首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12425篇
  免费   1053篇
  国内免费   207篇
耳鼻咽喉   133篇
儿科学   425篇
妇产科学   286篇
基础医学   975篇
口腔科学   211篇
临床医学   1737篇
内科学   3100篇
皮肤病学   260篇
神经病学   1067篇
特种医学   344篇
外科学   2685篇
综合类   32篇
预防医学   629篇
眼科学   408篇
药学   417篇
中国医学   9篇
肿瘤学   967篇
  2023年   163篇
  2022年   115篇
  2021年   270篇
  2020年   198篇
  2019年   197篇
  2018年   291篇
  2017年   304篇
  2016年   359篇
  2015年   297篇
  2014年   432篇
  2013年   575篇
  2012年   488篇
  2011年   485篇
  2010年   466篇
  2009年   537篇
  2008年   471篇
  2007年   450篇
  2006年   483篇
  2005年   426篇
  2004年   371篇
  2003年   325篇
  2002年   299篇
  2001年   340篇
  2000年   322篇
  1999年   316篇
  1998年   242篇
  1997年   267篇
  1996年   375篇
  1995年   308篇
  1994年   243篇
  1993年   150篇
  1992年   249篇
  1991年   250篇
  1990年   166篇
  1989年   221篇
  1988年   183篇
  1987年   160篇
  1986年   168篇
  1985年   148篇
  1984年   165篇
  1983年   120篇
  1982年   98篇
  1981年   90篇
  1980年   104篇
  1979年   80篇
  1978年   87篇
  1977年   56篇
  1976年   72篇
  1975年   59篇
  1972年   52篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Vaginal candidosis is one of the most common infections of the vagina and the first accredited record of the disease appeared in 1849. Over the years the terms ‘candidiasis’ and ‘candidosis’ have been used, but it is generally accepted now that the terms are synonymous, and the term most commonly in use today is ‘candidosis’. Mainly caused by the yeast Candida albicans, the condition is characterised by intense inflammation of the vaginal mucosa and a curdy, off-white discharge; it is often associated with severe vulval itching and possibly burning pain. The severity of symptoms seems to vary greatly from patient to patient and the reason for this is unclear. It is suggested that in some patients there may be an element of hypersensitivity. Vaginal candidosis may occur in children but is most common in adults and only sometimes affects the elderly. The majority of women will suffer at least one attack of vaginal candidosis during their lifetime, and there are several predisposing factors such as diabetes, pregnancy and antibiotics. Some authorities consider the condition more frequent in those taking oral contraceptives or other hormones.  相似文献   
32.
We investigated the antitumoral effect of bovine seminal RNase (BS-RNase) in vivo and in vitro on a model system of epithelial tumor- and metastasis-derived cells as well as on epithelial tumors derived from the same system. We found that while BS-RNase significantly inhibited the growth in vitro of the epithelial tumor-derived cells, its inhibitory effect was even more dramatic on the growth of metastasis-derived cells. BS-RNase exerted no appreciable growth inhibition on normal thyroid epithelial cells. When administered in vivo to rats bearing solid carcinomas, having the same thyroid origin, BS-RNase induced a drastic reduction in the tumor weight, with no detectable toxic effects on the treated animals. These data show, for the first time on a system of neoplastically transformed epithelial cells, that BS-RNase has a potent specific antitumoral activity.  相似文献   
33.
The role of an operation in patients receiving neoadjuvant chemotherapy for clinically localized but invasive transitional cell carcinoma of the bladder currently is evolving. An operation is essential for case selection and evaluation of local response but it also contributes to bladder preservation and survival. The procedure that is necessary to select for and assess response to chemotherapy may itself alter the actual or proceed to evolution of invasive bladder cancer. Neoadjuvant chemotherapy is a reasonable therapeutic strategy in selected patients but it remains to be seen whether the results will prove to be superior to those achieved with standard endoscopic and open operations.  相似文献   
34.
Twenty patients (15 males; five females) aged 11-70 years, with urinary tract infections were treated with one 250 mg tablet of ciprofloxacin every 12 h for 5-10 days. Clinical response to this treatment was the complete disappearance of symptoms in 85% of cases and the elimination of the micro-organism responsible for infection. In only three patients, who all had urinary calculus in addition to an infection, clinical failure of the therapy occurred and the causative micro-organism persisted. Tolerance to the therapy was excellent in this study, no adverse reactions connected with the treatment being reported.  相似文献   
35.
Percutaneous transluminal balloon angioplasty (PTA) is being currently used in patients with coronary artery disease. Laser irradiation (LI) has been effective in vaporizing atherosclerotic plaques. The purpose of this work was twofold: to compare PTA and LI techniques in the recanalization of experimental obstructive arterial lesions, and to evaluate the possibility of reducing the failures and local complications and increasing the success rate of PTA by the combined use of LI. Atherosclerotic iliac stenoses were induced in 27 rabbits; lesions were evaluated angiographically before and after intervention and were studied histologically and by electron microscopy. Argon-ion LI delivered through microlens-tip optic fibers reduced the stenotic area from 64.2 +/- 21.8% to 40.3 +/- 10.7% (n = 10, P less than .01) and PTA from 60.7 +/- 15.9% to 30.4 +/- 7.7% (n = 9, P less than .01). However, percentage reduction was higher in PTA-treated stenoses (48.4 +/- 10.1% vs 34.5 +/- 13.5%, P less than .0125). In eight more rabbits, low power LI (4.55 +/- 1.25 J) was delivered after PTA in dilated segments. Post-PTA LI further decreased stenoses (from 31.2 +/- 7.8% to 29.1 +/- 8.1%, P less than .0125); laser-irradiated segments showed diffuse carbonization of the disrupted intimal layer. The normalized transtenotic pressure gradient decreased significantly in all groups: LI reduced the gradient from .40 +/- .25 to .17 +/- .07 (P = .005); PTA from .37 +/- .14 to .11 +/- .04 (P = .001); LI after PTA from .40 +/- .16 to .12 +/- .06 (P = .001). Thus, LI is effective (less than PTA) in relieving experimental atherosclerotic stenoses and seems useful when combined with PTA.  相似文献   
36.
