全文获取类型
收费全文 | 6792篇 |
免费 | 256篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 100篇 |
儿科学 | 103篇 |
妇产科学 | 127篇 |
基础医学 | 899篇 |
口腔科学 | 97篇 |
临床医学 | 338篇 |
内科学 | 1744篇 |
皮肤病学 | 49篇 |
神经病学 | 613篇 |
特种医学 | 291篇 |
外科学 | 1205篇 |
综合类 | 28篇 |
一般理论 | 1篇 |
预防医学 | 180篇 |
眼科学 | 45篇 |
药学 | 584篇 |
中国医学 | 12篇 |
肿瘤学 | 664篇 |
出版年
2023年 | 27篇 |
2022年 | 52篇 |
2021年 | 103篇 |
2020年 | 47篇 |
2019年 | 94篇 |
2018年 | 127篇 |
2017年 | 85篇 |
2016年 | 131篇 |
2015年 | 139篇 |
2014年 | 188篇 |
2013年 | 235篇 |
2012年 | 381篇 |
2011年 | 417篇 |
2010年 | 243篇 |
2009年 | 214篇 |
2008年 | 381篇 |
2007年 | 384篇 |
2006年 | 403篇 |
2005年 | 456篇 |
2004年 | 404篇 |
2003年 | 427篇 |
2002年 | 432篇 |
2001年 | 59篇 |
2000年 | 65篇 |
1999年 | 88篇 |
1998年 | 105篇 |
1997年 | 91篇 |
1996年 | 76篇 |
1995年 | 107篇 |
1994年 | 84篇 |
1993年 | 77篇 |
1992年 | 83篇 |
1991年 | 77篇 |
1990年 | 64篇 |
1989年 | 73篇 |
1988年 | 64篇 |
1987年 | 62篇 |
1986年 | 60篇 |
1985年 | 57篇 |
1984年 | 51篇 |
1983年 | 43篇 |
1982年 | 41篇 |
1981年 | 38篇 |
1980年 | 25篇 |
1979年 | 30篇 |
1978年 | 22篇 |
1977年 | 25篇 |
1976年 | 19篇 |
1975年 | 23篇 |
1965年 | 14篇 |
排序方式: 共有7080条查询结果,搜索用时 15 毫秒
101.
Zenda T Masunaga T Fuwa B Okada T Ontachi Y Kondo Y Nakao S Minato H 《Journal of gastrointestinal cancer》2005,36(2):113-119
A 49-yr-old Japanese woman underwent upper gastrointestinal endoscopy because of nonspecific dyspepsia. Endoscopy revealed a flat elevated lesion about 15 mm in diameter adjacent to the duodenal papilla, the surface of which was uneven and covered with whitish granules. Based on the results of histological examination with immunohistochemistry (positive for CD10, CD20, CD79a, and bcl-2 protein, negative for CD5 and cyclin D1), a diagnosis of grade 1/3 follicular lymphoma was established. Systemic staging examinations suggested the lymphoma was restricted to the mucosa and superficial portion of the submucosa in the duodenal wall. The patient was treated with a combination of CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine, and prednisolone) and monoclonal anti-CD20 antibody (rituximab), in addition to radiotherapy. After six courses of this combination chemotherapy, complete regression of the lymphoma was observed. Although reports of small duodenal lymphoma (<20 mm or localized to the mucosa or submucosa) are extremely rare, the features of this case are characteristic of small duodenal lymphoma in terms of evolution around the ampulla of Vater, low-grade follicular type, occurrence in a women, occurrence in the fourth decade of life, and favorable outcome, and this type of tumor may need to be distinguished by pathogenesis and clinical behavior from various other gastrointestinal lymphomas. 相似文献
102.
