary glucose excretion was noted in only 1 out of 6 animals. Histologically, macro- and micro-vesicular steatosis in the liver, glomerular and tubular damages in the kidney and islet hyperplasia mainly of beta cells in the pancreas were characteristically noted. In SHR/NDcp rats fed the diabetogenic diet, obesity was more severe, with higher blood glucose and HbA1c levels, increased numbers of animals with urinary glucose excretion, and more pronounced hepatic steatosis and renal tubular changes. However, elevation of blood glucose levels and urinary glucose excretion proved transient. These observations indicate that the diabetic state and associated histopathological alterations in SHR/NDcp rats are exacerbated by feeding a diabetogenic diet, but the effects are limited. Elevated islet function with compensative insulin secretion might be related to amelioration of the hyperglycemic state. Further diet modification could be needed to induce a more prominent and persistent diabetic state in SHR/NDcp rats.  相似文献   
76.
77.
78.
Calcium ions (Ca2+) are indispensable for the physiology of organisms and the molecular regulation of cells. We observed that CGK733, a synthetic chemical substance, induced non-apoptotic cell death and stimulated reversible calcium sequestration by vesicles in pancreatic cancer cells. The endoplasmic reticulum (ER) stress eukaryotic translation initiation factor 2-alpha kinase 3/C/EBP homologous protein (PERK/CHOP) signaling pathway was shown to be activated by treatment with CGK733. Ionomycin, an ER stress drug and calcium ionophore, can activate PERK/CHOP signaling and accelerate CGK733-induced calcium sequestration. Knockdown of CHOP diminished CGK733-induced vesicular calcium sequestration, but had no effects on the cell death. Proteomic analysis demonstrated that the ER-located calcium-binding proteins, calumenin and protein S100-A11, were altered in CGK733-treated cells compared to non-treated controls. Our study reveals that CGK733-induced intracellular calcium sequestration is correlated with the PERK/CHOP signaling pathway and may also be involved in the dysregulations of calcium-binding proteins.  相似文献   
79.
BACKGROUND/OBJECTIVESRecent studies have reported an association of the angiotensin II type 2 receptor (AT2R) 3123Cytosine/Adenine (3123C/A) polymorphism with essential hypertension and cardiovascular diseases. The purpose of the study was to investigate whether the AT2R 3123C/A polymorphism affects blood pressure for free-living hypertensive men during a 5-month intervention period.SUBJECTS/METHODSThe subjects were free-living hypertensive Japanese men aged 40 to 75 years who agreed to intervention in the period from 2004 to 2011. Detection of the AT2R 3123C/A polymorphism was determined by polymerase chain reaction. The dietary intervention was designed to decrease salt level and to increase potassium level through cooking instructions and self-monitoring of the diet. The exercise session consisted of activities such as stretching, resistance training, and walking. Blood pressure, urinary sodium and potassium excretion, dietary and lifestyle data, and non-fasting venous blood sample were collected at baseline and after the intervention period.RESULTSThirty nine subjects were eligible for participation and the follow-up rate was 97.4%. The C allele proportion was 57.9%. AT2R 3123C/A polymorphism was X-chromosome-linked, therefore we analyzed the C and A genotypes. At baseline, no significant differences were observed between the genotype groups. After the intervention, there were no significant differences in lifestyle habit between the groups. Nevertheless, the estimated salt excretion (g/day) was significantly decreased only in the C genotype (13.0-10.3, P = 0.031). No significant change was observed in systolic blood pressure (SBP) (mmHg) in the A genotype, but a significant decrease was observed in the C genotype (150.0-141.5, P = 0.024).CONCLUSTIONSIn the C genotype, it might be easy to improve SBP through lifestyle intervention in free-living hypertensive Japanese men, however generalization could not be achieved by the small sample size.  相似文献   
80.
Toxic epidermal necrolysis (TEN) is a rare condition, causing life‐threatening adverse cutaneous reactions. TEN occurrence after bone marrow transplantation (BMT) is a well‐known phenomenon; however, to date, only a few cases have been reported in the published work. Here, we describe the case of a 53‐year‐old woman who experienced TEN after undergoing allogenic BMT for malignant lymphoma. Skin erosion spread across a maximum of 70% of the body surface area and severe mucosal lesions developed. Steroid pulse therapy, plasma apheresis and immunoglobulin therapy were administrated, which resulted in the complete resolution of TEN. However, she developed hemophagocytic lymphohistiocytosis and died 38 days after BMT, owing to rupture of the lower digestive tract complicated by multi‐organ failure. In our case, engraftment failure occurred, and the peripheral white blood cell count was less than 100/μL during the TEN course, suggesting that the presence of only a few immune cells could cause TEN. Our findings showed that high mortality rates and widespread skin erosion could be regarded as the most important characteristics of TEN occurring after BMT.  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