全文获取类型
收费全文 | 7294篇 |
免费 | 508篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 341篇 |
妇产科学 | 116篇 |
基础医学 | 828篇 |
口腔科学 | 208篇 |
临床医学 | 591篇 |
内科学 | 1807篇 |
皮肤病学 | 101篇 |
神经病学 | 257篇 |
特种医学 | 426篇 |
外国民族医学 | 1篇 |
外科学 | 677篇 |
综合类 | 379篇 |
一般理论 | 2篇 |
预防医学 | 810篇 |
眼科学 | 156篇 |
药学 | 621篇 |
1篇 | |
中国医学 | 66篇 |
肿瘤学 | 425篇 |
出版年
2023年 | 57篇 |
2022年 | 170篇 |
2021年 | 280篇 |
2020年 | 141篇 |
2019年 | 197篇 |
2018年 | 184篇 |
2017年 | 159篇 |
2016年 | 176篇 |
2015年 | 200篇 |
2014年 | 237篇 |
2013年 | 316篇 |
2012年 | 509篇 |
2011年 | 445篇 |
2010年 | 279篇 |
2009年 | 285篇 |
2008年 | 339篇 |
2007年 | 347篇 |
2006年 | 334篇 |
2005年 | 324篇 |
2004年 | 256篇 |
2003年 | 253篇 |
2002年 | 194篇 |
2001年 | 157篇 |
2000年 | 143篇 |
1999年 | 144篇 |
1998年 | 146篇 |
1997年 | 154篇 |
1996年 | 148篇 |
1995年 | 106篇 |
1994年 | 97篇 |
1993年 | 120篇 |
1992年 | 80篇 |
1991年 | 67篇 |
1990年 | 56篇 |
1989年 | 97篇 |
1988年 | 72篇 |
1987年 | 51篇 |
1986年 | 70篇 |
1985年 | 66篇 |
1984年 | 43篇 |
1983年 | 34篇 |
1982年 | 34篇 |
1981年 | 46篇 |
1980年 | 31篇 |
1979年 | 30篇 |
1978年 | 19篇 |
1977年 | 32篇 |
1976年 | 23篇 |
1975年 | 19篇 |
1973年 | 16篇 |
排序方式: 共有7850条查询结果,搜索用时 15 毫秒
11.
The activities of several flavonoids and the related nonflavonoid compound epicatechin were compared with respect to Cu(II)-induced strand scission of DNA by using two different assays. The same series of compounds was used to study the stoichiometry of Cu(II) reduction in the absence of DNA. The compounds were compared for their ability to generate superoxide, hydrogen peroxide and the Cu(II)-dependent production of hydroxyl radicals. Flavonoids were examined to assess the production of a charge-transfer complex with Cu and the rate of decay of the complexes were compared. All the compounds tested had some ability to cause DNA strand scission in the presence of Cu(II), with myricetin being the most active and galangin the least active. The ability to cause such scission correlated with the rate of decay of the charge-transfer complex, the ability to generate active oxygen species and with the stoichiometry of Cu(II) binding. Analysis of the data in the light of the structural differences between the flavonoids led to a discussion of alternative Cu(II)-sequestering mechanisms. 相似文献
12.
Multiple congenital supratentorial intracerebral cysts occurred in a newborn infant. The cysts, of varying size, content and lining, occupied the cerebral hemispheres. They formed a mosaic pattern on CT scan and left no trace of a recognisable ventricular system. Multiple surgical procedures were performed during the first year of life, and at one year the child was very well and asymptomatic, with two functioning shunts. 相似文献
13.
Plasmid profiles have been established for 68 isolates of Staphylococcus aureus from 13 episodes of epidemic spread in hospital wards between 1958 and 1962. Despite the original lack of care in preservation of strains the profiles give, in general, the same epidemiological patterns as were established originally on the basis of phage type, antibiotic sensitivity, ward and date of isolation. 相似文献
14.
15.
Jamal M. Arif Sikandar G. Khan Mohammad Aslam Nayyara Mahmood Qamar Rahman 《Basic & clinical pharmacology & toxicology》1992,71(1):37-40
Abstract: In order to determine the pulmonary toxicity of kerosene and its ignition product (soot) in asbestos exposed subjects, the activities of phase I and phase II drug metabolizing enzymes in rat lungs after single intratracheal coexposure to Indian chrysotile asbestos and kerosene or its soot and Indian chrysotile were assayed. Exposure to kerosene or its soot resulted in a significant increase in the level of microsomal cytochrome P-450 and the activity of P-450 dependent monooxygenase, benzo(a)pyrene hydroxylase, as well as in the activities of microsomal epoxide hydrase and cytosolic glutathione-S-transferase (GST). However, in chrysotile exposed animals a reverse pattern in these parameters was recorded. The co-exposure to chrysotile and kerosene or chrysotile and soot led to a significant depletion in cytochrome P-450 level and a decrease in the activities of benzo(a)pyrene hydroxylase, epoxide hydrase and GST when compared to kerosene and soot controls, respectively. These results suggest that asbestos by altering the pulmonary drug metabolizing enzyme system may increase the toxic potential of kerosene and its ignition product in the respiratory system. 相似文献
16.
