全文获取类型
收费全文 | 535871篇 |
免费 | 27974篇 |
国内免费 | 507篇 |
专业分类
耳鼻咽喉 | 6775篇 |
儿科学 | 17117篇 |
妇产科学 | 12593篇 |
基础医学 | 93156篇 |
口腔科学 | 12432篇 |
临床医学 | 48991篇 |
内科学 | 96737篇 |
皮肤病学 | 11948篇 |
神经病学 | 34455篇 |
特种医学 | 20034篇 |
外国民族医学 | 53篇 |
外科学 | 79119篇 |
综合类 | 7702篇 |
现状与发展 | 2篇 |
一般理论 | 110篇 |
预防医学 | 38779篇 |
眼科学 | 12190篇 |
药学 | 41865篇 |
1篇 | |
中国医学 | 1146篇 |
肿瘤学 | 29147篇 |
出版年
2021年 | 4124篇 |
2019年 | 4082篇 |
2018年 | 5942篇 |
2017年 | 4294篇 |
2016年 | 5057篇 |
2015年 | 5531篇 |
2014年 | 7403篇 |
2013年 | 10821篇 |
2012年 | 16070篇 |
2011年 | 17937篇 |
2010年 | 10231篇 |
2009年 | 9078篇 |
2008年 | 16075篇 |
2007年 | 17837篇 |
2006年 | 17263篇 |
2005年 | 16568篇 |
2004年 | 16155篇 |
2003年 | 15563篇 |
2002年 | 14994篇 |
2001年 | 22486篇 |
2000年 | 23006篇 |
1999年 | 18965篇 |
1998年 | 5274篇 |
1997年 | 4391篇 |
1996年 | 4418篇 |
1995年 | 4144篇 |
1992年 | 14431篇 |
1991年 | 15833篇 |
1990年 | 15965篇 |
1989年 | 15640篇 |
1988年 | 14308篇 |
1987年 | 14209篇 |
1986年 | 13176篇 |
1985年 | 12689篇 |
1984年 | 9398篇 |
1983年 | 8002篇 |
1982年 | 4179篇 |
1979年 | 8939篇 |
1978年 | 6385篇 |
1977年 | 5153篇 |
1976年 | 5508篇 |
1975年 | 6615篇 |
1974年 | 7419篇 |
1973年 | 7159篇 |
1972年 | 6597篇 |
1971年 | 6311篇 |
1970年 | 5890篇 |
1969年 | 5471篇 |
1968年 | 5163篇 |
1967年 | 4621篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
CT- or sonography-guided biopsy of the liver in the presence of ascites: frequency of complications 总被引:1,自引:0,他引:1
F B Murphy K P Barefield H V Steinberg M E Bernardino 《AJR. American journal of roentgenology》1988,151(3):485-486
The presence of ascites has been considered a contraindication to percutaneous biopsy of the liver. To determine the validity of this assumption, we performed percutaneous biopsies of the liver under CT or sonographic guidance in 28 patients who had ascites and in 28 patients who did not have ascites and compared the complication rates in the two groups. Twenty-two patients (79%) in the group with ascites and 19 patients (68%) in the group without ascites had biopsies to determine the cause or extent of chronic liver disease. The remainder were oncologic patients who had biopsies to determine the cause of a focal hepatic mass. The complication rate in the patients who had ascites (32%) was less than that in the patients who did not have ascites (43%) (the difference did not reach statistical significance, p less than .30). In the ascites group, complications included transient hypotension (five patients), a mild-to-moderate fall in hematocrit (three patients), and a small leak of ascites from the biopsy site (one patient). In the control group, minor complications included transient hypotension (three patients), a mild-to-moderate fall in hematocrit (seven patients), and a small subcapsular hematoma (one patient). One major complication occurred in the control group: a patient required a blood transfusion because of the fall in his hematocrit. We conclude that the complication rate in liver biopsies guided by CT or sonography in the presence of ascites is not higher than similar biopsies done in the absence of ascites. Ascites should not be considered a contraindication for performing such biopsies. 相似文献
102.
