全文获取类型
收费全文 | 193411篇 |
免费 | 4029篇 |
国内免费 | 440篇 |
专业分类
耳鼻咽喉 | 2750篇 |
儿科学 | 7396篇 |
妇产科学 | 5881篇 |
基础医学 | 24971篇 |
口腔科学 | 5779篇 |
临床医学 | 15013篇 |
内科学 | 34746篇 |
皮肤病学 | 4481篇 |
神经病学 | 11485篇 |
特种医学 | 10572篇 |
外国民族医学 | 97篇 |
外科学 | 29287篇 |
综合类 | 1087篇 |
一般理论 | 2篇 |
预防医学 | 16185篇 |
眼科学 | 4290篇 |
药学 | 13382篇 |
2篇 | |
中国医学 | 140篇 |
肿瘤学 | 10334篇 |
出版年
2018年 | 3516篇 |
2017年 | 3872篇 |
2016年 | 3170篇 |
2015年 | 4833篇 |
2014年 | 4249篇 |
2013年 | 3336篇 |
2012年 | 9744篇 |
2011年 | 4590篇 |
2010年 | 2125篇 |
2009年 | 3815篇 |
2008年 | 1944篇 |
2007年 | 2665篇 |
2006年 | 2912篇 |
2005年 | 11037篇 |
2004年 | 12547篇 |
2003年 | 8135篇 |
2002年 | 3349篇 |
2001年 | 4323篇 |
2000年 | 1674篇 |
1999年 | 5820篇 |
1998年 | 499篇 |
1995年 | 378篇 |
1992年 | 6858篇 |
1991年 | 7099篇 |
1990年 | 7348篇 |
1989年 | 6938篇 |
1988年 | 6475篇 |
1987年 | 6234篇 |
1986年 | 5951篇 |
1985年 | 5244篇 |
1984年 | 3591篇 |
1983年 | 2910篇 |
1982年 | 1001篇 |
1981年 | 766篇 |
1980年 | 836篇 |
1979年 | 3828篇 |
1978年 | 2362篇 |
1977年 | 1782篇 |
1976年 | 1560篇 |
1975年 | 2473篇 |
1974年 | 3105篇 |
1973年 | 2738篇 |
1972年 | 2757篇 |
1971年 | 2742篇 |
1970年 | 2555篇 |
1969年 | 2464篇 |
1968年 | 2237篇 |
1967年 | 2163篇 |
1966年 | 1898篇 |
1965年 | 1131篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The relationship between the immunoglobulin kappa light chain allotypes and autoantibodies was studied in a series of seven human monoclonal kappa-bearing IgM antibodies with Rheumatoid Factor (RF) activity, two IgM anti-low density lipoprotein (LDL) antibodies, and one IgM anti-intermediate filament (IF) antibody. Residues at amino acid positions 153 and 191 related to the Km allotypes in human kappa chains were determined by an HPLC tryptic fingerprint and corroborated by amino acid sequence analysis. All the autoantibodies shared similar variable regions derived from the V kappa IIIb gene(s). The seven RF and the anti-IF were associated with the Km(3) constant region allotype whereas the two anti-LDL were associated with the Km(1,2) allotype. Thus, monoclonal autoantibodies showed the same Km allotypic distribution as the normal population. However, although the number of samples is small, it seems likely that a preferential association may exist between particular V kappa genes and Km alleles in the generation of autoantibodies with different specificities. 相似文献
72.
Bioavailability and biological efficacy of a new oral formulation of salmon calcitonin in healthy volunteers. 总被引:6,自引:0,他引:6
Thierry Buclin Monica Cosma Rochat Peter Burckhardt Mo?se Azria Martine Attinger 《Journal of bone and mineral research》2002,17(8):1478-1485
Salmon calcitonin (SCT) is a well-tolerated peptide drug with a wide therapeutic margin and is administered parenterally for long-term treatments of bone diseases. Its clinical usefulness would be enhanced by the development of an orally active formulation. In this randomized crossover double-blinded phase I trial, controlled by both a placebo and a parenteral verum, we have tested a new oral formulation of SCT associated with a caprylic acid derivative as carrier. Eight healthy volunteers received single doses of 400, 800, and 1200 microg of SCT orally, a placebo, and a 10-microg (50 IU) SCT intravenous infusion. SCT was reliably absorbed from the oral formulation, with an absolute bioavailability of 0.5-1.4%, depending on the dose. It induced a marked, dose-dependent drop in blood and urine C-terminal telopeptide of type I collagen (CTX), a sensitive and specific bone resorption marker, with the effects of 1200 microg exceeding those of 10 microg intravenously. It also decreased blood calcium and phosphate, and increased the circulating levels of parathyroid hormone (PTH) and, transiently, the urinary excretion of calcium. It was well-tolerated, with some subjects presenting mild and transient nausea, abdominal cramps, diarrheic stools, and headaches. This study shows that oral delivery of SCT is feasible with reproducible absorption and systemic biological efficacy. Such an oral formulation could facilitate the use of SCT in the treatment of osteoporosis and other bone diseases. 相似文献
73.