Rosenberg ZS; Jahss MH; Noto AM; Shereff MJ; Cheung Y; Frey CC; Norman A 《Radiology》1988,167(2):489-493
Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture. 相似文献
17.
Pharmacokinetics of two alternative dosage forms for cyclosporine: liposomes and intralipid 总被引:2,自引:0,他引:2
Cyclosporine (CsA), commercially available as iv or oral Sandimmune, is a potent immunosuppressant which can induce dose-related nephrotoxocity. In addition, the iv product contains a solubilizing agent, Cremophore EL, which in itself is reported to be nephrotoxic and can induce, in sensitized patients, anaphylactic reactions. Solubilization of CsA with liposomes or lipid emulsions could provide a suitable alternative dosage form for iv administration. With this in mind, male New Zealand white rabbits were given iv CsA (10 mg/kg) in three different dosage forms: (1) CsA:liposomes; (2) CsA:Intralipid (soybean oil and phospholipids); and (3) the commercially available Sandimmune (cyclosporine). The CsA concentration in whole blood samples was analyzed by HPLC. The terminal disposition half-life of CsA (t1/2 beta) ranged from 400 to 475 min and was not statistically different among the three groups. However, the distribution characteristics of CsA changed dramatically depending on the dosage form. The volume of distribution of CsA at steady state (Vdss) in Sandimmune was 2.7 +/- 0.2 L/kg and was significantly lower than that of either Intralipid (10.6 +/- 2.7 L/kg) or liposomes (7.4 +/- 2.3 L/kg). A significantly lower total body clearance (TBC) of CsA also was seen for Sandimmune (12.7 +/- 0.3 mL/min/kg) as compared with that of either Intralipid (24.4 +/- 8.2 mL/min/kg) or liposomes (18.9 +/- 3.9 mL/min/kg). Since CsA is extensively bound to lipoproteins, it is surprising that both test vehicles showed a different distribution pattern.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
18.
Abdul Rahman D El Kinge Rami A Mahfouz Ali I Shamseddine Ali T Taher 《Blood coagulation & fibrinolysis》2007,18(6):577-579
Recombinant activated factor VII has been Food and Drug Administration approved to treat hemorrhages in hemophiliac patients with inhibitors and in acquired hemophilia patients. Recombinant activated factor VII use has also been considered for the management of uncontrolled bleeding in a number of congenital and acquired hemostatic abnormalities. The myeloproliferative disorders are a group of clonal hematologic diseases where, frequently, abnormal platelet function is considered a hallmark. This is the first case report addressing the clinical benefit of off-label use of recombinant activated factor VII in an attempt to control intractable bleeding in a patient with a myeloproliferative disorder after splenectomy. 相似文献
19.
LN Weinberger MJ Zirwas JC English III 《Journal of the European Academy of Dermatology and Venereology》2007,21(2):156-162
Male genital oedema can be defined as swelling or the appearance of swelling of the scrotum and/or the penile shaft and prepuce. Despite the various causes of genital oedema reported in the published work, a concise approach to the evaluation and management has not been sufficiently addressed. 相似文献
20.
Picotamide inhibition of excess in vitro thromboxane B2 release by colorectal mucosa in inflammatory bowel disease. 总被引:1,自引:0,他引:1
Collins CE Benson MJ Burnham WR Rampton DS 《Alimentary pharmacology & therapeutics》1996,10(3):315-320
BACKGROUND: Inflammatory bowel disease is associated with increased mucosal release of eicosanoids. Among these, thromboxane A2 has been proposed as a possible inflammatory mediator; its suppression may be a useful therapeutic option. METHODS: Using a tissue incubation technique, we compared release of immunoreactive thromboxane B2 by colonic biopsies from patients with ulcerative colitis, Crohn's disease and controls, and assessed the inhibitory effect of picotamide, a thromboxane synthesis inhibitor-receptor antagonist, which has been widely used in Italy for management of ischaemic heart and cerebrovascular disease. RESULTS: Increased amounts of thromboxane B2 were released from biopsies from patients with active ulcerative colitis (median 238 pg/20 min/mg wet weight (interquartile range 147- 325), n = 12) and active Crohn's disease (252 (174-450), 6) compared with those from patients with quiescent ulcerative colitis (95 (61- 140), 12) or Crohn's disease (105 (57-201), 13), or controls (136 (64- 206), 8). Incubation with picotamide at concentrations between 100 microM and 1 mM reduced thromboxane B2 release (IC50 890 microM). CONCLUSION: Since increased thromboxane A2 production may have pathogenetic importance, thromboxane synthesis inhibitor-receptor antagonists such as picotamide merit therapeutic trial in the management of inflammatory bowel disease. 相似文献