全文获取类型
收费全文 | 5171篇 |
免费 | 328篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 223篇 |
妇产科学 | 182篇 |
基础医学 | 717篇 |
口腔科学 | 77篇 |
临床医学 | 473篇 |
内科学 | 1103篇 |
皮肤病学 | 125篇 |
神经病学 | 551篇 |
特种医学 | 169篇 |
外科学 | 607篇 |
综合类 | 74篇 |
一般理论 | 4篇 |
预防医学 | 448篇 |
眼科学 | 58篇 |
药学 | 310篇 |
中国医学 | 8篇 |
肿瘤学 | 327篇 |
出版年
2022年 | 60篇 |
2021年 | 133篇 |
2020年 | 67篇 |
2019年 | 113篇 |
2018年 | 119篇 |
2017年 | 54篇 |
2016年 | 59篇 |
2015年 | 75篇 |
2014年 | 102篇 |
2013年 | 156篇 |
2012年 | 196篇 |
2011年 | 245篇 |
2010年 | 121篇 |
2009年 | 127篇 |
2008年 | 182篇 |
2007年 | 208篇 |
2006年 | 168篇 |
2005年 | 182篇 |
2004年 | 183篇 |
2003年 | 147篇 |
2002年 | 163篇 |
2001年 | 168篇 |
2000年 | 172篇 |
1999年 | 145篇 |
1998年 | 68篇 |
1997年 | 41篇 |
1996年 | 45篇 |
1994年 | 41篇 |
1993年 | 42篇 |
1992年 | 118篇 |
1991年 | 134篇 |
1990年 | 158篇 |
1989年 | 117篇 |
1988年 | 111篇 |
1987年 | 88篇 |
1986年 | 101篇 |
1985年 | 89篇 |
1984年 | 77篇 |
1983年 | 49篇 |
1982年 | 46篇 |
1981年 | 41篇 |
1980年 | 37篇 |
1979年 | 68篇 |
1978年 | 48篇 |
1977年 | 59篇 |
1976年 | 41篇 |
1974年 | 38篇 |
1972年 | 45篇 |
1971年 | 38篇 |
1970年 | 40篇 |
排序方式: 共有5501条查询结果,搜索用时 15 毫秒
1.
2.
3.
Summary Intracavitary application of ultrasound was first performed for diagnostic purposes in 1967; since that time, it has been
more and more widely used. As far as the gastrointestinal tract is concerned, endoscopically controlled ultrasonic probes
provide visualization of the various layers of the intestinal wall. It is therefore possible to describe lesions of the esophagus,
stomach, and the rectum with regard to their nature and depth of infiltration. Furthermore, periesophageal and perigastric
organs can be visualized. It has become evident that endosonography is particularly important for pretherapeutic staging of
tumors of the esophagus, stomach, and rectum. Here prospective comparative studies confirm the superiority of this new diagnostic
procedure when compared to the methods available to date. 相似文献
4.
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
5.
In comparative histological and cytological studies on 270 prostatic carcinoma patients highly and moderately differentiated tumors were found to be more frequent histologically than cytologically. An early and reliable sign of response to hormone therapy proved to be reticularization and vacuolization of the nuclear chromatin. Follow-up studies by means of multiple aspiration biopsies with cytologic examinations seem to be more reliable in prognostic terms than examination of the histological tumor structure. 相似文献
6.
7.
A K Kant A Schatzkin G Block R G Ziegler M Nestle 《Journal of the American Dietetic Association》1991,91(12):1532-1537
We developed a method for evaluating food group intake patterns using dietary recall data (n = 11,529) from the second National Health and Nutrition Examination Survey. We used this method to examine the relationship of these food group intake patterns to nutrient intake and to selected biochemical indexes of nutritional status. We evaluated each 24-hour dietary intake recall for the presence or omission of five broad food groups--dairy, meat, grain, fruit, and vegetable. The five most prevalent patterns and the proportion of the population reporting them was as follows: all food groups, 33.6%; no fruit, 23.9%; no dairy and fruit, 9.0%; no dairy, 8.0%; and no fruit and vegetable, 5.6%. In the most prevalent pattern, all food groups were consumed; this was the only pattern that provided mean amounts of all of the key vitamins and minerals at levels greater than or equal to the Recommended Dietary Allowances (RDAs). This pattern also was reported by the lowest proportion of individuals consuming less than 100% RDA of the key nutrients. Patterns in which both fruit and vegetables were consumed were associated with highest levels of serum vitamin C. The consistency of these results indicates that screening diets for food group consumption can quickly provide meaningful information about their quality. 相似文献
8.
W. Ziegler D. von Cramon 《European archives of psychiatry and clinical neuroscience》1986,236(1):44-49
Summary This paper deals with a particular aspect of speech motor control in patients suffering from apraxia of speech. Three experiments are reported concerning the phase relations between individual speech gestures. These include the timing of laryngeal, velar and labial movements relative to lingual gestures.A total of 8 patients and 12 normal controls were examined using speech material which was designed according to appropriate phonetic paradigms. Evaluation was performed on the basis of speech signal parameters referring to the kinematics of inter-articulatory phasing. Deviations of the patient group were found in all three experiments. This suggests that disturbed phase relations of individual speech movements are a general feature of apraxic speech. It is further hypothesized that the described motor symptoms are the origin of a variety of phonemic errors. Support for this view is provided by appropriate examples which refer to the examined paradigms. By this argument, much of the disturbed phonemic structure of apraxic speech may be accounted for by timing deficits. 相似文献
9.
Secondary prevention of coronary events in coronary artery disease (CAD) patients with aspirin is generally accepted because of ease of administration, predictable safety, and proven efficacy. The use of long-term anticoagulant therapy with heparins, vitamin-K antagonists (VKAs), or thrombin inhibitors is, however, more controversial. During the last 40 years, several trials have been conducted in order to evaluate the role of anticoagulant therapy in patients with CAD as a protection against subsequent death and thrombo-embolic complications. The conducted trials are heterogeneous in many ways, concerning comparative medications, patient populations, endpoints and follow-up, which makes a standardized recommendation on the basis of these studies difficult. This review is an overview of the largest and best studies on this topic and discusses the scientific background for a possible use of VKA or an alternative anticoagulant treatment in CAD patients, looking at both the beneficial effects and the risk of bleeding. 相似文献
10.