全文获取类型
收费全文 | 38971篇 |
免费 | 2775篇 |
国内免费 | 1006篇 |
专业分类
耳鼻咽喉 | 817篇 |
儿科学 | 644篇 |
妇产科学 | 759篇 |
基础医学 | 6959篇 |
口腔科学 | 775篇 |
临床医学 | 3243篇 |
内科学 | 5873篇 |
皮肤病学 | 366篇 |
神经病学 | 4820篇 |
特种医学 | 1079篇 |
外国民族医学 | 4篇 |
外科学 | 3210篇 |
综合类 | 3264篇 |
现状与发展 | 2篇 |
一般理论 | 1篇 |
预防医学 | 2822篇 |
眼科学 | 449篇 |
药学 | 4136篇 |
10篇 | |
中国医学 | 1009篇 |
肿瘤学 | 2510篇 |
出版年
2024年 | 82篇 |
2023年 | 633篇 |
2022年 | 1011篇 |
2021年 | 1726篇 |
2020年 | 1483篇 |
2019年 | 1276篇 |
2018年 | 1295篇 |
2017年 | 1300篇 |
2016年 | 1348篇 |
2015年 | 1477篇 |
2014年 | 2370篇 |
2013年 | 3084篇 |
2012年 | 2030篇 |
2011年 | 2356篇 |
2010年 | 1814篇 |
2009年 | 1926篇 |
2008年 | 1889篇 |
2007年 | 1712篇 |
2006年 | 1617篇 |
2005年 | 1277篇 |
2004年 | 1150篇 |
2003年 | 1023篇 |
2002年 | 836篇 |
2001年 | 699篇 |
2000年 | 616篇 |
1999年 | 533篇 |
1998年 | 473篇 |
1997年 | 439篇 |
1996年 | 379篇 |
1995年 | 377篇 |
1994年 | 365篇 |
1993年 | 300篇 |
1992年 | 299篇 |
1991年 | 299篇 |
1990年 | 231篇 |
1989年 | 218篇 |
1988年 | 212篇 |
1987年 | 204篇 |
1986年 | 200篇 |
1985年 | 303篇 |
1984年 | 293篇 |
1983年 | 181篇 |
1982年 | 249篇 |
1981年 | 189篇 |
1980年 | 170篇 |
1979年 | 171篇 |
1978年 | 109篇 |
1977年 | 95篇 |
1976年 | 97篇 |
1975年 | 69篇 |
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
991.
Caspase-12在D-氨基半乳糖联合脂多糖诱导小鼠急性肝功能衰竭中的表达及作用 总被引:6,自引:0,他引:6
目的探讨Caspase-12在D-氨基半乳糖(D-Gal)/脂多糖(LPS)诱导小鼠急性肝功能衰竭发生发展过程中表达水平的变化及Caspase-12介导的内质网应激肝细胞凋亡途径在急性肝功能衰竭中的作用。方法以D-Gal/LPS联合腹腔注射诱导小鼠急性肝功能衰竭建立实验模型,在不同时间点动态检测血清氨基转移酶水平和观察肝组织病理变化,评估肝细胞凋亡和肝坏死演变过程;应用琼脂糖凝胶电泳检测肝细胞DNA凋亡条带;用半定量逆转录聚合酶链反应检测肝组织中Caspase-12 mRNA表达水平;west- ern blot检测Caspase-12、Bip/GRP78蛋白表达。结果药物诱导5h时肝组织中典型凋亡细胞增多,血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)开始升高,Caspase-12 mRNA表达明显增加, Caspase-12蛋白量表达反而减少;7h镜下出现大量肝细胞凋亡和坏死,ALT、AST水平达高峰,分别为(2564±1384)U/L和(1198±497)U/L,正常对照组为(59±17)U/L和(135±12)U/L,Caspase- 12 mRNA表达仍增加,Caspase-12蛋白表达量继续降低;9h 肝细胞坏死明显,伴散在凋亡细胞,ALT、AST水平明显下降,Caspase-12 mRNA表达较7 h下降。Bip/GRP78蛋自表达从5 h开始,至7 h逐渐增加。结论D-Gal/LPS诱导小鼠急性肝功能衰竭早期Caspase-12 mRNA表达水平逐渐升高,后期(7-9 h)降低,与肝细胞凋亡发生的时相一致;Caspase-12蛋白酶因内质网应激而被大量活化,提示Caspase-12介导的内质网应激肝细胞凋亡参与炎症性急性肝功能衰竭的发生发展,是急性肝功能衰竭中肝细胞损伤的重要机制之一,提示早期干预Caspase-12表达及活化对急性肝功能衰竭可能具有保护作用。 相似文献
992.