Morinaga S Yamamoto Y Noguchi Y Imada T Rino Y Akaike M Sugimasa Y Takemiya S Takanashi Y 《Hepato-gastroenterology》2003,50(53):1521-1526
BACKGROUND/AIMS: Platelet-derived endothelial cell growth factor (PD-ECGF) is one of the angiogenic factors. The aim of this study was to examine the PD-ECGF concentrations in hepatocellular carcinoma, background liver, and normal liver tissues, and to elucidate their significance on clinicopathological outcomes. METHODOLOGY: The concentration of PD-ECGF in the tissue extract was determined by enzyme-linked immunosorbent assay. RESULTS: PD-ECGF concentrations were significantly higher in hepatocellular carcinoma and background liver tissues compared with normal control liver (p = 0.003, p = 0.001, respectively). PD-ECGF concentrations in hepatocellular carcinoma tissues were positively correlated with intratumoral arteriole densities (r = 0.667, p = 0.009), and were higher in less differentiated carcinomas (p = 0.039). However, tumor PD-ECGF concentration did not affect the patients' disease-free survival rates. Those in the background liver tissues were positively correlated with histological activity index scores (r = 0.650, p = 0.001) and serum alanine aminotransferase levels (r = 0.0452, p = 0.035). CONCLUSIONS: PD-ECGF is up-regulated in hepatocellular carcinoma and the corresponding hepatitis liver. The PD-ECGF concentrations in hepatocellular carcinoma correlated positively with microvessel density, lower differentiation, yet not with patients' prognosis. The concentrations of PD-ECGF in the corresponding hepatitis liver correlated positively with the degree of active hepatitis. 相似文献
103.
Nishi J Minamino T Miyauchi H Nojima A Tateno K Okada S Orimo M Moriya J Fong GH Sunagawa K Shibuya M Komuro I 《Circulation research》2008,103(3):261-268
Vascular endothelial growth factor (VEGF) binds both VEGF receptor-1 (VEGFR-1) and VEGF receptor-2 (VEGFR-2). Activation of VEGFR-2 is thought to play a major role in the regulation of endothelial function by VEGF. Recently, specific ligands for VEGFR-1 have been reported to have beneficial effects when used to treat ischemic diseases. However, the role of VEGFR-1 in angiogenesis is not fully understood. In this study, we showed that VEGFR-1 performs "fine tuning" of VEGF signaling to induce neovascularization. We examined the effects of retroviral vectors expressing a small interference RNA that targeted either the VEGFR-1 gene or the VEGFR-2 gene. Deletion of either VEGFR-1 or VEGFR-2 reduced the ability of endothelial cells to form capillaries. Deletion of VEGFR-1 markedly reduced endothelial cell proliferation and induced premature senescence of endothelial cells. In contrast, deletion of VEGFR-2 significantly impaired endothelial cell survival. When VEGFR-1 expression was blocked, VEGF constitutively activated Akt signals and thus induced endothelial cell senescence via a p53-dependent pathway. VEGFR-1(+/-) mice exhibited an increase of endothelial Akt activity and showed an impaired neovascularization in response to ischemia, and this impairment was ameliorated in VEGFR-1(+/-) Akt1(+/-) mice. These results suggest that VEGFR-1 plays a critical role in the maintenance of endothelial integrity by modulating the VEGF/Akt signaling pathway. 相似文献
104.
Insulin alters cardiac muscle creatine kinase activity 总被引:1,自引:0,他引:1
The expression of mRNAs of creatine kinase (CK)-B and CK-M has been show to be affected by insulin, and myocardial CK-MB
activity is suppressed in insulin-deficient rats. We investigated the dose-related effect of insulin on CK-MB activity in
cardiac and skeletal muscles. Male Wistar rats were divided into three groups: (1) control group, (2) diabetic group, injected
with 65 mg/kg streptozotocin for 4 weeks, and (3) atenolol group, administered 30 mg/kg per day atenolol. Each group was further
divided into three subgroups and administered either saline, or 20 (Ins 20) or 30 (Ins 30) U/kg per day insulin. After 3 weeks,
the isoenzyme activity of CK and lactate dehydrogenase (LDH) in the left ventricle of the heart (LV) and the major pectoral
muscle (PM) was measured. Serum insulin increased and plasma glucose decreased in Ins 20 and Ins 30, dose-dependently, in
all three groups. Both CK-MB and -BB activity in LV increased dose-dependently with insulin treatment in the control, diabetes,
and atenolol groups, although these changes did not occur in skeletal muscles. CK-MB in LV correlated with the serum insulin
levels in all rats, while no correlation was found in the skeletal muscles. These findings suggest that insulin possibly regulates
the distribution of CK isoenzymes in rat heart muscle, and that the effect of insulin is not due to the sympathetic drive
induced by hypoglycemia.
Received: November 8, 1999 / Accepted: February 12, 2000 相似文献
105.