Clinical trials have utilized intermittent diethylstilbestrol diphosphate (DES) therapy in advanced symptomatic prostatic carcinoma to diminish the morbidity of standard endocrine therapy. To determine the effect of intermittent DES administration on the Dunning R3327 rat prostatic adenocarcinoma 60 days following tumor implant, 6 groups were randomly assigned: control (N = 8), castrate (N = 10), high dose DES (N = 8, 1.6 micrograms/ml DES continuously in drinking water), low dose DES (N = 10, 0.4 microgram/ml continuously in drinking water), intermittent high dose DES (N = 10, 1.6 micrograms/ml DES in drinking water for 1 week, then off for 3 weeks), and intermittent low dose DES (N = 10, 0.4 microgram/ml DES for 1 week, then off for 3 weeks). Results indicate that low or high dose DES, and intermittent low or intermittent high dose DES during the week of administration were able to reduce serum testosterone to castrate levels (0.1 ng/ml). After withdrawal of intermittent DES, serum testosterone returned toward control levels (1.0 ng/ml). Initial mean tumor burden between control and treatment groups was not significantly different. All DES exposed rats had a tumor volume at death (range, 15.6-18.3 cm3) smaller than control (mean, 25.4 cm3) or castrate (mean, 40.8 cm3) rats. Despite this significant survival advantage from the time of randomization was achieved only in castrate (median survival, 331 days) or high dose DES (median survival, 359 days) groups compared to control (median survival, 225 days). Similarly, significant prolongation in tumor doubling time was achieved only by rats receiving castration or high dose DES. Intermittent DES administration controls tumor volume but does not provide a survival advantage. In this respect, intermittent DES is inferior to castration.  相似文献   
37.
38.
Although observational studies suggest that hyperhomocysteinemia may be a risk factor for coronary allograft vasculopathy (CAV), prospective data on homocysteine-lowering interventions and CAV development are lacking. We, therefore, randomized 44 de novo heart transplant (HT) recipients to 15 mg/day of 5-methyl-tetrahydrofolate (n=22), or standard therapy (control group, n=22) to investigate the effect of homocysteine lowering on the change in coronary intimal hyperplasia during the first 12 months after transplant, as detected by intra-vascular ultrasound (IVUS). Although 12 months after HT, homocysteinemia was lower in folate-treated patients (p<0.001), coronary intimal area increased similarly in the two groups (p>0.4). Conversely, hypercholesterolemia and cytomegalovirus infection were both associated with increased intimal hyperplasia (p<0.04), independently from folate intake. Sub-group analysis revealed that folate therapy reduced intimal hyperplasia in patients with hyperhomocysteinemia before randomization (n=19; p=0.02), but increased intimal hyperplasia in patients with normal homocysteine plasma concentrations (p=0.02). This bimodal effect of folate therapy persisted significantly after adjusting for cytomegalovirus infection and hypercholesterolemia. Despite effective in prevent hyperhomocysteinemia after heart transplantation, folate therapy does not seem to affect early CAV onset. However, sub-group analysis suggests that folate therapy may delay CAV development only in patients with baseline hyperhomocysteinemia, while may favor CAV progression in recipients with normal baseline homocysteinemia.  相似文献   
39.
Akathisia as a side-effect of metoclopramide has received increasing attention in consultation-liaison psychiatry in recent years. A case of metoclopramide-induced akathisia resulting in a suicide attempt is reported in order to highlight the suffering of such patients and the factors that lead to misdiagnosis.  相似文献   
40.
Background: Thirty-three patients were candidates for laparoscopic choledochotomy. The indications for this operation are described. Methods: The procedure was completed 32 times (97%). We had 29 successful common bile duct (CBD) clearances, three negative explorations, and one failed clearance which needed to be converted to laparotomy. All the completed procedures ended with primary closure of the main duct. Median duration of surgery was 180 min (range 100–300), including three associated laparoscopic procedures. Results: There were three postoperative complications (9.4%), none major. Average postoperative hospital stay was 7.1 days (range 4–14). In May–June 1995 we controlled 31 out of the 32 consecutive patients (one patient was lost to follow-up) who had a successful laparoscopic choledochotomy from October 1991 to December 1994. Median follow-up was 22 months (range 5–44). Besides clinical control, 23 patients also had ultrasound (US) controls and 24 had blood tests. Eleven had intravenous cholangiotomography. Two patients died 11 and 22 months after the operation for unrelated causes and without biliary symptoms. Two patients had umbilical hernias. One had a small residual asymptomatic stone, which was removed endoscopically. None had signs of postoperative CBD stricture. At US, CBD was ≤7 mm in 15 patients, 8–10 mm in four patients, and 10–12 mm in three patients. The last group had preoperative CBD dilation, too. We could compare preoperative and postoperative CBD diameters in 22 patients: 11 had no change; in nine it decreased; and two had a slight increase (8–10 mm). Conclusions: We conclude that laparoscopic choledochotomy with primary closure is a very good operation: It has a high success rate and low morbidity. Mortality is nil so far. Medium-term results are very positive: We had no CBD stricture and only one case of asymptomatic residual stone, which could have been avoided. Our results suggest that intraductal biliary drainage is useless, and its specific complications are well known. Received: 20 October 1995/Accepted: 28 February 1996  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号