Sararak Choosakul Kamin Harinwan Sakkarin Chirapongsathorn Krit Opuchar Theeranun Sanpajit Wanich Piyanirun Chaipichit Puttapitakpong 《Pancreatology》2018,18(5):507-512
Background/Objectives
Aggressive fluid resuscitation is recommended for initial management of acute pancreatitis. However, there are few studies which focus on types of fluid therapy.Methods
We performed a randomized controlled trial in patients with acute pancreatitis. The patients were randomized into two groups. Each group received Normal Saline solution (NSS) or Lactated Ringer's solution (LRS) through a goal-directed fluid resuscitation protocol. Systemic inflammatory response syndrome (SIRS) at 24 and 48?h, mortality, presence of local complications and inflammatory markers were measured.Results
Forty-seven patients were included. Twenty-four patients (51%) received NSS and 23 patients received LRS. There was significant reduction in SIRS after 24?h among subjects who resuscitated with LRS compared with NSS (4.2% in NSS, 26.1% in LRS, P?=?0.02). However, SIRS reduction at 48?h was not different between groups (33.4% in NSS, 26.1% in LRS, P?=?0.88). Mortality was not different between NSS and LRS (4.2% in NSS, 0% in LRS, P?=?1.00). CRP, ESR and procalcitonin increased at 24?h and 48?h after admission with no difference between the two groups. Local complications were 29.2% in NSS and 21.7% in LRS (P?=?0.74). The median length of hospital stay was not significantly different in the two groups (5.5 days in NSS, 6 days in LRS, P?=?0.915).Conclusions
Lactated Ringer's solution was superior to NSS in SIRS reduction in acute pancreatitis only in the first 24?h. But SIRS at 48?h and mortality were not different between LRS and NSS. 相似文献993.
Erkek E Ayaslioglu E Erkek AB Kurtipek GS Bagci Y 《Journal of gastroenterology and hepatology》2005,20(10):1508-1511
BACKGROUND AND AIM: Hepatitis B virus infection is an important public health problem in Turkey. Although hepatitis B vaccination is regarded as safe and effective for the general population, recommendations for hepatitis B immunization in patients with Behcet's disease are not clear. The aim of the present study was to elucidate the response of patients with Behcet's disease to hepatitis B vaccination and to determine whether hepatitis B vaccination has any adverse effects on the course of the disease. METHODS: Thirteen patients with Behcet's disease and 15 healthy individuals were enrolled into a prospective study. All subjects received the 3-dose series of routine hepatitis B vaccine. Anti-hepatitis B surface response was evaluated 1-3 months after the third dose of vaccine. RESULTS: The responder rates for patient and control groups were 12/13 (92.8%) and 14/15 (93.8%), respectively. Statistical analysis showed no significant difference between the two groups in terms of both the responder rates and mean antibody titers. CONCLUSIONS: These preliminary findings might suggest that the majority of patients with Behcet's disease develop protective antibody response after hepatitis B vaccination and that the immune response against hepatitis B surface antigen is adequate, efficient and intact. 相似文献
994.
