全文获取类型
收费全文 | 964740篇 |
免费 | 68806篇 |
国内免费 | 1436篇 |
专业分类
耳鼻咽喉 | 13264篇 |
儿科学 | 25338篇 |
妇产科学 | 24087篇 |
基础医学 | 137930篇 |
口腔科学 | 28701篇 |
临床医学 | 85253篇 |
内科学 | 188964篇 |
皮肤病学 | 19877篇 |
神经病学 | 75865篇 |
特种医学 | 37571篇 |
外国民族医学 | 79篇 |
外科学 | 155067篇 |
综合类 | 18306篇 |
现状与发展 | 2篇 |
一般理论 | 267篇 |
预防医学 | 65308篇 |
眼科学 | 21877篇 |
药学 | 74703篇 |
3篇 | |
中国医学 | 2201篇 |
肿瘤学 | 60319篇 |
出版年
2018年 | 9972篇 |
2017年 | 7820篇 |
2016年 | 8644篇 |
2015年 | 9763篇 |
2014年 | 13262篇 |
2013年 | 19158篇 |
2012年 | 26702篇 |
2011年 | 27727篇 |
2010年 | 16280篇 |
2009年 | 15598篇 |
2008年 | 26894篇 |
2007年 | 28044篇 |
2006年 | 28607篇 |
2005年 | 27637篇 |
2004年 | 26540篇 |
2003年 | 25461篇 |
2002年 | 24897篇 |
2001年 | 54960篇 |
2000年 | 56679篇 |
1999年 | 47227篇 |
1998年 | 11102篇 |
1997年 | 9770篇 |
1996年 | 9820篇 |
1995年 | 9155篇 |
1994年 | 8462篇 |
1993年 | 7768篇 |
1992年 | 35604篇 |
1991年 | 34016篇 |
1990年 | 32822篇 |
1989年 | 31961篇 |
1988年 | 29068篇 |
1987年 | 28315篇 |
1986年 | 26347篇 |
1985年 | 25193篇 |
1984年 | 17903篇 |
1983年 | 15192篇 |
1982年 | 7853篇 |
1981年 | 6837篇 |
1979年 | 15811篇 |
1978年 | 10629篇 |
1977年 | 9084篇 |
1976年 | 7896篇 |
1975年 | 8647篇 |
1974年 | 10489篇 |
1973年 | 9873篇 |
1972年 | 9372篇 |
1971年 | 8856篇 |
1970年 | 8436篇 |
1969年 | 7932篇 |
1968年 | 7204篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
H. Nilsson J. Johansson K. Svanberg S. Svanberg G. Jori E. Reddi A. Segalla D. Gust A. L. Moore T. A. Moore 《British journal of cancer》1997,76(3):355-364
The biodistribution of two recently developed tumour markers, trimethylated (CP(Me)3) and trimethoxylated (CP(OMe)3) carotenoporphyrin, was investigated by means of laser-induced fluorescence (LIF) after i.v. injection into 38 tumour-bearing (MS-2 fibrosarcoma) female Balb/c mice. At 3, 24, 48 or 96 h after administration, the carotenoporphyrin fluorescence was measured in tumoral and peritumoral tissue, as well as in the abdominal, thoracic and cranial cavities. The fluorescence was induced by a nitrogen laser-pumped dye laser, emitting light at 425 nm, and analysed by a polychromator equipped with an image-intensified CCD camera. The fluorescence was evaluated at 490, 655 and 720 nm: the second and third wavelengths represent the carotenoporphyrin (CP)-related peaks, whereas the first one is close to the peak of the tissue autofluorescence. The tumour and the liver were the two tissue types showing the strongest carotenoporphyrin-related fluorescence, whereas the cerebral cortex and muscle consistently exhibited weak substance-related fluorescence. In most tissue types, the fluorescence intensities decreased over time. A few exceptions were observed, notably the liver, in which the intensity remained remarkably constant over the time period investigated. 相似文献
83.
Psychometric data are presented which examine the validity of using the concentration of benzoylecgonine in urine, a major metabolite of cocaine, as a measure of drug use, in studies of drug abuse treatments. In such research the standard biological indicator of drug use is usually a qualitative urine drug test, which merely indicates the presence or absence of a drug or its metabolite. A quantitative (i.e. continuous) outcome measure, such as the concentration of a drug or its metabolite in a biological fluid, has substantially more statistical power than a dichotomous measure and should, therefore, prove a more sensitive measure of drug use when viewed from a measurement perspective. Data from two placebo-controlled clinical trials of fluoxetine as an adjunct to treatment for cocaine abuse are analyzed to address this issue. Results indicate that urine benzoylecgonine level is closely related to self-reports of drug use and is independent of levels of anxiety, depression and hopelessness. 相似文献
84.
