全文获取类型
收费全文 | 1336529篇 |
免费 | 94313篇 |
国内免费 | 2914篇 |
专业分类
耳鼻咽喉 | 19713篇 |
儿科学 | 40232篇 |
妇产科学 | 38666篇 |
基础医学 | 187244篇 |
口腔科学 | 39822篇 |
临床医学 | 112665篇 |
内科学 | 262529篇 |
皮肤病学 | 30226篇 |
神经病学 | 106439篇 |
特种医学 | 53767篇 |
外国民族医学 | 435篇 |
外科学 | 208257篇 |
综合类 | 31044篇 |
现状与发展 | 6篇 |
一般理论 | 436篇 |
预防医学 | 92066篇 |
眼科学 | 31466篇 |
药学 | 100083篇 |
4篇 | |
中国医学 | 2989篇 |
肿瘤学 | 75667篇 |
出版年
2018年 | 11757篇 |
2015年 | 11888篇 |
2014年 | 16691篇 |
2013年 | 25261篇 |
2012年 | 33031篇 |
2011年 | 34896篇 |
2010年 | 20744篇 |
2009年 | 20246篇 |
2008年 | 33616篇 |
2007年 | 36717篇 |
2006年 | 37288篇 |
2005年 | 36058篇 |
2004年 | 35101篇 |
2003年 | 34088篇 |
2002年 | 33628篇 |
2001年 | 63625篇 |
2000年 | 65343篇 |
1999年 | 55410篇 |
1998年 | 14660篇 |
1997年 | 13463篇 |
1996年 | 12945篇 |
1995年 | 12222篇 |
1994年 | 11475篇 |
1992年 | 42772篇 |
1991年 | 41291篇 |
1990年 | 40564篇 |
1989年 | 39559篇 |
1988年 | 36966篇 |
1987年 | 36417篇 |
1986年 | 34903篇 |
1985年 | 33103篇 |
1984年 | 24828篇 |
1983年 | 21056篇 |
1982年 | 12669篇 |
1981年 | 11574篇 |
1980年 | 10774篇 |
1979年 | 23926篇 |
1978年 | 17079篇 |
1977年 | 14839篇 |
1976年 | 13387篇 |
1975年 | 15267篇 |
1974年 | 18084篇 |
1973年 | 17564篇 |
1972年 | 16814篇 |
1971年 | 15719篇 |
1970年 | 14914篇 |
1969年 | 14349篇 |
1968年 | 13465篇 |
1967年 | 12016篇 |
1966年 | 11261篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
The authors studied the cumulative probability of pregnancy for up to 4 consecutive embryo transfer (ET) cycles with ICSI performed for male factor. Transfers could be either fresh or frozen. The clinical pregnancy rate (PR) for the first 4 cycles were similar [44% (61/366); 31% (44/138); 45% (14/31); 44% (4/9)]. Delivery rates were also similar. There was a lower PR on the second retrieval vs. the first retrieval (47% vs. 29%), but this may be related to most of the second retrievals occurring in the second transfer cycle (67%, 31/55); this may be explained by women who were poor responders and required another retrieval without a frozen ET. The majority of transfers in cycle 1 were fresh, whereas cycles 2-4 used primarily frozen-thawed embryos. These data should be helpful for patients requiring IVF with ICSI in deciding to continue with more IVF cycles or consider other 相似文献
122.
Angiotensin Converting Enzyme Inhibitors: Animal Experiments Suggest a New Pharmacological Treatment for Alcohol Abuse in Humans 总被引:1,自引:0,他引:1
G. Spinosa MSc E. Perlanski Dipl Tech. F. H. H. Leenen MD R. B. Stewart MSc L. A. Grupp DSc 《Alcoholism, clinical and experimental research》1988,12(1):65-70
The prevalence of heavy alcohol consumption is a major problem of increasing proportions throughout the world. Although alcohol sensitizing drugs and more recently serotonin uptake inhibitors are drug interventions with some following, their long term beneficial consequences have yet to be demonstrated. In recent years, we have demonstrated that manipulating activity in the renin-angiotensin system will dramatically alter voluntary alcohol consumption in rats. Based on these findings, the present study evaluated the ability of a class of drugs known as the angiotensin converting enzyme inhibitors to reduce voluntary alcohol drinking in laboratory animals. These drugs prevent the conversion of angiotensin I to angiotensin II. They have been licensed for use in Europe and North America and are indicated in the treatment of hypertension. Our experiments showed that both captopril (Capoten, Squibb) and enalapril (Vasotec, Merck Sharpe & Dohme) can reduce alcohol drinking in both normotensive and hypertensive animals regardless of whether the pattern of intake is in a bout or of a less exaggerated nature. Furthermore, this change in alcohol intake can occur without concomitant changes in blood pressure, plasma renin activity, overall fluid balance, or the distribution and metabolism of alcohol. Taken together these findings suggest that the angiotensin converting enzyme inhibitors should be evaluated in a clinical setting for they may prove to be a useful new treatment or treatment adjunct for alcohol abuse in humans. 相似文献
123.