Romero GA de la Glória Orge Orge M de Farias Guerra MV Paes MG de Oliveira Macêdo V de Carvalho EM 《Acta tropica》2005,93(1):49-56
The antibody response against Leishmania (Leishmania) amazonensis crude antigen was measured through the indirect immunofluorescent assay (IFA) and the immunoenzymatic assay (ELISA) in 114 patients with cutaneous leishmaniasis (CL) in Brazil. Fifty-four patients were infected by Leishmania (Viannia) braziliensis, and 60 patients had L. (V.) guyanensis infection. Patients were comparable by age, sex, disease duration and the Montenegro skin test diameter. L. (V.) braziliensis-infected patients showed significant lower number of ulcerated lesions, greater ulcerated area and higher proportion of lymph node enlargement. Sensitivity of IFA was 79.6% (95% CI 66.1-88.9) and 71.7% (95% CI 58.4-82.2) for L. (V.) braziliensis and L. (V.) guyanensis-infected patients, respectively (P=0.324). Sensitivity of ELISA was 98.2% (95% CI 88.8-99.9) and 85.0% (95% CI 72.9-92.5) for L. (V.) braziliensis and L. (V.) guyanensis-infected patients, respectively (P=0.018). Significant differences were observed in the magnitude of the antibody response before treatment with higher levels detected in L. (V.) braziliensis-infected patients by both serologic techniques. Eighty-four patients had serologic evaluations before and 12 weeks after treatment with meglumine antimoniate, 20 mg/kg/day for 20 days. Significant lower optic density values were observed after treatment with both species independent of cure or failure. Our data showed that L. (V.) braziliensis induces a higher antibody response against L. (L.) amazonensis antigens than L. (V.) guyanensis and that down-modulation of the antibody response occurs shortly during disease evolution after treatment. Moreover the data support the use of ELISA as a better tool for detection of antibodies in CL. 相似文献
995.
996.
Jiang ZX Peng WJ Li WT Tang F Liu SY Qu XD Wang JH Lu HF 《World journal of gastroenterology : WJG》2008,14(38):5893-5899
AIM: To explore the diffusion gradient b-factor that optimizes both apparent diffusion coefficient (ADC) measurement and contrast-to-noise (CNR) for assessing tumor response to transarterial chemoembolization (TACE) in a rabbit model. METHODS: Twelve New Zealand white rabbits bearing VX2 tumors in the liver were treated with TACE. Diffusion-weighted imaging (DWI) with various b values was performed using the same protocol before and 3 d after treatment with TACE. ADC values and CNR of each tumor pre- and post-treatment with different b factors were analyzed. Correlation between ADC values and extent of necrosis in histological specimens was analyzed by a Pearson's correlation test.RESULTS: The quality of diffusion-weighted images diminished as the b value increased. A substantial decrease in the mean lesion-to-liver CNR was observed on both pre- and post-treatment DW images, the largest difference in CNR pre- and post-treatment was manifested at a b value of 1000 s/mm^2 (P = 0.036 ). The effect of therapy on diffusion early after treatment was shown by a significant increase in ADCs (P = 0.007), especially with large b factors (≥ 600 s/mm^2). The mean percentage of necrotic cells present within the tumor was 76.3%-97.5%. A significant positive correlation was found between ADC values and the extent of necrosis with all b values except for b200, a higher relative coefficient between ADC values and percentage of necrosis was found on DWI with bl000 and b2000 (P = 0.002 and 0.006, respectively). CONCLUSION: An increasing b value of up to 600 s/mm^2 would increase ADC contrast pre- and post-treatment, but decrease image quality. Taking into account both CNR and ADC measurement, diffusion-weighted imaging obtained with a b value of 1000 s/mm^2 is recommended for monitoring early hepatic tumor response to TACE. 相似文献
997.
998.
Klaus-Peter Ratzmann Siegfried Knospe Peter Heinke Bernd Schulz 《Acta diabetologica》1979,16(1):67-75
Summary We have studied the interrelationship of total body fat mass, carbohydrate tolerance and IRI response in 17 non-obese and
obese subjects, who were suspected of having early diabetes. We carried out an i.v. glucose infusion test consisting of a
priming injection of 0.33 g/kg followed by constant glucose infusion of 12 mg/kg/min in all persons. Total body fat mass was
estimated by the tritium dilution method. There was a positive correlation of body fat mass, fasting glucose concentration
and blood glucose concentration at 150 min as well as a strong correlation between body fat mass and BG area 60–120 min as
parameters of carbohydrate tolerance in all subjects, i.e. the degree of carbohydrate intolerance was directly related to
the quantity of total body fat mass. A similar correlation was found when the non-obese and obese groups were analyzed separately.
