全文获取类型
收费全文 | 4364篇 |
免费 | 154篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 95篇 |
妇产科学 | 43篇 |
基础医学 | 434篇 |
口腔科学 | 114篇 |
临床医学 | 340篇 |
内科学 | 857篇 |
皮肤病学 | 200篇 |
神经病学 | 283篇 |
特种医学 | 212篇 |
外科学 | 959篇 |
综合类 | 13篇 |
一般理论 | 1篇 |
预防医学 | 95篇 |
眼科学 | 126篇 |
药学 | 409篇 |
中国医学 | 4篇 |
肿瘤学 | 329篇 |
出版年
2021年 | 91篇 |
2020年 | 46篇 |
2019年 | 40篇 |
2018年 | 62篇 |
2017年 | 59篇 |
2016年 | 53篇 |
2015年 | 68篇 |
2014年 | 84篇 |
2013年 | 102篇 |
2012年 | 157篇 |
2011年 | 211篇 |
2010年 | 98篇 |
2009年 | 86篇 |
2008年 | 115篇 |
2007年 | 143篇 |
2006年 | 140篇 |
2005年 | 172篇 |
2004年 | 165篇 |
2003年 | 181篇 |
2002年 | 170篇 |
2001年 | 154篇 |
2000年 | 179篇 |
1999年 | 150篇 |
1998年 | 51篇 |
1997年 | 35篇 |
1996年 | 35篇 |
1995年 | 43篇 |
1994年 | 29篇 |
1993年 | 30篇 |
1992年 | 131篇 |
1991年 | 121篇 |
1990年 | 123篇 |
1989年 | 131篇 |
1988年 | 106篇 |
1987年 | 111篇 |
1986年 | 98篇 |
1985年 | 141篇 |
1984年 | 62篇 |
1983年 | 47篇 |
1979年 | 42篇 |
1978年 | 31篇 |
1977年 | 27篇 |
1976年 | 29篇 |
1975年 | 31篇 |
1974年 | 38篇 |
1973年 | 35篇 |
1972年 | 47篇 |
1971年 | 28篇 |
1969年 | 36篇 |
1968年 | 26篇 |
排序方式: 共有4540条查询结果,搜索用时 203 毫秒
31.
Hollow microspheres for use as a floating controlled drug delivery system in the stomach. 总被引:6,自引:0,他引:6
Hollow microspheres (microballoons), loaded with drug in their outer polymer shells, were prepared by a novel emulsion-solvent diffusion method. The ethanol:dichloromethane solution of drug (tranilast or ibuprofen) and an enteric acrylic polymer were poured into an agitated aqueous solution of polyvinyl alcohol that was thermally controlled at 40 degrees C. The gas phase generated in the dispersed polymer droplet by the evaporation of dichloromethane formed an internal cavity in the microsphere of the polymer with the drug. The drugs incorporated in the solidified shell of the polymer were found to be partially or completely amorphous. The flowability and packability of the resultant microballoons were much improved compared with the raw crystals of drug. The microballoons floated continuously over the surface of acidic dissolution media containing surfactant for greater than 12 h in vitro. The drug release behavior of the microballoons was characterized as an enteric property, and drug release rates were drastically reduced depending on the polymer concentration at pH 6.8. 相似文献
32.
Shimeru Kamihira Shigehiro Nakashima Shin Saitoh Michiko Kawamoto Yumiko Kawashima Mitoshi Shimamoto 《Cancer science》1993,84(8):834-837
A fully automated chemiluminescence immunoassay was developed for the detection of antibodies to HTLV-I. We used partially purified viral antigens coated on small polystyrene beads together with acridinium ester-labeled anti-human immunoglobulin G mouse immunoglobulin G in this method. A good agreement was observed between our proposed method, the indirect immunofluorescence assay, the particle-agglutination test and the enzyme immunoassay. This new method, which is simple, sensitive, specific and rapid, should be useful for mass screening of anti-HTLV-I antibodies. 相似文献
33.