Effect of unilateral ureteral occlusion on fibrin deposition in the kidney and renal blood flow during intravascular coagulation in rat 总被引:1,自引:0,他引:1
The effect of unilateral ureteral occlusion on fibrin deposition in the kidney and the interrelation of the fibrin deposition and the renal blood flow was studied in rat. Intravascular coagulation in the kidney was induced by infusion of thrombin and inhibition of fibrinolysis with tranexamic acid. The effects unilateral occlusion of the ureter for 1 and 24 h on fibrin deposition and renal blood flow were studied. Fibrin in the kidneys was quantitated by intravenous injection of 125I-labelled fibrinogen 24 h before the experiment. The renal blood flow was measured before and after infusion of thrombin by injection of 85Sr- and 141Ce-labelled microspheres into the left ventricle. After ureteral occlusion for 1 h the deposition of fibrin in the kidneys was unaffected. After 24 h substantially less fibrin deposition was found in the occluded than in the unoccluded kidney (0.3 +/- 0.2 and 5.7 +/- 1.6 mg, respectively; p less than 0.05). Before thrombin infusion the blood flow to the occluded kidney was less than that in the unoccluded kidney (2.1 +/- 0.8 and 3.7 +/- 1.2 ml/min, 100 g body weight, respectively; p less than 0.05). The blood flow after infusion of thrombin was equally reduced in both kidneys. The results contradict the hypothesis that vasoconstriction increases the amount of fibrin in the kidneys in thrombin-induced intravascular coagulation. 相似文献
74.
We found that thirteen per cent of all head and neck malignomas are malignant lymphomas. In 75% of these cases the Non-Hodgkin type could be found. The major salivary glands were involved by the lymphoma in 55% out of 104 patients. Paraglandular lymph nodes of the parotid gland were affected as well as intraglandular lymph nodes and the lymphoid tissue within the gland proper. The submandibular gland normally shows an involvement only with its paraglandular lymph nodes. Two thirds of the Non-Hodgkin lymphomas located in the salivary glands were low-grade. In case of clinical suspicion of a malignant lymphoma, fine needle biopsy is required for cytological diagnosis. However, surgery is mandatory for histological diagnosis, not as a therapeutic measure. 相似文献
75.
76.
77.
78.
Irradiation of a cytosolic fraction from vascular smooth muscle in the presence of [3H]felodipine resulted in the labelling of a protein with an apparent molecular weight of 62 kDa. The labelling was seen on UV-irradiation at 360 nm, but not at 254, 278 or at wavelengths above 410 nm. The photolabelling was enhanced in the absence of oxygen. In cytosolic fractions prepared from porcine liver, cardiac and skeletal muscle no photoaffinity labelling of proteins between 90 and 45 kDa could be demonstrated. The results suggest that felodipine is a photoaffinity ligand and that felodipine binds to a soluble protein present in vascular smooth muscle but not in the other tissues tested. 相似文献
79.
A new technique for ultrasonic examination of the hip joint was evaluated in neonatals and infants. An anterior approach was used with the sound sector centered over the femoral head and parallel to the femoral neck. The ultrasonograms corresponded to lateral radiographs of the joint with the leg in Lorenz' first position. It was possible to evaluate the size and depth of the acetabulum and the size and position of the femoral head. The projection also permitted a dynamic examination for determination of hip instability. Thus, the technique provided a method for an objective diagnosis in congenital dislocation of the hip (CDH). In 216 hips, the results of clinical evaluation for CDH were correlated with the degree of instability demonstrated by ultrasound. The comparison showed the clinical diagnosis to be highly inaccurate. 相似文献
80.