In neither group did total body fat mass correlate with parameters of IRI response. In obese subjects with pathological carbohydrate
tolerance, however, a positive correlation of basal IRI concentration and total body fat mass was found. Furthermore, a close
relation between basal IRI level and parameters of carbohydrate tolerance could be demonstrated in obese subjects. The present
study failed to demonstrate any correlation of parameters of carbohydrate tolerance and glucose-induced IRI response in either
group. Thus, the significant relationship between body fat mass and degree of carbohydrate intolerance indicates that total
body fat mass plays an important role in the disturbance of blood glucose homeostasis in early diabetes with and without obesity.
Investigation performed within the medical research project ‘Diabetes mellitus and disturbances of lipid metabolism’, Ministry
of Health, GDR. 相似文献
999.
Waage A Gimsing P Juliusson G Turesson I Gulbrandsen N Eriksson T Hjorth M Nielsen JL Lenhoff S Westin J Wislöff F;Nordic Myeloma Study Group 《British journal of haematology》2004,125(2):149-155
Sixty-five patients who were primary or secondary refractory to melphalan/prednisone or other type of chemotherapy, or relapsed within 6 months after high dose chemotherapy with stem cell support, were given thalidomide at a dose of 200 mg/d escalating to 800 mg. The patients were followed for a median of 2 years and 22 weeks. Response was evaluated according to M-protein reduction combined with improvement of haemoglobin (Hb) concentration, renal function and pain. Altogether, 14% of patients had a minor response, 14% partial response and 6% complete response. Median survival was 12 months and 29% were alive at last contact. Decline of M protein started early and a minimum 25% reduction of M protein was detected in 14 of 20 responders (70%) after 3 weeks, and in 20 of 22 responders (91%) after 5 weeks of treatment. Reduction of M protein continued for 3 months and further decline was observed in only four patients. The Hb concentration showed a different time course, with a significant increase after 3 months and further increases continued for up to 12 months. Blood concentration levels of thalidomide from 40 patients were used to evaluate the pharmacokinetics of the drug. Rate of absorption, rate of elimination, volume of distribution, clearance and elimination half-life were calculated to be 0.200/h, 0.140/h, 0.886 l/kg, 0.126 l/h/kg and 4.98 h respectively. We found no relationship between thalidomide concentration and effect after 12 weeks. 相似文献
1000.
FLORINE J. VAN MILLIGEN JAN B.W.J. CORNELISSEN INGRID M. HENDRIKS COR P.H. GAASENBEEK BEN A. BOKHOUT 《Parasite immunology》1998,20(6):285-292
We investigated the immune effector mechanisms that underlie protection against F. hepatica in the gut wall of immune rats, using (immuno)histochemistry. In the lamina propria of immune Wistar rats, four weeks after oral infection, frequencies of IgE-positive cells, eosinophils and mucosal mast cells were significantly increased, compared with naïve rats. These factors represent the traditional effector mechanisms against helminths. No significant differences were detected between the two groups in frequencies of IgM-, IgG2a-, IgG1- and IgA- positive cells, CD4- and CD8-positive cells, NK cells, macrophages, neutrophils or goblet cells. Upon challenge of immune rats with F. hepatica in an ex vivo gut segment, NEJs that migrated through the (sub)mucosa were coated with IgG1 and IgG2a antibodies and surrounded by eosinophils. No IgE or IgA antibodies were detected on the parasites. The onset of these immune effector responses, two h after challenge, was related to the expression of protection. These results suggest that NEJs are killed by an eosinophil-mediated cytotoxic response involving IgG antibodies. These antibodies were not produced in the intestine, but infiltrated the gut upon challenge. The observed immune effector responses were not restricted to the site where the primary infection is located, namely the small intestine, but were also detected in the large intestine. The presence of the protective immune mechanisms in two other rat strains demonstrates the pivotal importance of these responses, irrespective the genetic background of the host. 相似文献