Erito Mochiki Hideki Suzuki Seiichi Takenoshita Yukio Nagamachi Hiroyuki Kuwano Akiyoshi Mizumoto Zen Itoh 《Journal of gastroenterology》1998,33(6):835-841
Glucagon is commonly used during gastrointestinal examinations for the temporary inhibition of gastroduodenal movements.
Three preparations of glucagon are now clinically available: those prepared by extraction from the pancreas (GL-P), by chemical
synthesis (GL-S), and by genetic recombination (GL-G). The aim of this study was examine the mechanism of the inhibitory effect
of glucagon on gastrointestinal motility and the cause of its side effects by comparing three glucagon preparations. In four
conscious dogs, gastrointestinal contractions were monitored by means of chronically implanted force transducers. Each glucagon
preparation (GL-P [15 μg/kg], GL-S [5, 15, 45 μg/kg], GL-G [15 μg/kg]), scopolamine butylbromide (0.4 mg/kg), or saline was
administered intravenously 20 min after the termination of spontaneous phase III contractions, and blood samples were taken
at 5- to 10-min intervals. Barium was administered into the stomach 10 min after the infusion of each drug. The arrival of
a barium meal in the stomach immediately stimulated gastrointestinal contractions, and the barium meal was expelled into the
duodenum and jejunum from the stomach. Intravenous injection of 15 μg GL-S first stimulated duodenal contractions that propagated
to the jejunum, followed by strong inhibition of the barium-induced gastrointestinal contractions. This inhibitory effect
of glucagon and the activity of the glucagon-induced duodenal contractions were dose-related. The inhibitory effects of GL-G
and GL-S were stronger than that of GL-P. Blood glucose and plasma insulin concentrations were raised after intravenous injection
of each glucagon preparation, but there was no difference among the three preparations and no dose relationship. The inhibitory
effects of glucagon depend on the material purity and dose, and the inhibitory mechanism was independent of any effect on
carbohydrate metabolism. Glucagon administration caused phase III-like contractions in the duodenum and jejunum, which may
be responsible for the side effects of glucagon.
(Received Jan. 8, 1998; accepted June 26, 1998) 相似文献
106.
Hyoe Inomata Takehiro Watanabe Yoko Iizuka Yi-Qiang Liang Tomoji Mashimo Toru Nabika Katsumi Ikeda Kazuyuki Yanai Takanari Gotoda Yukio Yamori Mitsuaki Isobe Norihiro Kato 《Hypertension research》2005,28(3):273-281
Cardiac hypertrophy and left ventricular hypertrophy are known to be substantially controlled by genetic factors. As an experimental model, we undertook genome-wide screens for cardiac mass in F2 populations bred from the stroke-prone spontaneously hypertensive rats (SHRSP) and normal spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) of a Japanese colony. Two F2 cohorts were independently produced: F2(SHRSP x WKY) (110 male and 110 female rats) and F2(SHR x WKY) (151 male rats). The ratio of heart weight to body weight (Hw/Bw) was evaluated at 12 months of age in F2(SHRSP x WKY) after salt-loading for 7 months, and at around 15 weeks of age in F2(SHR x WKY) who had been fed a normal rat chow diet. Subsequent to an initial screen with 251 markers in F2(SHRSP x WKY) male progeny, 170 and 161 markers were selected and characterized in F2(SHRSP x WKY) female progeny and F2(SHR x WKY) male progeny, respectively. Markers from four chromosomal regions showed suggestive or significant linkage to Hw/Bw. The strongest and the most consistent linkage was found in the vicinity of D3Mgh16 on rat chromosome (RNO) 3 (a maximal log of the odds score reached 4.0 to 6.6 across the F2 populations studied). In the other three regions on RNO6, RNO10 and RNO13, the degree of linkage was more prominent in either males or females. These data provide solid evidence for a "principal" RNO3 quantitative trait loci regulating Hw/Bw in SHRSP and SHR, and also suggest the possible presence of sexual dimorphism in regard to genetic susceptibility for cardiac hypertrophy. 相似文献
107.