A prospective randomized study was done to compare the fluid contamination rates of two methods used to determine cardiac output by thermodilution under in-use conditions. Fifty patients were randomly assigned to have cardiac output measured by the capped syringe or closed loop method, and were followed with quantitative cultures of fluid and catheter. The two treatment groups (n = 25 each) were comparable in terms of age, sex, intensive care unit location, underlying diagnosis, and mean number of cardiac output determinations performed in the first 24 hours after placement of the catheter line. No differences in the rates of fluid contamination were seen at any time between the two groups. The overall fluid contamination rate was 2/124 cultures (1.8% with 95% confidence interval +/- 4.1%) with one colony of Staphylococcus epidermidis from a closed loop sample and one colony of Pseudomonas maltophilia in a capped syringe sample. Although no difference in contamination rates was documented, the closed loop system required less nursing time and effort. 相似文献
124.
H Struck 《Zeitschrift für Gerontologie》1988,21(2):106-109
Today old age represents no contraindication to operative treatment. The age dependence of normal coagulation, immunological system and connective tissue components is described with respect to the course of wound healing. Possible misinterpretations that may occur, if preoperative values do not exist and the subsequent course is not observed, are pointed out. 相似文献
125.
The role of hypertension and antihypertensive drugs in cardiovascular complications was evaluated in 380 elderly people living in the Tokyo Metropolitan Gerontology Center. The subjects were classified into four groups according to the presence or absence of hypertension and their antihypertensive treatment, and followed up prospectively for 5 years from 1979 to 1984. The average age of each group was 74 to 76 years. Cerebrovascular disease was observed in 19.3% of male hypertensives and 10.1% of male normotensives (p = 0.078). The drug treated group revealed no cerebral hemorrhage and less cerebral infarction. This tendency was not observed in females. Ischemic heart disease was prevalent in the drug treated group (10.9% vs 4.5%, p = 0.023) irrespective of blood pressure level. Risk factors such as body mass index, skinfold thickness, serum cholesterol, albumin, creatinine, blood urea nitrogen and uric acid at entry were elevated in the drug treated group. Diuretics were used in 92% of the drug treated group; in 53% as monotherapy and in 39% as combination therapy with other antihypertensive agents. The metabolic effect of diuretics may increase the incidence of ischemic heart disease in the elderly. We might conclude that hypertension in the aged accelerates cerebrovascular complications, and that antihypertensive treatment is effective even in this group. However, the wide use of diuretics could increase the incidence of ischemic heart disease. Careful selection of antihypertensive drugs as well as dose adjustment are needed in the treatment of elderly hypertensives. 相似文献
126.
Despite growing concern with rural elderly populations, little attention has focused on their mental health, ways it may correlate with physical health, or how rural mental health patterns compare to urban. Popular wisdom contends that elderly people in general, and rural elderly persons in particular, are at increased risk for mental illness. This article examines these questions. A review of available literature suggests that elderly people may be at only slightly greater risk of mental illness than the population at large, though there are some indications that rates of depression may be somewhat higher among the elderly population. Much of this same literature implies that objective environmental conditions play a significant role in the incidence of depression. Analysis of data gathered in a statewide random poll (N = 743) indicates that while physical health tends to be poorer among rural populations, when health is held constant there is actually an inverse relationship between age and depression. Therefore, rural elderly persons are no more likely to be depressed than their urban counterparts despite harsher living conditions. Both conceptual and policy implications are discussed. 相似文献
127.
128.
The use of additional epidural sympathetic block during and after microvascular surgery in the lower extremities to prevent vasospasm is generally agreed on. However, a significant fall in the perfusion rate of the transplants was seen after application of bupivacaine (Marcain) via the epidural catheter. This effect has, to our knowledge, not been described before and is probably caused by the sympathectomy effect of this type of analgesia. 相似文献
129.
Clinical versus ultrasonographic evaluation of scrotal disorders 总被引:1,自引:0,他引:1
B Kromann-Andersen L B Hansen P N Larsen K Lawetz P Lynge D Lysen S P Nielsen K H Stockholm P Foged 《British journal of urology》1988,61(4):350-353
Clinical and ultrasonographic examinations of scrotal disorders were compared in 166 patients in order to determine their ability to distinguish between those diseases requiring surgery and those requiring clinical follow-up only. Ultrasound examinations were efficient in discriminating between normal and pathological findings. Extra-testicular lesions were readily differentiated from testicular ones. Although both clinical and ultrasonographic examinations had high sensitivity (90%) in detecting testicular cancer, the number of false positive findings was smaller after ultrasound examination. This gave a predictive value of a positive test of 53% after ultrasound examination but only 33% after clinical examination. Ultrasound examination may, therefore, reduce the number of surgical explorations in the scrotum and should be performed in patients with suspected testicular pathology based on history and palpatory findings. 相似文献
130.
Multiple trauma is often associated with blunt thoracic injuries. Especially lung contusion can result in respiratory insufficiency and therefore a higher mortality rate. In our prospective study comparing 8 multiple trauma patients with and without associated lung contusion, we found that respiratory function was already significantly disturbed (decrease of paO2/FiO2 and increase of AaDO2, a rise in extravascular lung water (EVLW) both early after trauma and also with a second peak following the 4th day. This group (LK) developed significantly more cases of respiratory distress (ARDS). The disturbance of respiratory function seen initially was interpreted as a consequence of the direct mechanical impact, leading to the formation of interstitial fluid and hematoma. The frequent development of ARDS in the LK-group probably results from a pronounced activation of cellular and humoral mechanisms and therefore an enforced injury of the pulmonary capillary bed. A significant increase of pulmonary infections or the development of sepsis was not seen in the LK-group and is probably not responsible for the higher ARDS-rate in this group. 相似文献