In experiments on albino rats it was established that three administrations of indomethacin in a dose of 0.01 g/kg body weight induced a severe damage of the liver characterized by disturbances of hepatocytic membranes, bile-producing and protein-producing functions of the liver, an enhancement of lipid peroxidation, a decrease of reduced glutathione pool. Antioxidants (tocopherol acetate, essentiale, legalon, flacumin) limit manifestations of indomethacin, hepatotoxicity, as a result of which tha functional-biochemical disorders in the liver show up to a lesser degree. During the combined use of antioxidants in indomethacin-induced lesions of the liver their hepatoprotective activity increases. 相似文献
103.
L R?stam R V Luepker M B Mittelmark D M Murray J S Slater H Blackburn 《American journal of preventive medicine》1988,4(5):249-254
To determine the potential effect of screening on referral patterns, an adult population sample (4,404 men, 5,164 women, 20-69 years of age) was systematically recruited and screened for hypercholesterolemia and then analyzed by different cholesterol referral recommendations. Using levels suggested by the Lipid Research Clinics Coronary Primary Prevention Trial (greater than or equal to 265 mg/dL), 7.3% of men and 5.8% of women would be referred for follow-up. With the suggested recommendations of the National Cholesterol Education Program (NCEP), (greater than or equal to 200 mg/dL), 49.2% of men and 40.2% of women would be referred. The use of age-related definitions of the NIH Consensus Conference on Lipid Lowering results in 28.0% referrals in men and 21.8% in women. From this population, hypercholesterolemia subjects (greater than or equal to 265 mg/dL at screening; n = 624) were invited for a second cholesterol determination (58% returned), which found 36% below the 265 mg/dL level. Population screening for cholesterol is likely to produce large numbers of patients for follow-up, with the actual numbers strongly dependent on cutoff levels and age-sex distributions. Referral and follow-up of these patients may place a significant load on an unprepared health care community. 相似文献
104.
105.
106.
107.
A. Giacometti O. Cirioni G. Greganti A. Fineo R. Ghiselli M. Del Prete F. Mocchegiani B. Fileni F. Caselli E. Petrelli V. Saba G. Scalise 《European journal of clinical microbiology & infectious diseases》2002,21(7):553-556
The in vitro activities of povidone iodine, potassium peroxymonosulfate, and dimethyldidecylammonium chloride were investigated
against 379 nosocomial isolates of Staphylococcus aureus and Pseudomonas aeruginosa responsible for surgical wound infections in patients operated on between July 1995 and June 2001. Overall, the isolates
were inhibited by the antiseptics at concentrations below those used routinely. In spite of increasing resistance to the various
antibiotics used to treat surgical wound infections, no significant variation in the susceptibility to antiseptics was demonstrated
during this 6-year study.
Electronic Publication 相似文献
108.
109.
