全文获取类型
收费全文 | 1389538篇 |
免费 | 97932篇 |
国内免费 | 3157篇 |
专业分类
耳鼻咽喉 | 20298篇 |
儿科学 | 41353篇 |
妇产科学 | 39691篇 |
基础医学 | 194047篇 |
口腔科学 | 40622篇 |
临床医学 | 117909篇 |
内科学 | 274910篇 |
皮肤病学 | 30756篇 |
神经病学 | 111471篇 |
特种医学 | 55761篇 |
外国民族医学 | 435篇 |
外科学 | 216496篇 |
综合类 | 31753篇 |
现状与发展 | 6篇 |
一般理论 | 500篇 |
预防医学 | 95777篇 |
眼科学 | 32252篇 |
药学 | 103514篇 |
4篇 | |
中国医学 | 3106篇 |
肿瘤学 | 79966篇 |
出版年
2018年 | 13387篇 |
2016年 | 11777篇 |
2015年 | 13358篇 |
2014年 | 18784篇 |
2013年 | 27788篇 |
2012年 | 37222篇 |
2011年 | 39142篇 |
2010年 | 23213篇 |
2009年 | 22447篇 |
2008年 | 37326篇 |
2007年 | 40512篇 |
2006年 | 40978篇 |
2005年 | 39678篇 |
2004年 | 38362篇 |
2003年 | 37065篇 |
2002年 | 36262篇 |
2001年 | 64043篇 |
2000年 | 65636篇 |
1999年 | 55775篇 |
1998年 | 15135篇 |
1997年 | 13901篇 |
1996年 | 13315篇 |
1995年 | 12552篇 |
1994年 | 11722篇 |
1992年 | 42960篇 |
1991年 | 41471篇 |
1990年 | 40707篇 |
1989年 | 39684篇 |
1988年 | 37074篇 |
1987年 | 36520篇 |
1986年 | 35000篇 |
1985年 | 33223篇 |
1984年 | 24952篇 |
1983年 | 21176篇 |
1982年 | 12794篇 |
1981年 | 11683篇 |
1979年 | 23982篇 |
1978年 | 17150篇 |
1977年 | 14905篇 |
1976年 | 13444篇 |
1975年 | 15321篇 |
1974年 | 18133篇 |
1973年 | 17609篇 |
1972年 | 16835篇 |
1971年 | 15744篇 |
1970年 | 14941篇 |
1969年 | 14372篇 |
1968年 | 13491篇 |
1967年 | 12033篇 |
1966年 | 11271篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Kanji Takeo Eric Virtudazo Misako Ohkusu Susumu Kawamoto Shoko Ito-Kuwa Sigeji Aoki 《Nippon Ishinkin Gakkai Zasshi》2006,47(4):257-262
In Cryptococcus neoformans the DNA content of cells having tiny buds varied rather widely, depending on growth phases and strains used. Typically, buds of C. neoformans emerged soon after initiation of DNA synthesis in the early exponential phase. However, bud emergence was delayed to G2 during transition to the stationary phase, and in the early stationary phase budding scarcely occurred, although roughly half of the cells completed DNA synthesis. The timing of budding in C. neoformans was shifted to later cell cycle points with progression of the growth phase of the culture. Similarly, a deficit in oxygen was demonstrated to delay the timing of budding, prolong the G2 phase and cause accumulation of cells after DNA synthesis, but before commitment to budding. The C. neoformans homologue of the main cell cycle control gene CDC28/Cdc2 was isolated using degenerate RT-PCR. The full-length coding region was then amplified using primers to target the regions around the start and stop codons. The gene was called CnCdk1 and was found to have high homologies to S. cerevisiae CDC28 and S. pombe cdc2. To determine its function, its ability to rescue S. cerevisiae cdc28-temperature sensitive mutants was tested. S. cerevisiae cdc28-4 and cdc28-1N strains transformed with the pYES2-CnCdk1 construct exhibited growth at the restrictive temperature. Results of the sequence analysis and the ability of CnCdk1 to complement the S. cerevisiae cdc28-ts mutations support its assumed role as the CDC28/cdc2 homologue in C. neoformans. 相似文献
82.