Reis AD Fink MC Machado CM Paz Jde P Oliveira RR Tateno AF Machado AF Cardoso MR Pannuti CS;CHIADO RDGV/FAPESP Research Groups 《Revista do Instituto de Medicina Tropical de S?o Paulo》2008,50(1):37-40
A total of 316 samples of nasopharyngeal aspirate from infants up to two years of age with acute respiratory-tract illnesses were processed for detection of respiratory syncytial virus (RSV) using three different techniques: viral isolation, direct immunofluorescence, and PCR. Of the samples, 36 (11.4%) were positive for RSV, considering the three techniques. PCR was the most sensitive technique, providing positive findings in 35/316 (11.1%) of the samples, followed by direct immunofluorescence (25/316, 7.9%) and viral isolation (20/315, 6.3%) (p < 0.001). A sample was positive by immunofluorescence and negative by PCR, and 11 (31.4%) were positive only by RT-PCR. We conclude that RT-PCR is more sensitive than IF and viral isolation to detect RSV in nasopharyngeal aspirate specimens in newborn and infants. 相似文献
108.
109.
Antibody titer to gp210-C terminal peptide as a clinical parameter for monitoring primary biliary cirrhosis 总被引:5,自引:0,他引:5
Nakamura M Shimizu-Yoshida Y Takii Y Komori A Yokoyama T Ueki T Daikoku M Yano K Matsumoto T Migita K Yatsuhashi H Ito M Masaki N Adachi H Watanabe Y Nakamura Y Saoshiro T Sodeyama T Koga M Shimoda S Ishibashi H 《Journal of hepatology》2005,42(3):386-392
BACKGROUND/AIMS: The presence of antibodies to the 210-kDa glycoprotein of the nuclear pore complex (gp210) is highly indicative of primary biliary cirrhosis (PBC). However, the significance of anti-gp210 antibody titers for monitoring PBC remains unresolved. METHODS: We used an ELISA with a gp210 C-terminal peptide as an antigen to assess serum antibody titers in 71 patients with PBC. RESULTS: Patients were classified into three groups: Group A in whom anti-gp210 titers were sustained at a high level, Group B in whom anti-gp210 status changed from positive to negative under ursodeoxycholic acid (UDCA) therapy, Group C in whom anti-gp210 antibodies were negative at the time of diagnosis. The rate of progression to end-stage hepatic failure was significantly higher in group A (60%) as compared to groups B (0%) and C (4.2%). The sustained antibody response to gp210 was closely associated with the severity of interface hepatitis. The significance of anti-gp210 antibody was confirmed by National Hospital Organization Study Group for Liver Disease in Japan. CONCLUSIONS: The serial quantitation of serum anti-gp210-C-terminal peptide antibodies is useful for monitoring the effect of UDCA and for the early identification of patients at high risk for end-stage hepatic failure. 相似文献
110.
CETP is a determinant of serum LDL-cholesterol but not HDL-cholesterol in healthy Japanese 总被引:2,自引:0,他引:2
Makoto Kinoshita Tamio Teramoto Nobuko Shimazu Kazuko Kaneko Masato Ohta Toru Koike Shigemi Hosogaya Yukio Ozaki Shoji Kume Masami Yamanaka 《Atherosclerosis》1996,120(1-2):75-82
Cholesteryl ester transfer protein (CETP) is one of the factors that regulate plasma levels of HDL-cholesterol. To identify the factors that may regulate CETP activity, and to determine to what extent CETP is correlated with physiologic concentrations of lipoprotein, we performed an epidemiologic study in 586 healthy volunteers (317 males and 269 females, mean age 52.2 ± 10.9 years). CETP activity in these subjects was 192.96 ± 48.73 (mean ± S.D.) nmol/ml/h and distributed to a wide range (60–450 nmol/ml/h). Using multiple regression analysis, we found significant positive correlations between CETP activity and LDL-cholesterol (P < 0.03), apolipoprotein (apo) E (P < 0.005) and LCAT activity (P < 0.001). CETP activities showed significant negative correlation with apo A-I (P < 0.03). However, CETP activity showed no significant correlation either with HDL cholesterol or with apo B. One-way layout analysis of variance showed that alcohol drinking and cigarette smoking significantly reduced CETP activity, but there was no significant association between CETP activity and body mass index. Although CETP activities were significantly higher in females than in males (P < 0.001), multiple regression analysis showed no correlation between CETP activity and age in either the males or the females. Our results suggest that CETP activity regulates the concentration of apo A-I and LDL-cholesterol, and that such activity may be influenced by gender, alcohol consumption and cigarette smoking. 相似文献