全文获取类型
收费全文 | 3929557篇 |
免费 | 293097篇 |
国内免费 | 6743篇 |
专业分类
耳鼻咽喉 | 56435篇 |
儿科学 | 124461篇 |
妇产科学 | 105523篇 |
基础医学 | 565105篇 |
口腔科学 | 112363篇 |
临床医学 | 361098篇 |
内科学 | 750616篇 |
皮肤病学 | 83421篇 |
神经病学 | 319411篇 |
特种医学 | 151305篇 |
外国民族医学 | 1277篇 |
外科学 | 590288篇 |
综合类 | 89534篇 |
现状与发展 | 13篇 |
一般理论 | 1601篇 |
预防医学 | 317305篇 |
眼科学 | 93796篇 |
药学 | 294067篇 |
14篇 | |
中国医学 | 7545篇 |
肿瘤学 | 204219篇 |
出版年
2018年 | 42155篇 |
2017年 | 31981篇 |
2016年 | 35679篇 |
2015年 | 40297篇 |
2014年 | 57638篇 |
2013年 | 87685篇 |
2012年 | 119237篇 |
2011年 | 126768篇 |
2010年 | 75403篇 |
2009年 | 71365篇 |
2008年 | 119348篇 |
2007年 | 127159篇 |
2006年 | 128372篇 |
2005年 | 124772篇 |
2004年 | 120035篇 |
2003年 | 115494篇 |
2002年 | 113127篇 |
2001年 | 175007篇 |
2000年 | 180519篇 |
1999年 | 152750篇 |
1998年 | 45572篇 |
1997年 | 40420篇 |
1996年 | 40004篇 |
1995年 | 38313篇 |
1994年 | 35717篇 |
1993年 | 33533篇 |
1992年 | 121564篇 |
1991年 | 118592篇 |
1990年 | 115259篇 |
1989年 | 111030篇 |
1988年 | 102907篇 |
1987年 | 101058篇 |
1986年 | 95411篇 |
1985年 | 91683篇 |
1984年 | 69236篇 |
1983年 | 59071篇 |
1982年 | 35784篇 |
1981年 | 32029篇 |
1979年 | 64950篇 |
1978年 | 46065篇 |
1977年 | 38657篇 |
1976年 | 36861篇 |
1975年 | 39071篇 |
1974年 | 47643篇 |
1973年 | 45355篇 |
1972年 | 42864篇 |
1971年 | 40110篇 |
1970年 | 37345篇 |
1969年 | 35143篇 |
1968年 | 32280篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
A 65-year-old man with spontaneous rupture of the esophagus survived with a direct suture of the esophagus 15 hours after the onset of symptoms. Endoscopic examination of the esophagus was especially of great help in determining the surgical procedure in this patient, and we want to stress the importance of prompt diagnosis and immediate surgery for this disease. 相似文献
993.
A two-week elective to introduce first- and second-year medical students to primary care internal medicine was developed and evaluated. Course time is divided between conference sessions (25 percent) provided by full-time clinical faculty members and office experience (75 percent) provided by volunteer clinical faculty members (general internists in private practice and in prepaid health plans). Evaluations by the students (n = 58) who took the elective consisted of a questionnaire assessment of the conference session topics, the student's ability to carry out course objectives, and the preceptor's teaching activities. The conference topics were highly rated, with a mean score of 4.1 on a rating scale ranging from 1 (unfavorable) to 5 (favorable). The course objectives and teaching activities were also well rated, with a mean score of 4.1 and 3.9, respectively, on a rating scale ranging from 1 (none) to 5 (outstanding). 相似文献
994.
K el-Ghomari J W Gorrod 《European journal of drug metabolism and pharmacokinetics》1987,12(4):253-258
Biological oxidation of 2,4-diamino-6-substituted pyrimidines have been studied using hepatic microsomes from various mammalian species. The nature of the enzyme(s) involved in the oxidation has been elucidated using various enzyme inhibitors and inducing agents. The 3-N-oxides were formed with 6-piperidino-, 6-diethylamino-, 6-methyl-, and 6-chloro-substituted 2,4-diaminopyrimidines: no evidence of 1-N-oxide formation was obtained. With the 6-hydroxy-, 6-amino-, and unsubstituted 2,4-diaminopyrimidines and melamine, no N-oxidative metabolite was detected. The differences in N-oxide formation was discussed in terms of the effect of substituents on tautomerism and electron distribution. The N-oxygenation was mediated via a cytochrome P450 dependent system. 相似文献
995.