Prof. Dr. H. Delbrück 《Der Onkologe》2006,12(5):451-459
Rehabilitative and palliative measures in the follow-up care of pancreatic cancer patients will remain the dominant medical focus as long as potentially curative measures (recurrence prophylaxis, early detection and therapy of recurrence) have failed to show a significant survival benefit. Rehabilitative measures are possible for patients undergoing potentially curative as well as palliative treatment. Their aim is to alleviate the negative effects of the cancer and its therapy, not only physically, but also psychologically, socially and vocationally. The spectrum of possible somatic handicaps ranges from metabolic disorders, malnutrition and under-nutrition, as well as gastrointestinal symptoms to pain. Assistance in coping with illness, alleviating fears and depression and strengthening compliance are the main areas which are dealt with in psycho-oncology. Assessment of vocational fitness and the capacity to work depends on tumor location, whether R0 or R1 resection has taken place, the extent of pancreas resection, accompanying illnesses, whether or not adjuvant therapy has been given, and the physical condition of the patient 相似文献
83.
The aim of our study was to determine the incidence, timing, and severity of vaginal stenosis in patients with carcinoma of the cervix who had received pelvic and/or vaginal radiotherapy as part of their treatment. We also sought to determine if there were any predisposing factors for the development of stenosis. A retrospective chart review was undertaken for all the patients diagnosed with carcinoma of the cervix between January 1, 1990, and December 31, 2000 and treated with pelvic and/or vaginal radiation at Westmead Hospital. Since January 1, 1990, data regarding vaginal stenosis has been prospectively recorded on all the patients. Data collected included patient demographics, stage of disease, treatments administered, and incidence, timing, and severity of vaginal stenosis. One hundred and eighty-eight patients were treated. Mean age was 58.6 years. Thirteen percent of patients had stage IB disease, 45% had stage II disease, 39.5% had stage III disease, and 1.5% had stage IV disease. One hundred and seventy-nine patients returned for follow-up, and data regarding vaginal toxicity were available in 98%. Twenty-seven percent had grade 1 toxicity (partial stenosis or shortening but not complete occlusion), and 11% had grade 2 (complete occlusion). Stenosis of any grade was noted at a mean of 9.6 months and median of 7.5 months (range, 26 days-5.6 years) from completion of treatment. The only prognostic factor associated with increased risk of stenosis was age greater than 50 years (odds ratio 2.26). Vaginal stenosis is a common complication of pelvic and vaginal radiotherapy, occurring in 38% of patients. Stenosis occurs most often in the first year after treatment. Patients over the age of 50 are most at risk. 相似文献
84.
Jorge Guardado Carlos Cotrim Otília Sim?es Sofia Almeida Mário Ialá Luís Lopes Hélder Pereira Manuel Carrageta 《Revista portuguesa de cardiologia》2006,25(4):409-415
INTRODUCTION: Transesophageal echocardiography (TEE) has become increasingly useful in the study of patients with suspected pulmonary thromboembolism. OBJECTIVE: The aim of this study was to prospectively evaluate the usefulness of TEE in the study of the distal part of the left pulmonary artery (LPA) as well as the influence of this procedure on total echocardiographic exam duration. METHODOLOGY: A prospective study in two groups of consecutive patients referred for TEE with a one- year interval between evaluation of Group A: 33 patients, 17 male, mean age 54 +/- 24 years, and Group B: 42 patients, 20 male, mean age 48 +/- 27 years (p = NS). The procedure was considered long when it took more than 3 min to evaluate the distal part of the LPA. RESULTS: In group A we were able to visualize the distal part of the LPA in 24 patients (73%) without significant prolongation of total exam duration in 16 patients (48% of group A). In one of the patients with suspected pulmonary thromboembolism thrombi were only observed in the distal part of the LPA. In group B we were able to visualize the distal part of the LPA in 36 patients (86%) without significant prolongation of total exam duration in 26 patients (61% of group B). CONCLUSIONS: 1. Visualization of the distal part of the LPA was possible in more patients, and with TEE time prolongation in less patients, in group B. These differences can be accounted for by the training of the operator in this technique. 2. The importance of visualization of this part of the LPA in guiding treatment in the subset of patients with pulmonary thromboembolism confirms the usefulness of this specific procedure. 相似文献
85.
86.
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
87.
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
88.
89.
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
90.
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