T F Kruger J P Van der Merwe H J Odendaal F S Stander G M Grobler V A Hulme E L Erasmus K Coetzee M L Windt Y Swart 《Suid-Afrikaanse tydskrif vir geneeskunde》1990,77(12):634-636
The results of the in vitro fertilisation programme at Tygerberg Hospital for the period April 1983 to January 1988 are presented. Of the 1117 laparoscopies performed, 825 patients reached the transfer stage. A live-birth rate of 9.3% was achieved. The pregnancy rate after transfer of 4 embryos was 25.9% compared with 15.4% after 2 embryos and 10.8% after 3 embryos (P = less than 0.0001). The multiple pregnancy rate was 2.8% in the group receiving 2 embryos and 11.7% and 10.4% in those receiving 3 and 4 embryos, respectively. Of the 77 successful pregnancies (90 babies), 1 baby died at 34 weeks' gestation as the result of abruptio placentae due to preeclampsia and 1 cot death occurred. The only congenital abnormality encountered was a cleft palate. 相似文献
85.
Corpus cavernosography in a patient with erectile dysfunction revealed absence of communication between the 2 cavernous bodies. No similar case was found in a review of 100 consecutive cavernosograms or in the literature. The abnormality may be a source of error in pressure recordings or in intravenous injection of pharmaceutical agents. 相似文献
86.
Gallstone dissolution 总被引:2,自引:0,他引:2
Many methods are available for gallstone dissolution, including oral bile salts; cholesterol solvents such as mono-octanoin or methyl tert-butyl either; and calcium or pigment solvents such as EDTA and polysorbate. Which of these approaches will be appropriate for an individual patient depends on the type of stones; whether they are in the gallbladder or the bile ducts; whether access to the biliary tree is available; the patient's age and general medical condition; and the availability of necessary expertise. In the US, both chenodeoxycholate and ursodeoxycholate are now available. Ursodeoxycholate is more expensive but appears to produce fewer side effects and may be more efficacious. These agents are most effective in thin women with small floating, radiolucent cholesterol stones in a functioning gallbladder. Only about half of the small subset of patients will experience partial or complete dissolution of stones within a year. Stone recurrence and the potential toxicity of long-term therapy are problems with this approach. Therefore, for most patients, cholecystectomy, either in the traditional fashion or using a laparoscopic approach (see article later in this issue by Gadacz et al), is the most cost-effective and perhaps the safest option. Intragallbladder instillation of methyl tert-butyl ether probably will be applicable only to a small subset of patients, and treatment is likely to be followed by a high recurrence rate. In patients with retained common duct cholesterol stones and access to the biliary tree, mono-octanoin therapy is advantageous in that it can be initiated as soon as cholangiography demonstrates no extravasation. In properly selected patients, a 90% success rate with this technique can be expected within 7 days. 相似文献
87.
Technetium-99-labelled methylene diphosphonate uptake scans in patients with dialysis arthropathy 总被引:1,自引:0,他引:1
Patients on long-term haemodialysis suffer from dialysis arthropathy due to the deposition of dialysis amyloid. We investigated the use of 99Tc-labelled methylene diphosphonate bone scans in 17 patients as a possible in vivo diagnostic technique. In most clinically affected joints, with the exception of shoulders and hands, there was increased radioisotope uptake consistent with uptake by periarticular bone. In addition, we describe intense soft-tissue uptake around some clinically affected large joints. In contrast, control groups of patients on haemodialysis without arthropathy and patients without renal failure did not have increased uptake. A semi-quantitative scale of uptake was devised, and the following correlations were significant: pain perception and isotope uptake score in the ankles and feet, and the number of radiological lesions and isotope uptake scores in the wrists and knees. The following sites where the radioisotope might bind in the affected joints are proposed: amyloid deposits, areas of soft-tissue calcification, or areas of increased bone turnover. It is concluded that whereas the scanning technique cannot make a definite diagnosis of amyloid and, therefore, cannot be expected to supersede histological diagnosis, it is a useful adjuvant investigation, of particular importance in those patients unable or unwilling to undergo biopsy. 相似文献
88.
G Hasselgren R Jerre M Ullman A T?rnvall S Edshage 《The Journal of hand surgery, European volume》1990,15(1):35-39
Eleven patients with lunatomalacia were treated by excision of the lunate and instillation of liquid silicone. The silicone vulcanised and formed an in-situ molded prosthesis. The patients were reexamined after a mean of 7.1 years. Four patients were pain-free and two had pain only at work; three had not been improved by the operation and two had undergone arthrodesis. The patients with good results all belonged to group IV pre-operatively. Surprisingly, no patient showed any sign of silicone synovitis, although all the prostheses except one had either fractured or deformed. The reasons for this are discussed and the indications for the operation established. 相似文献
89.
90.
Excision of the rectum should take in account that the main lymphatic spread follows the cranial route and that dissection of the rectal wall should be performed across its adjacent anatomical lamellae. It is not clear whether an extensive pelvic dissection and high ligature of the inferior mesenteric artery are beneficial. Spontaneous or iatrogenic perforation of the tumour considerable increases the incidence of local recurrence. The frequency of postoperative urinary and sexual dysfunction ranges from 3.5-57% and 14-38% respectively. The reported surgical mortality averages 5-6%. 相似文献