Keigo Kohara Tomio Ono Keiko Tominaga-Yoshino Tomokazu Shimonaga Seiichi Kawashima Akihiko Ogura 《Brain research》1998,809(2):285
Neurons survive when their activity is maintained. An influential hypothesis on the cellular mechanism underlying this phenomenon is that there is an appropriate range of intracellular Ca2+ concentration ([Ca2+]i) for survival. The rat cerebellar granule neuron in culture serves as the most often used model system for the analysis of activity-dependent survival, since it does not survive unless an excitant (KCl or glutamate) is added to the culture medium. Against the above-mentioned hypothesis, we found in our previous examination no difference between steady-state [Ca2+]i in granule neurons cultured under high KCl (i.e., survival) and low KCl (i.e., death) conditions. In this report, we present the quantitative background of unchanged [Ca2+]i between the two culture conditions. Influx of Ca2+ due predominantly to L-type voltage-dependent calcium channels was higher in high KCl cultures than in low KCl cultures. At the same time, efflux of Ca2+ due to the activity of Ca2+/Na+ antiport was also higher in high KCl cultures. Additionally, we found that the endocytotic activity was greater in high KCl cultures than in low KCl cultures, as monitored by the rate of uptake of horseradish peroxidase added to medium. Since the uptake was blocked by an internal Ca2+ chelator, the increased endocytotic activity in high KCl cultures might be a consequence of the enhanced Ca2+ turnover. 相似文献
34.
Takeuchi Hirofumi Yamamoto Hiromitsu Niwa Toshiyuki Hino Tomoaki Kawashima Yoshiaki 《Pharmaceutical research》1996,13(6):896-901
Purpose. The mucoadhesiveness of polymer-coated liposomes was evaluated to develop a novel drug carrier system for oral administration of poorly absorbed drugs such as peptide drugs.
Methods. Multilamellar liposomes consisting of dipalmitoylphosphatidylcholine (DPPC) and dicetyl phosphate (DCP) (DPPC:DCP = 8:2 in molar ratio) were coated with chitosan (CS), polyvinyl alcohol having a long alkyl chain (PVA-R) and poly (acrylic acid) bearing a cholesteryl group. The adhesiveness of the resultant polymer-coated liposomes to the rat intestine was measured in vitro by a particle counting method with a Coulter counter. The CS-coated liposomes containing insulin were administered to normal rats and the blood glucose level was monitored.
Results. The existence of polymer layers on the surface of liposomes was confirmed by measuring the zeta potential of liposomes. The CS-coated liposomes showed the highest mucoadhesiveness and the degree of adhesion was dependent on the amount of CS on the surface of the liposomes. The blood glucose level of rats was found to be significantly decreased after administration of the CS-coated liposomes containing insulin. The lowered glucose level was maintained for more than 12h after administration of the liposomal insulin, which suggested mucoadhesion of the CS-coated liposomes in the intestinal tract of the rats. 相似文献
35.
Quantitation and identification of human monocytic colony-stimulating factor in human serum by enzyme-linked immunosorbent assay 总被引:4,自引:0,他引:4
Hanamura T; Motoyoshi K; Yoshida K; Saito M; Miura Y; Kawashima T; Nishida M; Takaku F 《Blood》1988,72(3):886-892
An enzyme-linked immunosorbent assay (ELISA) system for the quantitation of human monocytic colony-stimulating factor (hM-CSF) was established, which was based on the "dual antibody immunometric sandwich" principle using horse and rabbit polyvalent antibodies against human urinary colony-stimulating factor (CSF-HU). The minimal detectable level of hM-CSF was 10 U/mL, and the assays showed good reproducibility. As measured by this method, the average serum hM-CSF level of 20 normal adults was 540 +/- 110 U/mL (range, 300 to 800 U/mL). The peak of hM-CSF measured by ELISA was identical to that measured by bioassay when semipurified CSF-HU was fractionated by reversed-phase high performance liquid chromatography (HPLC). This method detected two types of hM-CSF, which had approximate molecular weights of 85 Kd (CSF-HU) and 45 Kd in human serum and urine; the ratio of 85:45 Kd was very high in serum and the amounts of the two types were nearly equal in urine. After anticancer chemotherapy, the serum hM- CSF level of one half of the patients with hematological malignancy was elevated according to the reduction in neutrophil number, while it was almost in the normal range in the other half of the patients, indicating the possibility that anticancer chemotherapy damaged the hM- CSF-producing cells. This ELISA method may be useful for monitoring the serum hM-CSF level after anticancer chemotherapy. 相似文献
36.