Clinical and hormonal effects of chronic gonadotropin-releasing hormone agonist treatment in polycystic ovarian disease 总被引:1,自引:0,他引:1
K Steingold D De Ziegler M Cedars D R Meldrum J K Lu H L Judd R J Chang 《The Journal of clinical endocrinology and metabolism》1987,65(4):773-778
Previously, we reported that short term administration of a highly potent GnRH agonist (GnRHa) for 1 month to patients with polycystic ovarian disease (PCO) resulted in complete suppression of ovarian steroidogenesis without measurable effects on adrenal steroid production. This new study was designed to evaluate the effects of long term GnRHa administration in PCO patients with respect to their hormone secretion patterns and clinical responses. Eight PCO patients and 10 ovulatory women with endometriosis were treated daily with sc injections of [D-His6-(imBzl]),Pro9-NEt]GnRH (GnRHa; 100 micrograms) for 6 months. Their results were compared to hormone values in 8 women who had undergone bilateral oophorectomies. In response to GnRHa, PCO and ovulatory women had rises of serum LH at 1 month, after which it gradually declined to baseline. In both groups FSH secretion was suppressed throughout treatment. Serum estradiol, estrone, progesterone, 17-hydroxyprogesterone, androstenedione, and testosterone levels markedly decreased to values found in oophorectomized women by 1 month and remained low thereafter. In contrast, serum pregnenolone and 17-hydroxypregnenolone were partially suppressed, and dehydroepiandrosterone, dehydroepiandrosterone sulfate, and cortisol levels did not change. Clinically, hyperplastic endometrial histology in three PCO patients reverted to an inactive pattern, and proliferative endometrium in two other PCO patients became inactive in one and did not change in the other. Regression of proliferative endometrial histology occurred in all ovulatory women. Vaginal bleeding occurred in all women studied during the first month of GnRHa administration, after which all but one PCO patient became amenorrheic. Hot flashes were noted by all ovulatory women and by four of eight PCO patients. All PCO patients noted subjective reduction of skin oiliness, and five had decreased hair growth. We conclude that in premenopausal women: 1) chronic GnRHa administration results in apparently complete persistent suppression of ovarian steroid secretion; 2) adrenal steroid secretion is not influenced directly or indirectly; and 3) its use may be helpful in the treatment of endometrial hyperplasia and ovarian androgen excess in women with PCO. 相似文献
996.
997.
998.
A retrospective study was done in 316 patients with primary cervical adenocarcinoma treated at the Research Institute for Clinical and Experimental Oncology in Brno over a period of 40 years (1939-1978). The treatment results were compared to those in 2571 patients with epidermoid carcinomas of the uterine cervix treated at the Institute over the same period. The 5-year survival rate was significantly lower in adenocarcinoma patients (in Stage I patients, 77.8% vs. 84.5%, and, in the whole group, 60.8% vs. 70.3%). The assessment of the treatment results of this study has clearly showed that in cervical adenocarcinomas, surgery combined with radiotherapy was much more effective than radical radiotherapy alone (77.4% vs. 64.7%). In contrast to this, in epidermoid carcinomas the treatment results were better after radical radiotherapy (86.5% vs. 81.3%). Thus, in the prognosis of cervical adenocarcinomas the mass of the tumor, the size of the uterus, as well as the grading play a role. That means that primary cervical adenocarcinomas at early stages can be successfully treated by a combination of radical surgery and radiotherapy, while radiotherapy of advanced stages of this tumor is less successful. 相似文献
999.
To investigate the simultaneous effects of dexamethasone on peripheral and central adrenocorticotropic hormone (ACTH) systems, rats were treated with dexamethasone or saline for 4 days. Pituitary, plasma, hypothalamus and cerebrospinal fluid (CSF) were then collected and analyzed for ACTH immunoreactivity. Additionally, hypothalamic tissue extracts were analyzed for corticotropin-releasing hormone (CRH) immunoreactivity. Dexamethasone significantly lowered peripheral levels of ACTH as measured in pituitary and plasma. Hypothalamic ACTH content significantly increased while CSF ACTH significantly decreased with dexamethasone treatment. Hypothalamic CRH concentrations showed a small but statistically insignificant decrease. These results suggest that prolonged exposure to dexamethasone affects central as well as peripheral ACTH activity, corroborate our previous findings in rhesus monkeys of decreased CSF ACTH in response to prolonged dexamethasone treatment, suggest that dexamethasone may inhibit the release of ACTH from hypothalamic neurons into the CSF, and provide evidence that the effect of dexamethasone on pituitary ACTH content is of greater magnitude than its effect on hypothalamic CRH. 相似文献
1000.
Differential diagnosis of poisoning by North American mushrooms, with particular emphasis on Amanita phalloides-like intoxication 总被引:2,自引:0,他引:2
It is possible to determine the management and prognosis of mushroom poisoning from the history and initial symptoms with a high degree of confidence. The most important intoxications are those involving Amanita phalloides or other potentially fatal amatoxin-containing mushrooms, which have a latent period of ten to 12 hours before the patient becomes symptomatic. Because aggressive gastroenteric decontamination can reduce the extent of hepatic damage, it is important to attempt to determine during this asymptomatic period whether amatoxin exposure has occurred. Various laboratory methods that might be useful are reviewed. 相似文献