Prevention of Bone Loss by Clodronate in Early Postmenopausal Women with Vertebral Osteopenia: A Dose-Finding Study 总被引:1,自引:0,他引:1
M. J. V?lim?ki K. Laitinen K. Laitinen A. Patronen H. Puolijoki H. Puolijoki J. Sepp?nen L. Pylkk?nenand the Probone Study Group 《Osteoporosis international》2002,13(12):937-947
This double-masked, placebo-controlled study was undertaken to determine the efficacy and safety of oral clodronate in the
prevention of bone loss in early postmenopausal women with vertebral osteopenia. Altogether 610 women with a mean age of 53
years were recruited for the study. They were 1–5 years postmenopausal and their lumbar spine bone mineral density (BMD) was
at least 1 standard deviation below the mean of premenopausal women (T-score ≤−1). The subjects were randomized into five study groups to receive either placebo, clodronate 65 mg, 400 mg or 800
mg daily, or intermittent clodronate in 3 month cycles with 400 mg daily for 15 days followed with no treatment for 75 days
for 3 years. One hundred and eighty-seven of 509 women who completed the primary study continued in the extension study of
2 years in which previous placebo users were switched to clodronate 800 mg daily, while previous users of 400 mg or 800 mg
of clodronate used either placebo or 800 mg of clodronate daily. In the primary study clodronate was administered in the evening,
and in the extension 1 h before breakfast on an empty stomach. In the primary study mean changes in lumbar spine BMD were
−3.4% in the placebo group and +0.4% in 800 mg clodronate group [difference between groups at 3 years 3.8% (95% CI 2.7% to
4.9%, p<0.0001)], and in the trochanter area BMD −1.1% in the placebo group, and + 0.4% in the 800 mg clodronate group [difference
between groups at 3 years 1.5% (95% CI 0.05% to 2.9%)]. During the extension study mean changes in lumbar spine BMD were +1.5%
in the clodronate group and −0.2 % in the placebo group [difference between groups 1.7% (CI 0.4% to 3.0%, p = 0.010)] and in trochanter BMD were +2.5% in the clodronate group and no change in the placebo group [difference between
groups 2.1% (CI 0.3% to 3.9%, p = 0.007)]. No statistically significant differences between the placebo and 800 mg clodronate groups were found in the femoral
neck BMD. In the primary study the urinary excretion of type I collagen aminoterminal telopeptide (NTX) decreased by 44% (p<0.0001 compared with placebo) and that of deoxypyridinoline by 18% (p<0.0001) in the clodronate 800 mg group. In the extension study urinary NTX decreased by 51% (p<0.0001) in those who were switched to 800 mg of clodronate and increased by 67% (p<0.0001) in those who stopped using that dose. There was no difference in the frequency of gastrointestinal complaints between
clodronate- and placebo-treated patients in the primary study, but they were more common among women who received clodronate
in the extension phase. Clodronate in daily doses of 400–800 mg caused a slight elevation of aminotransferase levels, usually
within the reference range. In bone biopsies no defect in mineralization was found. In conclusion, clodronate in a daily dose
of 800 mg prevents early postmenopausal bone loss at the sites of the skeleton in which cancellous bone predominates. It effectively
reduces bone resorption and bone turnover rate. Antifracture efficacy of clodronate remains to be established by prospective,
placebo-controlled trials.
Received: 4 March 2002 / Accepted: 9 July 2002 相似文献
110.
Deep venous thrombosis and pulmonary embolism 总被引:2,自引:0,他引:2
All surgical patients are at risk for the development of deep venous thrombosis and subsequent pulmonary embolism or postphlebitic syndrome. The evolution of ultrasonographic imaging has increased the awareness of prevention, diagnosis, and treatment of deep venous thrombosis. Duplex imaging and Doppler color flow imaging have made the diagnosis of deep venous thrombosis relatively simple, painless, inexpensive, and definitive. These procedures have gained acceptance by both patients and physicians. Several risk factors have been identified that increase the chance of the development of deep venous thrombosis. These factors include a history of deep venous thrombosis, presence of a malignant process, increasing age, cigarette smoking, obesity, prolonged bed rest, and general anesthesia. The greater the number of risk factors, the more aggressive prophylaxis should be. Means of prophylaxis have improved, and surgeons now generally agree that some form of prophylaxis is required. Heparin and intermittent compression devices appear to be equally effective in preventing deep venous thrombosis. The addition of venous monitoring in high-risk patients permits immediate identification of the presence of deep venous thrombosis. During the last decade, the treatment of patients with deep venous thrombosis has changed little. Heparin followed by warfarin remains the treatment of choice. A small group of patients receive fibrinolytic therapy for deep venous thrombosis. Although the incidence of postoperative deep venous thrombosis has decreased during the last decade, it remains a significant complication. 相似文献