Hikaru Matsuda Yoshiyuki Taenaka Nobukazu Ohkubo Masakatu Ohtani Kyouichi Nishigaki Shigeaki Ohtake Takuya Miura Nobuyuki Taenaka† Hisateru Takano Hajime Hirose Yasunaru Kawashima 《Artificial organs》1988,12(5):423-430
Pneumatic ventricular assist device (VAD) was utilized for cardiogenic shock after intracardiac operation in two children with complex cardiac anomalies based with single ventricle. In the first case (a 10-year-old), after a modified Fontan operation, VAD was placed between the functional left atrium and ascending aorta, serving as a "artificial single ventricle" with neither pumping chamber nor artificial support in the right side of the heart. The systemic circulation was maintained by keeping relatively high central venous pressure. In another child (a 3-year-old) who underwent repair of incompetent atrioventricular valve leaving intracardiac lesions, VAD was placed between the common atrium and ascending aorta, serving as a pump for both pulmonary and systemic circulation with regulation of pulmonary blood flow through an aortopulmonary Gore-Tex shunt. The circulatory assist with VAD was utilized for 5 and 6 days, respectively. Although weaning from the device was not feasible in both patients because of the pulmonary dysfunction, these experience showed the possible use of VAD for cardiogenic shock after surgery in patients with complex cardiac anomalies. 相似文献
37.
Sultamicillin fine granules were administered orally to 21 patients with impetigo contagiosa and 1 patient with erysipelas, and its clinical efficacy and safety were assessed. The dosage was 10-30 mg/kg daily. Clinical efficacies of impetigo contagiosa were "excellent" in 20 cases and "fair" in 1 case, with an overall efficacy rate of 95%. The result of treatment in erysipelas was "good". Out of 19 strains of Staphylococcus aureus isolated from foci, 17 strains had high beta-lactamase activities. In these 17 strains, sensitivity to the drug was 2-32-fold higher than to ampicillin, and in 14 out of these 17 strains 4-8-fold higher sensitivity was noted. As side effects, mild diarrhea was seen in 2 patients, but those recovered spontaneously in 3-4 days without particular treatment. 相似文献
38.
T Kawashima H Ajiki Y Asai H Nakakura S Komatsu 《Kyobu geka. The Japanese journal of thoracic surgery》1989,42(12):1009-1011
Two cases underwent a modified Fontan operation with simultaneous superior vena cava-right pulmonary artery end-to-side anastomosis, which we called "bidirectional Glenn shunt". This anastomosis seems to be so effective for reduction of right arterial volume loading, and could proved life-saving in the case with the acute obstruction at the site of the right atriopulmonary artery anastomosis immediately after surgery. 相似文献
39.
Kangouri K Miyoshi T Kawashima A Ikeda A Mizutani T Omura S Lian-Niang L Hong X 《Planta medica》1989,55(3):297-299
Neokadsuranic acid A, which is the first triterpenoid with the 14(13-->12) ABEO lanostane skeleton, was isolated from KADSURA HETEROCLITA together with (24 Z)-3-oxo-lanosta-8,24-dien-26-oic acid. The present paper deals with the isolation and structure elucidation of these two new compounds. 相似文献
40.
The aim of the present study was to know whether 22-28-kHz vocalizations have any communicatory role in the regulation of aggressive behavior in male rats of the Wistar strain. In pairs of intact rats 22-28-kHz vocalizations showed a positive correlation with the extent of aggressive behavior. The pattern of aggressive behavior during ultrasonic vocalizations was different from that just before and just after the vocalizations. However, surgically deafened rats were less active in aggressive behavior and more active in ambulatory activity in the open field than the controls. Muted rats were not different from the controls in both aggressive behavior and ambulatory activity. The present result that the deprivation of ultrasonic signals failed to increase aggressive behavior does not support the classical hypothesis that ultrasonic vocalizations inhibit the initiation of aggressive behavior. It is concluded that ultrasounds emitted during aggressive encounters may have little communicative value in male rats. 相似文献